This method statement represents the proposed construction procedure for the bituminous roads, kerbs, tiles and paver block installation activities. It is the overall responsibility of the project manager for road work, to ensure that the site preparation activities and safety requirements are conducted according to the project specifications and approved project safety plan.
The method statement covers the following activities:
- Formation Preparation
- Aggregate Sub-Base
- Kerbs works
- Tiles Works
- Bituminous Courses
Cleaning and Protection
After completion of paving operations, the surfaces will be cleaned of excess or spilled asphalt materials to the satisfaction of the consulting engineer.
Vehicular traffic will not be permitted on the pavement until it has cooled and hardened (not sooner than 24 hours).
Barricades and warning devices will be provided to protect pavement works.
Openings of structures in the area of paving will be covered until permanent coverings are placed.
Prior Activities
All existing underground utilities within the construction limit to be protected and or relocated.
All utilities and electrical conduit/duct works to be completed prior to commencement of Formation Preparation
Excavation / Filling up to Formation Level to be completed.
Formation Preparation and Compaction
Grading will be carried out for the proposed grades as shown on the approved shop drawings.
Levelling and wet compaction of the Formation will be carried out by passes of heavy rollers of at least 15 ton operating weight. The passes will be at minimum speed and maximum vibration frequency until the required degree of compaction achieved.
Levels will be checked.
Density Test will be carried out at random places. Frequency as per specifications to examining the degree of compaction.
Aggregate Sub-Base
Aggregate Sub-Base material shall be tested at an Independent laboratory and approved by Engineer.
After the Formation Preparation has been approved, Sub-base material will be placed in two equal layers (10cm each layer).
Spreading, levelling and compaction of Sub-Base layer (after checking the quantity required for the particular section) will be carried out using steel wheel tandem vibratory roller and pneumatic tyre roller, the test will be carried out as per specifications, and the required density achieved. (Extra water will be added for grading and spreading of the surface during levelling compaction).
Dimensions & levels will be checked up on compacted layer.
Density / Compaction tests will be carried out as per specifications.
Kerbs Work
After Sub-Base levels and degree of compaction and all services inside foot path has been completed and approved, a setting bed of mortar shall be laid as per specification requirements.
Precast concrete curbs including blinding and hunching shall be laid where indicated on the Drawings or as directed by the engineer.
On circular work kerbs shall be cut on both edges to suit the required line and the joints shall be grouted with mortar as per specification.
Interlocking Tile Work
Laying approved Interlocking tiles shall be in accordance with the construction drawings and specified herein: Colour of Tiles shall be approved by consultant.
All Interlocking Tiles shall be either 8cm / 6 cm. For cut blocks, block shall cut using mechanical block splitter.
Levelling of natural ground surface or proposed grades in the specified area to be levelled and compacted. 50mm sand bed placed evenly and tiles shall be placed symmetrically with proper level control. The joint between block shall not exceed (3mm). Objectionable tiles will be removed from the site.
Bituminous Pavement Works
Bituminous Base Course and Wearing Course Job Mix shall meet the Project Specifications, and to be approved by contractor and Engineer prior to starting the works.
Preparation
The area to receive asphalt surfacing shall be inspected for cleanliness. A prime coat with cut back bitumen (MC-70) shall be applied over the Aggregate Sub Base at a rate of between 1.13 to 2.26 liters per square meter. At least 48 hours curing time shall be maintained before starting asphalt works.
Laying of bituminous Base Course and Wearing Course
The compacted thickness of bituminous Base Course and Wearing Course shall be 60mm & 50mm as per the contract.
The bituminous material will be laid using paver.
Compaction of the bituminous material will be achieved using steel wheel tandem vibratory rollers and pneumatic tyre rollers.
Initial compaction or breakdown rolling will be by a tandem vibratory roller operating in the static mode. Subsequent compaction will be carried out using tandem vibratory rollers minimum 3 passes (in the vibratory mode) and followed by 12 passes with pneumatic tyre rollers until the material has been fully compacted to achieve the required degree of compaction as per specification.
A final ‘finishing’ roll will be carried out using a tandem vibratory roller in the static mode to remove any remaining roller marks.
Before laying Wearing course layer a tack coat of bitumen emulsion will be applied to a clean surface at a rate of between 0.23 to 0.68 liters per m². The emulsion shall be allowed to break prior to commencing surfacing.
In areas constrained by width (less than 2.5 meters) and/or minimal length or by limited access or other such constraints the bituminous material will be laid manually and compacted to level and a fair finish with a suitable roller or vibrating plate compactor commensurate with the area being laid.
Level Control
Where practicable the paving machine will be equipped with automatic level sensing equipment and / or averaging beam (dependent upon location ), referenced to dipped levels obtained from steel pins kerbs or other suitable datum at no more than 10 meter longitudinal intervals, and transversely at intervals commensurate with the required mat widths.
In constrained areas level adjustment will be by manual control by an experienced operator and referenced to dip levels obtained from steel pins kerbs or other suitable datum at no more than 10 meter longitudinal intervals and transversely at intervals commensurate with the required mat widths.
Testing of Materials
Bituminous materials will be delivered to site within the temperature range. Material delivered to site outside range will not be incorporated within the works.
Temperatures will be checked and recorded both at the depot mixing plant and the point of laying by either electrical probes pyrometers or conventional thermometers.
Bituminous materials will be quality control sampled and tested at the mixing plant facility for specification compliance with respect to aggregate gradation binder content and Marshall Design properties.
Sections of completed pavement layers will be cored on site as soon as practicable for testing for field density compliance.