ICS 91.100.15  
 
Reference number
DRS 529: 2023
© RSB 2023
  
 RWANDA 
STANDARD  DRS 
529 
 
First edition  
2023-mm-dd  
 
Natural stone test methods — 
Determination of the breaking load at 
dowel hole 
   
DRS 529: 2023 
©RSB 2023- 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 
 
 
 
 
 
 
 
 
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Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw  DRS 529: 2023 
iii                ©RSB 2023- All rights reserved 
 Contents Page 
Foreword ............................................................................................................................................................ iv  
1 Scope ...................................................................................................................................................... 1  
2 Normative references ............................................................................................................................ 1  
3 Terms and definitions ........................................................................................................................... 1  
4 Principal ................................................................................................................................................. 1  
5 Symbols (and abbreviated terms) ........................................................................................................ 1  
6 Apparatus ............................................................................................................................................... 2  
7 Preparation of the specimens .............................................................................................................. 2  
7.1 Sampling and position of bedding ...................................................................................................... 2  
7.2 Test specimens ...................................................................................................................................... 2  
7.2.1 General ................................................................................................................................................... 2  
7.2.2 Number of specimens ........................................................................................................................... 2  
7.2.3 Surface finish of the specimens .......................................................................................................... 5  
7.2.4 Dimensions of the specimens .............................................................................................................. 6  
7.2.5 Location of the holes ............................................................................................................................ 6  
7.2.6 Dimensions and tolerances of the holes ............................................................................................ 6  
7.2.7 Drilling the holes ................................................................................................................................... 7  
7.2.8 Planes of anisotropy ............................................................................................................................. 7  
7.2.9 Conditioning .......................................................................................................................................... 7  
7.2.10 Measuring d and d1 ............................................................................................................................... 7  
8 Dowels .................................................................................................................................................... 7  
8.1 Dimensions and tolerances .................................................................................................................. 7  
8.2 Material ................................................................................................................................................... 8  
8.3 Placing the dowels ................................................................................................................................ 8  
9 Test procedure ....................................................................................................................................... 8  
10 Expression of the results ..................................................................................................................... 9  
11 Test report .............................................................................................................................................. 9  
Annex A (normative)  Statistical evaluation of the test results ................................................................... 11  
A.1 Scope .................................................................................................................................................... 11  
A.2 Symbols and definitions ..................................................................................................................... 11  
A.3 Statistical evaluation of test results .................................................................................................. 12  
 DRS 529: 2023 
©RSB 2023- All rights reserved                  iv 
 Foreword 
Rwanda Standardsarepreparedby 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 Standards 
adopted by Technical committees are ratified by members of RSB Board of Directors for publication and 
gazettment as Rwanda Standards. 
DRS529 was prepared by Technical Committee RSB/TC 529, Civil engineering and building materials.  
In the preparation of this standard, reference was made to the following standard: 
BS EN 13364:2002, Natural stone test methods — Determination of the breaking load at dowel hole 
The assistance derived 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 9) in the preparation of this standard. 
A+Construction Group Ltd 
Africeramics Ltd 
Consultants Engineers Group (CEG) Ltd 
D&D Resources Ltd 
Dutureheza Ltd 
Enabel Rwanda 
Greenpack Africa Ltd 
Integrated Polytechnic Regional Centre (IPRC) - Musanze  
Mass Design Group 
NP Construction Company (NPCC) Ltd 
Road Transport Development Agency (RTDA) DRS 529: 2023 
v                ©RSB 2023- All rights reserved 
 Rwanda Housing Authority (RHA) 
Rwanda Inspectorate, Competition and Consumer Protection Authority (RICA) 
Rwanda Quarries Association (RQA) 
SKAT Consult  
St Joseph Engineering Company (SJEC) Ltd 
Standards for Sustainability (SfS) 
Stonecraft Industries Ltd 
University of Rwanda - College of Science and Technology (UR - CST) 
Rwanda Standards Board (RSB) – Secretariat 
  DRS 529: 2023 
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  DRS 529: 2023 
1                ©RSB 2023- All rights reserved 
 Natural stone test methods — Determination of water absorption 
coefficient by capillarity 
1 Scope 
This draft Rwanda standard specifies a test method to determine the breaking load at the dowel hole of 
natural stones used for cladding or lining in building. 
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 editioncited applies. For undated references, 
the latest edition of the referenced document (including any amendments) applies. 
RS EAS 18-1, Cement — Part 1: Composition, specifications and conformity criteria for common cements. 
3 Terms and definitions 
For the purposes of this standard, the terms and definitions given in DRS 515  and RS EAS 18-1  apply. 
4 Principal 
This test consists of applying a force in a direction perpendicular to the face of a specimen through a dowel 
previously placed in an hole drilled in one of its sides and measuring the breaking load of the specimen. 
5 Symbols (and abbreviated terms) 
d         is the thickness of the test specimen, in millimetres 
d1          is the distance from the hole wall to the face where fracture occurs, in millimetres 
bA          is the maximum distance of the centre of the hole to the fracture edge on the face, in 
millimetres 
F        is the individual breaking load, in newtons 
𝑑ଵതതത               is the mean value of d, in millimetres  
  
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 6 Apparatus 
5.1   A balance capable of weighing the specimens with an accuracy of 0,01 % of their mass. 
5.2 A ventilated oven capable of maintaining a temperature of (70 ± 5) °C. 
5.3   A linear measuring device with an accuracy of 0,05 mm. 
5.4   A rotary drilling machine equipped with a diamond or tungsten carbide tipped bit. 
5.5   A testing machine of appropriate force in accordance with EN 12390-4 and calibrated according to this 
standard. 
5.6   A clamping device consisting of two metal plates having the shape and sizes shown in Figure 1. 
5.7 A device for applying loads perpendicular to the axis of the dowel (see Figure 2). 
5.8   A room or chamber in which the temperature of the air can be maintained at (20 ± 5) °C. 
7 Preparation of the specimens 
7.1 Sampling and position of bedding 
The sampling is not the responsibility of the test laboratory except where specially requested. 
The position of any bedding or anisotropy shall be indicated on each specimen by means of at least two 
parallel lines. 
7.2 Test specimens 
7.2.1 General 
The test can be carried out as an identification test or as a technological test. 
Identification tests are tests carried out when the use of the stone with respect to the position of the planes of 
anisotropy and the thickness and surface finish of the elements in the cladding are not known. 
Technological tests are those carried out when the use of the stone with respect to the position of the planes 
of anisotropy and the thickness and surface finish of the elements in the cladding are known. In this case the 
major faces of the specimens shall have the same orientation of the face that will be loaded during use. 
7.2.2 Number of specimens 
The minimum number of test specimens depends on the presence of planes of anisotropy. DRS 529: 2023 
3                ©RSB 2023- All rights reserved If the stone does not show planes of anisotropy 10 tests of Type 0 (see Figure 3) shall be made on three 
specimens. 
If the stone shows planes of anisotropy: 
 10 tests of Type I (see Figure 4) shall be made on three specimens cut parallel to the planes of 
anisotropy; 
 10 tests of Type IIa (see Figure 5) and 10 tests of Type IIb (see Figure 6) shall be made on five 
specimens cut perpendicular to the planes of anisotropy. 
 
 
 
 
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DRS 529: 2023 
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7.2.3 Surface finish of the specimens 
a) Identification test 
The surface finish on the faces and sides of the specimens shall be sawn, honed or polished.  
b) Technological test 
The surface finish on the faces and sides of the specimens shall be carried out according to the application(for 
example sawn, honed, polished, sanded, rubbed, flamed, bush-hammered, riven). 
 
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7.2.4 Dimensions of the specimens 
c) Identification test 
The specimens are square slabs with faces (200 ± 1) mm and a thickness of (30 ± 3) mm. The permissible 
deviation on the squareness is a maximum of 2 mm. 
d) Technological test 
The specimens are square slabs with the following dimensions: 
 
7.2.5 Location of the holes 
a) Identification test 
 The centre of the hole shall be situated between 98 mm and 102 mm from the other sides, measured 
to the nearest 0,5 mm. 
 The thickness of stone between the edge of the hole and the two faces shall be (10 ± 2,0) mm, 
measured to the nearest 0,5 mm. 
b) b) Technological test 
 The centre of the hole shall be situated in the middle of the specimen’s length. 
 The thickness of stone between the edge of the hole and the face to be tested shall be according to the 
application, measured to the nearest 0,5 mm. 
7.2.6 Dimensions and tolerances of the holes 
a) Identification test 
The diameter of the holes shall be (10 ± 0,5) mm. The depth of the holes shall be (30 ± 2) mm.  
b) Technological test 
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 The diameter of the holes shall be in accordance with the requirement of the application. The depth of the hole 
shall be (30 ± 2) mm. 
7.2.7 Drilling the holes 
The holes shall be wet drilled with a diamond or tungsten carbide tipped drill bit without hammering. 
7.2.8 Planes of anisotropy 
If the stone shows planes of anisotropy, the specimens are to be prepared in accordance with one of the 
arrangements shown in Figures 4, 5 and 6 and the position of the bedding or anisotropy is to be marked on 
the specimen by at least two parallel lines. 
If the use of the stone with respect to the position of the planes of anisotropy is known, the test shall be 
carried out with the force applied on dowel placed in the hole in the side corresponding to the face that will be 
loaded during use. 
If the use of the stone with respect to the position of the planes of anisotropy is not known or if more than one 
anisotropy is likely to be present, then the test shall be carried out in three perpendicular orientations and the 
total number of tests will be 30. 
7.2.9 Conditioning 
The specimens shall be dried to constant mass at (70 ± 5) °C in a ventilated oven after the drilling of the holes 
but before the dowels are fixed in place. 
Constant mass is reached when the difference between two weighings carried out (24 ± 2) h apart is less than 
0,1 % of the first of the two masses. After drying and prior to placing the dowels the specimens shall be stored 
at (20 ± 5) °C until the thermal equilibrium is reached. 
7.2.10 Measuring d and d1 
After conditioning the thickness (d) and the distance from the edge of each hole to the lower face of the 
specimen in the direction of the force (d1) shall be measured to the nearest 0,5 mm. 
8 Dowels 
8.1 Dimensions and tolerances 
a) Identification test 
The diameter of the dowels shall be (6,0 ± 0,1) mm. The length of the dowel shall be 50mm.  
b) Technological test 
The diameter of the dowels shall be in accordance with the required use. The length of the dowel shall be 50 
mm  
©RSB 2023- All rights reserved                  8 8.2 Material 
The dowels shall be made of stainless-steel Type 1.4571 according to EN 10 088-1. 
8.3 Placing the dowels 
Place one of the sides of each specimen in an upper horizontal position. Place the dowel vertically and 
centrally in the hole. Fix the dowel in the hole for a length of (25 ± 1) mm using mortar prepared with cement 
CEM I 52,5 R in accordance with RS EAS 18-1 and a water/cement ratio of (0,6 ± 0,1) by mass. 
Wait at least one hour and then repeat the same procedure for the other sides of the specimen that are to be 
tested (see Figures 3, 4, 5 and 6). 
The specimens shall then be stored at (20 ± 5) °C for a minimum of 48 h prior to testing. 
9 Test procedure 
The specimen is clamped between the two metal plates of the clamping device on not more than 60 % of the 
specimen length (see Figure 1). 
The load is exerted in a direction perpendicular to the axis of the dowel at a maximum distance of 2 mm from 
the edge of the specimen by means of the system shown in Figure 2. 
The load is increased uniformly at a rate of (50 ± 5) N/s until the specimen breaks. The breaking load is 
recorded to the nearest 50 N. 
If the dowel bends then the test shall be repeated with a larger diameter dowel and a new specimen. 
After the specimen has failed the maximum distance from the centre of the hole to the fracture edge (bA)shall 
be measured (Figure 7). 
 
 
 
DRS 529: 2023 
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 10 Expression of the results 
For each relevant direction of loading the following mean values shall be calculated from the individual results 
recorded for each test: 
 the mean value of the distance from the hole to the face where the fracture occurs (d1) expressed in 
millimetres to the nearest 1,0 mm; 
 the mean value of the maximum distance from the centre of the hole to the edge of the fracture (bA) 
expressed in millimetres to the nearest 1,0 mm; 
 the mean value of the breaking load (F) expressed in newtons to the nearest 50 N. 
11 Test report 
The test report shall contain the following information: 
a) unique identification number for the report; 
b) the number, title and date of issue of this European Standard; 
c) the name and address of the test laboratory and the address of where the test was carried out if different 
from the test laboratory; 
d) the name and address of the client; 
e) it is the responsibility of the client to supply the following information: 
 the petrographic name of the stone; 
 the commercial name of the stone; 
 the country and region of extraction; 
 the name of the supplier; 
 the direction of any existing plane of anisotropy (if relevant to the test) to be clearly indicated on the 
sample or on each specimen by means of two parallel lines; 
 the name of the person or organization which carried out the sampling; 
 the surface finish of the specimens (if relevant to the test); 
f) the date of delivery of the samples or of the specimens;  
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 g) the date when the specimens were prepared (if relevant) and the date of testing; 
h) the number of specimens in the sample; 
i) the results of measurements 
 for each specimen: 
 diameter of the hole; 
 diameter of the dowel; 
 dimensions of the specimen; 
 thickness of the specimen; 
 for each test: 
 distance from the hole to the face in the direction of the force ( d1) in millimetres to the nearest 1,0 
mm; 
 maximum distance from the centre of the hole to the edge of the fracture ( bA) in millimetres to the 
nearest 1,0 mm; 
 breaking load ( 𝐹ത) in newtons to the nearest 50 N; 
 for each relevant direction of loading: 
 the mean value 𝑑ଵതതത and the mean value 𝑏஺തതത(in millimetres to the nearest 1,0 mm); 
 the mean value of breaking load ( 𝐹ത) in newtons to the nearest 50 N; 
j) all deviations from the standard and their justification; 
k) remarks. 
The test report shall contain the signature(s) and role(s) of those responsible(s) for the testing and the date of 
issue of the report. It shall also state that the report shall not be partially reproduced without written consent of 
the test laboratory. 11        Statistical evaluation of the test results
A.1 Scope 
This annex establishes a method for the statistical treatment of test results obtained following the natural 
stone test method described in this standard.
A.2 Symbols and definitions
         ©RSB 2023- All rights Annex A 
(normative)  
 
Statistical evaluation of the test results  
This annex establishes a method for the statistical treatment of test results obtained following the natural 
method described in this standard.  
Symbols and definitions  
DRS 529: 2023 
All rights reserved This annex establishes a method for the statistical treatment of test results obtained following the natural 
 
 
©RSB 2023- All rights reserved                  12 
 A.3 Statistical evaluation of test results 
For the calculation of the mean value x, the standard deviation (s) and the coefficient of variation (v) a normal 
distribution is assumed. 
For the calculation of the lower expected value (E) a logarithmic normal distribution is assumed. The lower 
expected value (E) corresponds to the 5 % quantile of a logarithmic normal distribution for a confidence level 
of 75 %. 
Table A.1  
Quantile factor (ks) dependent on the number of measured values (n) in correspondence to the 5 % quantile 
for a confidence level of 75 % 
n k s 
3 3,15 
4 2,68 
35 2,46 
6 2,34 
7 2,25 
8 2,19 
9 2,14 
10 2,10 
15 1,99 
20 1,93 
30 1,87 
40 1,83 
50 1,81 
  
8 1,64 
 
 
 
 
 
 DRS 529: 2023 
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 The following examples should help to clarify the method:  
Example 1: 
Calculation of mean value, standard deviation, maximum value and minimum value of six measured values 
Measurementno.  Measuredvalue x 
1 2000 
2 2150 
3 2200 
4 2300 
5 2350 
6 2400 
 — 
Meanvalue 2333 
Standarddeviation 147 
Maximumvalue 2400 
Minimumvalue 2000 
 
 
 
 
 
 
 
 
 
 
 
  
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 Example 2: 
Calculation of mean value, standard deviation, coefficient of variation and lower expected value of10 
measured values 
Measurementno.  Measuredvalue x (lnx) 
1 2000 (7,60) 
2 2150 (7,67) 
3 2200 (7,70) 
4 2300 (7,74) 
5 2350 (7,76) 
6 2400 (7,78) 
7 2600 (7,86) 
8 2750 (7,92) 
9 2900 (7,97) 
10 3150 (8,06) 
 — — 
Meanvalue 2480 (7,807) 
Standarddeviation 363 (0,143) 
Variationcoefficient 0,15  
From Table 1 for: n = 10  ks = 2,1 
 
Lower expected value 1 819 
 
 
 
 
 
 
 
 
 DRS 529: 2023 
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 Bibliography 
[1] DRS 528, Natural stone — Denomination criteria. 
[2] DRS 515, Natural stone — Terminology. 
 DRS 529: 2023 
 
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