KENYA STANDARD  KS2770 -5:2021  
ICS ##.### 
1stEdition  
  
 © KEBS 2021   
 Admixtures for sprayed concrete  
Part 5 : 
Definitions, requirements, conformity, marking and 
labelling.  
 
 
 
TECHNICAL COMMITTEE REPRESENTATION  
The following organizations were represented on the Technical Committee:  
1. Atkins Consulting Engineers Limited.  
2. Bamburi Cement Lafargeholcims  
3. Bens Electronics service Ltd  
4. East African Portland Cement Plc  
5. Handisi systems LTD  
6. Institution of Engineers of Kenya  
7. Institution of Quantity Surveyors of Kenya  
8. Jomo Kenyatta University of Agriculture and Technology  
9. Kenya Builders & Concrete Co Ltd 
10. Kenya Electricity Transmission Co. Ltd  
11. Malaba Keya and Partners Consultants  
12. Materials Testing and Research Division  
13. Ministry of Transport, Infrastructure, Housing, Urban Development & Public Works  
14. Ministry of water and sanitation  
15. Nairobi Western Bypass project  
16. National Housing Corporation  
17. Orkidstudio_ Design and Build  
18. QuestLinks Engineering Ltd  
19. Questworks Limited  
20. Stroutel Africa Limited  
21. Surtech  
22. Technical University of Kenya  
23. Kenya Bureau of Standa rds — Secretariat Kenya Bureau of Standards — Secretariat  
REVISION OF KENYA STANDARDS  
In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed.  Suggestions 
for improvements to published standards, addressed to the Manag ing Director, Kenya Bureau of Standards, 
are welcome.  
© Kenya Bureau of Standards, 2021 
Copyright. Users are reminded that by virtue of Section 25 of the Copyright Act, Cap. 130 of 2001 of  the Laws of Kenya, copyright 
subsists in all Kenya Standards and ex cept as provided under Section 25 of this Act, no Kenya Standard produced by Kenya Bureau of 
Standards may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in  writing 
from the Managing Director.   KS 2770 -5:2021  
Admixtures for sprayed concrete  
Part 5: 
Definitions, requirements, conformity, marking and 
labelling  
Kenya Bureau of Standards,Popo Road, Off Mombasa Road,  
P.O. Box 54974 - 00200,  Nairobi, Kenya  
 +254 020 6948000, + 254 722202137, + 254 734600471  
 info@kebs.org  
 @KEBS_ke  
 kenya bureau of standards (kebs)  
  
Foreword  
This Kenya Standard was prepared by the Concrete and concrete products Technical Committee under the 
guidance of the Standards Projects Committee, and it is in accordance with the p rocedures of the Kenya 
Bureau of Standards . 
The KS 2770 consist of the following parts, under the general title Admixtures for concrete, mortar and grout  
 Part 1: Admixtures for concrete, mortar and grout — Common requirements  
 Part 2: Concrete admixtures — Definitions, requirements, conformity, marking and labelling  
 Part 3: Admixtures for masonry mortar — Definitions, requirements, conformity, marking and labelling  
 Part 4: Admixtures for grout for prestressing tendons - Definitions, requirements, conformity,  marking 
and labelling  
 Part 6: Sampling, conformity control and evaluation of conformity . 
During the preparation of this standard, reference was made to the following document (s):  
BS EN 934 -5:2007 Admixtures for concrete, mortar and grout. Admixtures for sprayed concrete. Definitions, 
requirements, conformity, marking and labelling  
Acknowledgement is hereby made for the assistance derived from this (these) source (s)  
This draft Standard is used with the standards of the KS 2769: 2017 series which comprises  the test methods 
for admixtures.   KS 2770 -5:2021  
 KENYA STANDARD                           KS 2770 -5:2021   
 
© KEBS  2021 – All rights reserved   
 Admixtures for sprayed concrete  
Part 5: 
Definitions, requirements, conformity, marking and labelling.  
 
1. Scope  
This Standard defines and specifies requirements and conformity for ad mixtures specifically intended for use 
in sprayed concrete.  
The types of admixtures covered are:  
— set accelerating and non -alkaline set accelerating admixtures;  
— consistence control admixtures;  
— bond improving admixtures.  
 Provisions governing the p ractical application of these admixtures in the production of sprayed concrete are 
not part of this Standard.  
2.  Normative references  
The following referenced documents 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  
 
KS EAS 148 -1, Methods of testing cement — Part 1: Determination o f strength  
 
KS EAS 148 -3, Methods of testing cement — Part 3: Determination of setting times and soundness  
 
KS EAS 18 -1, Cement Part 1: Composition, specifications and conformity criteria for common cements  
 
KS 2769 -1, Admixtures for concrete, mortar and  grout — Test methods Part 1: Reference concrete and 
reference mortar for testing  
 
KS 2769 -2, Admixtures for concrete, mortar and grout Test methods — Part 2: Determination of setting time  
 
KS 2769 -6, Admixtures for concrete, mortar and grout Test methods — Part 6: Infrared analysis  
 
KS 2769 -8, Admixtures for concrete, mortar and grout Test methods — Part 8: Determination of the 
conventional dry material content  
 
KS 2769 -10, Admixtures for concrete, mortar and grout — Test methods — Part 10: Determination of water 
soluble chloride content  
 
KS 2769 -12, Admixtures for concrete, mortar and grout — Test methods — Part 12: Determination of the 
alkali content of admixtures  
 
KS 2770 -6:2001, Admix tures for concrete, mortar and grout Part 6: Sampling, conformity control and 
evaluation of conformity  KS 2770 -5:2021  
 
EN 1542:1999, Products and systems for the protection and repair of concrete structures — Test methods —
Measurement of bond strength by pull -off  
 
 
KS ISO 1920 -2: 2016 Testing of concrete — Part 2: Properties of fresh concrete  
 
KS ISO 1920 -4:2005  Testing of concrete -Part 4:Strength of hardened concrete.  
 
KS ISO 1158, Plastics Vinyl chloride homopolymers and copolymers — Determination of chlorine content  ( KS 
ISO 1158:1998)  
 
KS ISO 758, Liquid chemical products for industrial use — Determination of density at 20 degrees C  
 
KS ISO 4316, Surface active agents — Determination of pH of aqueous solutions — Potentiometric method  
3. Terms and definitions  
For the p urposes of this Standard, the following terms and definitions apply  
 
3.1. General definitions  
 
3.1.1.   
performance  
ability of an admixture to be effective in its intended use without detrimental effects  
 
3.1.2.   
compliance dosage  
dosage of an admixture, expressed in % by mass of cement, stated by the manufacturer, which will meet the 
requirements of this Standard  
 
NOTE The compliance dosage should be within the recommended range of dosage.  
 
3.1.3.   
recommended range of dosage  
dosages be tween limits expressed in % by mass of cement that the manufacturer recommends for the product 
based on experience on site  
 
NOTE The use of the recommended dosage does not imply that compliance with this Standard will be met over the whole range. Tr ial 
tests should be carried out with the materials to be used on site to find the dosage necessary to achieve the required result .  
 
3.1.4.   
maximum recommended dosage  
upper limit of the recommended range of dosage  
 
3.1.5.   
control mix  
prescribed mix without admixture  
 
 
3.1.6.   
test mix  
prescribed mix incorporating an admixture  
 
 
3.2. Specific definitions  
 
 3.2.1.   
sprayed concrete admixture  
material added to the concrete mix before or during the spraying process, in a quantity not exceeding 5 % by 
mass of cement, except for sprayed concrete set accelerating admixture, where the dosage should not 
exceed 12 %, to modify the properties of the mi x in the fresh and/or hardened state  
 
 
3.2.2.   
sprayed concrete set accelerating admixture  
admixture to develop very early setting of the sprayed concrete differing from set accelerating admixtures as 
defined and specified in KS 2770 -2 
 
3.2.3.   
non-alkaline sprayed concrete set accelerating admixture  
sprayed concrete set accelerating admixture according to 3.2.2 with an alkali content (given as Na 2O-
equivalent) not exceeding 1.0 % by mass of the admixture  
 
3.2.4.   
consistence control admixture  
admixture that retains consist ency for a long period  
 
NOTE This type of admixture is normally used in combination with a compatible sprayed concrete set accelerating admixture.  
 
3.2.5.   
bond improving admixture  
admixture added to the concrete mix before or during the process of spraying and which improves the bond 
between the sprayed concrete layers and/or the substrate surface  
 
4. Requirements  
 
4.1. General requirements  
 
All the admixtures defined in this Standard shall  conform to the general requirements given in Table 1.  
 
4.2. Specific requirements  
 
Additional to the general requirements in 4.1, the admixtures defined in 3.2.1 to 3.2.5 shall conform to the 
following specific requirements:  
 
Sprayed concrete set accelerating admixture Table 2  
 
Non-alkaline sprayed concrete set accelerating admixture Table 2  
 
Consistence control admixture Table 3  
 
Bond improving admixture Table 4  
 
These requirements shall be satisfied within the recommended range of dosage.  
 
 
Table 1 — General requirements  
 
 Property  Test method  Requirements  
1 Homogeneity a Visual  Homogeneous when used. Segregation shall not 
exceed the limit stated by the manufacturer.  
2 Colours  Visual  Uniform and similar to the description declared by 
the manufacturer.  
3 Effective component a KS 2667 -6b Infrared spectra to show no significant change with 
respect to the effective component when compared 
to reference spectrum provided by the 
manufacturer.  
 KS 2770 -5:2021  
4 Relative density a KS ISO 758   D ± 0.03 if D > 1.10  
 D ± 0.02 if D≤1.10  
Where D is the manufacturer's stated value of 
density.  
5 Conventional dry 
material content a KS 2667 -8 c 0.95 T≤X <1.05 T, if T ≥ 20 %  
0.90 T≤ 5 X < 1.10 T, if T < 20 %  
T is manufacturer's stated value % m/m.; X is test 
result % by mass  on dry material content.  
6 pH-Value a (only for 
liquid admixtures)  
KS ISO 4316  Manufacturer's stated  value  ±1 or within  
manufacturer's stated range.  
7 Total chlorine a d   KS ISO 1158e Either ≤       0.10  % by mass and not  above the  
manufacturer's stated range.  
8 Water soluble chloride a KS 2669 -10  
Either ≤ 0.10 % by mass h or not above the  
manufacturer's stated range.  
9 Alkali content (Na 2O-
equivalent) a KS 2669 -12 Not above the manufacturer's stated maximum.  
≤ 1.0%  by mass for non -alkaline sprayed  
concrete set accelerating admixture.  
10 Corrosion behaviour  f g No corrosion  promotion  effects  on steel 
embedded in concrete.  
 
 
 
 
 
 
 
 
 
  a Manufacturer's stated value shall be provided in writing, to the user, on request. 
 
b If the method in KS 2669 -6 is not suitable, the manufacturer shall recommend an alternative test 
method.  
 
 C If the method in KS 2669 -8 is not suitable, the manufacturer shall recommend an alternative test 
method.  
 
d if there is no significant difference between total chlorine content and water soluble chloride content, 
only the water soluble chloride content shall be determined in subsequent tests on the admixture 
involved.  
 
e The procedure in  KS ISO 1158 shall be m odified as follows: 
— increase the sample size to 0.1 g of dry admixture;  
— use silver nitrate and ammonium thiocyanate solutions 0.01 N.  
 
fFor testing, cement CEM I with C 3A content less than 5 % by mass shall be used.  
 
g If admixtures are tested for corr osion behaviour, tests should be performed in accordance with KS 
2669 -14 
h Where the chloride content is ≤ 0.10 % by mass, the admixture may be described as "chloride free".  
 
 
  
 
 
 
 
 
 
 
 
 Table 2 — Specific requirements for sprayed concrete set acceleration and non -alkaline set  
acceleration admixtures at equal w/c ratio  
 
 Property  Reference mortar  Test 
method  Requirements  
1 Setting  time Reference mortar 
KS 2669 -1 a b KS 2669 -2 c Initial setting time ≤ 10 min  
 
Final setting time ≤ 60 min (average of three 
tests)  
2 Compressive  strength  Reference mortar 
KS 2669 -1 a de KS EAS 
148-1 At 28 days:  
 
Compressive strength of test mix ≥ 75 %  
compressive strength of control mix or ≥ 90 
% for non-alkaline accelerators.  
 
At 90 days:  
Compressive strength of test mix 
compressive ≥ strength of test mix at 28 
days.  
a The w/c ratio shall be ≤ 0.50 and such that the test mix shall have the standard consistence defined in KS EAS 
148-3 immediately prior to addition of the admixture.  
 
bIn difference to KS 2669 -1, the set accelerating admixture is added to a cement mortar o f standard consistence, 
just before the  end of the mixing time. Adding the admixture, mixing and filling the mould, without undue 
segregation or vibration, shall be completed in a time not exceeding 30 s.  
 
c The difference to KS 2669 -2, the total mass of t he moving parts of the Vicat shall be (300 ± 2) g.  
 
d All components of the mortar shall be conditioned to a temperature of (5 ± 1) °C. The test specimen shall be 
stored at (20 + 2) °C.  
 
e The set accelerating admixture is added to the mortar just before t he end of the mixing time. The filling and 
compacting of the mould with the mortar shall then be completed as soon as possible.  
 
Table 3 — Specific requirements for consistence control admixtures at equal consistence  
 Property  Reference concrete  Test method  Requirements  
 
 
 
 
1 
 Retention  
of consistence  Annex A   KS ISO 1920 -
2 (slump) or  
KS ISO 1920 -
2 (flow)  Control mix:  
 
Initial slump: 180 mm to 230 mm, or  
 
 initial flow: 480 mm to 550 mm.  
 
6 h after addition of the admixture, the 
consistence of the test mix shall be ≥ 
80 % of the initial consistence of the 
test mix.  
 
2 Compressive  
strength  Annex A   KS ISO 1920 -
4 At 28 days:  
 
Compressive strength of test mix ≥  
strength of control mix  
 
 
Table 4 — Specific requirements for bond improving admixtures at equal consistence  
 Property  Reference concrete  Test method  Requirements  
 
Tensile   bond strength  Annex B   
Annex B  
 Tensile bond strength between layers at 
28 days: test mix  ≥ 125 % of control 
mix KS 2770 -5:2021  
2  
Compressive Strength  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Annex C   
 KS ISO 1920 -4 At 28 days:  
 
Compressive strength of test mix ≥ 80 
% of compressive strength of control 
mix  
5. Sampling  
 
Requirements for sampling are given in KS 2770 -6. 
 
6.  Conformity control  
 
Requirements for conformity control are given in KS 2770 -6, 5.3 and 5.4. The frequency of testing in 
connection with the factory production control is given in Table 5.  
 
Table 5 — Minimum frequency of test for factory production contro l 
 
Tests  Set accelerating  
and non -alkaline  
set accelerating  
admixtures  Consistence  
control admixtures  Bond improving  
admixtures  
Homogeneity, colour   B B B 
Relative density (for liquids only)  B B B 
Conventional dry material content  B B B 
pH value (for liquids only)  B B B 
Chloride content (Cl-) a 4 4 4 
Alkali content  2 2 2 
Compressive strength at 28 days  1 1 1 
Setting time  A - - 
Retention of consistence  - A - 
Tensile bond strength  - - A 
Numbers in this table denote minimum frequency of test per year, spread according to production; if the 
Production is less frequent every batch has to be tested.  
A: means test for every 1 000 t but not more than 3 times a year  
B: means test each batch  
NOTE The effective component (infrared analysis) need not be included in the programme of factory production control. It has been incl uded in initial type testing.  
aTotal chlorine content also has to be tested at this frequency if it is significantly different from the water 
soluble chloride content.  
 
 
7.  Evaluation of conformity  
 
Requirements for evaluation of conformity are given in KS 2770 -6:2001, Clause 5.  
 
8.  Marking and labelling  
 
8.1.  General  
 
When admixtures for sprayed concrete are supplied in containers they shall be clearly marked with the relevant 
information listed in 8.2 and 8.3. When the material is supplied into a bulk container at the point of delivery, the 
same information shall be provided in writing at the time of delivery.   
8.2.  Designation of admixture s 
 
Admixtures for sprayed concrete shall be designated by:  
a) name of type of admixture in English  
b) number of this Standard: KS 2770 -5; 
c) code, to identify the type of admixture, consisting of the number of this Standard and the number of the 
table which gives the additional performance requirements for the particular type of admixture.  
 
EXAMPLE  Set accelerating admixture for sprayed concrete; KS 2770 -5; T.2.  
 
8.3.  Additional information  
 
a) batch number and production plant;  
b) summary of storage requirements including any special requirements on storage life which      shall be 
clearly marked, e.g.: This admixture shall not be taken to comply with KS 2770 -5 after "date";  
c) instructions for use and any necessary safety precautions, e.g. if caustic, toxic or corrosive;  
d) manu facturer's recommended range of dosage;  
e) actions to be taken before use if segregation has occurred.  
 
 
Annex A  
(normative)  
Reference concrete for testing consistence control admixture  
 
A.1   General  
The constituent materials and the preparation of the reference concrete shall be in accordance with the 
requirements of KS 2669 -1 except as given in this annex below. The requirements for the consistence are 
given in Table 3. Alltests shall be carried out at the same consistence.  
 
A.2   Cement content  
The cement content shall be 450 kg/m3. 
 
A.3   Aggregates  
The sieve curve for the aggregate is given in Table A.1.  
 
Table A.1 — Aggregate for reference concrete  
 
Sieve size  
mm Percentage by mass passing the test sieve a b 
8.0 100 
4.0  73 to 100  
2.0  55 to 90 
1.0  37 to 72  
0.5  22 to 50  
0.25  11 to 26  
0.125  4 to 12  
0.063  <2 
a The range is selected to accommodate both crushed and uncrushed aggregate. 
b The variation in the quantity passing each sieve of the chosen grading for both mixes (control and test mix) 
shall not exceed ± 2.0 % by mass. 
 
A.4   Consistence  
 
Testing shall be carried out under standard laboratory conditions of (20 + 2) °C. The concrete shall be covered 
with a plastic sheet to prevent evaporation during the standing period. The initial consistence of the reference 
concrete shall be slump (180 mm  to 230 mm) or flow (480 mm to 550 mm). This shall apply to both the test KS 2770 -5:2021  
and control mixes. The test mix only, shall be re -tested 6 h after mixing and shall have a consistence ≥80% of 
the initial consistence of the test mix.  
 
 
A.5  Compressive strength  
 
Following the test for consistence, 6 h after adding the consistence control admixture, the test mix is returned 
to the mixer. After 60 s mixing the mixer is stopped and the concrete is placed in the compressive strength 
moulds. The concrete is cured in th e moulds under standard laboratory conditions according to EN 12390 -2 
until it has fully set. It is then de -moulded and curing continued under standard laboratory conditions until the 
age when it is to be tested for compressive strength.  
 
A control mix at equal consistence (see BA) is prepared at the same time as the test mix and placed in the 
compressive strength moulds immediately after mixing. The concrete is cured under normal laboratory 
conditions and tested for compressive strength at 28 days.  
 
A.6   Test report  
 
The test report shall include at least the following information:  
— Cement:  
a. manufacturer and factory;  
b. type;  
c.  class of strength in accordance with KS EAS 18 -1; 
 
— Sprayed concrete bond improving admixture  
d.  Manufacturer:  
e. type;  
f. dosage;  
 
— Tensile bond strength results rounded to 0.05 N/mm2 
g. Individual by specimen type:  
h. Average by specimen type;  
i. Average test specimen failure as percentage of average control specimen failure strength.  
 
 
 
Annex B  
(normative)  
Measurement of tensile bond strength  
 
B.1   General  
 
This test is intended for laboratory use only. Test and control concrete mixes are prepared and used to make 
the following test specimens each consisting of two layers:  
 
a) control concrete to control concrete;  
b) test concrete to test concrete.  
The t est procedure shall follow EN 1542 with the deviations shown in B.3.  
 
B.2   Preparation of the control and test mix  
 
The constituent materials and the preparation of the reference and test concrete shall be in accordance with 
the requirements of KS 2669 -1 with deviations as follows:  
a) cement content 450 kg/m3; 
b) aggregates in accordance with Table A.1;  
c) consistence (60 to 80) mm slump or (380 to 420) mm flow.  
 
B.3   Applying the concrete and storage of specimens  
 
All components of the concrete, together with the  moulds and tools used for preparing the mix and its 
application shall be located in the standard laboratory climate (EN 1542) for at least 24 h before use.   
The base of the moulds can be of any suitable material but a concrete slab has been found most sui table. 
Mould sides to contain a uniform 40 mm thickness of concrete are attached to the base.  
 
One mould shall be filled with control concrete and one with test concrete. The concrete shall be compacted by 
hand tamping, levelled and then finished with a si ngle pass of a steel float. The specimens are then left, 
uncovered, in the standard laboratory climate.  
 
After 24 h the mould is removed and the surfaces given just sufficient wire brushing to remove any latence. 
Double height mould sides are then fitted s o that a further layer of (30 to 40) mm of concrete can be added.  
 
The control concrete mould shall be filled with a further batch of control concrete. The test concrete mould shall 
be filled with a further batch of test concrete. The concrete in both moul ds shall be compacted by hand 
tamping, levelled and then finished with a steel float. The specimens are then left, uncovered, in the standard 
laboratory climate for 24 h before de -moulding. After de -moulding, the specimens are then left, uncovered, in 
the standard laboratory climate for a further 27 days.  
 
B.4   Testing  
 
The tests shall be carried out in accordance with EN 1542:1999, Clause 7, except that the drill shall pass 
through the top layer of concrete and approximately 20 mm into the first layer of concrete.  
 
Five bond tests are performed on each test specimen.  
 
B.5   Test report  
 
The test report shall include the following information:  
 Cement:  
a. manufacturer and factory;  
b. type;  
c. class of strength (in accordance with KS EAS 18 -1). 
 
 Sprayed concrete bond improving admixture:  
e. Manufacturer;  
f. Type;  
g.  Dosage.  
 
 Tensile bond str ength results rounded to 0.05 N/ mm2: 
h. Individual by specimen type;  
i. average by specimen type;  
j. average test specimen failure as percentage of average control specimen failure strength.