Method Statement ASPHA AS PHALT LTIC IC CON CONCR CRET ETE E WO WORK RKS S (Flexible Pavement)
CONTENTS 1.Purpose 2.Scope of Work 3.Definitions 4.References 5.Materials & Tools 6.Plant & Equipment Equipment 7.Safety 8.Prior Activities Activities 9.Procedure 10.Responsibilities
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1-
Purpose
To ensure that the bituminous pavement layers are executed 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.
2- Scope of Wo Work
a. This procedur proceduree is applica applicable ble to the followi following ng works works associated associated with with the project. b. This method statement outlines o utlines the procedures to be followed in construction of the bituminous pavement layers. c. It shall shall be carried carried out in the site site area of the project project accordi according ng to Technical Technical & General Specifications and approved drawings. 3- Defin finitions
CM
Construction Manager
PE / SE
Project Engineer / Site Engineer
CS
Chief Surveyor
ITP
Inspection Test Procedures
HSSE
Heath ,Safety, Security, and Environmental
T.S.
Technical Specifications
4- References
Technical Technical and GeneralSpecif GeneralSpecificati ications. ons. Project Quality Plan. Project Safety Plan. 5- Mate Materi rial alss & Tool Toolss
Warning tapes Temporary signs Safety Barriers Traffic Cones Grade Stakes
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6-
Plant & Equipment
The major equipment used for this construction works includes, but are not limits to the followings; Asphal Asphaltt Mix Mix Plant Plant - Bitumi Bituminou nouss Mixtur Mixturee Mixi Mixing ng Dump Dump Truc Trucks ks - Haulin Hauling g Hot Hot Asphal Asphaltt mate materia rials ls Asph Asphal altt Pave Paverr
- Spre Spread adin ing g & Leve Leveli ling ng
Water Water Bowser Bowser
- To fill fill up the the Roll Rollers ers and clean clean the the surf surface ace
Bitume Bitumen n Distrib Distributo utorr - Applica Applicatio tion n of bitumen bitumen mater material ialss Hand Ha nd Spra Spraye yerr
- Bond Bond Coat Coat Spra Spray ying ing
Surv Survey ey Equi Equipm pmen entt
- For For set setti ting ng out out
Stee Steell-Ti Tire red d Roll Roller er
- For For comp compac acti tion on
Pneuma Pneumatic tic-Ti -Tired red Roller Roller - Seconda Secondary ry Compact Compaction ion Stee Steell Roll Roller er
- Thir Third d Comp Compac acti tion on and and Smo Smoot othi hing ng
Plat Platee Comp Compac acto torr - For edge edge comp compac acti tion on Core Core Cut Cutti ting ng Mac Machi hine ne
- Core Core Cutt Cuttin ing g for for Test Testin ing g
Crew Crew Cab & Serv Service ice Cab Cab - Labor Labor Transp Transport ortati ation on & Servic Servicee works works Air Air Com Compr pres esso sorr
- Clea Clean n the the surf surfac acee
Roll Rollin ing g Stra Straig ight ht Edge Edge - Measu Measure re the the tole tolera rance nce Hand Hand Tool Toolss - Rakes, Rakes, shovel shovels, s, hand hand compac compactor tors, s, leveli leveling ng and and smoothing tools, Pavement saw machines, heaters, cleaning tools, hand brooms, small vibratory compactors, liquid asphalt painting, and all other other tools that that may be needed. needed. 7- HSSE
a. Approv Approved ed safety safety plan plan proced procedure uress shall be be strict strictly ly follow followed. ed. b. Where possible hazards may arise from filling activities, the necessary safety measures will be taken to prevent prev ent accident or injury at all times. This may include barriers, warning tape/ net, signage, watchman, and proper lighting. c. Where work upon existing existing services services may be required, required, the necessary necessary work permits and safety equipment should be obtained prior to the activity commencement. d. HSSE will will enforce enforce that that Personal Personal Protecti Protective ve Equipment Equipment be worn by site personnel at all times during construction activities. e. Provisions Provisions of adequate adequate cool drinking drinking water, water, shade, shade, and salt salt water water tablets tablets will be in place. TAHER AMMAR
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f. Plant & Equipment Equipment will be provided provided back-up alarms, alarms, lights, lights, and all other other applicable safety devices. g. Prior to the the commenceme commencement nt of any activit activities, ies, the workforce workforce will receive receive an induction talk on the project site safety requirements. This induction talk will include both activity safety issues, as well as general safety requirements. h. Safety engineer engineer will will ensure that Persona Personall Protective Protective Equipment Equipment is worn worn by site personnel at all times during construction activities. 8- Prio Priorr Acti Activi viti ties es
a. The Surveyor will locate locate and mark all live services that are present in the site (This includes above ground services as well as buried services). b. These services (Electric, Telephone, Gas, Oil, Chemical, Water, Drainage, etc) will be clearly marked using stakes and warning tapes. Near these services, special precautions will be undertaken a nd coordination with the Engineer will be carried out to avoid an y damages during the th e filling and compaction process. c. Any existing service if exposed during previous previous excavation will be clearly marked, protected, and properly supported during all activities. 9- Procedure 9.1 Binder Layer (Asphaltic (Asphaltic base course)
9.1.1 Prior to the placement placement of of bituminous bituminous base course course layer, the sub-base sub-base course will be cleaned and prepared by removal of dust and deleterious materials by air jetting or mechanically sweeping or b y any approved means. The cleaned course will be afterwards afterwards lightly made wet prior to the application of the prime coat. 9.1.2 An approved approved priming priming coat of grade grade MC-1 shall be applied applied to the non2 bituminous sub-base layer at the rate of ( 0.65 to 1.75) liters per m in accordance with Technical specifications. Prime coat is a cutback o bitumen spray that shall be applied (50~70 C) to all surfaces of the crushed aggregate base course. Blotter sand is used to correct areas with excess prime coat materials. 9.1.3 The Bitumen Bitumen Distributor Distributor shall shall be calibrated calibrated before use. The distributor distributor shall be self-powered and full circulation spray b ars adjustable laterally and vertically. Heating and Mixing of bituminous materials will be carryout accordance with T.S. TAHER AMMAR
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9.1.5 9.1.5 Suffic Sufficien ientt time time (48 Hour Hour Min.) Min.) will will be allo allowed wed for for the curi curing ng of the the prime coats before placing the following bituminous pavement layers. 9.1.6 The asphaltic concrete mixtures shall be transported to project site by strong clean trucks with smooth steel surfaces. s urfaces. The surfaces shall always be clean and free from any oil or dilutes or any materials which may affect the properties of asphalt mixtures. When necessary, the surfaces may be sprayed with a thin layer of lubricant to prevent sticking the mixtures with the surfaces. The transported asphaltic concrete materials shall be covered at cold times or in case of the mixing plant is far away from the project site to minimize the heat loss of the mix. 9.1.7 The asphalt cement is used in hot asphalt concrete mixes and some surface treatments. The asphalt cement shall conform to the requirement of the Standard Standard Egyptian Egyptian Specificati Specification on , which classifies classifies asphalt based based on viscosity; or shall conform to the requirements of AASHTO M -20, which classifies asphalt based on penetration grades. The asphalt cement shall be of 60/70 penetration grades and grades of asphalt materials shall conform to the requirements in Table 1 (Otherwise Specified).
Tack Coat RC-2
Wearing (*) cm
Prime Coat RC-1
Binder (*) cm Base (*) cm Sub-base (*) cm
Flexible Pavement Layers (*) Thicknesses According to Approved Drawings
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Table 1 : Quality Quality requirement requirement of penetration grade asphalt asphalt binder Penetration Grade AASHTO Test
Property
Penetration at 25 ° C, 1oogm, 5sec. Viscosity at 135 ° C (ASTM E102) Units of kinematic viscosity Flash point, Cleveland oven, o C, min.
40-50
60-70
85-100
Min.
Max.
Min.
Max.
Min.
Max.
T- 49
40
50
60
70
85
100
-
120
100
85
T- 201
240
200
170
T - 48
232.2
232.2
232.2
T - 49
55
52
47
T - 51
100
100
100
T - 44
5.99
5.99
5.99
T - 179 Penetration, of residue percent of original Ductility of residue 25 ° C Solubility in trichloroethylene, %
9.1.8 Placing Placing and and compaction compaction of Binder Binder bituminous bituminous layer layer will be carrie carried d out in accordance with T.S. 9.1.9 Asphalt lay down will proceeds proceeds from start to end direction direction along the Road. Placement of Binder course shall begin along the centerline of a Road or on the high side of areas with a one-way slope. The mixture shall be placed in consecutive adjacent strips towards the uphill direction of the Road as opposed to the downhill direction. 9.1.10 The paver will setup include the cut wooden blocks for the paver screed to rest upon at the start of each paving day. The wooden block will reflect the actual loose thickness of the asphalt concrete before compaction. Normally setup the paver to 7.5m width lane with screws. However, it can be adjusted depending on the available paving area. 9.1.11 Depending Depending on the availabl availablee area, area, pavers pavers will maximize maximize to continuous continuous operation. Every control point will be c hecked for elevation at the beginning of the works and while processing the work. 9.1.12 Two separate separate equipped equipped work teams teams will execute execute for asphalt asphalt placement placement at at adjacent lanes in echelon simultaneously. In order to minimize the formation of cold joints, two running pavers shall keep keep in a constant distance distance (D (D – Fig 1) in longitudi longitudinal nal direction direction..
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Fig 1 : Lay Down Plan
9.1.13 According According to the above above Fig 1, Paving shall shall be conducted conducted along the the center line line until complete the available working working area and follows follows the sequence from center to edge. o
9.1.14 9.1.14 The temp tempera eratur turee of the the mix mix (139 (139 ~ 163 C) will be checked in both the hauling truck and in the paver hopper and recorded. Temperature of asphalt materials at laying site will be control. 9.1.15 Placing Placing and compacting compacting of mixture will be uniform uniform with minimum minimum stopping stopping and starting of the paver. Placing and compaction shall be in accordance with T.S. 9.1.16 Once complete complete the compaction, compaction, string string line shall shall be used for first lift lift of bituminous surface course and then survey the grade of that lift. Provided grades of that lift of bituminous base course meet the tolerances in accordance with T.S. 9.1.17 Thickness Thickness and cross slope slope will be control controlled led by one gauge man man with the Asphalt paver, which shall be equipped with measure, depth stick and ruler. 9.1.18 Transverse Transverse joint shall shall be saw cut and carefully removed removed and painted painted with bituminous tack coat before new material is placed against it. 9.1.19 The longitudin longitudinal al joint in one course course shall offset the longitud longitudinal inal joint joint in the course immediately below by at least 15 cm and 30 cm Max. Max. (Otherwise Specified), however, the joint in the surface top course shall be at the centerline of final pavements surface.
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9.1.20 Transverse Transverse joints joints in one course course shall be offset offset by at least 3 m from from transverse joints in the previous course. Special care is required to avoid longitudinal pavement construction joints along the car gear wheel path. 9.1.21 Any irregular irregularitie itiess such as unevenness unevenness and/or deficient deficient thickness thickness that appear (before initial compaction) will be checked visually and b y using rolling straight edge. Then immediately make the rectifications. The The mixture will be loosened by raking, and as the case may be, material will be added, to correct the irregularity. Undue surface coarseness shall be remedied by the addition of finer material via hand sieves. Rolling straight edge will be continuously used to check the evenness of the surface. 9.1.22 Sufficient Sufficient compactio compaction n equipment shall shall be provided provided and compaction compaction shall continue until each lot of asphaltic concrete pavement is compacted to an in-place in-place density density within within ninety two to ninety-f ninety-five ive (92% - 95%) of the theoretical maximum density determined from AASHTO T-209 for all layers calculated based on three to five (3-5) percent air voids, and the compaction level of ninety-six (96%) of Marshall density (Otherwise Specified).
9.2 9.2
Surfac Surfacee / Wear Wearin ing g Laye Layerr (Asph (Asphal alti ticc weari wearing ng course course))
9.2.1 Prior to the placement of bituminous Wearing layer, layer, the Binder Binder layer will be cleaned and prepared by removal of dust and deleterious materials by air jetting or mechanically sweeping or by any approved means. 9.2.2 An approved bitumen tack coat of grade RC-2 shall be applied to the 2 binder courses at the rate of (0.25 to 0.35) litres per m or as ordered by the Engineer. 9.2.3 Sufficient time will be allowed allowed for for the curing of the the tack coat before placing Wearing bituminous pavement layer. 9.2.4 Placing Placing and compacting compacting of mixture mixture will will be uniform uniform with with minimum minimum stopping and starting of the paver. Placing and compaction shall be in accordance with T.S. 9.2.5 Every pass of the roller roller should proceed straight into the compacted mix and return in the same path. After the required passes are completed, the roller should move to the outside of the pavement on cooled material and repeat the procedure (Fig 2). TAHER AMMAR
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Fig 2 : Correct rolling pattern
9.2.6 Whenever Whenever it is possible possible,, longitudina longitudinall and transvers transversee joints joints shall be held held to the minimum practical number. The new asphaltic concrete layer shall overlap with the adjacent layers by the minimum of three (3) centimeters. 9.2.7 Contact surfaces, surfaces, where asphaltic concrete mixtures are placed against concrete or curb stone and gutter, bridge abutments, retaining walls, drainage facilities, a cold pavement joint or metal surface, sh all be tack coated properly in accordance with T.S. Shaping and dishing to to the sides of catch pits shall be carefully carried out to the profiles shown on the approved drawings. In places inaccessible to the rollers, compaction shall be achieved by suitable vibrating rollers or by plate compactor. 9.2.8 After final final rolling the surface shall be smooth and true to the established crown and grade. Any low or defective d efective spots shall immediately be remedied by cutting out the course, or planning to a depth of 50 mm ( or Full layer depth), at such spots and replacing it with with a fresh hot mixture that shall be immediately compacted to conform with the surrounding area and shall be thoroughly bonded to it. 9.2.9 The surface of the finished finished pavement shall be free free from depressions exceeding 4 mm as measured with a three (3) meter straight edge (Otherwise Specified). Tolerances of Wearing Wearing Layer shall be in accordance with T.S.
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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 The PE / SE SE will ensure that the site preparation activities are conducted according to the approved method statement and all in-situ tests are implemented. 10.3 Quality Control Engineer will ensure ensure that the materials materials being used used are in accordance to the project specifications. 10.4 The The HSSE 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 accorda accordance nce with with Project Project Safety Safety Plan. 10.5 The CS along with his team will ensure that all levels, coordinates and stations are accordance with the approved drawin gs.
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