KENYA STANDARD  DKS 829:2023  
ICS ##.###  
2nd  Edition  
  
 © KEBS 202 3  
 Specification for precast concrete 
channels, edgings and quadrants  
 
  
TECHNICAL COMMITTEE REPRESENTATION  
The following organizations were represented on the Technical Committee:  
1. Atkins Consulting Engineers Limited.  
2. Bamburi Cement Lafargeholcims  
3. Bens Elect ronics service Ltd  
4. East African Portland Cement Plc  
5. Handisi systems LTD  
6. Institution of Engineers of Kenya  
7. Institute of Quantity Surveyors of Kenya  
8. Jomo Kenyatta University of Agriculture and Technology  
9. Kenya Builders & Concrete Co Ltd  
10. Kenya Electricity Tra nsmission 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 Housin g Corporation  
17. Orkidstudio_ Design and Build  
18. QuestLinks Engineering Ltd  
19. Questworks Limited  
20. Stroutel Africa Limited  
21. Technical University of Mombasa  
22. Kenya Bureau of Standards — Secretariat  
REVISION OF KENYA STANDARDS  
In order to keep abreast of progress in in dustry, Kenya Standards shall be regularly reviewed.  Suggestions 
for improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards, 
are welcome.  
© Kenya Bureau of Standards,202 3 
Copyright. Users are reminded that by vi rtue of Section 25 of the Copyright Act, Cap. 130 of 2001 of the Laws of Kenya, copyright 
subsists in all Kenya Standards and except as provided under Section 25 of this Act, no Kenya Standard produced by Kenya Bure au 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 829:2021  
 
Specification for precast concrete channels, 
edgings and quadrants  
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 procedures of the Kenya 
Bureau of Standards.  
This is a second edition. The revvison was necessary to take into consideration the sizes that are widely 
specified by eng ineers.  
This standard was adapted from the following document:  
BS 7263:  Part 1: 1994 Specification for precast concrete flags, kerbs channels,  edgings and quadrant.  
 
Acknowledgement is hereby made for the assistance derived from this source.  KENYA STANDARD  KS 829:2021  
 
 © KEBS 202 3  
 Specificati on for precast concrete channels, edgings and quadrants  
 
1 Scope  
 
This Kenya Standard specifies the requirements for the following precast concrete products:  
 
a) Channels;  
b) Edgings;  
c) Quadrants.  
 
These precast concrete products, referred to as a product or product s in this standard, are intended for use in 
the construction of carriageways and footways laid in accordance with KS 1537.  
 
notes:  Annex D gives recommendations on information to be given to a manufacturer in an enquiry or order.  
 
2 Normative references  
 
The following referenced documents are indispensable for the application 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 E AS 18 -1, Cement Part 1: Composition, specifications and conformity criteria for common cements  
 
KS 987 -1 Modular coordination - Vocabulary applicable to modular coordination.  
  
KS 95 Specification for natural aggregates for use in concrete.  
 
 KS 2846 Mixin g water for concrete — Specification for sampling, testing and assessing the suitability of 
water, including water recovered from processes in the concrete industry, as mixing water for concrete.  
 
KS 1537 Code of practice for laying of precast concrete fla gs, kerbs, channels, edgings and quadrants.  
  
KS 2770 -1 Admixtures for concrete, mortar and grout -Part 1:Common requirements.  
 
KS 2770 -2 Admixtures for concrete, mortar and grout -Requirements Part 2:Concrete admixtures.  
 
KS 2770 -3 Admixtures for concrete , mortar and grout -Requirements -Part 3:Admixtures for masonry mortar  
 
KS 2770 -4: Admixtures for concrete, mortar and grout -Requirements -Part 4:Admixtures for grout for pre -
stressing tendons  
 
KS 2770 -5 Admixtures for concrete, mortar and grout. Admixtures f or sprayed concrete. Definitions, 
requirements, conformity, marking and labelling  
 
EN 12878 Pigments for the colouring of building materials based on cement and/or lime. Specifications and 
methods of test  
 
BS 4372 Specification for engineers' steel measuri ng rules  
 
BS 4484 -1 Specification for measuring instruments for constructional works. Metric graduation and figuring of 
instruments for linear measurement  
 
BS 957 Specification for feeler gauges  
 
KS ISO 7500 -2:2006 Metallic materials -Calibration and verif ication of static uniaxial testing machines -Part 
2:Tension creep testing machines -Verification of the applied force.  
  
2 © KEBS 2022  – All rights reserved  
 BS 2648 Performance requirements for electrically -heated laboratory drying ovens  
    
3  Definitions  
 
For the purposes of this standard, the  following definitions and those given in KS 987 -1 shall apply:  
 
3.1  
nominal size   
the size of which identifies a component  
 
3.2   
work size  
target size of a building component specified for its manufacture  
 
3.3  
secondary processing   
manufacturing process carried ou t after basic manufacture, before or after hardening, on the whole unit or any 
surface  
 
Note:   Secondary processing may be used to provide flat (e.g. ground) or textured (e.g. blasted) lsurfaces.  
 
3.4   
flag  
Small slab of natural or artificial stone or preca st concrete  
 
3.5   
tactile flag  
flag, provided with a profiled surface, used to give warning of hazards, or to enable locations to be recognized, 
e.g. a crossing flag.  
 
4 Binders  
 
Products shall be made using cement conforming to KS EAS 18 -1. 
 
5  Aggregates  
 
Prod ucts shall be made using aggregates conforming to KS 95.  
                 
6 Water  
The water shall conform to KS 2846.  
 
7 Admixtures  
 
Proprietary admixtures shall conform to KS 2770.  
 
8  Pigment  
 
Pigments supplied in powder form shall conform to EN 12878 or an eq uivalent Kenya Standard.  Where 
pigments are used in the preparation of suspensions or slurries the pigments shall conform to EN 12878  or 
an equivalent Kenya Standard.  
 
9  Finish  
  
Products described as ‘natural’ shall contain no pigment ( see Clause D1(b).  Where products are made with 
two-part mixes, the surface layer shall be not less than 25 mm thick.  The surface layer shall be produced as 
an integral part of the product.  
 
All arises that will be visible after laying shall be without nibs and fins.  KS 829: 2022  
© KEBS 2022  – All rights reserved  3 
  
 
Note:  Profiled surfaces may be functional, (e.g. tactile) or decorative (e.g. riven).  
 
10  Dimensions and tolerances   
 
10.1 Dimensions  
  
10.1.1  Channels and edgings   
 
Channels and edgings shall have the sizes shown in Figures  1 and 2, and shall have a length in the range 
450 mm to 915 mm.  The length shall be measured along the vertical contact face between the channel. The 
radius of the vertical contact face of a channel shall be as given in Table 1.   
                  
 
Table 1.  External and internal radii for channels  
 
Dimensions  
External only  Internal and External  
1.0 2.0 3.0 4.5 6.0 7.5 
  9.0 10.5 12.0  
 
All dimensions are in metres  
 
 
a) Channel  Type CS1  
 
b)Channel Type CS2  
  
4 © KEBS 2022  – All rights reserved  
 
 
c)Channel dished : Type CD  
Figure 1  —  Bullnosed, splayed and half square and dished   channels  
 
 
 
 
  
   
Figure 2 Edgings  
 
 
 
 KS 829: 2022  
© KEBS 2022  – All rights reserved  5 
 
                                                                                   
 
 
 
 
Note. Quadrants in these sizes may have the following profile  
1) Bullnosed type QBN  
2) Half battered type QHB  
3) 45° splayed type QSP  
 
d) Quadrants (Sizes 305 × 150 × 305 × 225 or 455 × 150 or 455 ×225)  
 
Figure 3 - Quadrants  
 
10.1.2  Quadrants   
 Quadrants shall have the sizes shown in Figure 3(d).  
 
10.2 Tolerances  
 
10.2.1  Channels and Edging   
The maximum dimensional deviations of any, channel and edging, measur ed as described in Annex A, shall 
be as follows:  
 
(a) Length, width or height: ± 3 mm;  
 
(b) Straightness and winding:  
 
(i) Measured over, 550 mm to 850 mm: ± 2 mm;  
 
(ii) Measured over 250 mm to 400 mm: ± 1 mm;  
 
(iii) Squareness: 2 mm clearance.  
 
11 Transverse strength  
   
11.2 Channels and edgings  
When sampled and tested as described in annex B, the failing loads shall be not less than the appropriate  
value given in Table 2  
 
Table 2. Transverse strength of channels and edgings  
 
depth as tested   
(see note 1)  
mm width as tested  
mm failing load ( see note 2)  
kN  
6 © KEBS 2022  – All rights reserved  
 150 
125 
125 
50 
50 
50 
100 305 
150 
255 
255 
205 
150 
125 22.2 
8.0 
13.3 
5.1 
4.5 
3.3 
4.8 
 
.   
Note  1.   Units are placed in the testing machine with the depth as tested being the smallest  
                 dimension.  
 Note 2. The failing load for channels of various lengths may be obtained by extrapolation,    
e.g. if the failing load for a 125 mm x 255 mm x 915 mm channel tested on a span 
of 750 mm is 13.3 kN, the failing load for a 550 mm kerb of the same cross -
section tested on  a span of x mm will be 13.3 x (750/x) kN.    
 
12 Water absorption  
 
When tested as described in Annex C, the water absorption for channels  and edgings    
shall not exceed the appropriate value given in Table 3.  
 
 
      Table 3.   Maximum water absorption of ch annels and edgings  
 
water absorption in % by mass  
channels and quadrants shown in Figures 1 and 3  Edgings shown in Figure 2  
3.0 3.6 
 
 
13 Sampling and independent testing  
 
Samples shall be taken before the products are laid and, wherever practicable, whil st they are being moved, 
e.g. during loading or unloading.  A sample of three products shall be taken from a consignment of not more 
than 1,000 products.  Each of the three products in the sample shall be taken from one of three approximately 
equal section s of the consignment to be tested.  
 
Each product of a sample shall be uniquely marked and accompanied by a certificate from the person 
responsible for taking the samples, stating that sampling was carried out in accordance with this standard.  
 
The sample s hall be dispatched to the test laboratory, taking precautions to avoid damage to the products in 
transit.  
 
Note:   Products used for dimensional cheeks may subsequently be used for transverse strength or water absorption tests.  
 
14 Marking  
 
The following parti culars relating to products made in accordance with this standard shall be clearly marked 
on the delivery note, invoice, manufacturer’s or suppliers certificate, or brochure relating to a consignment of 
products:  
 
(a) The name, trade mark or other means of  identification of the manufacturing plant;  
 
(b)  The number and date of this standard;  
 
(c) Type of admixture(s) used ( see Clause 7);  
 
15 Types of products  
  KS 829: 2022  
© KEBS 2022  – All rights reserved  7 
 The types of precast concrete, channels, edgings and quadrants supplied in accordance with this stan dard 
shall be designated as given in Table 4.  
 
 
Table 4 - Types of products  
 
Type  Designations  Reference  
Channels:  
Type 1  
Type 2  
Dished   
CS1 
CS2 
CD  
Figure 1(a)  
Figure 1(b)  
Figure 1(c)  
Edgings:  
Round top edging  
Flat top edging  
Bullnosed edging   
ER 
EF 
EBN  
Figure 2(a)  
Figure 2(b)  
Figure 2(c)  
Quadrants:  
Bullnosed quadrant  
45º splayed quadrant  
Half battered quadrant   
QBN  
QSP  
QHB   
Figure 3(d)  
Figure 3(d)  
Figure 3(d)  
 
 
 
 
Annex  A  
 
Measurement of dimensions  
 
A1. General  
 
Remove any fins or local protrusions.  
 
Note:    It is recommended that all measurements be made using a suitable steel rule conforming to  BS 4372 
or BS 4484 or an equivalent Kenya Standard.  
  
 
A3. Channels and edgings  
 
A3.1  Length  
 
Measure the length of each product to the nearest 1 mm on th e face, within 25 mm of the four extreme 
corners of the profile.  Calculate the average length to the nearest 1 mm.  
    
A3.2  Width and height  
 
 Measure the width and height of each product to the nearest 1 mm at both ends.  Measure the width at the 
top an d bottom of parallel faces and the overall height at the face and back of the product.  Calculate the 
average height and width to the nearest 1 mm.  
 
A5. Determination of squareness    
 
Place the stock of an engineer’s square in contact with the moulded face s of the product.  Bring the blade into 
contact with the side of the product.  Using a feeler gauge conforming to BS 957: Part 2, check that the 
clearance between the square and the side of the product at points not less than 30 mm from the top and the 
bottom does not exceed the appropriate tolerance.  
 
  
                    
8 © KEBS 2022  – All rights reserved  
  
 
 
 
 
 
 
 
 
 
Annex B  
 
Determination of transverse strength  
 
B1. Testing machine  
 
The transverse testing machine shall conform to a grade A or grade B machine when verified in accordance 
with KS ISO 7500 Part 1 or an equivalent Kenya Standard and be of sufficient capacity to apply loads up to 33 
kN.  It shall be provided with two steel supporting rollers, each (38 ± 3) mm in diameter, or two steel bearers, 
each (6 ± 1) mm in width, on the supp orting surfaces ( see Figure B1).  The spacing of the rollers or bearers 
shall be as given in Table B1.  
        
Table B1 - Spacing of rollers or bearers for transverse strength test  
 
Dimensions in millimetres  
Product  Minimum spacing centre to centre of roll ers or 
minimum clear distance between bearers  
Edgings   
250 
 
Channels  750 
Note:     For channels from 450 mm to 800 in length, the minimum spans given in the table will have to 
be adjusted to give a minimum overhang of 50 mm for each end.  
 
In either case , one support shall be horizontal and the other so mounted as to enable loads to be applied 
without inducing any torsional restraint in the specimen, e.g. by pivoting about an axis parallel to the length of 
the specimens. The upper member of the loading fr ame shall be provided with a spherical seating to ensure 
that the load is applied axially without inducing any torsion in the specimen, and a steel platen at least 50 mm 
wide and of length not less than the width of the widest specimen to be tested.  
 
B2. Procedure  
 
Place the specimen symmetrically on the bearers of the testing machine with its greater cross -sectional 
dimension horizontal and bed a 50 mm wide hardwood filled on the upper surface at midpoint of the span, 
using a thin layer of plaster.  Allow the plaster to set before the test is carried out.   
 
Apply the load without shock and increase it at a rate not exceeding 18.5 N/s for each 100 mm of width as 
tested, until the specimen fails or the capacity of the machine is reached. Record the individua l failing loads in 
the report, except when a specimen does not fail under the upper limit of the testing machine, in which case 
record the failing load as ‘greater than … kN’.  
 
 KS 829: 2022  
© KEBS 2022  – All rights reserved  9 
  
 
Figure B1 — arrangement of loading for transverse strength test  
 
 
10 © KEBS 2022  – All rights reserved  
  
 
 
Annex    C 
 
Determination of water absorption  
 
C1. Apparatus  
 
C1.1  Balance, capable of weighing the specimens up to 5 kg with an accuracy of 0.1 per cent.  
 
C1.2  Suitable Concrete Sawing Machine  
 
C1.3  Ventilated drying oven  
  
Conforming to BS 2648 or an equivalent Kenya Standard, except that the internal space may exceed 0.085 
m3 in which the temperature is controlled at (105 ± 5) ºC, and such that the specimens can be placed in the 
oven as described in C3.1 .  
 
C1.4  Tank, deep enough to  immerse  specimens,  contain ing  clean water maintained at a temperature of 
( 20 ± 1) ºC.  
 
C1.5  Dry Airtight Vessel, e.g. desiccator, of sufficient size to contain the specimens to be tested.  
 
C2. Preparation of specimens  
 
Saw two test specimens from each of the three sample produc ts.  Cut each specimen from either end of the 
product.  For channels take the sample from the part of the product to be exposed, which may include the 
profile face.  The size of each specimen shall be as given in Table C1.  
 
Table C1 -  Size of specimens of channels and edgings for Water absorption test  
 
Product shown in figures 1 and 2  Size of specimen  
channel square type CS2 and edgings of all 
types  100 mm long x cross -section of product  
Channel square type CS1 and channel dished 
type DC  100 mm long x fu ll depth of product x 100 mm 
wide 
 
 
C3. Procedure  
 
C3.1  Place the six specimens in the drying oven  (see C1.3 ) so that each one is not less than 25 mm 
from any heating surface and from each other.  Dry the six specimens in the oven for (72 ± 2) hours.  Do not 
place further specimens in the same oven during the drying process.  Allow free access of air to all surfaces of 
the specimens.  
 
C3.2  On removal from the oven, cool each specimen for (24 ± 0.5) hours in the dry airtight vessel ( see 
C1.5 ).  Weigh each s pecimen and immediately completely immerse in the tank ( see C1.4 ) with its longitudinal 
axis horizontal and at a depth such that there is (25 ± 5) mm of water over the top of the specimen.  
 
C3.3  Leave  the specimens immersed in the water for (30 ± 0.5) min utes.  Remove each specimen, shake 
it to  remove the bulk of the water and dry it with a cloth as rapidly as possible until all free water is removed 
from the surface.  Weigh each specimen.   
 
 
C4. Calculation and expression of results  
 
C4.1  Calculate the mean absorption of the two specimens from each of the three products and report the 
values for the three means to the nearest 0.1 per cent as the water absorptions of the products.  KS 829: 2022  
© KEBS 2022  – All rights reserved  11 
  
C4.2  Calculate the mean absorption of the two specimens from each of the t hree products and report the 
values of the three means to the nearest 0.1 per cent as the water absorptions of the products.  
 
 
Annex   D  
(informative)  
 
Information to be given to the manufacturer in an  
Enquiry or order  
 
The following particulars cover the  essential details to be given to the manufacturer for an enquiry or order to 
be fully understood.  
 
D1. General  
 
 Any special requirements, e.g.:  
 
 (a) Surface finish;  
 
(b) Colour;  
 
(c) Aggregate type;  
 
(d) Binder type;  
 
(a) Admixtures.  
 
 
D3. Channels   
  
(a) Figure 1 and/or channel profile (type CS1,  CS2 or CD of Figure 1) and overall dimensions;  
 
(b) Any sawn units or special instructions.  
 
D4. Channels  
 
(See Figure 1.)  
 
 (a) Number of units or number of quadrants of a circle;  
 
(b) Profile type (channel type CS1 , CS2 or CD of Figure 1);  
 
(c) External or internal radius of units ( see Figure1);  
 
(d) Radius in metres ( see 10.1.2 ). 
 
 
D6. Edgings  
 
(a) Number of units;  
 
(b) Profile (edgings type ER, EF or EBN of Figure 2).  
 
D7. Quadrants  
 
 (a) Number of units;  
  
12 © KEBS 2022  – All rights reserved  
 (b) Profile (quadrant type QBN,QHB or QSP of Figure 3);  
 
(c) Bed dimensions (305 mm or 455 mm);  
 
(d) Height dimensions (150 mm or 255 mm).  
 
 
Figure. D1 — Channels  
 
 
Annex    E  
(informative)  
 
Methods of manufacture  
 
There are many different methods for manufactur ing the type of products covered by this standard.  The most 
common methods are as follows:  
 
(a) Semi -dry process  — A moist mix is compacted by pressure or by simultaneous vibration and pressure or 
by taping.  The resulting products are demoulded immediate ly. 
 
(b) Wet press process — Starting with a very wet mix, excess water is removed under a pressure of at least 
5 MPa over the entire surface.  The products are demoulded immediately;  
 
(c) Wet cast process — A mix with water : cement ratio in the range 0.4 0 to 0.55 is placed into moulds and 
compacted.  The products are normally demoulded on the following day.  This wet cast process is not used for 
flags covered by this standard.  
 
This Standard defines and specifies requirements and conformity for admixtures  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 practic al application of these admixtures in the production of sprayed concrete are 
not part of this Standard.  
 
 
KS 829: 2022  
© KEBS 2022  – All rights reserved  13 
 .   
 
© KEBS 2021 – All rights reserved