Method Statement - Sub-base and Aggregate Base Course

METHOD STATEMENT

Sub-base and Aggregate Base Course

CONTENTS 1.

Purpose

2.

Scope of Work

3.

Definitions

4.

References

5.

Materials & Tools

6.

Plant & Equipment

7.

Safety

8.

Prior Activities

9.

Procedure

10.

Responsibilities

1- Pur urp pose ose To ensure that sub base, base, and related activities activities are executed safely safely and in accordance with the contract requirements and that all quality assurance / control activities are conducted in a systematic manner, works are inspected and conformance is verified and documented.

TAHER

AMMAR

[email protected]

Page Pa ge 1

Trusted by over 1 million members

Try Scribd FREE for 30 days to access over 125 million titles without ads or interruptions! Start Free Trial Cancel Anytime.





METHOD STATEMENT 2- Sc Scop opee of Work Work This procedure is applicable to the following works associated with the project titled (xxx) Sub-bases and Aggregate Base Course.

3- Defi Defini niti tion onss CM

Construction Manager

PE / SE

Project Engineer / Site Engineer

CS

Chief Surveyor

ITP

Inspection Test Procedures

H SS E

Heath ,Safety, Security, ty, and Environmental

4- Refe Refere renc nces es Project Specifications. Specifications. Project Drawings Project Quality Plan. Project Safety Plan.

5- Mater Material ialss & Tools Tools Warning tapes Temporary signs Safety Barriers Traffic Cones Grade Stakes

6- Plant Plant & Equ Equip ipme ment nt Mixing Plant for gravel base Wheel Loaders Dumper Trucks Graders Vibrating Rollers Pneumatic-Tyred Roller





METHOD STATEMENT 7 - H SS E safety plan procedures procedures shall be strictly followed. followed. a. Approved safety b. Where possible hazards may arise from filling activities, the necessary safety measures will be taken to prevent accident or injury at all times. This may include barriers, warning tape/ net, signage, watchman, and proper lighting. c. Where work upon existing services may be required, the necessary work permits and safety equipment should be obtained prior to the activity commencement. d. HSSE will enforce that Personal Protective Equipment be worn by site personnel personnel at all times during construction construction activities. activities. e. Provisions of adequate cool drinking water, shade, and salt water tablets will be in place. f.

Plant & Equipment will be provided back-up alarms, lights, and all other applicable safety devices.

8- Prior Prior Acti Activit vitie iess Surveyor will locate and mark all live services services that are present in the a. The Surveyor site (This includes above ground services as well as buried services). b. These services (Electric, Telephone, Gas, Oil, Chemical, Water, etc) will be clearly marked using stakes and warning tapes. c. Near these services, special precautions will be undertaken and coordination with the Engineer will be carried out to avoid any damages during the filling and compaction process. d. Any existing service if exposed during previous excavation will be clearly marked, protected, and properly supported during all activities.





METHOD STATEMENT 9- Proc Proced edur uree 9.1 9.1 Sub-ba Sub-base se 9.1.1 The materials and Quality Control Procedures to be used for Sub-base shall shall comply comply with with Project Project Specs Specs and tested tested acco accordin rdingly gly and and periodic periodically ally as per inspection, Project Quality Plan and Tabl Tables es 1&2 1&2. 9.1.2 Mixing of material will take place in a suitable area to be defined. 9.1.3 The material will inspected and tested accordingly and periodically as per inspection and Approved Project Quality Plan. 9.1.4 Prior to commencement of any sub base filling, the grade checkers will check formation levels and mark fill levels as required .The existing formation completed up to sub-grade level.. 9.1.5 The sub-base material will be mixed with water that will comply with Specs, and prepared prepared in the stockpile area (local (local and/or borrow) borrow) to the optimum moisture content. Then it will be transported to site via dump trucks where it will be spread and and leveled by graders, and and compacted initially by steel drum roller. 9.1.6 Should the need arise to adjust the moisture content, water will be sprayed uniformly using water tanker equipped with sprinkler bars. 9.1.7 The grader will have a second and third run (if required) accompanied by the steel roller till levels are reached. Thickness of each layer will

conform to the drawing “Typical Pavement Details” but in no case exceed 15 cm (Otherwise Specified). Specified). The finished finished surface will be moistened not damped and compacted to have a better cohesive layer and achieve achieve the requir required ed compacti compaction on of 100% (Otherwis (Otherwisee Specified Specified)) of laboratory Maximum Dry Density.





METHOD STATEMENT 9.1.9 Maximum Dry Density testing and CBR Testing will be performed in accordance accordance with specs. Additional Additional layer of sub-base material material will be placed in the same method as described above, up to the required elevation. The Surveyor will verify that final levels are within (-2 / +1 cm) toleranc tolerancee (Otherwis (Otherwisee Sspecifi Sspecified) ed) . 9.1.10 In all areas of fill, the P E / S E will verify that no visible voids are formed within the fill. If necessary, necessary, materials will be mixed to ensure an overall grading which will not result in visible voids being present in the fill. The P E / S E will ensure that all surfaces are well-closed and free from cracks and loose material. 9.1.11 Caution will be taken in order not to cause any disturbances to surrounding existing installations and/or structures.

Table 1: Quality Quality requirements requirements for Sub-base layer layer aggregate(Other aggregate(Otherwise wise Specified) Specified)

Property

Test Designation

Value

Los Angles Abrasion test %

AASHTO T-96

50% (Maximum)

Soundness by Na SO 4, 5 cycles

AASHTO T-104

25% (Maximum)

Liquid limit%

AASHTO T-89

Plasticity index %

AASHTO T-90

CBR %

ASTM D-1883

25% (Maximum) 6% (Maximum) 25% (Minimum)





METHOD STATEMENT Table 2: Quality Quality Control Control Procedures Procedures for Sub-base (Otherwise (Otherwise Specified) Specified)

Work

sl ai re t a M w a R

Properties

Test method

gradation

AASHTO T-27

Aggregate quality requirements

All requirements indicated in Table 1

MoistureDensity

AASHTO

Samples Location

At source

Sampling frequency

3 tests on different samples from each source and at source approval and at design job mix formula, or when source is changed, or when constructed works properties is changed and one test each month.

T-180

relationship Aggregate Gradation

g ni r u d g ai u

ni sl s re t a

MoistureDensity Relationship

M

Aggregate Gradation

AASHTO T-27 3 tests at the starting of material supply and one test each 5000 cubic meters of supplied materials or when constructed work properties is changed.

AASHTO T-180 All requirements indicated indicated in Table 1 AASHTO

Field density

s kr de

W

o

C

o

n

ts

At site site

One test every day or for every constructed 2000 square meters of each layer.

Thickness

Field Measurements

One measurement every day or for each 2000 square meters of the constructed layer.

Levels & Dimensions

Survey Measurements

Cross sectional levels at25 m interval or 5 cross sections each 2000 square meters whichever the greater.

Straight edge

Five (5) measurements each 2000 square meters or between cross sections indicated for levels whichever greater.

tc ur

T-191/T310-01 or any nondestructive test method

Surface Smoothness







METHOD STATEMENT 9.2 Aggregate Aggregate Base Base Course Course 9.2.1 The The material material shall comply comply with Project Specifications Specifications and will inspected inspected and tested accordingly and periodically as per inspection, Project Quality Plan and Tables 3&4. 3&4. 9.2.2 The sequence of works will be the same as for the sub-base. However, prior to placing any additional layer, the base shall be mechanically swept and cleaned with compressed air. 9.2.3 Final levels will be within (-1 (-1 / +1 cm) tolerance tolerance (Otherwise specified) 9.2.4 The final base layer shall be sealed by applying the prime coat to avoid its drying out. 9.2.5 Finished primed surface to be kept free from all non-essential traffic.

Table 3 : Quality Quality Requirements Requirements for Aggregate Aggregate Bases (Otherwise (Otherwise Specified) Specified)

Quality Requirements

Testing Method

Values

Soundness in sodium sulfate, 5 cycles, Min. , %

AASHTO T-104

18

Los Angles Abrasion Test, Max. , %

AASHTO T-196

45

Sand equivalent , Min. , %

AASHTO T-176

35





METHOD STATEMENT Table 4 : Quality Quality Control for the Aggregate Base(Otherwise Base(Otherwise Specified) Specified) Location of

Work

sl ai re t a M w a R

Properties

Test method

gradation

AASHTO T-27

Aggregate quality requirements

All requirements indicated in Table 3

MoistureDensity

AASHTO

Samples

Sampling frequency

3 tests on different samples from each source for source approval and At source

Design job mix formula approval or when source is changed, or material properties, or constructed works is changed, and a test each month.

T-180

relationship Aggregate Gradation

g ni r u g ai u

sl

d ni s re t a M

MoistureDensity Relationship Aggregate Gradation

AASHTO T-27 T-27 & T-1 T-11 1 3 tests at starting of material supply, and one test every 5000 cubic meters of supplied materials or when properties of Constructed works is changed or one test each week.

AASHTO T-180 All requirements indicated in Table 3 AASHTO

Field density

s W

o

kr Thickness

T-191/T310-01 or any nondestructive test method Field Measurements

At site

One test every day or for every constructed 2000 square meters of each layer.

One measurement every day or for each 2000 square meters of the constructed





METHOD STATEMENT 10.0 Responsibilities 10.1 The CM will coordinate with PE / SE and ensure that the necessary resources to implement the approved method statement have been allocated to the task. 10.2 The PE / SE will ensure that the site preparation activities are conducted according to the approved method statement and all in-situ tests according to the ITP are implemented. 10.3 Quality Control Engineer will ensure that the materials being used are in accordance accordance to the the project project specifications specifications and the approved approved method method statement. 10.4 The HSSE officer along with his team will ensure implementation of all HSSE procedures related to the nature of the works being carried out and in accordance with the HSSE Plan. 10.5 The CS along with his team will ensure that all levels, coordinates and stations are accordance with the approved drawings.

End of: Method Method Stateme Statement nt Sub-base and Aggregate Base Course

Method Statement - Sub-base and Aggregate Base Course

Recommend Documents