ICS 91.100.30 
 
Reference number  
DRS  503: 2022  
© RSB 2022  
  
  RWANDA 
STANDARD  DRS  
503  
 
First edition  
2022 -mm-dd 
 
Precast concrete products  — Performance 
requirements  
   
DRS  503: 2022  
©RSB 2022  - All rights reserved                  ii 
 In order to match with technological development and to keep continuous progress in industries, 
standards are subject to periodic review. Users shall ascertain that they are in possession of the latest 
edition 
 
 
 
 
 
 
 
 
© RSB 2022  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized 
in any form or by any means, electronic or mechanical, including photocopying and microfilm, without 
prior written permission from R SB. 
Requests for permission to reproduce this document should be addressed to : 
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
KK 15 Rd, 49  
Tel. +250 788303492  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw   DRS  503: 2022  
iii                ©RSB 2022  - All rights reserved  
  Contents  Page 
Common rules for precast concrete products  ................................ ................................ ........................  i 
Foreword  ................................ ................................ ................................ ................................ ....................  v 
Common rules for precast c oncrete products  ................................ ................................ .......................  1 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Terms and definitions  ................................ ................................ ................................ ..................  2 
3.1 General  ................................ ................................ ................................ ................................ ..........  2 
3.2 Dimensions  ................................ ................................ ................................ ................................ ... 3 
3.3 Tolerances  ................................ ................................ ................................ ................................ ..... 3 
3.4 Durability  ................................ ................................ ................................ ................................ ....... 3 
3.5 Mechanical prope rties ................................ ................................ ................................ ..................  4 
4 Symbols (and abbreviated terms)  ................................ ................................ ...............................  4 
5 Requirements  ................................ ................................ ................................ ................................  4 
5.1 Materials  requir ements  ................................ ................................ ................................ ................  4 
5.1.1  General  ................................ ................................ ................................ ................................ ..........  4 
5.1.2  Constituent  materials  of concrete  ................................ ................................ ..............................  4 
5.1.3  Reinforcing  steel  ................................ ................................ ................................ ..........................  5 
5.1.4  Prestressing  steel  ................................ ................................ ................................ .........................  5 
5.1.5  Inserts and connectors  ................................ ................................ ................................ ................  5 
5.2 Production  requirements  ................................ ................................ ................................ .............  5 
5.2.1  Concrete  production  ................................ ................................ ................................ ....................  5 
5.2.2  Hardened  concrete  ................................ ................................ ................................ .......................  8 
5.2.3  Structural  reinforcement  ................................ ................................ ................................ ..............  9 
5.3 Finished  product  requirements  ................................ ................................ ................................ . 11 
5.3.1  Geometrical  properties  ................................ ................................ ................................ ..............  11 
5.3.2  Surface  characteristics  ................................ ................................ ................................ ..............  12 
5.3.3  Mechanical  resistance  ................................ ................................ ................................ ...............  12 
5.3.4  Durability  ................................ ................................ ................................ ................................ ..... 13 
5.3.5  Other  requirements  ................................ ................................ ................................ ....................  14 
6 Test methods  ................................ ................................ ................................ ..............................  15 
6.1 Tests  on concrete  ................................ ................................ ................................ .......................  15 
6.1.1  Compressive  strength  ................................ ................................ ................................ ................  15 
6.1.2  Water  absorption  ................................ ................................ ................................ ........................  15 
6.1.3  Dry density  of concrete  ................................ ................................ ................................ ..............  15 
6.2 Measuring  of dimensions  and surface  characteristics  ................................ ...........................  15 
6.3 Weight  of the products  ................................ ................................ ................................ ...............  16 
7 Marking  ................................ ................................ ................................ ................................ ........  16 
8 Technical  documentation  ................................ ................................ ................................ ..........  17 
Annex  A (informative)  Concrete cover as regard to corrosion  ................................ .........................  18 
A.1 Minimum  concrete  cover  for base  conditions  ................................ ................................ .........  18 
A.2 Alternative  conditions  ................................ ................................ ................................ ................  19 
Annex  B (informative)  Concrete quality control ................................ ................................ ..................  20 
B.1 Statistical  representative  values  ................................ ................................ ...............................  20 
B.2 Conformity  criteria  for potential  strength  ................................ ................................ ................  20 
B.3 Direct  structural  strength  ................................ ................................ ................................ ...........  20 
B.4 Indirect  structural  strength  ................................ ................................ ................................ ........  21 
B.5 Direct  assessment  of possibly  non-conforming  units  ................................ ............................  21 
Annex  C (informative)  ................................ ................................ ................................ .............................  23 
C.1 General  ................................ ................................ ................................ ................................ ........  23 DRS  503: 2022  
©RSB 2022  - All rights reserved                  iv 
 C.2 Reduction  based  on quality  control  and reduced  tolerances  ................................ ...............  23 
C.3 Reduction based on using reduced or measured geometrical parameters in  design  ........  23 
C.4 Reduction  based  on assessment  of concrete  strength  in finished  structure  .....................  24 
C.5 Reduction  of 𝜸𝑮 based  on control  of self-weight  ................................ ................................ ... 24 
Annex  D (normative)  ................................ ................................ ................................ ...............................  25 
D.1 General  ................................ ................................ ................................ ................................ ........  25 
D.2 Equipment  inspecti on................................ ................................ ................................ ................  25 
D.3 Materials  inspection  ................................ ................................ ................................ ..................  26 
D.4 Proc ess inspection  ................................ ................................ ................................ ....................  28 
D.5 Finished  product  inspection  ................................ ................................ ................................ ..... 31 
Annex  E (normative)  ................................ ................................ ................................ ...............................  33 
E.1 Method  ................................ ................................ ................................ ................................ ........  33 
E.2 Sampling  ................................ ................................ ................................ ................................ ..... 33 
E.3 Materials  ................................ ................................ ................................ ................................ ..... 36 
E.4 Apparatus  ................................ ................................ ................................ ................................ ... 36 
E.5 Preparation  ................................ ................................ ................................ ................................ . 36 
E.6 Procedure  ................................ ................................ ................................ ................................ ... 36 
E.7 Results  ................................ ................................ ................................ ................................ ........  37 
Annex  F (normative)  ................................ ................................ ................................ ...............................  38 
F.1 Length,  height,  width  and thickness  ................................ ................................ ........................  38 
F.2 Warp  and straightness  ................................ ................................ ................................ ..............  39 
F.3 Out of squareness  ................................ ................................ ................................ .....................  39 
F.4 Surface  characteristics  ................................ ................................ ................................ .............  40 
F.5 Angular  deviation  lateral  bow,  camber  and sag ................................ ................................ ..... 42 
Annex  G (informative)  Technical documentation  ................................ ................................ ...............  44 
G.1 General  ................................ ................................ ................................ ................................ ........  44 
G.2 Production  documentation  ................................ ................................ ................................ ....... 44 
G.3 Erection  documentation  ................................ ................................ ................................ ............  44 
 DRS  503: 2022  
v                ©RSB 2022  - All rights reserved  
  Foreword  
Rwanda Standard s are prepared  by Technical Committees and approved by Rwanda Standards Board (RSB) 
Board  of Directors in  accordance with the procedures of RSB, in compliance with Annex 3 of the WTO/TBT 
agreement on the preparation, adoption and application of standards.  
The main task of technical committees is to prepare national standards.  Final Draft Rwanda S tandards adop ted 
by technical  committ ees are ratified  by me mbers of RSB Board of Director s for publication and gazettement  as 
Rwanda Standards.  
DRS 503 was prepared by Technical Committee RSB/TC 009, Civil engineering and building materials . 
In the preparation of this standard, reference was made to the following standard s: 
1) BS EN 13369: 2018: Common rules for precast concrete products  
2) BS EN 1097 -6, Tests for mechanical and physical properties of aggregates — Part 6: Determination of 
particle density and water absorption  
The assistance de rived from the above source is hereby acknowledged with thanks.  
Committee membership  
The following organizations were represented on the Technical Committee on Civil engineering and building 
materials  (RSB/TC 009) in the preparation of this standard.  
Advanced Construction Technology Services (ACTS) Ltd  
Afriprecast Ltd  
Amajyambere Industry Company Ltd  
Bridges to Prosperity  
Integrated Infrastructure Company (IIC) Ltd  
MASS Design Group  
Prime Cement Ltd  
Rwanda Inspectorate, Consumer Protection and Competition Authority (RICA)  
Rwanda Transport Development Agency (RTDA)  
Standards for Sustainability  
University of Rwanda -College of Science and Technology (UR -CST)  
Rwanda  Standards Board  (RSB) – Secretariat  DRS  503: 2022  
©RSB 2022  - All rights reserved                  vi 
 Introduct ion 
This document is intended to outline the general common requirements applicable to a large variety of  precast 
concrete products manufactured in a factory environment. It acts as a reference standard for  other standards to 
enable a more consistent appro ach to standardization in the field of precast concrete  products . 
The design of precast concrete products should be verified to ensure the fitness of their properties for  the 
particular application, particular attention being paid to design co -ordination w ith other parts of the  construction.  
 
 DRS 503 : 2022  
1                ©RSB 2022  - All rights reserved  
  Precast concrete products  ─ Performance requirements  
1 Scope  
This Draft Rwanda Standard  provides  the common requirements , sampling  and test methods  for unreinforced, 
reinforced and prestressed precast  concrete products made of compact light, normal and heavyweight concrete 
according to  RS ISO 22965 with no appreciable amount of entrapped air other than entrained air.  
It may also be used to specify products for which there is no standard. Not all of the requirements (Clause 5) of 
this standard  are relevant  to all precast  concrete  products.  
If a specific  product  standard  exists,  it takes  precedence  over this standard . 
The precast concrete products dealt with in this standard are factory produced for building and civil  engineering  
works.  This document can also be applied to products manufactured in temporary plants on site if the production 
is protected against adverse weather conditions and controlled . 
It does  not cover  prefabricated  reinforced  components  of lightweight  aggregate  concrete  with open  structure.  
The analysis and design of precast concrete products is not within the scope of this document . 
2 Normative references  
The following documents are referred to in the text in such a way that some or all of  their content  constitutes 
requirements of this document.  For dated references, only the edition  cited applies. For undated references, the 
latest edition of the referenced document (including any amendments) applies.  
RS ISO 22965 -1, Concrete — Part 1: Methods of specif ying and guidance for the specifier  
RS ISO 22965 -2, Concrete — Part 2: Specification of constituent materials, production of concrete and 
compliance of concrete  
RS ASTM C494/C494M , Standard Specification for Chemical Admixtures for Concrete  
ISO 12439 , Mixing water for concrete  
RS 142 , Design of concrete structures — General rules and rules for buildings — Code of practice  
RS ISO 6934 -1, Steel for the prestressing of concrete — Part 1: General requirements  
RS ISO 6934 -2, Steel for the prestressing of conc rete — Part 2: Cold -drawn wire  
RS ISO 6934 -4, Steel for the prestressing of concrete — Part 4: Strand  
RS ISO 6934 -5, Steel for the prestressing of concrete — Part 5: Hot -rolled steel bars with or without subsequent 
processing  
RS ISO 1920 -1, Testing concrete — Part 1: Sampling of fresh concrete  
RS ISO 1920 -2, Testing concrete — Part 2: Properties of fresh concrete  
RS ISO 1920 -3, Testing concrete — Part 3: Making and curing test specimens  
RS ISO 1920 -4, Testing concrete — Part 4: Strength of hardened c oncrete  
RS ISO 1920 -5, Testing concrete — Part 5: Properties of hardened concrete other than strength   
©RSB 2022  - All rights reserved                  2 
 RS ISO 1920 -6, Testing concrete — Part 6: Sampling, preparing and testing of concrete cores  
RS ISO 1920 -7, Testing concrete — Part 7: Non -destructive test s on hardened concrete  
ASTM C173/C173M, Standard Test Method for Air Content of Freshly Mixed Concrete by the Volumetric Method  
RS ISO 6935 -1, Steel for reinforcement of concrete — Part 1: Plain bars  
RS ISO 6935 -2, Steel for reinforcement of concrete — Part 2: Ribbed bars  
RS ISO 6935 -3, Steel for reinforcement of concrete — Part 3: Welded fabric  
3 Terms and definitions  
For the purposes of this standard, the follow ing terms and definitions apply  
3.1 General  
3.1.1 
precast  concrete  product  
product which is made of concrete and is manufactured in accordance with this standard or a specific  product 
standard in a place different from the final destination of use, protected from adverse weather  conditions during 
production and which is the result of an industrial proces s under a factory production  control  system and  with 
the possibility  of sorting  before  delivery  
3.1.2  
(concrete) cover  
distance between the surface of the reinforcement closest to the nearest concrete surface (including links and 
stirrups and surface reinforcement where relevant) and the nearest concrete surface  
3.1.3  
concrete  family  
group  of concrete  compositions  for which  a reliable  relationship  between  relevant  properties  is   established 
and documented  
3.1.4  
tendon  
prestressing  unit (wire,  strand  or bar) subjected  to pre- or post-tensioning  
 
3.1.5  
lightweight  concrete  
concrete  with a  closed  structure  and with an oven -dry density  of 800 kg/m3 to 2 000 kg/m3 
3.1.6  
normal  weight  concrete  
concrete  with an  oven -dry density  of 2 000 kg/m3 to 2 600 kg/m3 DRS 503 : 2022  
3                ©RSB 2022  - All rights reserved  
  3.1.7  
heavyweight  concrete  
concrete  with an  oven -dry density  of more  than 2 600 kg/m3 
3.2 Dimensions  
3.2.1  
principal  dimensions  
length,  width,  depth  or thickness  
3.2.2  
nominal  dimension  
dimension  declared  in the technical  documentation  and targeted  at manufacture  
3.3 Tolerances  
 3.3.1  
tolerance  
sum of the absolute  values  of the upper  and the lower  permitted  deviation  
3.3.2  
deviation  
difference  between  an actual  measure  and the corresponding  nominal  dimension  
3.4 Durability   
3.4.1  
durability  
ability  of a precast  concrete  product  to satisfy,  with anticipated  maintenance,  the design  performance  
requirements  during  its design  working  life under  the influence  of the expected  environmental  actions  
3.4.2  
design  working  life 
assumed period for which a structure or part of it is to be used for its intended purpose with anticipated  
maintenance  but without  major  repair  being  necessary  
3.4.3  
environmental  conditions  
physical  or chemical  impacts  to which  the precast  concrete  product  is exposed  and which  result  in effects  on the 
concrete  or reinforcement  or embedded  metal  that are not considered  as loads  in structural  design  
3.4.4  
ambient  conditions  
hygrothermic  conditions  in the factory  which  result  in effects  on the hardening  process  of the concrete   
©RSB 2022  - All rights reserved                  4 
 3.5 Mechanical properties  
 3.5.1  
potential  strength  
compressive  concrete  strength  derived  from tests  on cubes  or cylinders  moulded  and cured  in laboratory  
conditions  in accordance  with RS ISO 1920 -3  
3.5.2  
structural  strength  
compressive concrete strength derived from tests on specimens (drilled cores or cut prisms) taken from  the 
precast concrete product (direct structural strength) or derived from tests on moulded specimens  cured  in the 
same  ambient  conditions as the  product  itself (indirect  structural  strength)  
3.5.3  
characteristic  strength  
value  of strength  below  which  5 % of the population  of all possible  strength  determinations  of the volume  of 
concrete  under  consideration  are expected  to fall 
4 Symbols (and abbreviated terms)  
𝑓𝑐𝑘 characteristic compressive strength of the concrete at the age of 28 days  
𝑓𝑐𝑚 mean  compressive  strength of  concrete  
𝑓𝑐,𝑐𝑢𝑟𝑒 Compressive strength at the end of curing  
𝜂 Conversion factor  
∝  the safety  conver sion factor  
Δcdev    maximum deviation  of concrete  cover  
5 Requirements  
5.1 Material s requirements  
5.1.1  General  
5.1.1.1  Only materials  with established  suitability  shall be used.  
5.1.1.2  For a particular material, the establishment of suitability may be based on a relevant standard which  
refers specifically to the use of this material in concrete or in precast concrete products .  
5.1.2  Constituent  materials  of concrete  
5.1.2.1  General  
5.1.2.1.1  Constitu ent materials shall not contain harmful ingredients in such quantities as can be detrimental 
to the strength, consistence, setting time and durability of the concrete, or cause corrosion of the reinforcement, 
and shall be suitable for the intended use in c oncrete.  
5.1.2.1.2  Cements, additions, aggregates, mixing water and admixtures shall be as per RS ISO 22965 -2, 
clause 5. DRS 503 : 2022  
5                ©RSB 2022  - All rights reserved  
  5.1.2.2  Reclaimed  crushed  aggregates  and recycled  coarse  aggregates  
5.1.2.2.1  Reclaimed crushed aggregates and recycled coarse aggregates, mixed in concrete with other 
aggregates,  shall not adversely alter the rate of setting and hardening of concrete, nor shall it be detrimental to 
the durability  of the precast  concrete  product  in the end use conditions.  
5.1.2.2.2  When reclaimed crushed or recycled coarse aggregates are used in percentage up to 5 % in weight 
of the  total content of aggregates in the concrete mix, no verification of the concrete properties other than  
concrete strength is required.  
5.1.2.2. 3 The amount of reclaimed crushed aggregates obtained from precast concrete products 
manufactured in  the same factory, can be used up to 10 % in weight of the total content of aggregates in the 
concrete mix  with no further testing of the mechanical  strength  of the product  or of hardened  concrete  properties  
other  than testing  of compressive  concrete  strength.  
5.1.2.2. 4 Where required and for specific applications, the amount of reclaimed crushed aggregates might 
be limited  to 5 % in weight.  
5.1.2.2. 5 Contamination of crushe d recycled aggregates from internal source by impurities shall not be 
allowed. Typical contaminations may be organic material, steel, plastic or insulation debris and oil.  
5.1.2.2. 6 Recycled aggregates should not be used in concrete for which durability re quirements are higher 
than those for the concrete from which the recycled aggregates originate. This does not apply for concrete in 
exposure class X0, XC1 and XC2.  
NOTE  Alternative provisions are given in RS ISO 22965 -2 and should be considered  
5.1.3  Reinforcing  steel  
Reinforcing steel (bars, coils and welded fabric) shall comply with RS ISO 6935 .  
5.1.4  Prestressing  steel  
Prestressing steel (wire,  bars and strand)  shall comply  with RS ISO 6934 -1, RS ISO 6934 -2, RS ISO 6934 -4 
and RS ISO 6934 -5 as appropriate.  
5.1.5  Inserts  and connectors  
5.1.5.1  Mechanical  inserts  and connectors  shall:  
a) resist the design actions;  and 
b) have the necessary ductility.  
5.1.5.2  Permanent  connecting  parts  and fasteners  shall maintain  these  properties  for the design  working  
life of the precast  concrete  product.  
5.2 Production  requirements  
5.2.1  Concrete  production  
5.2.1.1  General  
For concrete  composition,  type of cement,  use of aggregates,  additions  and admixtures,  and for resistance  to 
alkali -silica  reaction,  chloride  content,  air content  and concrete  temperature,  RS ISO 22965 -2, clause 6 shall 
apply.  For specification  of concrete  RS ISO 22965 -1 shall apply.   
©RSB 2022  - All rights reserved                  6 
 5.2.1.2  Casting and compaction  of concrete  
Concrete shall be cast and compacted so as to retain no appreciable amount of entrapped air other  than 
entrained air (e.g.  to achieve sufficient frost resistance) to avoid detrimental segregation and to  ensure  that the 
reinforcement  shall be properly  embedded.  
5.2.1.3  Curing  (protection  against  drying  out) 
5.2.1.3.1   The concrete shall be protected during curing so that loss in stren gth and cracking due to 
temperature  and shrinkage  and that, if relevant,  detrimental  effects  on durability,  are avoided.  
5.2.1.3.2   All surfaces of newly cast concrete may be protected by one of the methods listed in Table 1  or 
by any  other method applicable in the place of use, unless it is shown by tests and inspection on the finished  
product  or on representative  samples,  that other  means  are relevant  in the production  environment.  
Table  1 — Protection  against  drying  out 
 
5.2.1.3.3  For methods A and B, the protection shall be maintained until the compressive strength of the 
sample at         the end of curing ( fc,cure) is equal to or greater than the smallest value of the pa rameters Dd.fck and 
fc,L (cylinders  or cubes).  The parameters  Dd et fc,L are defined  in Table  2. 
𝑓𝑐,𝑐𝑢𝑟𝑒≥𝑀𝐼𝑁 (𝐷𝑑.𝑓𝑐𝑘;𝑓𝑐,𝐿)                                             (1) 
where  
fck is the characteristic compressive strength of the concrete at the age of 28 days targeted by the manufacturer . 
5.2.1.3.4   The measure  of the mean  compressive  strength  fc,cure  shall be done  on concrete  samples  that are 
submitted  to the same  protection  against  drying  out as the  product  and for the  design  working  life of not more  
than 50 years.  
5.2.1.3.6   The degree  of hardening  in Table  2 may be measured  by testing  a concrete  sample.  The test 
result  shall be obtained  from an individual  specimen  or the average  of the results  when  two or more  specimens 
made  from one  sample  are tested  at the same  age. 
 Method  Typical  means  of protection  
A - Without  addition  of 
water  ─ keeping  the concrete  in an environment  with a relative  humidity  
above 65 % for CEM I and CEM II/A, 75 % for all the other types 
of binders;  
─ keeping  the formwork  in place;  
─ covering  the concrete  surface  with vapour -resistant  sheets  
B - Keep  the concrete  
moist  by addition  of water  ─ maintaining  wet coverings  on the concrete  surface;  
─ keeping  the concrete  surface  visibly  wet by spraying  with water  
C – Use  of curing  
compounds  Curing  compounds  used  shall conform  to provisions  valid in the place  
of use.  DRS 503 : 2022  
7                ©RSB 2022  - All rights reserved  
  Table  2 — Minimum  strength  of the concrete  at the end of protection  against  drying  out 
Exposure  conditions  in the place  
of use  (RS ISO 22965  exposure  
classes)  Degree  of hardening  Dd 
 
% Cylinder/cube  fc,L 
 
MPa  
X0, XC1  only requirements on  fc,L apply.  12/15  
XC2,  XC3,  XC4,  XD1,  XD2, XF1  35 12/15  a 
All other  exposure  conditions  
(wetting/drying  cycles)  50 16/20  b 
a This value has to be substituted by 0 .25.fck if 0 .25.fck ≥ 12 MPa (cylinder); 15 MPa (cube).  
b This value has to be substituted by 0 .35.fck if 0 .35.fck ≥ 16 MPa (cylinder); 20 MPa (cube). 
 
5.2.1.3.7  Other means than those defined in Table 1 may be employed if the value of the water absorption 
of the  concrete,  measured  according  to the test procedure  defined  in Annex  E, does  not exceed  10 % (in relative  
proportion)  of the value  of water  absorption  of the concrete  complying  with the requirements  in Table  2. 
NOTE  The water absorption test is run on (30 ± 1) mm thick samples that include the surface exposed to the  
environment.  
5.2.1.4  Accelerated  hydration  by heat treatment  
5.2.1.4.1  Where heat treatment at atmospheric pressure is applied to concrete during production in order to  
accelerate  its hardening,  it shall be demonstrated  by initial  testing  that the required  strength  is achieved for  each 
concrete  family  concerned.  
5.2.1.4.1 .1  Depending on material and climatic conditions, more restricting requirements may apply to 
the heat treatment of outdoor products in certain areas according to provisions valid in the place of use. The 
following conditions shall be fulfilled when the maximu m mean temperature 𝑇𝑚𝑒𝑎𝑛 within the concrete exceeds 
40 °C during the curing process unless previous positive experience has shown that special measures are not 
necessary to avoid micro cracking and/or durability defects: a preheating period shall be applied during which 
𝑇𝑚𝑒𝑎𝑛 does not exceeds 40 °C; 5.2.1.4.1 .2  The temperature difference between adjacent parts of the 
product during the heating and the cooling phases shall be limited to 20 °C.  
5.2.1.4.2   The duration  and heating  rate of the full heating  and cooling  period  (if appropriate)  shall be 
documented.  
5.2.1.4.3   During the full heating and cooling period Tmean shall be limited to the values of Table 3. However 
higher  temperatures may be accepted provided the durability of concrete under the specified environment is  
demonstrated  by long term positive  experience.  
Table  3 — Conditions  for accelerated  hydration  
Product  environments  Maximum  mean  concrete  temperature  
Tmeana 
Predominantly  dry or moderate  
humidity  Tmean  ≤ 85 °C b 
Wet  and cyclic wet  Tmean  ≤ 65 °C  
©RSB 2022  - All rights reserved                  8 
 a Individual  values  may  be 5 °C higher.  
b When  70 °C < Tmean  ≤ 85 °C  initial  tests  shall  have  demonstrated  that  the structural  strength  at 90 d 
corresponds  with normal  evolution  of hardening  with  respect  to the structural  strength  obtained  at 28  days.  
 
5.2.1.4.4   For wet and cyclic wet environments, in case of no long-term positive experience, the suitability of 
the higher  temperature  treatment  shall be demonstrated;  the following  limits  may be a basis  for this 
demonstration:  for concrete:  𝑁𝑎 2𝑂𝑒𝑞𝐶𝑜𝑛𝑡𝑒𝑛𝑡  ≤3.5𝐾𝑔/𝑚3  , for cement  SO3 content  ≤ 3.5 % by mass.  
5.2.1.4.5   The above limits for Na2Oeq and SO3 content may be changed in value, or limits on other 
constituents may be put, according to the results of scientific or technical experience.  
5.2.2  Hardened  concrete  
5.2.2.1  Strength  classes  
5.2.2.1.1   For compressive  strength  classes  of concrete  RS ISO 22965 -2, 6.3.1 applies.  
5.2.2.1.2   For design purposes, the properties of strength classes for normal and heavy weight concrete up 
to B120/140  are given  in RS ISO 22965 -2, Table 3  and for lightweight  concrete up  to LB 80/88 in   RS ISO 
22965 -2, Table  4. 
5.2.2.1.3   The manufacturer  may select  intermediate  classes,  in 1.0 MPa steps  of the characteristic  strengths.  
In this case,  other  concrete  properties are  obtained  by linear  interpolation.  
5.2.2.1.4   For reinforced or prestressed precast concrete products, the minimum strength class of concrete 
shall be: 
⎯ B20/25 for reinforced precast concrete products;  
⎯ B30/37 for prestressed precast concrete products.  
5.2.2.1.5   When  lightweight  concrete  is used,  the minimum  strength  class  shall be LB 16/18  both for reinforced  
and prestressed precast  concrete  products.  
5.2.2.2  Compressive  strength  
5.2.2.2.1  General  
The compressive  strength  to verify  the strength  class  of concrete  is defined  by the potential  strength;  the 
manufacturer  may use direct  structural  strength  or indirect  structural  strength to  confirm it.  
5.2.2.2.2  Potential  strength  
5.2.2.2.2.1  The potential  strength  shall be tested  at 28 days.  Tests of potential strength may be performed 
before 28 days in order to evaluate the progression of  potential strength or  to estimate  at early age  the potential  
strength  at 28  days.  When  relevant,  tests  may be performed  at an age greater  than 28 days.  
5.2.2.2.2.2  For determination  of potential  strength  RS ISO 22965 , 6.3.1  and 6.3.2  shall apply.  
5.2.2.2.3  Direct  structural  strength  
Compressive  direct  structural  strength  shall be determined  from the finished  product  by drilling  cores  in 
accordance  with RS ISO 1920 -6 or by cut prisms  converted to  cube  or cylinder with  the appropriate  correction 
factor. Non -destructive tests on the finished product in accordance with RS ISO 1920 -7 may be  used,  but a 
correlation  with tests as  specified  in 6.1.1 shall be established.  DRS 503 : 2022  
9                ©RSB 2022  - All rights reserved  
  5.2.2.2.4  Indirect  structural  strength  
5.2.2.2.4.1  For stabilized production processes where the composition of the concrete and curing methods 
are not changed, compressive indirect structural strength may be determined by test specimens, made from  
fresh  concrete,  cured  and stored  in factory  conditions  as close  to the precast  concrete  product  as possible,  
provided  an initial  test has determined  the correlation  with the direct  structural  strength.   
5.2.2.2.4.2  Density  may be used  as a characteristic  for the establishment  of the correlation.  
5.2.2.2.5  Conversion  factor  
The relation between the structural strength and the potential strength is esta blished by dividing the  structural  
strength by  η = 0.85. 
5.2.2.3  Tensile  strength  
If required, tensile strength should be determined according to RS ISO 1920 -4  
5.2.2.4  Shrinkage  
For lightweight concrete,  the drying  shrinkage  shall be declared  by the manufacturer  according to RS 142.  
5.2.2.5  Dry density  
If required,  dry density  shall be determined  in accordance  with RS ISO 22965 , 6.3.3 . 
5.2.2.6  Water  absorption  
If required  for durability reasons  or by provisions  applicable  in the place  of use of the concrete  product,  water  
absorption  shall be determined  following  Annex  E. 
5.2.3  Structural  reinforcement  
5.2.3.1  Processing  of reinforcing  steel  
5.2.3.1.1  Reinforcing  steel  for structural  purposes  that is  straightened,  bent or welded in  the factory  shall 
remain  in conformity  with 5.1.3 after this treatment.  
5.2.3.1.2   Welded connection of reinforcing bars may only be used when the weldability of the steel is fully 
documented.  
5.2.3.1.3   Indications  on welding  process  may be found  in RS 142, 6.2.5. 
5.2.3.2  Tensioning  and prestressing  
5.2.3.2.1  Initial  tensioning  stresses  
5.2.3.2.1.1  The maximum  prestressing  force  applied  to a unit immediately  after release  of tendons  shall 
satisfy  the following  conditions:  
⎯ absence of uncontrolled longitudinal cracking, spalling or bursting of the concrete;  
⎯ the stress in the concrete does not lead to excessive creep or deformation of the product.  
5.2.3.2.1.2  When  conformity  of the product  with the relevant  require ments  of the product  standard  is 
demonstrated by  initial type testing and factory production control and the tightened tolerances of 5.2.3.2.2 are 
met, the maximum value  of tensioning  stress 𝜎0𝑚𝑎𝑥 can be taken  as:  
©RSB 2022  - All rights reserved                  10 
 𝜎0𝑚𝑎𝑥 =𝑚𝑖𝑛 (0.85𝑓𝑝𝑘 𝑜𝑟 095 𝑓𝑝0,1𝑘)   Class  1                                                                     (2) 
If the conditions mentioned in the previous paragraph are not met, RS 142, 5.6.2.1, shall  apply:  
𝜎0𝑚𝑎𝑥 =𝑚𝑖𝑛 (0.80𝑓𝑝𝑘 𝑜𝑟 090 𝑓𝑝0,1𝑘) class  2                                                                        (3) 
5.2.3.2.2  Accuracy  of tensioning  
5.2.3.2.2.1  If class 1 according to 5.2.3.2.1 .2 is applied, tightened tolerances on the prestressing force s hall 
be applied  with an  accuracy  of at least:  
⎯ single tendon/force: ± 5 %.  
5.2.3.2.2.2  If class 2 according to  5.2.3.2.1 .2 is applied, normal tolerances on the prestressing force shall 
be applied with an accuracy at least:  
⎯ single tendon/force: ± 10 %;  
⎯ total force:  ± 7 %.  
5.2.3.2.3  Minimum  concrete  strength  at transfer  
5.2.3.2.3.1  At transfer  of the prestressing  force,  the concrete  shall have  a minimum  strength  𝑓𝑐𝑚,𝑝of 1,5 
times  the maximum  compressive  stress  in the concrete  and not less than  20 MPa  (cylinder  strength).  
5.2.3.2.3.2  The requirements according to RS 142, 5.6.2.2.5 shall be considered.  In any case  the strength 
shall be adequate  for the anchorage  of the strands.  
5.2.3.2.4  Slippage of tendons  
5.2.3.2.3.1  Slippage, which is the shortening of the tendon at each end of the element after transfer of the 
prestress force, shall be limited to the following values:  
— for individual tendons (strands or wires): 1,3 𝛥𝐿0; 
— for the mean value of all tendons on one end of an element: 𝛥𝐿0. 
5.2.3.2.4.2  For strands the average value of three circumferentially positioned wires shall be taken into 
account. The value of 𝛥𝐿0, in millimetres, shall be calculated from:  
 ∆𝐿0=0.4𝑙𝑝𝑡2𝜎𝑝𝑚 0
𝐸𝑝                                                                                            (4) 
Where 
𝑙𝑝𝑡2 is the upper bound value of transmission length = 1,2 lpt, in mm;  
𝜎𝑝𝑚𝑜 is the initial  stress  in the prestressing  steel  immediately  after release,  in MPa;  
Ep is the modulus  of elasticity  of the prestressing  steel,  in Mpa. 
5.2.3.2.4.3  In general,  slippage  of tendons  is measured  except  for one piece  moulded  products  (see 
Table  D.3).  On  sawn  products,  visual  inspection  alone  may indicate  no slippage  and no further  measurement  is 
required.  DRS 503 : 2022  
11                ©RSB 2022  - All rights reserved  
  5.3 Finished  product  requirements  
5.3.1  Geometrical  properties  
5.3.1.1  Production  tolerances  
6.3.2.7.1  Recommendations  for maximum  deviations  of cross -sectional  dimensions  [width  (Δb) and height  
(Δh)],  and for maximum deviation  of concrete  cover  (Δc dev) to bars,  wires and  strands are  given  in 
Table  4: 
Table 4  — Deviations  
 
5.3.1.1. 2  The structural design of the works shall take into account the tolerances on the supports as 
specified in the structural design for the works.  
5.3.1.1.3  For slabs and beams, the average deviation of concrete cover may be determined as the mean 
deviation of the individual bars, wires or strands in a beam cross -section or over a maximum width of 1 m in a 
slab. No in dividual bar, wire or strand shall have a negative deviation numerically larger than the recommended 
negative deviation.  
NOTE  Guidance  on concrete  cover  can be found  in Annex  A. 
5.3.1.1.4  Production tolerances of geometrical properties may be determined by  measurements according 
to F.1 to F.3 of Annex F. 
a) Recommendations for maximum deviations on length:  
∆𝑙=±(10+𝐿
1000)≤±40𝑚𝑚(5) 
where  
L is the nominal length in millimetres.  
b) Recommendations  for maximum  deviations  on holes,  openings,  steel  plates,  inserts,  etc: 
1) size of hole or opening  ± 10 mm. 
 
2) location  of holes,  openings,  steel  plates,  inserts,  etc. ± 25 mm. 
 Target  dimension  
mm  Cross -section  Δb, Δh a 
mm  Concrete  cover  a b Δcdev 
mm  
L ≤ 150  + 10/−  5 ±5 
L = 400  +15/−  10 + 15/− 10  
L ≥ 2 500 ±30  +25/−  10 
a        Linear  interpolation  for intermediate  values.  
B        According  to RS 142 , 7.4.1.1 : 
cnom = cmin+Δcdev (use the numerical value for − Δcdev).    
©RSB 2022  - All rights reserved                  12 
 5.3.1.2  Minimum  dimensions  and detailing  
5.3.1.2.1  The geometrical  characteristics  of precast  concrete  products  shall comply  with the required  
minimum  dimensions  and detailing.  
5.3.1.2.2  The values  of the minimum  dimensions  and detailing  are based  on the nominal  dimensions  and 
may be taken  from the  relevant  Clauses of  RS 142.  
5.3.2  Surface  characteristics  
For the specification  of the surface  characteristics  of a finished  product,  reference  should  be made  to F.4, where  
also recommended  values are  given.  
5.3.3  Mechanical  resistance  
5.3.3.1  General  
6.3.2.7.1  The compressive  strength class  of the concrete shall  be declared  unless  both of the following  
conditions  are fulfilled:  
⎯ mechanical  resistance  of the product  is verified  and declared  on the basis  of initial  type testing  and regular  
tests  for this property  during  factory  production  control  on the finished  product;  
⎯ compressive  strength  class  is not a relevant  parameter  to demonstrate  durability  of the finished  product  
(see 5.3.7.1  and 5.3.7.5).  
5.3.3.1.2  All relevant  structural  properties  of the product  shall be considered  in both ultimate  and 
serviceability  limit states.  
5.3.3.2  Verification  by calculation  
Design  values  of mechanical  resistance  obtained  by calculation  shall be verified  according  to the relevant  clauses 
of RS 142, or to the rules valid in the place of use. Pertinent complementar y rules given in  this and in product  
standards apply.  
5.3.3.3  Verification  by calculation  aided  by physical  testing  
6.3.2.7.1  Physical  testing  on finished  products is  required  to aid calculation  in the following  cases:  
a) alternative  design  rules  with respect  to 5.3.3.2;  and 
b) structural  arrangements  with unusual  design  models  not covered  by 5.3.3.2.  
5.3.3.3.2  In these cases, physical testing on a small number of full-scale  specimens is needed before starting  
production in order to verify the reliability of the design model assumed for calculation. This shall be  done  with 
load-tests up  to ultimate  limit state  (design  conditions).  
5.3.3.3.3  Physical  testing  is not required  in case  of reliable  theoretical  verification  following  the principles  
of  RS 142.  
5.3.3.4  Verification  by testing  
In case  of verification  by testing,  declared  values  shall be verified  by direct  load testing  made  on samples  taken  
following  proper  statistical  criteria.  DRS 503 : 2022  
13                ©RSB 2022  - All rights reserved  
  5.3.3.5  Safety  factors  
Recommended  values  for partial  safety  factors  can be found  in RS 142 . These standards also permit  lower  
values  under  certain  conditions.  Annex  C provides  such  information.  
5.3.3.6  Transient  situations  
6.3.2.7.1  The following  transient  situations  shall be considered:  
a) demoulding;  
b) transport  to the storage  yards;  
c) storage  (support  and load conditions);  
d) transport  to site; 
e) erection  (lifting);  
f) construction  (assembly).  
5.3.3.6.2  When relevant for the type of element, for transient situations a nominal transverse ho rizontal force 
to cover out of plane effects due to dynamic actions or verticality deviations shall be considered. This may  be 
taken  as 1.5 % of the self-weight  of the element.  
5.3.4  Durability  
5.3.4.1  Durability  requirements  
5.3.4.1.1  The following  specifications  refer to concrete  structural  products  with a design  working  life of 
50years consistent  with RS 142. 
5.3.4.1.2  The durability  of precast  concrete  products  is ensured  by the following  requirements  as relevant:  
a) adequate  content  of cement  and additions  (see 5.2.1.1);  
b) maximum  water/binder  ratio (see 5.2.1.1);  
c) maximum  chloride  content  (see 5.2.1.1);  
d) maximum  alkali  content  (see 5.2.1.1);  
e) protection  of newly  cast concrete  against  drying  out (see 5.2.1.3);  
f) minimum  concrete  strength  (see 5.2.2.1);  
g) minimum concrete cover and concrete quality of cover (see 5.3.4.4); and, where  applicable:  
h) air content  (see 5.2.1.1);  
i) adequate  hydration  by heat treatment  (see 5.2.1.4);  
j) specific  requirements  to ensure  internal  integrity  (see 5.3.4.2); 
k) specific  requirements  to ensure  surface  integrity  (see 5.3.4.3); 
l) water  absorption  (see 5.3.4.5); and  
©RSB 2022  - All rights reserved                  14 
 m) use of performance  design  methods .  
5.3.4.1.3  In case of non -structural concrete products or when the design working life of the concrete product 
is shorter or longer than the corresponding value in RS 142 (50 years), the durability specifications  may be 
adapted  to the specific  field of application  of the product.  
5.3.4.2  Internal  integrity  
The potential properties concerning resistance and durability of the concrete mix shall be safeguarded  during 
production by adequate hydration, possibly by heat treatment (where applicable) a nd limitation  of early  cracking  
of concrete;  see 5.2.1.3  and 5.2.1.4.  
5.3.4.3  Surface  integrity  
5.3.4.3.1  When relevant, the surface resistance of concrete against deterioration processes such as 
chemical  reactions,  freeze -thaw  effects,  mechanical  abrasion,  etc. shall be ensured  by proper  provisions.  
5.3.4.3.2  Depending on the provisions valid in the place of use of the product, one of these methods may be 
the combination  of limiting  values  for each  exposure  class  related  to maximum  water/ cement ratio,  minimum  
strength  class  and maximum  water  absorption  of the concrete  from the  finished  product.  
NOTE  Example  for class XC3 (moderate humidity, concrete inside buildings with moderate or high air humidity,  
external concrete sheltered from rain) the combination could be: maximum water/ cement  ratio 0,50, minimum  strength  class 
35/45,  maximum  water absorption  6 %. 
5.3.4.4  Steel  corrosion  resistance  
5.3.4.4.1  Resistance  against  steel  corrosion  shall   be   obtained   by   following   the   principles   of   
7.1   of   RS 142. To fulfil these  principles,  Annex  A of this standard  gives  a scale  of ambient  conditions  related  to 
the concrete  covers adopted  in the design  of the precast  concrete  product . 
5.3.4.4.2  Corrosion  resistance  may also be obtained  by protection  of reinforcement  or by using  stainless  
steel.  
5.3.4.5  Water  absorption  
When  water  absorption  is specified , it shall be measured  according  to 6.1.2. 
5.3.5  Other  requirements  
5.3.5.1  Safety  in handling  
The concrete product shall be designed and manufactured so that it can be handled safely, with no  detrimental 
effect on the product itself. Provisions for handling and storage during transport and on site  shall be given  and 
documented  by the manufacturer.   
5.3.5.2  Safety in use 
The properties of a concrete product, regulatory related to safety in its intended final use, should be  considered  
if required  (e.g. surface  regularity,  slip resistance,  sharp  edges,  etc.).  
5.3.5.3  Self-weight  
5.3.5.3.1  If required, the self-weight of the finished product shall be declared.   
5.3.5.3.1  If C.5 is applied , the manufacturer  shall control  the self-weight.  DRS 503 : 2022  
15                ©RSB 2022  - All rights reserved  
  6 Test methods  
6.1 Tests  on concrete  
6.1.1  Compressive  strength  
6.3.2.7  The concrete  strength shall  be tested  according  to RS ISO 1920 -4: 
⎯ on representative  moulded  specimens  according  to RS ISO 1920 -1 and RS ISO 1920 -3; 
⎯ or on representative  cores  according  to RS ISO 1920 -6. 
6.1.1.2  For the determination  of structural  strength,  the curing  conditions  of RS ISO 1920 -3 do not apply.  
NOTE  1 The different  shapes  and dimensions  of test specimens  give different  values  for the concrete  strength.  
6.1.1.3  Proper  shape  factors  shall be applied  to give the standard  cylinder  or cube  strength.  
6.1.1.4  Cubes with a nominal size of at l east 100 mm and not more than 150 mm and cylinders or cores 
with equal nominal length and diameter from 100 mm up to 150 mm can be assumed to give a strength value  
equivalent  to the standard  cube  strength value  obtained  under  the same  ambient  conditions.  
6.1.1.5  Cylinders and cores with a nominal diameter of at least 100 mm and not larger than 150 mm and 
with a  nominal length to diameter ratio equal to 2 can be assumed to give a strength value equivalent to the  
standard  cylinder  strength value  obtained  under  the same  ambient  conditions.  
6.1.1.6  Cores  with a nominal  diameter  less than 50 mm and/or  a nominal  length  less than 0,7 times  the 
diameter  shall not be used.  Cubes with a  nominal  size less than  50 mm shall not be used.  
NOTE  2     When direct structural strength of concrete is tested in drilled cores, cores with d ≥ 50 mm diameter  should be 
employed; the length h should be not less than 0,7d; the end faces of the test sample should be  ground.  
6.1.1.7  Conversion  factors  for the relations hip between  indirect  structural  strength  and direct  structural  
strength shall be established by initial testing. Depending on the shape and/or size of the specimens to  be 
considered  this conversion  factor  may or may not include  a shape  and/or  size conversion  factor.  
6.1.2  Water  absorption  
When the water absorption of concrete is measured, the test method given in normative Annex E shall apply . 
6.1.3  Dry density  of concrete  
When  the dry density  of concrete  is required,  the test shall be carried  out on representative  specimens  in 
accordance  with RS ISO 1920 -5. 
6.2  Measuring  of dimensions  and surface  characteristics  
6.2.1  When  not defined  in the specific  product  standard,  information  on measuring  of dimensions  are given  in   
Annex  F. 
6.2.2  Dimensions  are assumed  at reference  temperatures  between  10 °C  and 30 °C, and at the reference  age 
of 28 days. If necessary, theoretical corrections shall be made for inherent deviations of the dimensions  when  
measuring  at other  temperatures or  ages.  
6.2.3  The equipment  used  to check  deviations  shall be read with an accuracy  of at least  1/5 of the deviation  
to be checked.   
©RSB 2022  - All rights reserved                  16 
 6.2.4  Angular  deviation  of a plane  surface  shall be measured  in two perpendicular  directions.  
6.2.5  For wide elements, such as ribbed elements and special roof elements, the length should be measured 
at three  locations,  for example  at 100 mm from both edges and  in the centre.  
6.2.6  If considered necessary, the width and he ight shall also be measured at least at three locations along 
the length of the element. For dimensions that may be difficult to measure directly on the element, levelling  rods 
or levelling  instruments may  be used  to aid in the measuring.  
6.2.7  Lateral  bow and camber  shall be measured  at midspan.  
6.3 Weight  of the products  
6.3.1  When  the reduction  of 𝛾𝐺 according  to C.5 is applied,  the self-weight  of the precast  concrete  product  shall 
be determined  by weighing  with an  accuracy  of ± 3 % or estimated  by calculation.  
6.3.2  Estimated  weight  shall be calculated  from:  
a) the nominal  dimensions  of the finished  product;  
b) the mean value of concrete density representative  for the finished  product  considered,  and measured  from 
the test specimen  used  for potential  strength according  to RS ISO 1920-4; and 
c) the amount  of reinforcement  of the finished  product.  
7 Marking  
7.1 Each  produced  unit shall be marked  or labelled  to show:  
a) identification  of the manufacturer;  
b) identification  of the place  of production;  
c) number  of the product  standard;  
d) identification  code  of the unit when  necessary,  (e.g. to trace  declared  unit properties  and performances  and 
other  relevant  product  data in the technical  documentation  or to trace  production  process  data);  
e) date of casting;  
f) self-weight  of the unit when  required;  
g) other  information  relevant  for installation  in the work  (e.g. location  and orientation)  when  required.  
7.2 For identical or serial units of a concrete product, the above procedure may be simplified or replaced by  
overall  marking  or labelling  of packaged  units or  lots of  units.  
7.3 In addition to the above data, the following accompanying information shall be provided on the marking  
or labelling  or in the accompanying  documents:  
a) product  identity  (description  according  to the standard  and/or  commercial  name);  and 
b) technical  documentation  where  applicable.  . DRS 503 : 2022  
17                ©RSB 2022  - All rights reserved  
  8 Technical  documentation  
8.1 At the latest at the time of delivery, technical docume nts shall be available, which are appropriate for the 
chosen method of declaration, and which:  
a) ensure traceability of design assumptions, methods, results and detailing of the element including  
construction  data such  as the dimensions,  the tolerances,  the layout of  the reinforcement  and the concrete  
cover;  
b) meet  national  provisions  on design  documents in  the place  of use; 
c) give guidance  on safe transportation,  handling  and storing;  
d) give specifications  for the erection  of the elements;  and 
e) give supplementary  information  referred  to in the marking  labelled  to the elements.  
8.2 Different technical documents for structural concrete products meeting the requirements above are 
exemplified in the informative Annex G.  
©RSB 2022  - All rights reserved                  18 
 Annex  A 
(informative)  
 
Concrete cover as regard to corrosion  
A.1 Minimum  concrete  cover  for base  conditions  
With reference  to the durability  of precast  concrete  products  in terms  of steel  protection  against  corrosion,  Table  
A.1 gives  the scale  of environmental  conditions  and corresponding  exposure  classes.  
Table  A.1 — Nominal  scale  of environmental  conditions  
 
Environmental  conditions  Aggressivity  Exposure  classes  of RS ISO 22965  
A Null X0 
B Low XC1 
C Moderate  XC2-XC3 
D Normal  XC4 
E High XD1-XS1 
F Very high XD2-XS2 
G Extreme  XD3-XS3 
For precast concrete products intended for normal design working life (50 years), the recommended  values  of 
minimum  concrete  cover  as given  in Table  A.2 can be used,  provided  that special  quality  control  of the factory  
production  is ensured.  
Table  A.2 — Minimum  concrete  cover  
Dimensions  in millimetres  
 
  
Slab  
reinforcing  bars  Reinforcing  
bars for  
products  other 
than  slabs   
Slab  
pretensioned  
tendons  Pretensioned  
tendons for  
products  other 
than  slabs  
Environmental  
conditions  Cmin C0 Ambient  
conditions  ≥ C0 < C0 ≥ C0 < C0 ≥ C0 < C0 ≥ C0 < C0 
A B20/25 B30/37 A 10 10 10 10 10  10  
B B20/25 B30/37 B 10 10 10 10 15  15  
C B25/30 B35/45 C 10 15 15 20 20 25 25 30 
D B30/37 B40/50 D 15 20 20 25 25 30 30 35 
E B30/37 B40/50 E 20 25 25 30 30 35 35 40 DRS 503 : 2022  
19                ©RSB 2022  - All rights reserved  
  F B30/37 B40/50 F 25 30 30 35 35 40 40 45 
G B35/45 B45/55 G 30 35 35 40 40 45 45 50 
In Table A.2, C min is the minimum concrete class required for the given exposure class, and C 0 is the  concrete 
class being two strength classes higher than C min. Where freeze/thaw or chemical attack on  concrete (Classes 
XF and XA of RS ISO 22965 ) is expected, special attention should be given to the conc rete composition.  Covers  
in accordance  with Table  A.2 will normally  be sufficient  for such  situations.  
A.2 Alternative  conditions  
In applying RS 142, 7.4.1.2 , the following alternative conditions are recommended  
— For products with intended design working life o f 100 years in environmental 
conditions C to G, the  values  of Table  A.2 should  be increased  with 10  mm. 
 
— When steel with protection against corrosion by coating is  used, the concrete cover as  
given in  Table  A.2 may be reduced  by 5 mm;  when  stainless  steel  is used  the concrete  
cover  could  be reduced  to the value  required  for bond,  fire resistance  or specific  
aggressive  environment.  
 
— When  the concrete  class  is ≥ B40/50 and its water  absorption  is less than 6,0 % 
(characteristic  value)  the concrete  cover  as given  in Table  A.2 may be reduced  by 5 
mm. 
 
— For concrete  classes  higher  than B50/60 and water  absorption  less than 5,0 % 
(characteristic  value)  the reduction  may be taken  to 10 mm.  
 
— For uneven  surfaces  (e.g. exposed  aggregate)  the minimum  concrete  cover  should  be 
increased  with the maximum depth of the unevenness. When a sufficient protection of 
concrete exposed surface is  ensured,  the exposure  class  may be decreased  and the 
concrete  cover  accordingly.  
 
— For products with a design working life shorter than 50 years and/or for non -structural 
products,  the values in Table A.2 may be reduced. Unless rules valid in the place of 
use specify other values, a  reduction  of 5 mm is recommended,  
 
— The minimum concrete  cover  should  be 10 mm. 
 
   
©RSB 2022  - All rights reserved                  20 
 Annex  B 
(informative)  
 
Concrete quality control  
B.1  Statistical  representative  values  
The test strength  results  should  be subjected  to statistical  analysis  applied  to a moving  group  of samples  to 
evaluate  the current  characteristic value  with reference  to the continuing  production.  
If needed, supplementary tests made before the target age of curing (28 days) can be carried out in the  same 
way for early statistics. The test values should be previously subjected to a uniform correlation to  a given age 
on the basis of  a proved  hardening  law. 
This procedure  applies  for potential  strength  or structural  strength  (direct  or indirect).  
B.2 Conformity  criteria  for potential  strength  
Conformity  criteria  for standard  compressive   strength   at   28   days   shall   be   taken   from   RS ISO 
22965 -2, 9.4.2  and 9.4.3 . However;  
Conformity assessment shall be based on the following criteria;  
𝑓𝑐𝑚≥𝑓𝑐𝑘+4𝑀𝑃𝑎                                                                                                  B.1 
𝑓𝑐𝑖≥𝑓𝑐𝑘−4𝑀𝑃𝑎                                                                                                   B.2 
where  
𝑓𝑐𝑖 is each test result  
𝑓𝑐𝑚  is the mean  compressive  strength of  concrete;  and 
𝑓𝑐𝑘  is the characteristic value of the compressive strength of concrete;  
B.3 Direct  structural  strength  
For concrete  quality  control,  direct  structural  strength  may be chosen  by the manufacturer  as an alternative to 
potential strength. Strength tests on drilled c ores may be performed in order to verify the  conformity  of the direct  
structural  strength.  As a rule the sampling  should  follow  the procedure  below:  
⎯ with reference to every production day, two cores are taken from different positions in one product  (e.g. one 
end upper  position  and one middle  lower  position),  each  core representing  one sample;  
⎯ the core strength  is measured  (see 6.1.1),  obtaining  the two values : 𝑓10  ≤𝑓20  
Conformity  criteria  are applied,  as specified  in B.2 for potential  strength,  with: 
∝𝑓𝑘0<𝑓𝑐𝑘                                                                      (B.3) 
where  
𝑓𝑘0 is the  characteristic  value  of the standard  period;  DRS 503 : 2022  
21                ©RSB 2022  - All rights reserved  
  ∝ is 1/0,85  is the  safety  conversion  factor  according  to 5.2.2.2.5;  
𝑓𝑐𝑘 is the characteristic  value  of compressive  strength  of concrete.  
B.4 Indirect  structural  strength  
Indirect structural strength should be correlated to direct structural strength with an initial calibration  testing. 
Tests on drilled cores as specified in B.3 should be  performed, for a minimum period of five  production days, in 
parallel to the corresponding tests performed on the moulded samples cured in the  same  conditions  of the 
elements.  
For the calibration  of indirect  to direct  structural  strength,  comparison  is made with reference  to the test data of 
the same  day of production  and to the whole  group  of the last five test data.  
The ratio between  indirect  and direct  structural  strength is  assumed  to be 1,0 if: 
𝑓𝑚0≥0.95𝑓                                                                                                               (B.4) 
𝑓10≥𝑓−3.0 𝑀𝑃𝑎                                                                                                     (B.5) 
𝑓𝑚0= (𝑓10+𝑓20)/2                                                                                                      (B.6) 
where  
𝑓10 and 𝑓20 are direct  structural  strength  measured  on cored  specimens;  
𝑓 is the indirect structural strength of the moulded sample;  
And if  
𝑓𝑘0≥𝑓𝑘                                                                                                                     (B.7)                                                                                                                                                                                                                                                                                             
where  
𝑓𝑘 is the characteristic indirect structural strength of the moulded samples for the last five  production  days.  
After  this calibration  the same  conformity  criteria  of B.2 can be applied  to indirect  structural  strength  with: 
 
∝𝑓𝑘≥𝑓𝑐𝑘                                                                                                               (B.8) 
where  
∝ is 1/0,85  is the  safety  conversion  factor  according  to 5.2.2.2.5;  
B.5 Direct  assessment  of possibly  non-conforming  units  
When from test ing it results that conformity verification of B. 4, B.5 or B. 6 is not satisfied,  the units  produced  in 
the corresponding  day can be submitted  to a direct  assessment.  
This assessment  should  be made  by means  of testing  of direct  structural  strength  on cores  drilled  from the 
products themselves,  with the  following  procedure:  
⎯ a representative  unit is selected  from the stock  of products  manufactured  with the non-conforming  concrete  
type;   
©RSB 2022  - All rights reserved                  22 
 ⎯ three cores are taken from different positions in the unit (i.e.  one upper end position, one lower end  position,  
one middle  position);  
⎯ the standard  direct  structural  strength  is measured  (see 6.1.1) obtaining  the three  values  
𝑓10≤𝑓20≤𝑓3; 
 
⎯ an equivalent design value 𝑓𝑑=(𝑓𝑚−∆𝑓)/𝛾 
is computed  from the mean 𝑓𝑚=(𝑓10+𝑓20+𝑓30)/3 and from the total deviation ∆𝑓=𝑓3−𝑓1(≥3.5𝑀𝑃𝑎 ) 
⎯ the product is accepted if;  
∝𝑓10>𝑓𝑐𝑘−4𝑀𝑃𝑎                                                                                  (B.9) 
And 
∝𝑓𝑑≥𝑓𝑐𝑑/∝𝑐𝑐                                                                                          (B.10) 
where  
𝑓𝑐𝑑 is the intended potential design cylinder strength assumed in resistance calculations  (ultimate  limit state);  
∝𝑐𝑐  is the related  long term effect  coefficient  (see RS 142, 6.1.6.1); 
𝛾 is the additional confidence factor necessary to extend the result of the assessment from the  selected  unit to all the 
non-conforming  stock  of units (the  value  1,2 is recommended);  
otherwise the  product is  rejected,  unless  it can be  appropriately strengthened,  or downgraded for other  suitable  
uses.  
Rules  valid in the place  of use may define  the deviation   f differently  and in that case  the rule valid in the place  
of use should  be used.  
If the questionable stock is large or contains products manufactured with the same concrete type but  with 
different production processes leading to different structural strengths, a single unit submitted to  the procedure 
as des cribed may not be representative for the whole stock. In that case the stock should  be subdivided in 
appropriate batches and the procedure should be applied for a representative unit of  each batch.  
                                                                 DRS 503 : 2022  
23                ©RSB 2022  - All rights reserved  
  Annex  C 
(informative)  
Reliability  considerations  
C.1 General  
The values  of partial  safety  factors  for materials  may be assumed  as given  in C.2 to C.4. 
C.2 Reduction  based  on quality  control  and reduced  tolerances  
If factory  production  control  (see Annex D)  ensures  that unfavourable  deviations  of cross   sectional dimensions 
are within the tightened tolerances given in Table C.1, the partial safety factor for  reinforcement  may be reduced  
to: 
𝛾𝑠=1.10                                                                                                                               (C.1)  
Under the condition given above, and if the coefficient of variation of the concrete strength is shown not  to 
exceed  10 %, the partial  safety  factor  for concrete  may be reduced  to: 
𝛾𝐶=1.4                                                                                      (C.2) 
Table  C.1 — Tightened  tolerances  
 
h or b (mm)  Tightened  tolerances  
mm  
Cross section dimension  
Δh, Δb 
mm Position of reinforcement  
Δc 
mm 
≤ 150 ±5 ±5 
400 ±10 ±10 
≥ 2 500  + 25 + 20/− 10  
With  linear  interpolation  for intermediate  values.  
+Δc refers  to the mean  value  of reinforcing  or prestressing  steel  in the cross  section  or over  a width  of one  meter  
(e.g.  slabs  and walls).  
C.3            Reduction based on using reduced or measured geometrical 
parameters in  design  
If the calculation of design resistance is based on critical dimensions, including effective depth (see  Figure  C.1),  
which are  either:  
⎯ reduced  by tolerances,  or 
⎯ measured in the finished structure,  the following  values may  be used:   
©RSB 2022  - All rights reserved                  24 
 𝛾𝑠=1.05, 𝛾𝑐=1.45 
 Under  the condition  given  above  and provided  that the coefficient  of variation  of the concrete  strength  is shown  
not to exceed  10 %, the partial  factor  for concrete  may be reduced  to   𝛾𝑐=1.35                  
                                              
Figure  C.1 — Cross -section  tolerances  
C.4 Reduction  based  on assessment  of concrete  strength  in finished  structure  
For concrete strength values based on testing of direct structural strength as defined in 5.2.2, 𝛾𝐶 may be  reduced  
with the  conversion  factor  𝜂; normally  𝜂 = 0,85 may be assumed.  
The value of 𝛾𝐶 to which this reduction is applied may already be reduced according to C.2 or C.3.  However,  
the resulting  value  of 𝛾𝐶 should  not be less than  1,30.  
C.5 Reduction  of 𝜸𝑮 based  on control  of self-weight  
Partial safety factor for self -weight of precast concrete product 𝜸𝑮 may be reduced by factor 0,95 when  the 
measured  weight or the  estimated  weight of the  product does  not exceed  that used in design  calculations.  The 
weight  is determined  according  to 6.3. 
Partial safety factor for self -weight of precast concrete product 𝜸𝑮  may be reduced by factor 0,90 when  
statistical  95 % fractile  of weighted  or evaluated  weight  does  not exceed  that used  in design  calculations.  
If the reduction of 𝜸𝑮  is applied, tightened tolerances shall be used and controlled systematically, see  Table  
C.1. 
 
 
DRS 503 : 2022  
25                ©RSB 2022  - All rights reserved  
  Annex  D 
(informative)  
Inspection schemes  
D.1 General  
Inspection  subjects  do not apply  if they are not relevant  for the specific  product  or if their purpose  is fulfilled  
by other  appropriate  inspection.  
D.2 Equipment  inspection  
Table  D.1 — Equipment  inspection  
 SUBJECT  METHOD  PURPOSE  FREQUENCYa 
D.1.1  - Testing  and  measuring  equipment  
1 Strength  testing  
equipment  Except as  indicated in the  test 
method,  calibrating  against  
equipment  which  has been  
calibrated  to National  
Specifications  and is used  
exclusively  for this purpose  Correct  functioning  
and accuracy  — On (re)  installation  or 
after  major  repair  
— Once  per year  
2 Weighing  equipment  
3 Dimension  
measuring  
equipment  
4 Temperature  and 
humidity  measuring  
equipment  
D.1.2  - Storage  and  production  equipment  
1 Storage  of 
materials  Visual  inspection  or
 other   appropriate  
method  Absence  
of contamination  — On installation  
— Weekly  
2 Weighing  or 
volumetric  batching  
equipment  Visual  inspection  Correct  functioning
 a
nd cleanliness  Daily  
3 Calibrating  against  equipment  
which  has been  calibrated  to 
National Standards and is used  
exclusively  for this purpose  Manufacturer  
declared  accuracy  — On (re)installation  or 
after  major  repair  
— Weighing:  once  a 
year  
—  Volumetric:  
twice  a year  
— In case  of doubt   
©RSB 2022  - All rights reserved                  26 
 4 Equipment  for continuous  
measurement  of water  
content   of  fine 
aggregates  a Comparison  of the actual  amount 
with the reading of the  meter  Manufacturer  
declared  accuracy  — On (re)installation  
— Twice  a year  
— In case  of doubt  
5 Mixers  Visual  inspection  Wear  and correct  
functioning  — Weekly  
6 Moulds  Visual  inspection  Condition (e.g.  
Wear and  
deformation)  — Regularly depending on  
the type of material and  
frequency  of use 
7 Prestressing   equipment  Calibrating  against  equipment  
which  has been  calibrated  to 
National Standards and is used  
exclusively  for this purpose  Correct  
functioning  and 
accuracy  — On (re)  installation  
— Twice  per year  
— In case  of doubt  
8 Visual  inspection  Wear  of anchorage  
equipment  — Weekly  for each  
equipment  used  
9 Casting  
machine/equipment  Manufacturer  inspection  
instructions  Correct  
compaction  of 
concrete  — Manufacturer inspection  
instructions and at least  
monthly  
10 Storage  of reinforcing  
steel  Visual  inspection  To ascertain  
separate  and clean  
storage,  absence  
of contamination  
and of strongly  
rusted  steel  bars  — Regularly  
11 Storage  of prestressing  
steel  Visual  inspection  Dry,  airy  storage,  
absence  of 
contamination  — Regularly  
a Only  if the equipment  is available  and the purpose  is not covered  by appropriate  inspection(s)  under  D.3.1  in Table  
D.3 or D.4.1  in Table D.4.  
D.3 Materials  inspection  
Table  D.2 — Materials  inspection  
 SUBJECT  METHOD  PURPOSE  FREQUENCY  
D.2.1  - All materials  
1 All materials  Inspection  prior  to discharge  of 
delivery ticket and/or label on  the
 package  showing  
conformity  with the  ordera To ascertain  that  the 
consignment  is as 
ordered  and from  the 
correct  source  Each  delivery  DRS 503 : 2022  
27                ©RSB 2022  - All rights reserved  
  D.2.2  - Materials  not submitted  to an assessment  of conformity  before  deliveryb 
1 Cement  and 
other  
cementitious  
materialsc Appropriate  test methods  Conformity  with  
requirements  
(see  5.1.2)d Each  delivery  
2 Aggregates  Visual  inspection  prior  to discharge 
with respect to the  grading  shape  and 
impurities  Conformity  with  
requirements  
(see  5.1.2)d — Each  delivery  
— When  delivery  is by belt
 conveyor  and 
from  the same  source,  
periodically  depending  on 
local  or delivery  conditions  
3 Sieve  analysis  according  to RS 96 -4 Conformity  with  
agreed  grading  — 1st delivery from new  
source  
— In case  of doubt,  following
 visual  inspection  
— Periodically  depending  on 
local  or delivery  conditions  4 Appropriate  test method  Assessment  of 
impurities  or 
contamination  
5 Test  for water  absorption  
according  to BS EN 1097 –6e Assessment   of 
effective  water  
content  of concrete  (see  
RS ISO 22965e — 1st delivery from new  
source  
— In case  of doubt,  following
 visual  
inspection  
6 Admixturesf Visual  inspection  Conformity  with  
normal  appearance  Each  delivery  
7 Test  to RS ASTM C494/C494M  Uniformity  of 
density  
8 Tests  for identification  according  to RS 
ASTM C494/C494M , e.g. density,  
infrared  etc. Conformity  with  
suppliers  stated  
data  In case  of doubt  
 
 SUBJECT  METHOD  PURPOSE  FREQUENCY  
9 Additions/  
pigmentsf Visual  inspection  Conformity  with  
normal  appearance  — Each  delivery  
— Periodically  during  
production  of 
concrete  
10 Appropriate  test methodg Uniformity  of 
densityg —  
©RSB 2022  - All rights reserved                  28 
 11  Test  of loss  of ignitiong Identification  of changes  
in carbon  content  which  
may  affect  air entrained  
concrete  h Each  delivery  to be used  for air-
entrained  concrete  
12 Water  not 
taken  from  a 
public  
distribution  
system  Test  according  to ISO 12439  To ascertain  that  the 
water  is free  from  
harmful  constituents  — 1st use of new  source  
— Water  from  open  water  
course :  Three  times a year, 
or more  depending  on local  
conditions  
— Other sources: once a  year  
— In case  of doubt  
13 Recycled  
water  Visual  inspection  Check  for solid  content
 and 
contaminants  
(see  5.1.2)d Weekly  
14 Test  to ISO 12439  In case  of doubt  
15 Steel  Visual  inspection  Conformity with  
requirements  (see 
5.1.3 and  5.1.4)d  
Each  delivery  16 Appropriate  test method  
17 Inserts  and 
connections  Manufacturers  method  Conformity  with  
requirements  
(see  5.1.5)d Each  delivery  
a The order  shall  mention  the specification(s).  
b Materials  not certified  before  delivery  by the precast  concrete  product  manufacturer  or by other  means.  
c It is recommended  that  samples  are taken  and are stored  once  per week  per type  of cement  for testing  in case  of doubt.  
d The requirements  of this standard  may  be completed  by the manufacturers  requirements.  
e Not necessary  if the purpose  is fulfilled  by other  appropriated  inspection(s)  under  D.3.1  in Table  D.3 or D.4.1  in Table D.4.  
f It is recommended  that samples  are taken  at each  delivery  and stored  for testing  in case  of doubt.  g Only  for 
additions in suspension.  
h Only  for bulk  powder  additions  to be used  for air-entrained  concrete.  
D.4 Process  inspection  
Table  D.3 — Process  inspection  
 SUBJECT  METHOD  PURPOSE  FREQUENCY  
D.3.1  – Concretea DRS 503 : 2022  
29                ©RSB 2022  - All rights reserved  
  1 Mixture  
composition  
(except  water  
content)  — Visual  on 
equipment  
— Checking  
production  
documents  weighing  
against  Conformity  with  
intended  composition  
(weight or volumetric  
batched)  — Daily  for each  
composition  used  
— After  each  change  
2 Appropriate  analysis  Conformity    with  
intended  mixture  
values   (only  
volumetric  batched)  Monthly  for 
composition  used  each  
3 Water  
content  
fresh  
concrete   
of Appropriate  method  To provide  data  for the 
water/binder  ratio  — Daily  for each  
composition  used  
— After  each  change  
— In case  of doubt  
4 Chloride  
content  
concrete   
of Calculation  To ensure  
maximum  
content  
exceeded  that  the 
chloride  is
 not In case of an increase in  the 
chloride  content  of the 
constituents  
5 Water/bind  er 
ratio  of fresh  
concrete  Calculation  
(see RS ISO 22965 ) To assess  specified  
water/binder  ratio  Daily,  if specified  
6 Air content  of
 fresh  
concrete  
where  
specifiedb Test       according       to RS ISO 
1920 -2 for normal - weight and 
heavy -weight  concrete  
ASTM  C173  / C173M for  light  
weight  concrete  To assess  conformity  with  
the specified  content  of 
entrained  air First  batch  of 
production  day 
values  stabilize  each  
until  
7 Concrete  
mix Visual  check  Correct  mixing  Daily  for each mixture  
8 Potential  
strength  Testing  according  to 6.1.1 To assess  conformity  with  
intended  valuec Daily  for each  type  of 
concreted 
9 Structural  
strengthe  To assess  conformity  with  
intended  valuef Each  five production  days per 
concrete family  usedf 
10 Density  of 
hardened  
light - or 
heavy -weigh  t 
concretee Test  according  to   
RS ISO 1920 -6 To assess  specified  
density  (see  5.2.2.5)  As frequently  as 
potential  strength  test 
 
 SUBJECT  METHOD  PURPOSE  FREQUENCY   
©RSB 2022  - All rights reserved                  30 
 11 Water  
absorption e Testing  according  
Annex  F to Intended  (see  
5.3.7.5  
Annex  E) value  
and Each  five production  days  per 
type  of hardened concrete 
used  and casting  technique  
applied.  D.5.2  may  be applied  
after  5 positive  results  
D.3.2  - Other  process  subjectsg 
1 Reinforcem  
ent and 
inserts  
(including  
lifting  inserts)  Visual  inspectionh Conformity with  
required type,  
quantity, shape,  
dimensions and  
position  Daily  
2 Measuringh Depending on  manufacturer 
inspection  instructions  
3 Welding  Visual  inspection  Quality  of welds  Daily  
4 Appropriate  
method(s)  test Conformity of welded  
steel  (see 5.2.3.1)  Depending on  manufacturer 
inspection  instructions, but 
not less  than every  400 t of 
steel  
5 Straightenin  g Visual  inspection  Quality of  
straightening  Daily  
6 Appropriate  
method(s)  test Conformity of  straightened 
steel (see  5.2.3.1)  Depending on  manufacturer 
inspection  instructions, but 
not less  than every  400 t of 
steel  
7 Bending  Visual  inspection  Quality  of bending  Daily  
8 Appropriate  
method(s)  test Conformity of bended  
steel  (see 5.2.3.1)  Depending on  manufacturer 
inspection  instructions, but 
not less  than every  400 t of 
steel  
9 Moulds  and 
beds  Visual  inspection  Cleanliness  and oiling  Daily  
10 Check for wear and  
deformation  Depending on moulding  
material and frequency  of 
use 
11 Measuring  Determination of  
dimensions  Each new mould or after  
major  modification  
12 Prestressing  Measuring  of force  
elongation  or Correct force  
(see 5.2.3.2)  Depending on  manufacturer 
inspection  instructions  
13 Before  
casting  Visual  inspection  Conformity with  
production  drawings  Daily with frequency  
depending on moulding  
process  
 
 SUBJECT  METHOD  PURPOSE  FREQUENCY  DRS 503 : 2022  
31                ©RSB 2022  - All rights reserved  
  14 Concrete  
placing  Visual  inspection  Correct  compaction  Daily  
15 Protection  
against  
drying  out Visual  inspection  Conformity with  
specification  (see 
5.2.1.3)  and 
documented factory  
procedures  Daily  
16 Verification  of relevant  
process  conditions  Weekly  
17 Accelerated  
hardening  (by
 heat 
treatment)  Verification  of relevant  
process  conditions  Conformity with  
specification and  
documented factory  
procedures  Daily  
18 Measuring  temperatures   Depending  on process  
19 Post casting  
processing  As appropriate  Conformity with  
specifications and  
documented factory  
procedures  Depending on process  
and specifications  
20 Slippage  of 
tendons  Appropriated  check/  
measurement  Conformity with  
specification  (see 
5.2.3.2)  Depending on product  
and/or  processi 
21 Temperature  e When relevant, check the  
temperature  (outdoor,  in the 
production  and storage  areas)  Take appropriate  
measures  Daily  
a The indicated  tests  and frequencies  may be adapted  or even  deleted  when  equivalent  information  is obtained  directly  
or indirectly  from the product.  
b Only for concrete  containing  entrained  air  
e For example, required strength class in the case of compressive strength Only  if the 
property  is specified.  
f According  to the manufacturers  process  requirements.  
g This inspection  scheme  may be adapted  or completed  for specific  product  purposes.   
h Check  against  approved  production  drawings.  
i Need  and frequency  of effective  measurement  may depend  on the possibility  of visual  check  on product  
sections.  
D.5 Finished  product  inspection  
Table  D.4 — Finished  product  inspection  
 SUBJECT  METHOD  PURPOSE  FREQUENCY  
D.4.1  - Product  Testinga  
©RSB 2022  - All rights reserved                  32 
 1 Production  
tolerances  
(including  
concrete  
cover)  Testing  according  to F.1 to H.3 
and/or  other  appropriate  
method  Conformity with the  
requirements of this  
standard and the  
requirements for the  
manufacturer declared  
properties  Depending on  
product and  
geometrical  
properties  
2 Surface  
characterist  
ics Testing  according  to F.4 and/or 
other appropriate  method  Conformity with the  
requirements for the  
manufacturer declared  
properties  Depending on  
product and  surface  
properties  
3 Mechanical  
resistance  by 
testing  b Appropriate  test method  Conformity with the  
requirements for the  
manufacturer’s declared  
mechanical resistance  
properties  Depending on  
product and  
mechanical  
resistance  
properties  
4 Marking/  
Labelling  Visual  check  Conformity with the  
requirements of this  
standard  Daily  
5 Storage  Visual  check  Conformity with the  
requirements of this  
standard  Daily  
Segregation of non - 
conforming  products  
6 Delivery  Visual  check  Correct delivery age,  
loading and loading  
documents  Daily  
7 Final  
inspection  Visual  check  To ascertain  intactness  Daily  
a This inspection  may be adapted  and/or  completed  for specific  product  purposes.  
b Only if regular inspection by full scale testing is relevant in addition to type testing (e.g. if full scale testing of  
mechanical  resistance replaces  concrete  strength  inspection).  DRS 503 : 2022  
33                ©RSB 2022  - All rights reserved  
  Annex  E 
(normative)  
Test of water absorption  
E.1 Method  
After conditioning, the test specimen shall be immersed in water to constant mass and then oven -dried  to 
constant  mass.  The water  absorption  of the concrete  by immersion  is considered  to be the loss of mass  
expressed  as a percentage  of the mass of  the dry test specimen.  
E.2 Sampling  
The test may be carried out on a whole product unit, on a specimen either sawn or drilled from the  product, or 
on a moulded specimen cast with the same concrete as for the product and stored under  similar  ambient  
conditions as the  product.  
As a reference,  the test specimen  shall be at least  28 days old  when  starting  the test procedure  (see E.6). 
NOTE  If the same test specimens are used for the determination of density, the minimum volume required should be 
as per RS ISO 1920 -5. 
a) Test specimen  consis ting of a whole  product  unit 
 
If the test specimen have a mass at least 1,5 kg and less or equal than 5,0 kg, the whole product unit is  tested  
without  protection  of any surface  with resin.  
b) Test specimen  cut by sawing  or drilling  
 
The test specimen may be either a cylindrical specimen cut by drilling or a prismatic specimen cut by  sawing  
from a  product  unit. 
The size of a cylindrical specimen having a diameter D and a height H, and a prismatic specimen with a  square  
section  having  a side length  A and a height  H, shall fulfil the size requirements  of Table E.1 in which      two types of  
specimens have  to be considered:  
1) thin products (thickness  E at least  30 mm and  less than 100 mm);  
 
2) thick products (thickness  E at least  100 mm).  
 
If no cylindrical  or prismatic  specimen  satisfying  the above  conditions  can be taken  from the product  unit, other 
shapes of specimen are admitted provided its volume V and its developed surface S fulfil the  requirements  of 
Table  E.1. 
— Thin products  
 
The test specimen is cut (by sawing or drilling) through the full thickness of the product. The cut sides  may be 
protected with a resin (see preparation in E.5). The two opposite sides which are not cut shall be  left unprotected  
(Figure  E.1). 
— Thick  products   
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The te st specimen is cut (by sawing or drilling) through the full thickness of the product. This specimen  can be 
shortened, if required, by cutting the sample, taking care that the exposed surface is included in  the test 
specimen  and that the size requirements  of Table  E.1 are fulfilled.  The cut sides  corresponding  to the 
surrounding  of the specimen  may be protected  with a resin  (see preparation  in E.5). The two remaining  
opposite  faces  shall be left unprotected  (Figure  E.1). 
 
Keys  
A edge  length  
D diameter  
H height  
a unprotected  exposed  surfaces  
b unprotected opposite side surface  
(exposed or cut surfaces)   
c cut surfaces  potentially  protected  
 
Figure  F.1 — Test specimen cut  from  a product  
c) Moulded  test specimen  (either  cylinder  or prism)  
 
The moulded test specimen shall fulfil the size requirements of Table E.1. It may be either a cylinder  having  a 
diameter  D and a height  H, or a prism  with a squared  section  having  a side length  A and a height  H. 
For cylinders, the top and bottom faces may be protected with a resin (see preparation in E.5). The  surrounding 
of the test specimen shall be left unprotected. Unprotected surfaces should be moulded  surfaces  (Figure  E.2). 
For prisms, the surrounding of the test specimen may be protected with a re sin (see preparation in E.5). The 
two remaining opposite sides shall be left unprotected. Unprotected faces should be two opposite  moulded  
surfaces (Figure  E.2). 
DRS 503 : 2022  
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Key 
A edge  length  
D diameter  
H height  
a possibly protected levelling surfaces  
b possibly protected moulded surfaces  
c unprotected moulded surfaces  
Figure  F.2 — Moulded  test specimen  
 
Whatever  preparation  method  is chosen  (i.e. with or without  resin),  the results  shall fulfil the criteria.  
d) Size requirements  for test specimens  
 
The requirements  on the specimen  size are indicated  in the following  Table  E.1: 
Table  E.1 — Geometrical  requirements  for test specimens  
 
 Product  
thickness  Cylinder  Prism  Other  shape  
E 
(mm)  H 
(mm)  D 
(mm)  H 
(mm)  A 
(mm)  V 
(cm3) S 
(cm2) 
 
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 Test  
specimen  
cut from  
a 
product  
unit  Thin  
product  30 ≤ E < 50  E 200  ≤ D < 
250  E 200  ≤ A < 
250  800  ≤ V 
≤ 
2 000  1,2 ≤ 
V/S 
≤ 2 50 ≤ E < 70  E 160  ≤ D < 
200  E 160  ≤ A < 
200  
70 ≤ E < 100  E 140  ≤ D < 
160  E 140  ≤ A < 
160  
Thick  
product  E ≥ 100  1/2 
D ≤ H < 
D 100  ≤ D ≤ 
160  1/2 A ≤ 
H 
< A 100  ≤ A < 
150  
Moulded  specimen   1/2 
D ≤ H < 
D 100  ≤ D ≤ 
160  1/2 A ≤ 
H 
< A 100  ≤ A < 
150    
 
E.3 Materials  
Potable  water  shall be used  for immersing  the specimen.  
E.4 Apparatus  
The following  equipment  shall be  used:  
E.1.1  Ventilated drying oven , with enforced ventilation or with a ratio of capacity in litres 
to area of  natural  ventilation  channels  in square  millimetres  less than 0,2 in which  the temperature  
is controlled  to (105 ± 5)  °C; it shall have a volume at least 21/2 times greater than the volume of 
test specimens to be  dried  at any one time.  
 
E.1.2  Flat based vessel having a capacity at least 21/2 times the volume of the test 
specimens to be  immersed and a depth at least 50 mm greater than the height of the test specimens 
in the attitude that  they will be soaked.  
 
E.1.3  Balance  reading  in grams  and accurate  to 0,1 % of the reading.  
 
E.1.4  Stiff brush . 
 
E.1.5  Sponge  or drying  leather.  
 
E.5 Preparation  
Remove  all dust,  flashing,  etc. with a brush  and ensure  that the test specimen  is at a temperature  of (20 ± 
3) °C. The surfaces  defined  in E.2 may be protected  with a resin.  The choice  of the resin  and the way of sheltering  
shall ensure  full protection  of the treated  surface  during  the whole  testing  procedure.  
E.6 Procedure  
Immerse  the test specimen in potable water at a temperature  of (20 ± 5) °C  using the  vessel. Test  specimens 
shall be distanced from each other by at least 15 mm and have a minimum of 20 mm water  above them. The 
minimum period of immersion shall be three days and continued until constant mass  M1 is reached. Constant 
mass is deemed to be reached when two weighings performed at an interval of  24 h show  a difference  in mass 
of the test specimen  of less than  0,1 %. DRS 503 : 2022  
37                ©RSB 2022  - All rights reserved  
  Before  each  weighing,  wipe the test specimen  with a drying  leather  or sponge  which  has been  moistened  and 
squeezed to remove any excess water. The condition is correct when the surface of the concrete is  dull. The 
mass M1  of the test specimen  is then  recorded.  
Then place the test specimen inside the oven in such a way that the distance between specimens is at  least 15 
mm. Dry the specimen at a temperature of (105 ± 5) °C to constant mass. The minimum period  of drying shall 
be thre e days and continued until constant mass M2 is reached. Constant mass shall be  deemed  to be reached  
when  two weighings  performed  at an interval  of 24 h show  a difference  in mass  of the specimen of less than 
0,1°%. The specimen shall be allowed to cool down  between 30 min to 1 h  before  it is weighed  and the mass 
M2 is recorded.  
The oven should not be filled with a new wet specimen when the cycle of already drying specimen has  reached  
48 h. 
E.7 Results  
Calculate  the value  of the water  absorption  100 × (M1-M2)/M2  for each  test specimen.  
The test report  shall indicate  for each  specimen  tested  the nature  of the test specimen  (moulded,  sawn  or drilled), 
the specimen dimensions, the conditions of preparation, the age of the test specimen when  starting the te st 
procedure, eventually the wet mass M1, the dry mass M2 and the value of water  absorption  of the test specimen.  
NOTE  If the test is made  on more  than one specimen  from the same  sample,  the result  is the average  of the test results  
on these specimens.  
 
  
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 Annex  F 
(normative)  
Measurement of dimensions  
F.1  Length,  height,  width  and thickness  
Dimensions  should  not be measured  along  the edges.  
 
 
Key 
b width  
1 either  - or 
Figure  F.1 — Measuring  points  for length,  height,  width  and thickness  
 
DRS 503 : 2022  
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  F.2  Warp  and straightness  
 
Figure  F.2 — Measurement  of warp  and straightness  
 
F.3  Out of squareness  
 
Figure  F.3 — Measurement  of diagonals  
The tolerance  requirement  should  be given  as the difference  in length  between  the two diagonals:  
𝑑1 – 𝑑2                                                                              (F.1) 
 
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 F.4  Surface  characteristics  
For the specification of the surface characteristics of a finished product, reference should be made to the  
vocabulary  defined  in Figure  F.4. 
Speci ally treated  surfaces,  such  as with exposed  aggregate,  polished,  cast against  a matrix,  etc. are not 
covered  by these  tolerance  recommendations.  
 
Key 
1 recess  4 ridge  
2 lump  5 step discontinuity  
3 groove  6 undulation  
 
Figure  F.4 — Definitions  of surface  characteristics  
DRS 503 : 2022  
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Figure  F.5 — Measurement  of surface  characteristics  
The distance  d0 given  in Figure  F.5 is from the concrete  surface  at the location  of the support  of the 
reference  ruler to the ruler.  In most  cases  this will  be the height  of the supporting  piece.  
Recommended  values  for surface  deviations  are given  in Table  F.1. 
 
 
 
Table  F.1 — Surface  deviations  
 
  Recommended  maximum  deviation  
Class  1 Class  2 
 
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Characteristic  Length of  ruler  Against  form  Trowelled  Against  form  Trowelled  
Recess  200 mm 4 mm 3 mm 4 mm 3 mm 
Lump  200 mm 2 mm 3 mm 2 mm 2 mm 
Groove  200 mm 2 mm 2 mm 1 mm 1 mm 
Ridge  b h 200 mm 5 mm 
3 mm 5 mm 
3 mm 3 mm 
2 mm 3 mm 
2 mm 
Step discontinuity  200 mm 3 mm 2 mm 1 mm 2 mm 
Undulation  3 000 mm 15 mm 8 mm 5 mm 4 mm 
 
NOTE  Requirements  on surface  tolerances  cannot  be used  to describe  the appearance  of the surface.  
F.5  Angular  deviation  lateral  bow,  camber  and sag 
 
Key 
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  h height  
b width  
1 angular deviation  
2 camber  
3 sag 
4 lateral bow  
Figure  F.6 — Measurement  of angular  deviation,  lateral  bow,  camber  and sag 
  
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 Annex  G 
(informative)  
 
Technical documentation  
G.1 General  
For precast  concrete  products,  the technical  documentation  (including  references  to national  requirements  in 
the place  of use) comprises the  following  items:  
a) product  documentation  (see G.2);  
b) production  documentation  (seeG.3);  
c) erection  documentation  (see G.4).  
The documentation may refer unambiguously to product catalogues presented by the manufacturer,  containing  
the general  data describing  the product  and its destination  for building  and other  civil engineering  works  as well 
as sketches  with principal  dimensions,  indications  about  the relevant  performances  and any other  information  
useful  to define  the use of the product.  
G.2 Product  documentation  
The product  documentation  contains  all the relevant  product  specifications.  
When  design  calculations  are requested,  the load conditions  and the consequent  principal  ultimate  and 
serviceability  verifications and  safety  factors used  shall be given.  
Since  the design  of the product  may be performed  partly  by the client  and partly  by the manufacturer,  the 
documentation  will usually  be separated  into: 
d) client’s  specifications;  
e) manufacturers  specifications;  
f) design calculations, with the load conditions  and the consequent  principal  ultimate  and serviceability  
verifications  and safety  factors used.  
G.2 Production  documentation  
Production  documentation  consists  of: 
g) production  drawings  with the detailing  of the precast  concrete  products  (dimensions,  reinforcing  and 
prestressing  steel,  lifting  devices,  inserts,  etc.);  
h) production  data with the required  material  properties  and the product  tolerances  and weights.  
G.3 Erection  documentation  
Erection  documentation  consists  of: 
i) installation  drawings  consisting  of plans  and sections  showing  the position  and the connections  of the 
products in  the completed  works;  DRS 503 : 2022  
45                ©RSB 2022  - All rights reserved  
  j) installation  data with the required  in situ material  properties  where  applicable;  
k) installation  instructions  with the necessary  data for the handling,  storing,  setting,  adjusting,  connection  
and completion  works.  
  
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 Bibliography  
[1] EN 12390 -6, Testing  hardened  concrete  — Part 6: Tensile  splitting  strength  of test 
specimens  
 
[2] EN 12504 -2, Testing  concrete  in structures — Part 2: Non-destructive  testing - 
Determination of  rebound  number  
 
[3] EN 12620 , Aggregates  for concrete  
 
[4] EN 13670:2009 , Execution  of concrete  structures  
 
[5] EN 13791 , Assess ment  of in-situ compressive  strength  in structures  and precast  
concrete  components  
 
[6] CEN/TR  15728,  Design  and use of inserts  for lifting  and handling  of precast  concrete  
elements  
 
[7] CEN/TR  15739,  Precast  concrete  products  — Concrete  finishes  – Identification  
[8] EN 1990:2002 , Eurocode  — Basis  of structural  design  
 
[9] EN 13055  (all parts),  Lightweight  aggregates  DRS 503 : 2022  
 
Price based on  50 pages  
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