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

e) Mixing temperature range and minimum compaction temperature for the performance

grade asphalt to be used in the mix

iii. Antistrip additives: If part of the job-mix formula:

a) 0.5 liter of liquid antistrip additive or 5 kg of cement, fly ash, or lime antistrip additive

b) Name of product

c) Manufacturer

d) Material safety data sheet

e) Dosage rate

iv. Recycled asphalt pavement material. If part of the job-mix formula:

a) Source and percentage of recycled asphalt pavement material

b) Average gradation of the recycled asphalt pavement material

c) Percent asphalt binder in the recycled asphalt pavement

d) Target value for the asphalt binder content (that considers the percent asphalt binder

in the recycled asphalt pavement) and the percent new (virgin) asphalt binder to be
added to the mix

e) 100 kg representative sample of recycled asphalt pavement material. For existing

pavements, mill where designated by the Engineer to the pavement removal depth.
Sample the removed material and replace it with an approved asphalt concrete mix.
Do not use the replacement material in the recycled mix

f) 4 liters of recycling agent, if part of the job-mix formula

3. Verification

Engineer will review and shall perform design verification testing. If verification testing is
performed, the information supplied in the Contractor

’s design must agree with the verification

test results within the tolerances shown below.

i. Aggregate gradations: Representative aggregate samples from each stockpile, when

combined according to the Contractor

’s recommendation for stockpile percentages, shall

be within the gradation defined by the target values plus or minus the following tolerance
for each sieve.

Table 3-25: Aggregate gradation target value tolerances

Sieve Size

Tolerance, % (±)

25 mm

3.0

19 mm

3.0

12.5 mm

3.0

9.5 mm

3.0

4.75 mm

3.0

2.36 mm

3.0

425



2.0



1.0

ii. Voids in mineral aggregate (VMA): Contractor

’s VMA result is verified if the Engineers

result is not below the minimum specification limit.

iii. Voids filled with asphalt (VFA).

The Contractor

’s VFA result is verified if the Engineers

result is within the specification limits in Table 3-24

iv. Air voids (Va): Contractor

’s Va result is verified if the Engineers result at the same design

asphalt binder content is within 1.0 % of the specification value.

v. Tensile strength ratio (TSR): Contractor

’s percent retained strength result is verified if the

Engineers result is above the minimum specification value.

4. Changes and Resubmissions

If  a  job-mix  formula  is  rejected  or  a  material  source  or  the  recycled  asphalt  pavement  is
changed, submit a new job-mix formula for acceptance.  Up to 21 days may be required to
evaluate a change.  Approved changes in target values will not be applied retroactively for
payment.

Engineer

’s job-mix formula evaluation costs will be deducted from the Contractors payment,

when resulting from the following:

i. Contractor-requested changes to the approved job-mix formula

ii. Contractor requests for additional job-mix formula evaluations

iii. Additional testing necessary due to the failure of a submitted job-mix formula

5. Acceptance

Do not begin mix production until the job-mix formula is accepted by the Engineer.

b. Marshall Method

All of the criteria shown in

Table 3-27 shall be considered in designing and evaluating each type of mix. Optimum bitumen
content determined by the Marshall Method, as per the latest edition of Asphalt Institute MS-2 for
calculating the volumetric properties and for fixing the optimum bitumen content of each type of mix
and the same, shall be used in preparing specimens for the Immersion compression (AASHTO T-
165) test.

1. Types of Asphaltic Concrete

Types of asphaltic concrete mixes shall be as shown on the Contract plans/ typical cross-
sections of the contract drawings and the combined grading shall conform to table 3-28

Table 3-26: Aggregate grading of asphaltic concrete mixes

Base course

Binder course

Wearing course

Coarse

Fine

Sieve opening

size

Percent passing by weight

37.5 mm

100

25.0 mm

72-100

100

19.0 mm

60-89

80-100

86-100

100

12.5 mm

46-76

63-85

69-87

66-95

9.5 mm

40-67

57-77

58-78

54-88

4.75 mm

30-54

40-60

37-70

2.36 mm

22-43

25-45

26-52

Base course

Binder course

Wearing course

Coarse

Fine

Sieve opening

size

Percent passing by weight

1.18 mm

15-36

20-36

20-37

18-40

600 µm

10-28

13-27

13-30

300 µm

6-22

8-19

8-23

150 µm

4-14

5-13

6-16

75 µm

2-8

Table 3-27 Design criteria for hot mix asphalt (HMA)

Properties

Bituminous

base course

Bitumin

ous

binder

course

Bituminous

wearing course

Type/category of

road

Parkin

g lots,

minor

roads,

drivew

ays,

etc.

(light,
traffic

volum

Sector

roads

(mediu

traffic

volume)

Main

roads,

highway

s, truck

roads,

etc.

(heavy

traffic

volume)

All

roads

categori

Parkin

g lots,

minor

roads,

drivew

ays,

etc.

(light,
traffic

volum

Sector

roads

(mediu

m traffic

volume)

Main

roads,

highw

ays,

truck

roads,

etc.

(heavy

traffic

volum

Penetration grade of
bitumen*

60/70

40/50 or

60/70

40/50 or

60/70

60/70 or

40/50

60/70

40/50 or

60/70

40/50

or PG

Number of compaction
blows each end of
specimen by freely
held Marshall hammer

Stability (Marshall)
minimum kg

1000

1100

1200

1300

1400

1500

1600

Flow (Marshall) mm

2 - 4

Stiffness minimum
kg/mm (minimum)

400

500

450

550

❖

Percent air

voids in mix

3 - 5

4 - 7

5 - 7

3 - 5

4 - 7

5 - 7

❖

Percent voids

in mineral
aggregate
(VMA), %
minimum

14.5

❖

Percent voids

filled with

60-75

55-70

50-65

50-70

60-75

55-70

50-65

Properties

Bituminous

base course

Bitumin

ous

binder

course

Bituminous

wearing course

Type/category of

road

Parkin

g lots,

minor

roads,

drivew

ays,

etc.

(light,
traffic

volum

Sector

roads

(mediu

traffic

volume)

Main

roads,

highway

s, truck

roads,

etc.

(heavy

traffic

volume)

All

roads

categori

Parkin

g lots,

minor

roads,

drivew

ays,

etc.

(light,
traffic

volum

Sector

roads

(mediu

m traffic

volume)

Main

roads,

highw

ays,

truck

roads,

etc.

(heavy

traffic

volum

Asphalt Binder
%

Bitumen content % by
weight of mix

3.3-4.0

3.2-3.9

3.1-3.8

3.4-4.1

3.4-4.4

3.4-4.2

Loss of Marshall
stability by
submerging
specimens in water at
60

C for 24 hours as

compared to stability
measured after
submersion in water at
60

C for 30 minutes

(max. % loss)

Residual voids in total
mix checked on the
Job standard grading
but upper percentage
limit of binder content
applying

600 blows

on each face

Residual voids in
total mix by PRD as
per BS 598-104

Filler to bitumen ratio

0.8

–

1.4

Material for asphaltic concrete shall be combined so as to be well graded within the limits given
in Table 3-28. Combined gradations which approach maximum limits on some sieves and
minimum limits on other sieves shall be avoided.

2. Job Mix Formula and Allowable Tolerances

The Contractor shall be responsible for the design and performance of all bituminous mixes.
The  Contractor  shall  submit,  for  the  Engineer's  approval,  a  proposed  "Laboratory  Design
Mixture"  together  with  all  applicable  design  data  meeting  these  specifications  and
requirements of Table 3-26 and

Table 3-27 at least 30 days prior to commencement of the works.

Engineer will review the proposed job-mix formula by the Contractor and shall perform design
verification testing.  The Engineer will take samples of materials proposed for use in the mix in
order to check their quality and to cross check the proposed mix design for which the Contractor
shall  repeat  the  laboratory  design  exercise  in  the  site  laboratory  under  the  supervision  of
Engineer to confirm the Marshall properties submitted by the Contractor and fix the job mix
formula.

The information supplied by the contractor for the laboratory design mixture must agree with
the verification test results

After receiving the approval of aggregate and bitumen from the Engineer, the Contractor shall
make a written request for the approval of the job mix formula prepared by the Contractor under
the supervision of the Engineer in the laboratory.

Approval of the job mix formula by the Engineer shall in no way relieve the Contractor of his
responsibilities and obligations stipulated in the contract and the Contractor shall be
responsible for the soundness of the asphalt paving mixes and the satisfactory execution and
performance of the asphalt paving courses.

After the job mix formula has been established and approved the contractor shall carry out
plant and site trials. All mixes from the plant shall be produced within the following tolerance
as indicated to table 3-30.

Table 3-28: Job mix tolerance (for plant produced mix)

Aggregate retained on 4.75mm sieve or large

± 5.0 %

Aggregate passing 4.75mm sieve and retained on 1.18mm sieve

± 4.0 %

Aggregate passing 1.18mm sieve and retained on 0.075mm sieve

± 2.0 %

Aggregate passing 0.075mm sieve

± 1.0 %

Bitumen Binder

± 0.2 %

Temperature of mixing

± 10

The approved Laboratory Design Mixture shall be used for agreeing the approved Job
Standard Mixture.

Consistently produce a mixture with asphalt content at the target value. Do not use the above
operational tolerance as a means to alter the asphalt content target value.

3. Acceptance Sampling and Testing of HMA Mixture

Samples  of  loose  asphaltic  concrete  mix  shall  normally  be  taken  behind  the  paver  before
compaction  and  shall  be  obtained  in  accordance  with  AASHTO  T-168.  Samples  of
compacted asphaltic concrete shall be obtained by coring in accordance with Method B of
AASHTO  T-230.    Determination  of  bitumen  content  and  extraction  gradation  may  be
performed on either loose or  compacted samples in accordance with AASHTO  T-164 and
AASHTO T-30 except that the ash correction shall be determined by using a bitumenometer.
Specific  gravity  of  the  compacted  asphalt  concrete  cores  will  be  measured  in  accordance
with AASHTO T-230.

4. Marshall Mix Materials

a. Fine Aggregate

Fine  aggregate  is that  portion  of  the  mineral  aggregate  passing  the  2.36  mm  sieve.    Fine
aggregate shall consist of crushed sand and shall be of such gradation that when combined
with  other  aggregates  in  proper  proportions,  the  resultant  mixture  shall  meet  the  required
gradation.  Source of crushed fine aggregate is considered as the crusher site at which it is
produced. Crushed  sand shall be produced by crushing clean coarse aggregate and shall
not be thin, flaky or elongated.

Fine aggregate including filler shall be obtained from 100% crushed gravel or crushed rock
pre-screened to exclude natural uncrushed fine material or weathered unsound fines. Use of
dune sand will not be permitted.

Fine  aggregate  shall  be clean  and  free from  organic  matter,  clay,  cemented  particles  and
other extraneous or detrimental materials.  Individual stockpiles of aggregate containing more
than 10 % by weight of fine aggregate shall be tested for sand equivalent.  Fine aggregates
shall meet the additional requirements listed in Table 3-29

Table 3-29: Hot mix asphalt concrete fine aggregate requirements

Mix design tests

Test method

Requirements

Sampling

AASHTO T-2

Sieve analysis

AASHTO T-27 and AASHTO T-

Sand equivalency

AASHTO T-176

Min. 55 %

Sodium sulfate soundness

AASHTO T-104

Max. 10 %

Magnesium sulfate soundness

AASHTO T-104

Max. 12 %

b. Coarse aggregate

Coarse  aggregate  is  that  portion  of  the  mineral  aggregate  retained  on  the  2.36  mm  sieve.
Coarse aggregate shall consist of crushed natural stones and gravel.  Crushed particles shall
be cubic and angular in shape and shall not be thin, flaky or elongated.  Gradation shall be
such that when combined with other aggregate fractions in proper proportions, the resultant
mixture shall meet the required gradation.  Source of crushed aggregate is considered to be
the crushing site from which it is produced.

Coarse aggregate shall be clean and free from organic matter, clay, cemented particles and
other extraneous or detrimental material. Coarse aggregate shall meet the requirements of
Table 3-30 and Table 3-31.

Table 3-30: Hot mix asphalt concrete coarse aggregate requirements

Project control and mix design

tests

Test method

Requirements

Sieve analysis

AASHTO T-27

and AASHTO T-11

Sampling

AASHTO T-2

Fractured faces base course

AASHTO TP-61

90 % min.

(Two fracture

faces)

Fractured faces wearing course

AASHTO TP-61

90 % min.

(Two fracture

faces)

Project control and mix design

tests

Test method

Requirements

Flakiness

B.S. 812

Less than 30 %

Sodium sulfate soundness

AASHTO T-104

10 % max.

Abrasion loss

AASHTO T-96

40 % max.

Plasticity index (blending with sand to

eliminate plasticity will not be

permitted)

Non plastic

Absorption of coarse aggregate

AASHTO T 85

2 % max.

Table 3-31: Hot mix asphalt concrete aggregate source requirements

Source requirement tests

Test methods

Requirements

Percentage of wear (500 Rev.)

AASHTO T96

37 % max.

Soundness (coarse aggregate)

(5 Cycles, magnesium sulfate)

AASHTO T104

10 % max loss

Soundness (coarse aggregate)

(5 Cycles, magnesium sulfate)

AASHTO T104

12 % max. loss

Absorption of coarse aggregate

AASHTO T85

2 % max.

Specific gravity (fine aggregate)

AASHTO T84

2.75 min.

Specific gravity (coarse aggregate)

AASHTO T85

2.75 min.

c.  Steel slag aggregate

Steel slag aggregate shall be accepted for use in HMA mixtures, as partial or complete
replacement of natural crushed aggregate, for all projects  only within the geographical
areas  under  the  jurisdiction  of  Abu  Dhabi  City  Municipality.  The  percentage  of
replacement of natural aggregates with steel slag aggregate shall be based on suitable
trials  and  tests  to  demonstrate  compliance  with  performance  criteria.  Steel  slag
aggregate  and  HMA  mixtures  with  steel  slag  aggregate  shall  meet  the  requirements
specified in the Appendix 1 of Chapter 3 of these specifications.

d.  Commercial mineral filler

Commercial mineral filler shall consist of finely ground particles of limestone, cement, or
hydrated lime in accordance with AASHTO M-17. It shall be thoroughly dry and free from
lumps and shall meet the gradation requirements of AASHTO M-17.

When hydrated lime is used as mineral filler, the hydrated lime shall comply with the following
requirements:

•

Hydrated lime shall comply with the definitions given in ASTM C51

•

Sampling, packaging and marking of hydrated lime shall be in accordance with ASTM

C50

•

Storage and use of the hydrated lime shall at all times be such as to protect the material

from the weather

•

Hydrated lime shall comply with the gradation shown in Table 3-32 when tested in

accordance with AASHTO T-219.

Table 3-32: Gradation of hydrated lime

Sieve Size

Minimum % passing

600 µm

75 µm

•

When tested by ASTM C25, hydrated lime shall comply with the chemical requirements

shown in Table 3-33

Table 3-33: Chemical requirements for hydrated lime

Test

Requirement

Min.

Max.

Free moisture (%)

3.0

Available lime index as CaO (%)

Carbon dioxide CO

(%)

Unhydrated lime (%)

When cement is used as mineral filler, it shall meet the requirements of Type V cement in
accordance with AASHTO M-85 (ASTM C150).

e. Asphalt Binder

Unless otherwise required in the particular specifications, asphalt binder specified for use in
the asphalt mixes shall be 60-70 or 40-50 penetration grade as per Table 3-34, in accordance
with AASHTO M-20

and as shown in Table 3-34. Asphalt binder for Marshall mix designs

requiring a performance graded (PG) bitumen shall meet the requirements of article 3.3.2.5,
sub-article (a), point 1.

Table 3-34: Penetration grade Asphalt Binder

60 – 70

40 - 50

Test

Min

Max

Min

Max

Penetration @ 25



C, 100 g 5 sec

Flash point, Cleveland open cup,



232

Ductility at 25° C, cm

100

Solubility in trichloroethylene, %

Kinematics viscosity (centistokes) at 135 ° C

240

280

Softening Point Ring & Ball apparatus

Thin film oven test, 3.2 mm, 163



C, 5-hour loss on

heating, %

0.8

Penetration of residue, % of original

(after thin film oven test)

Ductility of residue @ 25



5 cm per minute, cm

ORKS

Second Edition -SEP 2020

Automatic recording equipment shall maintain a record of each material used, including quantity,
number of batches mixed and classification of mix, and dates and times of operations. Form of data
output shall be acceptable to the Engineer.

At all times when concreting is being carried out, the Contractor shall have available sufficient
standby plant to cover the operations of mixing, transporting, placing and compaction of concrete in
the event of plant breakdowns.

A plant appraisal has to be conducted and approved by the Engineer prior to any approval of
concrete mix and batching commencement.

4.3.11.2

Transporting and Placing

Contractor shall arrange his methods for transporting and placing concrete so that:

1. Contamination, segregation or loss of constituents does not occur;

2. Concreting shall proceed continuously for the whole of a pour without interruption by meal

breaks, change of shift, movements of placing positions, and the like;

3. Transport of concrete from mixer to placing equipment shall be only by means of purpose

made a

gitating trucks operated at the manufacturer’s recommended agitating and discharge

speeds, operating continuously from commencement of the pour and discharging within  the
time  specified  in  Table  4-27  from  the  introduction  of  cement  into  the  mixer.  Time  of  such
introduction shall be recorded on the delivery note together with the weight of the constituents
of each mix;

4. Concrete shall be compacted in its final position within 15 minutes of its discharge from the

mixer or from the agitator truck.

Before concreting is commenced, the reinforcement and other embedded items shall be cleaned of
all deleterious matter including concrete 'splash' from previous concreting operations. All forms and
falsework shall be carefully examined and the space to be occupied by the concrete thoroughly
cleaned out.

Adequate notice must be given to the Engineer that areas are ready for concreting to enable the
Engineer to attend and make necessary tests, inspections and checks.

Concrete shall not be placed in any part of the works until the Engineer's consent has been given. If
concreting is not started within 24 hours of consent being given, consent shall again be obtained
from the Engineer. Concreting shall then proceed continuously over the area between construction
joints.

All concrete shall be placed in the positions and to the sequences indicated on the Contract plans,
in the Specification or as directed by the Engineer and by such means as shall prevent
contamination, segregation or loss of constituent materials.

When deposited, concrete shall not have a temperature of more than 32

Concrete shall be deposited as nearly as possible in its final position and shall be brought up in
horizontal layers not exceeding 300mm in compacted depth. Where lateral spreading of concrete in
the forms is necessary it shall be carried out by approved means and not by the use of vibrators.
Concrete shall not be allowed to freely fall more than 1.2 m.

Where chutes are used in the placing of concrete they shall be of an accepted design and shall be
used at slopes acceptable to the Engineer. Concrete shall not be pumped or discharged through
aluminium alloy conduits.

Where concrete is placed by pumping, the Contractor shall take all precautions necessary to regulate
the velocity of discharge in order to prevent segregation of the concrete or damage and distortion to
the reinforcement and other embedded items and formwork.

During the placing of concrete for reinforced work a competent steel-fixer and carpenter shall be in
constant attendance to adjust or correct the position of reinforcement and formwork as necessary.

ORKS

Second Edition -SEP 2020

Time-table for a pour of concrete is to be so arranged that no face of concrete shall be left more than
20 minutes before fresh concrete is deposited against it or more than 90 minutes after the mixing of
the concrete forming the face, whichever is the less.

All concrete shall be compacted using internal (immersion) mechanical vibrators unless otherwise
specified or ordered. Vibrating shall be carried out to a plan acceptable to the Engineer and no
workmen shall be allowed to be operators without having received special training. Vibrators shall
be of approved pattern and arrangement, and care shall be taken to avoid segregation and to ensure
adequate.

A sufficient number of vibrators in serviceable condition shall be on site to ensure that spare
equipment is always available in the event of breakdowns.

Vibration shall not be applied by way of the reinforcement. Where vibrators of the immersion type
are used, contact with reinforcement and all inserts shall be avoided as far as is practicable.

4.3.11.3

Qualification of Concrete Suppliers

All commercially available concrete shall be batched in a prequalified manual, semi-automatic, or
automatic plant as described in this section of these Standard Specifications and per the applicable
requirements of Article 4.3.11.1. Delays to the Contractor due to problems in getting the plant
certified shall not be the responsibility of the Engineer.

Batch plant qualification shall be obtained through a National Ready Mixed Concrete Association
(NRMCA) certified batch plant inspector using the NRMCA batch plant checklist or an equivalent
method as approved by the Engineer. Copies of the following documentation shall be provided by
the Contractor to the Engineer:

Current certificate of conformance

Concrete mix designs

Truck list

Batch plant scale certification

Admixture dispensing certification

Volumetric water batching devices, including water metres and verification

Requirements for central-mixed concrete include the following:

a. Mixers shall be equipped with a timer that prevents the batch from discharging until the batch

has been mixed for the prescribed mixing time.

b. Concrete shall be mixed for at least 1 minute after all materials and water have been introduced

into the drum. Shorter mixing time may be allowed if the mixer performance is tested in
accordance with AASHTO M 157 Annex A1, Concrete Uniformity Requirements.

c. Concrete transported by truck mixer/agitator shall not undergo more than 250-revolutions

before beginning discharging. To remain below this limit, the supplier may agitate the concrete
intermittently within the prescribed time limit. When water or admixtures are added after the
load is initially mixed, an additional 30-revolutions shall be required at the recommended
mixing speed.

d. Tests shall be conducted by either:

1. The project site lab

2. An approved independent lab certified by ADQCC

e. Flow of water into the mixer shall be uniform with a portion of the water entering in advance of

the cementitious material and aggregates and all of the water entering within the first 15
seconds of the mixing time.

Requirements for shrink-mixed concrete include the following:

ORKS

Second Edition -SEP 2020

•

Mixing time in the stationary mixer shall be at least 30 seconds or until the ingredients have

been thoroughly blended.

•

Mixing time in the transit mixer shall be at least 70 revolutions at the mixing speed designated

by the manufacturer of the mixer.

•

Following mixing, the concrete in the transit mixer may be agitated at the manufacturer’s
designated agitation speed.

•

A maximum of 320 revolutions total for mixing and agitation shall be permitted prior to

discharge.

Requirements for transit-mixed concrete include the following:

1. Mixers and agitators shall always operate within the capacity and speed-of-rotation limits set

by the manufacturer.

2. Any fully loaded mixer shall keep the concrete uniformly mixed.

3. All mixers and agitators shall be capable of discharging the concrete at a steady rate.

4. In transit-mixing, mixing shall begin within 30 seconds after the cementitious material is added

to the aggregates.

5. Water used for cleaning the mixer shall be discharged prior to further batching.

Only those transit mixers that meet the following requirements shall be allowed to deliver concrete:

a. Operational revolution counter

b. Functional device for measurement of water added

c. Mixing drums free of concrete build-up

d. Mixing blades that meet the minimum specifications of the drum manufacturer

e. Metal data plates attached to each mixer and agitator that clearly display:

1. Maximum concrete capacity of the drum or container for mixing and agitating; and

2. Rotation speed of the drum or blades for both the agitation and mixing speeds

A copy of the manufacturer’s blade dimensions and configuration on file at the concrete
producer’s office

g. No components made of aluminium or magnesium alloys that contact plastic concrete during

mixing and transporting

h. Smooth, mortar-tight, metal bodies capable of discharging the concrete at a satisfactory

controlled rate without segregation. If discharge of concrete is accomplished by tilting the body,
the surface of the load shall be retarded by a suitable baffle.

For each project, the plant manager shall examine mixers and agitators to check for any build-up of
hardened concrete or worn blades biannually, or as required. If this examination reveals a problem,
or if the Engineer wishes to test the quality of the concrete, slump tests may be performed with
samples taken at approximately the one-quarter and three-quarter points as the batch is discharged.
Maximum allowable slump difference shall be as follows:

•

If the average of the 2 slump tests is <100 mm, the difference shall be <25 mm; or

•

If the average of the 2 slump tests is >100 mm, the difference shall be <37 mm

If the slump difference exceeds these limits, the equipment shall not be used until the faulty condition
is corrected. However, the equipment may continue in use if longer mixing times or smaller loads
produce batches that pass the slump uniformity tests. All concrete production facilities shall be
subject to verification inspections at the discretion of the Engineer. Verification inspections are a
check for current scale certifications, accuracy of water metering devices, accuracy of the batching

ORKS

Second Edition -SEP 2020

process, and verification of coarse aggregate quality. If the concrete producer fails to pass the
verification inspection, the following actions shall be taken:

1. For the first violation, a written warning shall be provided.

2. For the second violation, the Engineer shall give written notification and assess a price

reduction equal to 15% of the invoice cost of the concrete that is supplied from the time of the
infraction until the deficient condition is corrected.

3. For the third violation, the Contractor is suspended from providing concrete until all deficiencies

causing the violation have been permanently corrected and the plant and equipment have
been re-inspected and meet all the prequalification requirements.

4.3.11.4

Batching and Delivering Permeable Concrete

Batching of permeable concrete requires special attention.  Batch plant shall ensure that aggregate
has been triple washed to remove fines and stored in a no-fines silo.  Trucks to be used in delivering
and mixing the material shall have their drums thoroughly flushed and cleaned prior to loading.

4.3.12

Acceptance of Concrete

All concrete shall be accepted based on the approved qualifications of the materials, mix and the
testing of the as-delivered mixed concrete to the jobsite. All concrete shall be accepted based on
adherence to the requirements of these standard specifications for temperature, slump, air content,
and compressive strength at 28 days, as tested and determined by the Engineer.

A sublot is defined as the material represented by an individual strength test. An individual strength
test is the average compressive strength of cubes from the same sample of material.

Each sublot shall be deemed to have met the specified compressive strength requirement when both
of the following conditions are met:

a. Individual strength tests do not fall below the specified strength by more than 12.5 % or 3.5

MPa, whichever is least.

b. An individual strength test averaged with the 2 preceding individual strength tests meets or

exceeds specified strength for the same class and exact mix number of concrete on the same
Contract.

When compressive strengths fail to satisfy one or both of the above requirements, the Contractor
may request acceptance of in-place concrete strength based on core results. This method shall not
be used if the Engineer determines coring would be harmful to the integrity of the structure. If allowed,
the Contractor shall obtain the cores in accordance with AASHTO T 24M and deliver them to the
Engineer for testing in accordance with AASHTO T 22. If the concrete in the structure will be dry
under service conditions, the core will be air dried at a temperature of between 15

C and 27

C and

at a relative humidity of less than 60 % for 7 days before testing, and shall be tested air dry.

Acceptance for each sublot by the core method requires that the average compressive strength of 3
cores be at least 85 % of the specified strength with not 1 core less than 75 % of the specified
strength. When the Contractor requests strength analysis by coring, the results obtained shall be
accepted by both parties as conclusive and supersede all other strength data for the concrete sublot.

If the Contractor elects to core, cores shall be obtained no later than 50 days after initial concrete
placement. Engineer must concur in the locations to be cored. Repair of cored areas shall be the
responsibility of the Contractor. Cost incurred in coring and testing, including repair of core locations,
shall be borne by the Contractor.

4.3.12.1

Certification of Compliance

Commercial suppliers shall provide a certificate of compliance for each truckload of concrete.
Certificate of compliance shall verify that the delivered concrete is in compliance with the mix design
and a responsible representative of the concrete producer shall sign it, affirming the accuracy of the
information provided. For ready-mix concrete, the certificate of compliance shall include as a

ORKS

Second Edition -SEP 2020

minimum the batching facility, date, and quantity batched per load. Certificates of compliance shall
include the information given in Table 4-23, and may be machine-produced records or printed forms
filled in by hand. Ready-mix commercial concrete shall be subject to the Engineer

’s acceptance

testing of the as-delivered product as specified in Section 4.3.12.

Table 4-23: Certificate of compliance requirements for each truckload of concrete

Manufacturer plant or batching facility

Contracting agency Contract number

Date

Time batched

Truck number

Initial revolution counter reading

Quantity batched this load

Type of concrete by class and producer design mix number

Cementitious material producer, type, and mill certification number. Mill test number as required
by Section

Packaging and Marking i

s the basis for acceptance of cementitious material

10.

Fly ash, if used, brand and type

11.

Mix design weight per cubic metre and actual batched weights for:

12.

Cementitious material

13.

Fly ash, if used

14.

Coarse aggregate and moisture content for each size

15.

Fine aggregate and moisture content

16.

Water, including free moisture in aggregates

17.

Admixtures brand and total quantity batched

18.

Air-entraining admixture

19.

Water reducing admixture

20.

Other admixtures

21.

Approved aggregate gradation designation

22.

For concretes that use combined aggregate gradation, the certificate of compliance shall include
the aggregate components and moisture contents for each size in lieu of the aggregate information
described above.

4.3.12.2

Conformance to Mix Design

Cementitious materials and coarse and fine aggregate weights shall be within the following
tolerances of the mix design:

Table 4-24: Conformance to mix design in production

Condition:

Batch Volume ≤ 4 m

Batch Volume > 4 m

Cementitious materials in mix

Cement

+5 % -1 %

Aggregate

+10 % -2 %

+2 % -2 %

Fly ash

+5 % -1 %

Ground granulated
blast-furnace slag

+5 % -1 %

Microsilica

±10 %

Water shall allow for moisture content of aggregates, volume of liquid admixtures, and shall not
exceed the maximum water specified in the mix design.

ORKS

Second Edition -SEP 2020

4.3.12.3

Sampling and Testing Methods

Concrete properties shall be determined from concrete as delivered to the project and as accepted
by the Contractor for placement. It shall be the Contractor

’s responsibility to provide adequate and

representative samples of the fresh concrete to a location designated by the Engineer for the testing
of concrete properties and making of specimens. Sampling and testing methods for acceptance of
concrete for slump, temperature, and air content, if applicable, shall be completed by the Contractor
and Engineer as follows:

Table 4-25: Sampling and testing methods for acceptance of concrete

Concrete Property or Process

Test Method

Sampling freshly mixed concrete

AASHTO T 141

Slump of hydraulic cement concrete

AASHTO T 119M

Temperature of freshly mixed cementitious material concrete

AASHTO T 309M

Air content of freshly mixed concrete by the pressure method

AASHTO T 152

Making and curing of concrete cube test specimens

BS EN 12390-1, BS EN 12390-2

Compressive strength testing of cube test specimens

BS EN 12390-3

Sampling and testing shall be performed as follows:

a. Before concrete placement from the first truck load.

b. For each load until 2 successive loads meet all applicable acceptance test requirements.

c. On 1 for every 5 truckloads, after 2 successive tests indicate that the concrete is within

specified limits.

d. When the results for any subsequent acceptance test indicate that the concrete, as delivered

and approved by the Contractor for placement, does not conform to the specified limits, the
sampling and testing frequency shall be resumed for each truck load. Whenever 2 successive
subsequent tests indicate that the concrete is within the specified limits, the random sampling
and testing frequency of 1 for every 5 truckloads may resume.

Except for the first load of concrete, up to 0.5 m

may be placed prior to testing for acceptance.

Loads to be sampled shall be selected per a random selection process.

Sampling and testing for a placement of one class of concrete consisting of 50 m

or less shall be

as listed above, except that sampling and testing shall continue until 1 load meets all of the applicable
acceptance requirements. After 1 set of tests indicate that the concrete is within specified limits, the
remaining concrete to be placed may be accepted by visual inspection.

Contractor performed testing shall be performed by a testing laboratory whose equipment has been
calibrated within 1 year prior to testing, and testers shall be either ACI certified or qualified in
accordance with AASHTO R 18.

Concrete shall be tested for compressive strength per BS EN 12390-3 at the same frequency as the
acceptance tests for temperature, consistency, and air content. Six test cubes shall be taken at each
time, numbered consecutively and marked with the date, the section of work from which it was taken
and any other information required. Cubes shall then be dispatched to the approved laboratory for
curing and testing for compressive strength.

Contractor shall provide and maintain cure boxes for curing concrete test cubes and shall provide,
maintain, and operate all necessary power sources and connections needed to operate the curing
box. Concrete cubes shall be cured in a cure box in accordance with AASHTO T 23. Cure boxes
shall maintain a temperature between 16

C and 27

C for concrete with specified strengths less than

40 MPa and between 20

C and 26° C for concrete with specified strengths of 40 MPa and higher. A

ORKS

Second Edition -SEP 2020

minimum/maximum thermometer shall be installed to measure the internal temperature of the cure
box. Thermometer shall be readable from outside of the box and be capable of recording the high
and low temperatures in a 24-hour period. Cure boxes shall create an environment that prevents
moisture loss from the concrete specimens. Box tops shall have a working lock and the interior shall
be rustproof.

A  moisture-proof seal  shall  be  provided  between  the  lid  and  the  box.  Each  cure  box shall  be the
appropriate  size  to  accommodate  the  number  of  concrete  acceptance  cubes  necessary  or  the
Contractor shall provide additional cure boxes. Once concrete cubes are placed in the cure box, the
box  shall  not  be  moved  until  the  cubes  have  been  cured  in  accordance  with  these  Standard
Specifications. When concrete is placed at multiple locations simultaneously, multiple cure boxes
shall be provided.

Concrete cubes shall be protected within the cure boxes from excessive vibration and shock waves
during the curing period.

4.3.12.4

Point of Acceptance

Determination of concrete properties for acceptance shall be made based on samples taken at the
discharge of the placement system, or otherwise at the truck discharge.

Once the Contractor has turned over the concrete for acceptance testing, no more mix adjustment
shall be allowed, and the concrete shall be accepted or rejected.

Concrete shall not be placed until tests for slump, temperature, and entrained air, if applicable, have
been completed by the Engineer, and the results indicate that the concrete is within acceptable limits.

Test cubes Nos. 1, 3 and 5 (from an individual sample as required in Article 4.3.12.3) shall be tested
after 7 days.

If the average of the three 7-day test cubes is below the minimum requirement, the Contractor shall
immediately stop all concreting until the material and equipment are checked and any deficiencies
are corrected. If the Contractor elects to remove and replace the defective concrete without waiting
for the results of the 28-day test, concreting can then continue entirely at the responsibility of the
Contractor. Cube numbers 2, 4, and 6, shall be considered three individual samples or sets and after
28 days of curing shall be tested as specified above. If any cube in any set shows definite evidence,
other than low strength, of improper sampling, moulding, handling, curing, or testing, it shall be
discarded and the strength of the remaining cube shall then be considered the test result for that set.

Final acceptance of the concrete works is based on 28 days of compressive strength testing on the
cubes. Work is considered in compliance if the average of the compressive strength tests equals or
exceeds the minimum specified for the class of concrete being placed, and if the average of the three
cubes in any one set does not fall below the specified minimum strength by more than 3.5 MPa.

If  the  results  of  the  28-day  testing  are  unsatisfactory,  the  Contractor,  in  accordance  with  the
instructions of the Engineer, shall conduct tests in the suspect parts of the structure. Concrete may
be  test  loaded  in  situ  or  cylindrical  test  cores  may  be  drilled  out  and  tested  in  accordance  with
AASHTO  T 22. Should the tests prove that the concrete is unsatisfactory or  below the standards
specified, the Engineer may order the removal and replacement of existing concrete with concrete
of the specified quality or accept it at a reduced payment. All the above shall be at the expense and
responsibility of the Contractor.

4.3.12.5

Water-to-cement Ratio Conformance

Actual water-to-cement ratio shall be determined from the certified proportions of the mix. No water
shall be added after acceptance testing or after placement has begun. Excess water shall not be
permitted and any batch containing such excess will be rejected.

ORKS

Second Edition -SEP 2020

For slip-formed concrete, water may be added during placement but shall not exceed the maximum
water cement ratio in the mix design, and shall meet the requirements for consistency as described
in Article 4.3.12.6. If water is added in concrete used in slip forming, an air and temperature test shall
be taken prior to resuming placement to ensure that specification conformance has been maintained.

Frequent tests, including the slump test, shall be carried out to ensure that consistent water content
is maintained.

4.3.12.6

Consistency

Slump shall not exceed the allowable range identified herein. Slump tests shall be performed in
accordance with AASHTO T 119M or ASTM C143M. Maximum slump for concrete should be as
indicated in Table 4-26, unless otherwise approved by the engineer.

Table 4-26: Maximum slump for concrete

Condition

Maximum Slump

Maximum Slump with a

High-Range Water Reducer

Vibrated Class C25 or stronger concrete

90 mm

140 mm*

All other vibrated concrete

115 mm

165 mm

Non-vibrated concrete

180 mm

230 mm

Pipe and utility bedding and cases where
water reducer is used per Section

4.3.6

230 mm

Concrete placed in kerbs, gutters, and
sidewalks

140 mm

190 mm

*Some mixes with combinations of mineral/chemical additives may produce slumps higher than this value
while meeting the other specified performance values. Approval for this case will be based on review and
acceptance of trial mixes.

Concrete transport and placement equipment shall be shaded or wrapped, as necessary, to prevent
loss of slump and workability during high temperature conditions.

4.3.12.7

Temperature and Time for Placement of Concrete

Temperature and time for placement of concrete shall meet the requirements of Table 4-27.

Table 4-27: Acceptable time and temperature limits for placement of concrete

Time to Completely Discharge Batch of Concrete

(Measured from time cement added to concrete mixture)

Allowable Concrete

Temperature Range

0 to 1.5 hours maximum

12° C to 32° C

1.5 hours to 1.75 hours maximum

12° C to 24° C

1.75 hours to 2 hours maximum with the Engineer

’s approval

12° C to 24° C

Time to discharge may be extended upon written request from the Contractor. This time extension
shall be considered on a case-by-case basis and requires the use of specific retardation admixtures
and the approval of the Engineer.

When conditions are such that the concrete may experience an accelerated initial set, the Engineer
may require a shorter time to discharge.

Precast concrete that is heat-cured per Article 4.4.84.4.8.3 shall remain between 10° C and 32

while being placed.

Abu Dhabi, United Arab Emirates. STANDARD CONSTRUCTION SPECIFICATIONS (PART 1 - ROADS, Second Edition 2020) - page 25