Abu Dhabi, United Arab Emirates. STANDARD CONSTRUCTION SPECIFICATIONS (PART 1 - ROADS, Second Edition 2020)

ONSTRUCTION

Kerb openings at driveways and sidewalk ramps shall be constructed by the Contractor as shown
on Contract plans and as directed by the Engineer.

Formwork, expansion joints, curing, and finishing shall be completed in accordance with the
requirements of Article 7.5.3.3, with the following exceptions:

1. Surfaces shall be finished immediately after slip-forming

2. Foundation pavement shall be dry and cleaned of loose and deleterious material prior to slip-

form kerb placement

3. Placing concrete on an unstable, saturated base will not be permitted. If required, the base

shall be damped with water prior to placing concrete

In constructing the slip-form work, the Contractor shall do the following:

a. Consolidate concrete so as to be free of honeycomb

b. Provide concrete of a consistency that will maintain the shape of the barrier, parapet, kerb, or

gutter without support

c. Minimise starting and stopping of the slip-form operation by ensuring a continuous supply of

concrete.

d. Provide a wire line or laser guided controls to maintain vertical and horizontal alignment of the

slip-form machine

e. Operate the slip-form machine within th

e manufacturer’s recommended speed

f. Provide rails or supports at the required grade instead of sensor controls, at the Contractor

’s

option

Curing shall conform to Article 4.4.2.5 of Chapter 4, Concrete Works.

7.5.3.5

Precast Kerb, Parapet and Barrier

Units shall be precast in sections per the Contract plans and as directed by the Engineer. Unless the
Engineer agrees otherwise, the manufacturer shall be a company with at least 3 years experience
in fabricating precast concrete units. Precast sections shall be 6 m or less in length with end faces
perpendicular to their bases. Casting method shall be either one of the following, as approved by the
Engineer:

•

By hydraulically pressing concrete

•

Per Section 4.4.8 of Chapter 4, Concrete Works

Requirements for each casting method are described in the following subsections. Additional
requirements shall be as follows:

•

No concrete barrier shall be shipped until test cylinders made of the same concrete and cured

under the same conditions show the concrete has reached 30 MPa

•

No concrete kerb shall be shipped from the manufacturing plant prior to 21 days after

manufacture, however, shorter period may be accepted, if approved by engineer, but shall not
be less than 14 days in all cases. If Type III cement has been used, the units may be shipped
14 days after manufacture.

All barriers in the same project, except end sections and variable-length units needed for closure,
shall be the same length. All barriers shall be new, unused, and true to the required dimensions
within the tolerances established in Table 7-30. Any damage or distortion from fabrication shall be
the responsibility of the Contractor.

Table 7-30: Tolerances for precast barrier

Dimension

Tolerance

ONSTRUCTION

Length

±25 mm

Insert placement

±13 mm

Horizontal alignment

±3 mm per metre of length

Horizontal skew at end

±6 mm

Vertical batter

±3 mm per 300 mm of depth

Tolerances for precast kerb sections shall be ±3 mm in any dimension.

Precast concrete units damaged in the process of fabricating, curing, handling, or placing shall be
repaired or replaced by the Contractor, as directed by the Engineer.

a. Hydraulically Pressed Precast Method

Precast kerb, gutter, kerb and gutter, parapet, and barrier shall consist of hydraulically pressed
precast products manufactured in a fully automatic batching plant and comply with the requirements
of BS EN 1340, except as modified herein, as approved by the Engineer. Units shall be fabricated
by the manufacturer using steel or other approved moulds, in compliance with the approved
manufacturing and testing procedures.

Unless otherwise approved by the Engineer, precast kerbs shall be 900 mm long for straight line
applications or as short as 200 mm long for curves, depending on the radii of the curves. Quality
control recommendations and dimensional tolerance shall be in accordance with BS EN 1340.

If required by the Engineer, testing for compressive strength shall conform to the following procedure:

1. Sample size shall consist of 3 products from a consignment of up to 1,000 products.

2. 2-100-mm-diameter cores shall be cut from each of the 3 samples.

3. Cores shall be tested in accordance with BS 1881: Part 120.

4. Mean compressive strength of 2 cores shall be reported as the compressive strength of that

product.

5. Average compressive strength of 3 products shall not be less than 35.05 N/mm

6. Mean water absorption of cubes, per BS EN 1340, shall not exceed 3.0 %.

b. Standard Precast Method

When kerb, kerb and gutter, gutter, parapet, or barrier are cast in accordance with Section 4.4.8 of
Chapter 4, Concrete Works, then curing, shipping, and handling shall be per the same section, as
approved by the Engineer. Forms shall be steel.

Test results from the manufacturer’s testing shall demonstrate compliance to the consistency,
temperature, and time of placement; air content; and compressive strength requirements of Chapter
4, Concrete Works.

c. Curing and Finishing Precast Units

Immediately after each unit has been cast, it shall be cured by one of the following:

•

Low-pressure steam

•

Steam vapour

•

Radiant heat and moisture

•

Other similar process, as approved by the Engineer

Radiant heat and moisture shall be provided by water sprays and a relative humidity at least 90 %
with a temperature between 16

C and 38

Each unit shall remain in the curing room for at least 10 days, or at least 5 days if Type III cement is
used.

Exposed surfaces of kerb, parapet, and barrier shall be smooth with uniform colour and appearance.
Finish on the bottom of precast kerbs shall prevent mechanical interlocking of the mortar bed and
the kerb bottom or anchor groove.

After release, barriers shall be finished to an even, smooth, dense surface, free from any rock
pockets or holes larger than 6 mm across. Towelling shall remove all projecting concrete from the
bearing surface of the barrier. Barriers shall be cured in the forms until test cylinders that have been
cured under the same conditions as the barrier indicate the concrete has reached a compressive
strength of a least 15 MPa. No additional curing is required once the barrier is removed from the
forms.

d. Surface Treatment and Marking of Kerbs

After  installation  of  units  on  site,  the  exposed  surfaces  of  all  precast  and  cast  in-situ  concrete
kerbs, which will not to be painted for parking classifications (turquoise, black, white) or restrictions
(yellow, grey)  as  per  clause  8.2.3.3  (b),  shall  receive  2  brush  or  roller-applied  coats  of  a  water-
repellent  compound,  meeting  the  requirements  of  Table  24-13  of  Chapter  24,  Painting.  When
the first coat has dried, the second coat of water-repellent compound shall be applied.

At the manufacturing plant, each piece of kerb shall be marked in black paint on the back or end of
the unit with the date of manufacture, length, and identification number corresponding to the detail
layout. Alternatively, each bundle of precast kerbs shall have a robust tag attached to it with
the aforementioned information printed on the tag.

Rejected kerb shall be marked on the back or end to identify each cause of rejection.

e. Placing Concrete Kerb

Kerb shall be constructed as shown on the Contract plans, to be placed on top of the pavement base
courses or on a separately cast concrete footing. At time of placement, kerb shall be firmly bedded
for its entire length and breadth on either a wet concrete base or a mortar bed composed of Class
M6 mortar per Article 4.3.10.4 of Chapter 4, Concrete Works, 25 mm thick, placed on approved sub-
grade. Dimensions of the base and haunching shall be as shown on the Contract plans. Concrete
base shall be constructed with Class C20 concrete. Kerb placement will be inspected and approved
by the Engineer prior to placement of the concrete kerb haunching or other work adjacent to or
against the freshly placed kerb line.

Anchor grooves in the bottom of the kerb shall be entirely filled with the mortar. Before the cement
mortar bed is laid, all dirt shall be cleaned from the pavement surface by washing.

Expansion joints, consisting of approved joint filler 10 mm thick, shall be placed every 9 m, or as
shown on the Contract plans or otherwise approved by the Engineer. Filler shall extend through the
kerbs, bed, backing, and gutter and shall be trimmed to the finished slope of the kerb and gutter.

All joints between adjacent pieces of kerb, except expansion or drainage joints, shall adhere to the
following:

•

Measure 4 mm or less in width

•

Be filled with joint mortar meeting the requirements for M1 in Article 4.3.10.4 of Chapter 4,

Concrete Works, with one-fifth part hydrated lime and sufficient water to make the mixture
plastic and easily smoothed. A grooving tool shall be used to produce a smooth, circular
section groove not more than 3 mm deep in all joints.

Alignment and the top surface of adjoining sections of kerb shall be true and even with a maximum
tolerance of 1.5 mm.

Unless otherwise indicated, after kerb units have been laid, a continuous backing of Class C20
concrete shall be poured. No pavement layers shall be laid against kerbing until such time as the
backing is complete, back filled and approved by the Engineer.

Immediately after any concrete is in place and for seven days thereafter, the kerbs, base backing
and mortared joints shall be fully cured and protected from drying out and against the harmful effects
of weather, including rain and rapid temperature changes. Concrete not properly cured and protected
will be rejected and shall be removed from the works.

Nosing pieces, connecting dividers, and radial sections for kerbs shall be as detailed in the Contract
plans and will be required at the ends of the kerb lines, at transitions between different kerb types,
and kerbs with radii less than 3 m. Bull noses and curved faces shall be of constant radius with a
smooth change from radius to plain face.

For sloped mountable kerb installed in curves, the units shall be either curved blocks precast to the
radii shown in the Contract plans or tangent blocks sawn to the dimensions shown in the Contract
plans to conform to the specified radii.

At the end of any kerb run, the end element shall be sloped down to ground level and angled away
from the road at 30 degrees.

f. Placing Precast Barrier

Precast barrier lengths shall be as shown on the Contract plans, except that the Contractor may use
one short section to adjust a line for length. Creating a short section by cutting or breaking a section
will not be allowed. Short sections shall be manufactured to meet the material requirements as
otherwise specified. Hardware identical to that used with other sections shall interlock such a section
with adjacent precast sections.

Precast concrete barrier shall rest on a paved foundation shaped to a uniform grade and section.
Foundation surfaces shall meet the following test for uniformity:

When a 3 m straightedge is placed on the surface parallel to the centreline for the barrier, the surface
shall not vary more than 6 mm from the lower edge of the straightedge.

Precast segment joins shall be aligned so that they offset no more than 6 mm transversely and no
more than 18 mm vertically. Grouting to correct alignment is not permitted. If foundation grade and
section are acceptable, the Engineer may permit the Contractor to obtain vertical alignment of the
barrier by shimming. Shimming shall be done with a polystyrene, foam pad measuring 300 mm by
600 mm under the end 300 mm of bearing surface.

Barrier connection voids for permanent installations of precast barrier shall be filled with grout.

g. Rejecting Precast Kerb, Gutter, Parapet, and Barrier

Precast units shall be uniform in colour; free from cracks, flaws, or other defects; and shall have well-
defined edges.

Excessive cracking, surface checking, broken or rounded corners, air holes, or lines of discolouration
due to a damaged mould are cause for rejection or repair of precast concrete kerb, gutter, parapet,
or barrier. An air hole shall be defined as any hole measuring 3 mm or larger in diameter or depth
that is visible on the surface or appears when the surface is struck with a rubber hammer. A crack is
defined as any separation of the concrete of a continuous length greater than 75 mm.

A piece of kerb, gutter, parapet, or barrier shall be rejected for any of the following conditions:

1. Variation in dimensions, alignment, or surface contour exceeding ±6 mm in length and ±3 mm

in alignment

2. Failure to comply with the Contract plans, Specifications, or instructions of the Engineer

3. Evident cracking immediately after removal from the moulds.

4. Surface checking within the first 5 days after manufacture

ONSTRUCTION

5. Excess honeycombing in the back, unless the Engineer states it is not detrimental

6. More than 2 % of the top area is deemed defective.

7. More than 5 % of the total length of the top corners of reflecting faces is broken or rounded

8. More than 40 holes in any linear 250 mm

9. Sum of the length of lines of discolouration exceeds 50 % of the length of the unit.

10. Any single line of discolouration exceeds 450 mm long

For the total amount of precast units of a single type installed in the works, 75 % of each total shall
be entirely free from lines of discolouration, and 90 % of the total laid shall demonstrate the following:

•

Less than 0.2 % of the top area is deemed defective

•

Less than 0.5 % of the total length of the top corners of reflecting faces is broken or rounded

•

Less than 4 holes in any 250 mm length

Totals shall be taken by type of precast unit, including total kerb, total gutter, total parapet, or total
barrier. Failure to reject a unit at the time of manufacture will not ensure its final acceptance.

h. Repairing Precast Kerb, Gutter, Parapet, and Barrier

Precast units having defects that are not sufficient cause for rejection shall be neatly repaired
immediately after removal from the moulds in a manner subject to the approval of the Engineer. No
patching or repairs shall be made without the permission of the Engineer.

Chipped or broken moulds shall be repaired such that broken or chipped areas will not be apparent
on the precast units made in those moulds. Heat shall not be used to obliterate lines of discolouration.
Processes used to obliterate lines of discolouration shall be subject to the approval of the Engineer.

Patches shall be undercut if, in the opinion of the Engineer, this operation is necessary to achieve a
satisfactory patch.

All holes larger than a 1.5 mm diameter in the exposed surface of acceptable kerb or buttons shall
be filled with cement mortar.

i. Sampling and Inspection of Precast Kerb, Gutter, Parapet, and Barrier

An advanced sample of precast kerb, gutter, parapet, and barrier that demonstrates the required
colour, texture, and bottom finish shall be submitted to the Engineer for approval. No repairing of any
kind shall be done on the advance sample.

Upon approval, the advance sample shall be stored at the plant or site of manufacture in a location
readily accessible to the Engineer where there is adequate daylight for examination. Advance
samples shall be protected from damage and discolouration and shall be used as a standard of
comparison for colour, surface texture, and bottom finish. All precast units furnished to the worksite
shall be equivalent to the advance sample in the foregoing respects.

Inspections at the plant will be made just prior to shipment, at which time examination will be made
of the alignment, contour, colour, cracks, surface damage or discolouration, broken corners or
edges, and any other defects that may have developed; and to check the laboratory test reports for
strength. Intermediate inspections may be made to determine surface checking and hidden air holes,
if examination for these defects is impractical at the final inspection.

j. Removing and Resetting Permanent Concrete Barrier, Parapet, and Kerbs

Contractor shall reset concrete barrier, parapet, or kerb if the Contract plans or the Engineer require.
If resetting is impossible immediately after removal, the Contractor shall store the units at Engineer-
approved locations and protect them from damage.

k. Temporary Concrete Barrier

Temporary concrete barrier shall be new or used precast barrier complying with the requirements of
the Contract plans for precast barrier, except the following:

•

Lengths may differ from those shown in the Contract plans

•

Permanent lifting holes less than 100 mm in diameter may remain

•

Lifting loops are permitted

•

A stamp or stencil reading “temporary” shall be visible on each barrier segment

Permanent barriers that will be removed and reset per the Contract plans or the direction of the
Engineer may be used as temporary concrete barrier without being stamped or stencilled
“temporary.” Any permanent barrier damaged during its use as a temporary barrier will become the
property of the Contractor and be replaced with an undamaged permanent barrier at no expense to
the Owner when the permanent barrier is reset to its location.

All barrier shall be in good condition, without cracks, chips, spalls, dirt, or traffic marks. If any barrier
segment becomes damaged during or after placement, the Contractor, at no expense to the Owner,
shall immediately repair it to the Engineer

’s satisfaction or replace it with an undamaged section.

As soon as the temporary barrier is no longer needed, the Contractor shall remove it from the site of
the works. Owner-furnished barrier shall remain Owner property, and the Contractor shall deliver it
to a stockpile site noted in the Contract or to locations approved by the Engineer. Contractor-
furnished barrier shall remain the property of the Contractor.

As an alternative to precast temporary barrier, and only with the approval of the Engineer, the
Contractor may use a quick-change moveable barrier (QMB) system with a QMB machine, both of
which shall be installed and operated by the Contractor

in accordance with the manufacturer’s

instructions.

7.6 Sidewalks

7.6.1 Description

This work constructs sidewalks in accordance with lines, grades, and details shown in the Contract
plans and these standard specifications or as established by the Engineer. Types of sidewalk consist
of the following:

•

Cement concrete sidewalks

•

Pervious concrete sidewalks

•

Pavers sidewalks

•

Tile sidewalks

•

Architectural concrete sidewalks

7.6.2 Materials

Materials shall meet the requirements of Table 7-31. Concrete for cement concrete sidewalks shall
be Class C20/20 concrete that meets the requirements of Chapter 4, Concrete Works.

Table 7-31: Material requirements for sidewalks

Material

Specifications Requirements

Concrete

and

its

constituent

materials;

premolded joint filler; curing materials

Section 4.3 of Chapter 4, Concrete Works

Concrete pigment; decorative finishes; concrete
stain

Section 7.8

Geotextile fabric

Article 2.5.2.9 of Chapter 2, Earthworks

Pervious concrete

Article 4.3.10.6 of Chapter 4, Concrete
Works, and Section 7.6.5

Adhesives for tiles

Epoxy-resin-base adhesive

BS EN 12004:2007

ASTM C881M

For the purpose of examining and sampling the materials, the Engineer shall have access at all times
to the place where paving blocks and other items and their constituent materials are manufactured
and stored.

Before the Contractor may begin the work, the Engineer must approve all materials.

7.6.2.1

Quarry Tiles

Quarry tiles shall be standard grade per the minimum grade specifications established by the Tile
Council of North America (TCNA) and in compliance with the following standards:

•

BS EN 14411

•

ANSI A 137.1

Materials shall match the Engineer

’s samples. Quarry tiles shall be manufactured from fine

stoneware clay mixed with 15 % chamotte, which is burnt klinker fragments and fired in a kiln with a
minimum temperature of 1,200

C. Quarry tiles shall also meet the materials specifications of Table

7-32.

Table 7-32: Required physical properties for quarry tiles

Property

Standard

Requirement

Material

Burnt (kiln fired), extruded clay tile, unglazed,
with

ribbed

underside

and

coloured

throughout.

Dimensions

240 mm by 115 mm by 13 mm, ±5 %

Density

2200 kg/m

to 2500 kg/m³

Water absorption

6 % maximum

Flexural strength

27 N/mm² minimum

Scratch hardness

– 7 hardness according to Moh's scale

Coefficient

thermal

expansion

4.0 by 10

-6

Chemical resistance

ASTM C650

No visible change

Static coefficient of friction

Walkways and steps

Ramps

ASTM C1028

Minimum 0.6

Minimum 0.8

Materials for quarry spalls shall additionally conform to Section 4.3 of Chapter 4, Concrete Works,
including, but not by way of limitation, cement, sand, joint filler, and sealer for expansion joints. Sealer
colours shall match that of the grouted tile joints. Other materials shall be used only with the approval

of the Engineer. Manufacturer specifications and installation instructions for materials to be used
shall be submitted to the Engineer for approval prior to start of the work.

Contractor shall obtain each material required for any type and colour of tile work from a single
source, so as to minimise variations in appearance and quality. Tile shall be factory-blended and
packaged accordingly, so that tile units taken from one package show the same range in colours as
those taken from other packages and match approved samples. If the tiles have not been factory
blended, the Contractor shall either return them to the manufacturer or blend tiles at the site of the
works before installing, to the satisfaction of the Engineer.

Packaged  materials  shall  be  delivered  and  stored  in  original  containers  with  seals  unbroken  and
labels intact until time of use. Labels shall comply with ANSI A 137.1. Damage or contamination to
materials by water, foreign matter, or other causes shall be prevented.  Handle tile with temporary
protective coating on exposed surfaces to prevent coated surfaces from contacting backs or edges
of  other  units.  If  despite  these  precautions  coating  does  contact  bonding  surfaces  of  tile,  the
Contractor shall remove coating from bonding surfaces before setting tile.

Adhesives formulated for tile and recommended by their manufacturer shall by used for the
application indicated. Materials for setting the tiles shall conform to the following requirements:

1. For thick bed applications: Latex-Portland cement mortar per ANSI A 118.4 with liquid-latex

additive such as Laticrete 3701 or approved equal

2. For thin-set applications and slurry bond coats at mortar and bed applications: a mixture of

dry-mortar mix and latex additive such as Laticrete 4237 or an approved equal

Grout shall be as recommended by the manufacturer for the type of tiles. Latex-portland cement
grout shall meet the requirements of Article 4.3.10.4 of Chapter 4, Concrete Works.

7.6.2.2

Precast Tile Blocks

Precast tile blocks consist of a precast  concrete base and quarry tiles specified in  Article 7.6.2.1.
Precast  tile  blocks  shall  be  furnished  as  shown  on  the  Contract  plans  to  the  lines  and  grades
approved by the Engineer. Installation of precast tile blocks shall likewise comply with the Contract
plans, these Specifications, as approved by the Engineer.

Quarry tile shall be per Article 7.6.2.1. Latex-portland cement mortar shall meet the latex
manufacturer's recommendations. Concrete shall be Class C25/20 and its reinforcing shall conform
to ASTM A185M.

Precast tile blocks shall be constructed as follows:

1. Precast tile blocks shall be installed, where quarry tiles cross service reservations and ducts

are not provided, to the lines and grades determined by adjacent quarry tiles

2. Construction of the precast concrete base shall be as shown on the Contract plans using Class

C25/20 concrete

3. Placement of quarry tiles shall be on a 5-mm-thick latex portland cement mortar in accordance

with ANSI A 108.5 and ANSI A 118.5 and shall match the pattern and colour of quarry tiles
elsewhere in the project

4. Pointing and grouting material shall be latex portland cement mortar

7.6.3 Construction Requirements

7.6.3.1

General

Sidewalks shall be installed to the lines, grades, and details shown on the Contract plans, as may
be required by the Particular Specifications, as approved by the Engineer. Geotextile fabric shall be
used  where  shown  on  the  Contract  plans,  as  approved  by  the  Engineer.  Except  as  otherwise
approved  in  writing  by  the  Engineer,  the  following  standards  shall  be  met  for  all  new  sidewalk
installations:

ONSTRUCTION

•

Detectable warning strip extending the width of the ramp and 600 mm from the kerb flow line

shall be installed per the details provided on the Contract plans

•

Abrupt changes in sidewalk elevation shall not exceed 6 mm

•

Cross slope of the sidewalk shall not exceed 2 %

•

Kerb ramp grades shall not exceed 8.3 %

•

Sloped flares adjacent to the kerb ramps shall not exceed 10 % slope

Where a sidewalk crosses a concrete driveway, the sidewalk depth and reinforcement shall not be
less than the driveway cross-sectional details shown on the Contract plans.

Completed sidewalks shall demonstrate a well-compacted mass, a surface free from voids and
honeycombs, and dimensions true-to-line shape and grade.

Unless otherwise shown on the Contract plans or required by the Particular Specifications, sidewalks
shall typically be 100 mm thick, or 150 mm thick where they parallel depressed kerbs or cross
driveway entrances.

Sidewalks on bridge decks shall not be constructed until prestressing is complete, formwork has
been removed, and the bridge deck has been surveyed to establish final lines and levels.

7.6.3.2

Preparation of the Foundation

Excavations shall be made to the required depth and to a width that will permit the installation and
bracing of the forms. Foundations shall be shaped and compacted to a firm-even surface conforming
to the section shown in the Contract plans. Foundation materials shall be compacted to a density of
not less than 95 % of the maximum density.

All soft and yielding material shall be removed and replaced with acceptable material at least 150
mm deep, per Article 2.4.2.5 of Chapter 2, Earthworks. If borrow is required, it shall conform to
2.5.2.2 of Chapter 2, Earthworks. If bedding aggregate is required, it shall be placed in layers of not
more than a 100-mm compacted thickness. Each layer shall be compacted with at least 3 passes of
a lightweight mechanical tamper, roller, or vibratory system. If a base course of concrete is required,
it shall be Class C15 concrete.

After the forms have been set to line and grade, the foundation shall be brought to the required
grade. Prior to concrete placement, the Contractor shall thoroughly wet the foundation. At the time
of concrete placement, the forms shall contain no extraneous material or standing water.

Existing concrete surfaces shall be free of loose or foreign material, scrubbed with wire brooms, and
kept wet before new concrete is placed. Immediately before placement, the old surface shall be thinly
coated with a Class M5 mortar meeting the requirements of Article 4.3.10.4 of Chapter 4, Concrete
Works.

7.6.3.3

Formwork

Formwork shall comply with Section 1.20.8 of Chapter 1, General Requirements, and extend for the
full depth of the concrete.

Forms shall be of wood or metal in accordance with Article 1.20.8.2 of Chapter 1, General
Requirements, and shall extend for the full depth of the concrete. All forms shall be straight, free
from warp, and of sufficient strength to resist the pressure of the concrete without springing. Bracing
and staking of forms shall be such that the forms remain true to the required alignment, horizontal
and vertical, until their removal.

Clamps, spreaders, and braces shall be used, where required, to insure rigid forms.

7.6.3.4

Screed Rail Supports

Screed rail supports, if used, shall be placed 600 mm on centres.

ONSTRUCTION

Before concrete operations are started, the screed shall be operated over the full length of sidewalk
to be constructed and the depth of construction shall be checked. Screed rails shall be adjusted, as
needed, to install sidewalks as shown on the Contract plans, as approved by the Engineer.

7.6.3.5

Acceptance

Completed sidewalks shall have clean planar faces, be free of segregation, honeycombing, pits,
broken corners or other defects, and show no evidence of external rendering.

After curing, the Contractor shall wash the surface with brush and water to remove all laitance and
cement from the exposed, coarse aggregate.

Before acceptance of the work, all sidewalks shall be cleaned of all discolouration resulting from the
Contractor's operations, including, but not limited to, dirt, stains, bitumens, and equipment tire marks.
Cleaning may be by abrasive blast methods or by other methods approved by the Engineer.

Concrete sidewalk surfaces shall be tested with a 3-m straightedge. Any deviation in excess of 6
mm shall be corrected by the Contractor to the satisfaction of the Engineer at no additional expense
to the Owner.

7.6.3.6

Kerb Ramps

Kerb ramps shall be of the type specified in the Contract plans. Along kerb ramps, the kerb, including
the bed backing, shall be dropped to show a face of 25 mm or less, or as otherwise designated.

Kerb ramps shall be cast-in-situ. Forms shall meet the requirements of Article 7.6.3.3 and Section
1.20.8 of Chapter 1, General Requirements.

Expansion joints shall be placed in all concrete sections larger than 3 m in any direction as well as
between existing concrete works and the new concrete. New concrete shall be tied to adjacent
existing concrete by drilling and epoxying dowels into the existing concrete face where any of the
following conditions are met:

•

Excessive load transfers are possible

•

Foundation for the ramp provides only marginal support capability

Ramp finishes shall be as shown on the Contract plans and in conformance with the requirements
of the applicable section of these specifications. For instance, a sidewalk finish, a tile finish, or other
finish may be specified. Exposed ramp surfaces shall be protected by a clear, penetrating sealant
meeting the requirements of Section 29.6.1 of Chapter 29, Miscellaneous Items for Structures.

A detectable warning pattern shall be required for all new sidewalk ramp installations. Detectable
warning patterns shall have a truncated-dome shape and may be installed using a manufactured
material before or after the concrete has cured, or by installing masonry or ceramic tiles. Embossing
or stamping the wet concrete to achieve the truncated-dome pattern or using a mould into which a
catalyst hardened material is applied shall not be allowed. When masonry or ceramic tiles are used
to create the detectable warning pattern, the Contractor shall block out the detectable warning
pattern area to the depth required for installation of the tiles and finish the construction of the concrete
ramp. After the concrete has set and the forms have been removed, the Contractor shall install the
tiles using standard masonry practices.

Dimensions and details of the detectable warning pattern area on the ramp shall be as shown on the
Contract plans. Unless otherwise shown on the Contract plans, colour shall be yellow and match
Federal Standard 595C, colour number 33538.

7.6.3.7

Ramp Detectable Warning Retrofit

Where shown in the Contract plans, the Contractor shall retrofit existing cement concrete sidewalk
ramps by installing a detectable warning pattern having a truncated-dome shape and in conformance
to the details shown on the Contract plans. Warning patterns shall be the width of the ramp and

cover the bottom 600 mm of the ramp. Truncated-dome patterns shall be perpendicular to the long
axis of the ramp.

Warning patterns shall be capable of being bonded to an existing cement concrete surface. Surface
of the warning pattern, excluding the domes, shall not be more than 10 mm above the surface of the
concrete after installation.

7.6.4 Cement Concrete Sidewalks

7.6.4.1

Concrete Placement, Finishing and Texturing

Concrete shall be mixed and placed in accordance with Sections 4.3 and 4.4 of Chapter 4, Concrete
Works. Sidewalks may be constructed either by the use of conventional fixed forms or by slip-form
machines.

Slip-form equipment shall comply with the requirements established in Article 7.5.3.4, for slip-form
equipment. All applicable requirements of sidewalk construction by use of fixed forms shall apply to
the use of slip-form equipment.

After  placement  in  the  forms,  concrete  shall  be  struck  off  or  screeded  with  approved  equipment.
During  the  placing  and  finishing  of  concrete,  premolded  joint  filler  for  expansion  joints  shall  be
restrained in its proper position.

Concrete shall be thoroughly worked so that the coarse aggregate is below the surface and the
mortar comes to the top.

7.6.4.2

Joints

Expansion, Contraction, and construction joints shall be constructed in the locations, at the intervals,
and to the thicknesses shown on the Contract plans. All free mortar and concrete shall be removed
from the joints.

Expansion joints shall be placed vertically across the full cross section of the sidewalk at the following
locations, unless otherwise shown in the Contract plans or directed by the Engineer:

1. At locations that match the spacing of expansion joints in adjacent kerb, kerb and gutter, or

pavement.

2. At tangent points or kerb returns

3. Between the sidewalk and all structures and foundations.

4. At a maximum of 12-m intervals.

5. Between sidewalks and driveways.

6. Around poles, posts, boxes, and other fixtures that protrude through the sidewalk.

Workday production shall be terminated at an expansion joint.

Contraction joints shall be formed with a jointing tool or sawed, and shall consist of the following:

a. Constructed vertically

b. Installed at locations shown on the Contract plans or indicated by the Engineer

c. Sawed to a depth of 50 mm or one-third the thickness of the concrete, whichever is greater

d. Formed by parting the large aggregates in the fresh concrete with a straightedge to a depth of

50 mm

e. Constructed at a maximum of 4.5 m intervals

f. Placed at locations that match the spacing of expansion joints in adjacent kerb, kerb and gutter,

or pavement

Longitudinal Contraction joints shall be constructed in the centre of sidewalk having a width greater
than 2 m and parallel to or concentric with the lines of the work.

Where scoring lines are indicated, they shall measure at least 6 mm deep with a 3-mm radius.

Final joint finishing shall be accomplished with a jointer tool having a radius of 6 mm and leaving a
finished joint depth of at least 19 mm. If indicated on the Contract plans or by the Engineer, joints
shall be sealed with a sealer that meets the requirements of Section 4.3.15 of Chapter 4, Concrete
Works.

Contraction joints shall be formed around all appurtenances, such as manholes, utility poles,
buildings, bridges, and where abutting an existing or separately placed kerb.

7.6.4.3

Curing

Concrete sidewalks shall be cured for at least 72 hours using Method A or Method C, as described
in Articles 4.4.2.1 and 4.4.2.3 of Chapter 4, Concrete Works.

During the curing period, all traffic, both pedestrian and vehicular, shall be excluded. Sidewalks shall
be protected from pedestrian traffic for at least 72 hours and from vehicular traffic for at least 7 days.

7.6.4.4

Finishing

Type of finish shall be as shown on the Contract plans, as approved by the Engineer.

Broom finishes shall be constructed in the following manner:

1. Strike-off the surface using a strike board and then float the surface

2. Using a steel trowel, smooth the surface as soon as it can be worked

3. Brush the walking surfaces of the sidewalk and ramps in a direction perpendicular to the

centreline with a stiff bristled broom. Broom from edge to edge with adjacent strokes slightly
overlapped to produce regular corrugations not more than 3 mm deep without tearing the
concrete

4. While the concrete is plastic, correct porous spots, irregularities, depressions, small pockets,

and rough spots

5. Install the Contraction joints or perimeter edging, using an approved grooving tool

6. Tool all exposed edges, including those at expansion joints, using an edging tool with a 6 mm

radius, or as indicated on the Contract plans

Exposed aggregate finish shall be accomplished as follows:

a. Strike-off the surface using a strike board and then float the surface

b. As soon as the concrete hardens sufficiently to prevent particles of gravel from being

dislodged, broom the surface with stiff brooms approved by the Engineer in the following
manner:

1. Broom transversely across the pavement

2. Pull the loosened semi-stiff mortar entirely off the pavement

3. Remove the mortar from all adjacent pavements

4. Broom parallel to the pavement centreline

5. Repeat this operation to expose the required amount of coarse aggregate

c. Exercise care to prevent marring of the surface and cracking or chipping of slab edges or joints

d. If approved by the Engineer, apply a light spray of retardant to the unfinished surface to

facilitate this work

e. Other methods of aggregate exposure, such as using a water spray attachment on a special

exposed aggregate broom, will be permitted if satisfactory results are demonstrated and the
Engineer provides written approval

f. Install the Contraction joints or perimeter edging, using an approved grooving tool

g. Tool all exposed edges, including those at expansion joints, using an edging tool with a 6 mm

radius or as indicated on the Contract plans.

7.6.5 Pervious Concrete Sidewalks

Concrete for pervious concrete sidewalks shall meet the requirements of permeable concrete, as
specified in Article 4.3.10.6 of Chapter 4, Concrete Works.

Pervious concrete sidewalks shall be constructed in careful compliance to the  Contract plans, the
Particular  Specifications,  and  these  Specifications.  Pervious  concrete  shall  be  properly  mixed,
placed, and compacted, as approved by the Engineer, to be effective. Documentation that proves
the following shall be provided by the Contractor to the Engineer:

a. Pervious concrete supplier, the Contractor, and each individual responsible for the installation

of pervious concrete have successfully completed at least 3 pervious concrete installations
within the past 3 years

b. Contractor has at least 3 years of competent work with pervious concrete

c. Any applicable test results from previous jobs, if so requested by the Engineer

Alternately, the Engineer may approve the Contractor for pervious concrete sidewalk installation
based on his successful performance of mixing and placing of trial sections of sidewalk as required
below.

Preparation for the Engineer

’s inspection and approval of a test panel shall be done at the

Contractor

’s expense.

Construction of pervious concrete sidewalks shall not commence until the Contractor has
successfully produced a test panel meeting the following requirements:

1. Test panels shall measure at least 9 m

and be of the same depth as the proposed sidewalk

2. Test panels shall be prepared with the same materials and means, and on the same sub-base,

that the Contractor proposes for use in the final product

3. Test panel shall be marked for identification of batch number and date

4. There shall be no skin of cement or mortar at the bottom or top of the pavement. Such skin

could prevent passage of water through the slab at its designed percolation rate

5. Concrete void spaces shall be 15 % to 20 %

6. Unit weight shall be within ±5 % of the mix design unit weight

7. Using a permeameter, or a procedure that the Engineer and the Contractor agree upon, the

Contractor shall demonstrate that the pavement has a percolation rate of at least 5 m per hour

Preparation of the foundation shall be per Article 7.6.3.17.6.3.2, except that no organic material,
clay, or organic sludge shall be allowed to remain in the soil below subbase.

Subbases shall be installed in accordance with the dimensions, materials, and compaction shown
on the Contract plans, with the additional requirement that the subbase beneath the pervious
concrete must be of enough depth and properly installed to temporarily store the water while it
infiltrates into the soil. If not otherwise shown on the Contract plans, the subbase depth, aggregate
void ratio, aggregate sizing, and subgrade preparation shall meet the requirements of

ADQCC (WA-

726) Stormwater and subsoil drainage system (Vol. 1,2,3, and 4);

for permeable pavement design.

Sub-bases typically consist of at least 150 mm to 250 mm of open-graded aggregate or crushed or
recycled concrete with a geotextile fabric layer between the subgrade soil and the subbase
aggregate.

Prior to the placement of pervious concrete, the sub-base shall be tested for the rate of permeability
by the double-ring infiltrometer, or another suitable test, as approved by the Engineer. Test borings
are recommended to determine soil conditions and water table level. Borings may not be required,
if undisturbed soil under the base demonstrates good permeability and stability and has not been
disturbed for 3 years or more. Permeability testing and certification, if required, shall be the
responsibility of the Contractor.

Forms shall be steel unless the Contractor can successfully demonstrate that reinforced plastic or
plastic-coated plywood forms will not warp or move under screed vibration and compaction.
Appropriate release agents shall be applied to the forms before placing concrete and rollers used in
compaction. When debris or aggregate begins to stick to compaction rollers, they shall be cleaned
and recoated with a release agent to prevent ravelling.

Pervious  concrete  shall  be  delivered,  installed,  finished,  and  cured  in  a  similar  manner  to
conventional concrete except that the requirements  of  Table 7-33 shall supersede any conflicting
requirements for conventional concrete.

Table 7-33: Requirements for the installation of pervious concrete

Preparation of the subgrade:

•

Subgrade shall be moist with no standing water immediately prior to concrete placement.

Acceptance of concrete:

•

Shall be based on visual inspection of each load for consistency and aggregate coating.

•

Shall be based on unit weight of each load in lieu of slump tests. Pervious concrete is so

stiff that slump testing does not provide meaningful quality control.

Placement:

•

Pervious concrete shall not be pumped.

•

Discharge shall be a continuous operation completed as quickly as possible.

•

Concrete shall be deposited as close to its final position as practicable.

•

Fresh concrete shall be entered and adhere to the mass of previously placed green

concrete.

•

Workers shall spread pervious concrete in advance of the screed without stepping in the

pervious concrete because footsteps could prevent formation of a successful void
structure.

•

A screed shall be used to level off the surface of the pervious concrete.

•

Vibrating screeds, manual screeds, laser screeds, or other screeds are acceptable as

approved by the Engineer with the following qualifications:

i. For vibrating screeds, frequency of vibration shall be low enough to avoid over-

compaction or closing off of the surface.

ii. Manual screeds shall be discontinued if they cause tears in the surface.

•

Screed shall strike-off material above the forms, typically 15 mm to 20 mm, to allow for

compaction.

i. This may be accomplished using temporary strips attached to the top of the form.

ii. Alternatively, height-adjusting screeds may also be used.

•

Edges near forms shall be compacted using 300 mm by 300 mm steel tamp, or a similar

device, to prevent ravelling.

•

Any vibration shall be shut off immediately when forward progress is halted for any reason.

•

An evaporation retarder may be applied before compaction to minimise surface water loss,

if approved by the Engineer.

Compaction shall be complete within 15 minutes after placement:

ONSTRUCTION

•

Pervious concrete shall be compacted by a heavy steel roller after screeding.

•

Unless otherwise approved by the Engineer in writing, the Contractor shall provide either

slip-form or form-riding equipment with a following compactive unit that will provide a
minimum of 70 kPa vertical force.

•

After strike-off and compaction, no other finishing operation will be allowed. Pervious

concrete shall not be floated, trowelled, or worked in any other way that might cause the
pavement surface to be sealed or the voids to be filled.

•

Proper compaction shall result in at least 15 % voids.

Curing shall begin within 20 minutes after compaction:

•

After placement, pervious concrete shall be misted with water and then covered with plastic

sheeting and kept damp for at least 7 days.

•

Curing materials shall be secured as quickly as possible.

•

Sheeting shall overlap all exposed concrete and film edges by at least 300 mm.

•

Sheeting shall be secured to the pervious surface to minimise air invasion between the

sheeting and the pervious concrete.

i. If the Contractor elects to use a layer of soil to secure the cover, the Contractor shall

take precautions to prevent spillage or contamination of the fresh pavement in placing
and removing the soil layer. Soil shall be swept off of the sheeting prior to removing
the sheeting.

ii. If rebar or wood are used to secure the sheeting, the Contractor shall make every effort

to minimise bubbles and openings for air.

•

Placement and securing of plastic sheeting shall be approved by the Engineer, and the

Contractor shall comply with the Engineer

’s direction for adjustments to curing

arrangements.

Completed installation shall be the dimensions shown on the Contract plans, ±12 mm in 3 m.

During placement all tools, including screed machines, compaction rollers, rakes, trowels, and forms
shall be kept clean and coated with a release agent to reduce the possibility of ravelling. Compaction
rollers displaying aggregate adhesion will accelerate ravelling and disintegration.

Contraction joints shall not be installed due to the potential for excessive ravelling at the joints.
Expansion joints sufficiently accommodate Contraction, and minor cracking is not detrimental to the
surface aesthetic or the structural integrity of pervious concrete. Expansion joints shall be installed
in the following manner:

a. At the locations and to the dimensions shown in the Contract plans or directed by the Engineer

b. At the same locations as in adjacent pavements to avoid reflective cracking

c. At intervals of 12 m to 18 m

d. Directly after consolidation using a rolling joint tool approved by the Engineer, or by driving a

steel straightedge to the required depth with a hammer

e. To a depth of one-quarter the thickness of the pavement

If joints are not installed directly after compaction, they may be saw cut into the pervious pavement,
preferably occurring within 4 days of completing concrete placement, and no later than 7 days after
concrete placement. To perform saw cuts during the curing period, the Contractor shall sweep the
plastic covering, slit it, and fold it back to accommodate the saw cut. Upon completion of the saw
cut, the Contractor shall fold the plastic back over the edges, cover the slit with a new piece of plastic
that overlaps each side by 300 mm or more, and secure the plastic for the remainder of the curing
period.

When a pour is interrupted, it should be terminated against a form and properly compacted. A 45°
groove measuring 25 mm deep shall be created adjacent to the form. When the pour is continued

thereafter, a similar groove shall be formed into the joint formed by the new pour, matching the
previous groove. Resulting V-shapes can then be filled with an approved joint filler.

No sand or soil shall be stored or placed directly on pervious surfaces. Contractor shall schedule
pervious installation as near the conclusion of a construction project as possible. At the Engineer

’s

request, the Contractor shall vacuum pervious concrete before opening the area to pedestrians and
traffic.

7.6.6 Paver Sidewalks

Materials, tolerance, curing, and installation requirements for interlocking concrete paving blocks
shall be in accordance with Section 7.9. Other type of pavers for sidewalks shall be in accordance
with the requirements specified herein.

Kerbs or edging abutting the areas to be paved shall be laid in advance of paver installation.

Preparation of the foundations shall be per Article 7.6.3.17.6.3.2. Where specified, or required by
the Engineer, the prepared surface shall be treated with an approved environmentally compatible
herbicide and ant poison before the layer of sand for bedding is placed.

Layers of uncompacted sand shall be screeded to a depth of 50 mm over the compacted base. This
layer of bedding sand shall not be used for levelling. Sand shall be spread and then left loose and
protected against precompaction, including compaction by rain or dew. Any sand that has
precompacted shall be loosened in advance of the laying face to the extent to which paving will be
completed that day. Sand shall continue to be lightly screeded by the Contractor in a loose condition
to the predetermined depth, slightly ahead of laying the paving units.

Pavers with chips, cracks, voids, discolouration, and other visible defects shall not be used. Pavers
from several pallets or cubes shall be mixed as they are placed to produce a uniform blend of colours
and textures. Pavers shall be cut with a motor-driven masonry saw or block splitter equipment to
provide clean, sharp, unchipped edges.

When laying the pavers, the Contractor shall ensure that the blocks avoid disturbance of the sand
cushion until the unit is in its correct position. Disturbances to adjacent pavers shall likewise be
avoided.

Pattern for laying the paving blocks and their thickness shall be as shown on the Contract plans, as
approved by the Engineer. Unbroken blocks shall first be laid and filler pieces afterwards. Filler
pieces shall be neatly sawn or hewn to fit exactly into the space to be filled. Spaces of less than 25
% of a full-sized block may be filled with Class C30 concrete. Top faces of blocks shall be flush.

After each 15-m

to 20-m

area of paving blocks has been laid, the pavement shall be compacted by

2 passes of a suitable vibrating-plate compactor operating at a frequency of 65 hz to 100 hz and a
low amplitude with the following requirements:

1. For 60-mm-thick blocks, the compactor shall have a centrifugal force of 7 kN to 16 kN and a

plate area of 0.2 m

to 0.4 m

2. For 80-mm-thick blocks, the compactor shall have a centrifugal force of 16 kN to 20 kN and a

plate area of 0.35 m

to 0.5 m

Two  passes  shall  be  made  at  90  degrees  of  each  other,  and  the  plate  compactor  shall  not  pass
closer  than  1  m  to  a  temporarily  unrestrained  edge  during  laying.  No  paving  shall  be  left  in  an
uncompacted condition overnight, except for the 1 m strip at the temporarily unrestrained edge.

After compaction of the pavement as described above, joint and Class M3 mortar, per Article 4.3.10.4
of Chapter 4, Concrete Works, shall be spread and brushed into the joints until the joints have been
properly  filled.  After  the  joint  material  has  dried,  any  surplus  sand  shall  be  broomed  off  and  the
pavement shall then be subjected to 2 further passes by the plate vibrator.  If necessary, the joint
sand shall be filled again and further passes of the plate vibrator shall be made in each direction,
until  the  sand  is  no  longer  absorbed  into the  joints.  Joint  widths  between  blocks  shall  be  per the
Contract plans, typically between 2 mm and 6 mm.

Abu Dhabi, United Arab Emirates. STANDARD CONSTRUCTION SPECIFICATIONS (PART 1 - ROADS, Second Edition 2020) - page 47