REFERENCE MATERIALS FOR PPC SELUNA PROJECT
Introduction
In an effort to preparation of seluna river basin flood management project has identified recommended core collection of materials especially for sediment trap and long storage libraries. Suggested reference materials for preparation of seluna river basin flood management project from seven general categories of material, all of which are
representative of knowledge deemed essensial for preparation of seluna river basin flood management project.
The committee selected materials based on the recommendations used in project completion. The committee also identified recommended materials which follow the core list. Since there are too many to list individually, most conferences and workshop papers were omitted. However, the committee realize their importance, and greatly recommended.
REFERENCE MATERIALS PPC SELUNA PROJECT
1. STANDARD
1.1Guidance Note to Specification 1.1.1 Introduction
The Materials and workmanship specification as follows has been based on International Standards As scheduled below.
The Contractor shall be responsible for detailing in his specification the standards on which his materials and workmanship shall be based, and these shall be in accordance with the workmanship shall be based, and these shall be in accordance with the guidance given in clause 3 of the employer’s requirements – General. Relevant standards of JIS, JSCE, AASHTO, and ASTM are scheduled below:
Section 2: Earthworks
AASHTO T99 The Moisture-Density Relations of Soil using a.5.5lb (2.5 kg) Rammer and a 12 in (305 mm) drop
AASHTO T193 The California Bearing Ratio
AASHTO T180 The Moisture-Density Relations of Soils using a 10lb (4.54 kg) Rammer and a 18 in (457 mm) Drop
AASHTO T27 Sieve Analysis of fine and Coarse aggregate AASHTO T89 Determining the Liquid Limit of Soils
AASHTO T90 The Plastic Limit and Plasticity Index of Soils AASHTO T191 Density of Soil in-Place BY Sand-Cone Method Section 3: Road Works
AASHTO M147 Materials for Aggregate and Soil Aggregate Subbase, base and surface courses
AASHTO T96 Resistance to Degradation of Small-Size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine
AASHTO T89 Determining the Liquid Limit of Soils
AASHTO T90 Determining the Plastic Limit and Plasticity Index of Soils
AASHTO T112 Clay Lumps and Friable Particles in Aggregate Section 4: Concrete
JIS R210 Portland Cement SNI 15-2049-2004 Portland Cement
SNI 03-6813-2002 Procedure for making test cylinders and prisms for determining strength and density of preplaced- aggregate concrete in laboratory
ASTM C150 Standard Specification for Portland Cement JIS A1101 Method of test for slump of concrete
JIS A1102 Method of test for sieve analysis of aggregates
JIS A1103 Method of test for amount of material passing test sieve 75 micro m in aggregates
JIS A1107 Method of sampling and testing for compressive strength of drilled cores of concrete
JIS A1108 Method of test for compressive strength of concrete JIS A1109 Method of test for density and water absorption of
coarse aggregates
JIS A1110 Method of test for density and water absorption of coarse aggregates
JIS A 1116 Method of test for unit mass and air content of fresh concrete by mass method
JIS A 1150 Method of test for slump flow of concrete JIS A5308 Ready – mixed concrete
JIS A6204 Chemical admixtures for concrete
JSCE-B101 Specification for mixing water for concrete 2. EARTHWORKS
2.1Earthworks Definitions and Classifications 2.1.1 Definitions and Classifications
The following definitions of earthworks materials shall apply to this and other Clauses of these specifications in which reference is made to the defined materials.
(1) Top Soil
Top soil shall mean the top layer of soil that can support vegetation, and shall include turf.
(2) Suitable Material
Suitable Material shall comprise all that which is acceptable in accordance with the specification for use in the works.
(3) Unsuitable Material
Unsuitable Material shall mean other than suitable material and shall comprise:
(i) Material from swamps, marshes and bogs, highly organic clay or silt (ii) Peat, logs, stumps, perishable and toxic materials
(iii) Material susceptible to spontaneous combustion
(iv) Clay of liquid limit exceeding 80% and/ or plastic limit exceeding 55%
(v) Material which contains appreciable amounts of mica, or material with finely dispersed mica and of liquid limit exceeding 40%
(vi) Material having a loss on ignition greater than 2.5% by weight
(vii)Material with a CBR (California Bearing Ratio) value of less than 2%
(when compacted to 95% of the maximum dry density determined by
AASHTO Test Method T99 and CBR shall be tested in accordance with AASHTO Test Method T193)
Note: Materials that are soft or unstable merely because they are too wet or dry shall not be classified as unsuitable material but may be rendered suitable by drying or adding water respectively.
(4) Rock Fill:
Shall be clean well graded material provided by the Contractor from sources outside the Site or from rock excavation. The maximum size particles in the material shall pass through a rigid 200 mm square grid and the largest dimension of any particle shall not exceed 300 mm.
(5) Waste:
Waste shall be unsuitable material. Waste shall be the property of the Contractor. The Contractor shall dispose of waste at areas outside the Site at his own expense including charges arising from the use of private land.
2.1.2 Plant
The Contractor shall employ plant which is suited to the soils to be handled.
2.1.3 Care of Suitable Material
The Contractor shall be responsible for maintaining the condition of suitable material so that when it is placed and compacted it remains suitable in accordance with the Contract.
2.1.4 Removal of Suitable Material
No excavated suitable material other than that surplus to requirements of the Contract shall be removed from the Site except on the direction or with the permission of the Engineer. The Contractor shall be permitted to remove suitable material from the Site to suit his operational procedure, then he shall make good at his own expense any consequential deficit arising thereof.
2.1.5 Pollution Control
The Contractor shall detail in his Earthworks Method Statement measures to be undertaken to prevent water pollution and erosion of earthworks.
The Method Statement shall include, but not be limited to:
(1) Stream turbidity (2) Sedimentation (3) Siltation
(4) Erosion of cut faces (5) Erosion of embankments (6) Diesel and oil pollution (7) Flooding
2.2Clearing and Grubbing 2.2.1 General
(1) Scope
(i) Clearing and grubbing shall consist of clearing the designated areas of all trees, timber, snags, vegetation, rubbish and objectionable material and shall include grubbing stumps and roots and disposing of all material resulting from clearing or grubbing. It shall also include the demolition, removal and disposal of structures that obtrude into, encroach upon, or obstruct the work, removal of all existing utilities remaining within the right of way after removal of houses and the removal of existing road surfaces, except where provided for elsewhere in the Specifications.
(ii) Disposal of debris and foundations remaining after removal of houses or other structures is considered to be included in the unit rates for clearing and grubbing.
(iii) Also included in this work shall be the removal of loose pavement material, road signs, right of way markers, kilometer stones, guide posts and all other incidentals within the limit of construction. Where necessary, items shall be removed, if outside of the site boundary but within the right of way, subject to agreement with the Highway Authority. The Contractor shall exercise care so as not to damage these incidental items during the removal operation. All signs, markers and incidentals removed from the project shall be stacked in neat piles so they may be collected by relevant authorities or become the property of the Employer.
(2) Preservation of Property
(i) Attention is directed to the Contractor’s obligations both in law and under this Contract with regard to damage, particularly with regard to protection of property, forest, and landscape and to his responsibility for damage claims.
(ii) Existing highways improvements, facilities, adjacent property, Utilities, services, and trees and plants designated for preservation shall be protected from injury or damage which could result from the Contractor’s operations.
(iii) In order to reduce the risk of erosion, no topsoil shall be removed from the areas outside the limits of earthworks. Any topsoil outside these limits, which is inadvertently removed during clearing and grubbing operations or otherwise, the Contractor shall replace immediately at this own expense.
(iv) No trees outside of the Site Boundary shall be felled or pruned unless the Contractor has obtained permission from the owner and the agreement of the Engineer. Trees at risk of damage resulting from the Contractors operations shall be protected. Outside the worksite boundary, certain trees or plants shall be left undisturbed, if the
Engineer directs, for ecological reasons. Trees or plants that are not to be removed shall be protected from damage resulting from the Contractor’s operations.
2.2.2 Execution (1) General
(i) Clearing and grubbing shall be executed in the areas designated by staking or shown in the drawings. If no areas are designated in the drawings, the area to be cleared and grubbed will be as directed by the Engineer. Clearing and grubbing shall be restricted to the areas identified on the drawings unless a design change has been processed.
(ii) Clearing and grubbing of pits, channels, and ditches will be required only to the depth necessitated by the excavation within those areas.
(iii) All topsoil (include turf) shall be removed from areas of cuttings and embankments and stockpiled if required for re-use in replacing soil for slopes, berms verges and for the provision of beds for the cultivation of trees and shrubs. The following conditions shall apply:
- The storage of stripped topsoil shall be to a maximum height of 3 m and shall on no account be consolidated or compacted by heavy machinery.
- The storage of topsoil shall be kept completely separate from that of the fill material.
- Where natural ground is situated less than 2 m bellow formation level or side slopes, topsoil shall be removed to a depth of 150 mm below the original ground level.
- The use of topsoil shall be restricted to surface layers not subject to loading by pavements of structures.
(2) Clearing
(i) Clearing shall consist of the removal and disposal of everything above ground level including overhanging branches. The material to be cleared shall include, but not necessarily be limited to, trees, stumps, logs, brush, undergrowth, grass crops, loose vegetable matter, structures (other than those structures where removal or clearance is separately specified and measured)
(ii) In cut areas, clearing shall include the removal of stumps and roots exceeding 80 mm in diameter, to a depth of 450 mm below the finished surface except that in surrounding areas at the tops of cut slopes they may be cut flush.
(3) Grubbing
(i) Grubbing shall be carried out on the area of embankment foundations where the embankment height is less than 1.5 m. Grubbing shall consist of the removal and disposal of topsoil, stumps, and roots to a depth of at least 150 mm below ground level and at least 450 mm
below the bottom of the lowest sub base or base course of road pavement.
(ii) Material thus removed may be used as topsoil for slope protection.
Materials not used as topsoil shall be the property of the Contractor and shall be disposed of in areas out with the Site at his own expense, including charges arising from the use of private land.
(iii) Materials more than 150mm below the original ground level, within embankment areas, which are removed during the operation of clearing and grubbing, shall be replaced by acceptable fill which shall be compacted to the density prescribed for layers. All unsuitable materials shall be treated as waste and shall be the property of the Contractor. The Contractor shall dispose of waste out with the Site at his own expense including charges arising from the use of private land.
(iv) Where existing road embankments shall be raised or widened, all vegetation and topsoil shall similarly be completely removed from shoulders, slopes and ground under the widening before the operations of actual widening can be commenced.
(v) Where roadway excavations are carried out and where ditches, streams and rivers are diverted, all vegetation, roots, stumps and the like shall be completely removed and placed outside the excavation area concerned before the excavation works are commenced.
(vi) At all remaining areas inside the right-of-way, the work of clearing and grubbing shall include the leveling of terraces and ditches, the neat and complete removal of all remnants from structures and buildings, roots, stumps, untidy vegetation, rubbish, garbage and the like, so that these materials shall not obstruct future maintenance, by machines, of the right-of-way area or access to the works.
(vii)The clearing and grubbing within areas under embankments shall include the removal of all vegetation, roots and stumps from trees and palms, garbage, rubbish, etc., remnants from houses and structures.
Holes left after such removal shall be backfilled with acceptable materials and compacted to the density prescribed for layers.
(viii) Ditches, streams and ponds in the embankment areas shall be properly cleared, drained and dried out.
(4) Finish
The entire right-of-way area shall be left with an orderly and neat appearance.
2.3Excavation 2.3.1 General
(1) Scope
(ix) This work shall consist of all the required excavation within the limits of the Site. The excavation shall include the removal, hauling and
proper utilization or disposal of all excavated materials, the shaping of excavations and the preparation of exposed surfaces of excavation in accordance with these Specifications and the lines, levels, grades, dimensions and cross sections indicated on the Drawings
(i) Work Includes:
- Excavation of al l materials for formation work, roads, gutters, ditches, berm ditches, drains and flumes.
- The removal and disposal of existing surfacing, footpaths, curbs and gutters within the limits of construction.
- The demolition, removal and disposal of all foundations, foundation walls, basement or ground level floors, timber, rubble, masonry pipe, pipe structures and pipe culverts within the limits of construction and otherwise provided for in the Contract.
- Excavation for removal of slides, breakages and cave-ins.
- Excavation for stream and channel changes.
- Excavation required in cuts or under embankments below the lowest normal limit of excavation indicated on the Drawings or below ground line, for the removal of unsuitable material, and below the ground line under embankments where benching is required, or as otherwise indicated on the Drawings.
- Prevention of erosion of exposed surfaces.
2.3.2 Materials
(1) Materials to be excavated (i) Classified Excavation
Classified Excavation shall include all earth excavation except that classified as rock or soft rock as described in Section 2.1: Earthwork Definitions and Classifications of these Specifications.
(ii) Unsuitable Material
Unsuitable Material shall be material described as unsuitable material in Section 2. 1: Earthwork Definitions and Classifications of these Specifications.
2.3.3 Execution (1)General
(i) All excavation and embankment construction shall be performed as specified herein and in Section 2.6: Embankment and the complete earthwork shall conform to the required alignment, levels, grades, and cross-sections.
(ii) Where the excavation reveals a combination of suitable and unsuitable materials the Contractor shall carry out the excavation in such a manner that the suitable materials are excavated separately for use in the Works without contamination by the unsuitable materials.
(iii)Where any material under an embankment or below formation level in cuttings is required to be excavated, it shall be removed to such a depth and over such areas as are indicated on the Drawings and disposed of in a manner depending on its nature and condition at the time. The whole of the excavation shall not be carried out in one operation but shall be progressively excavated and filled one width at a time, such that the excavated surface is not left exposed or unsupported during wet weather, or overnight. All excavation below embankments shall take place from ground level. It shall be the responsibility of the Contractor to ensure the stability and safety of the excavation at all times. The resultant excavation shall be backfilled with suitable material as defined in Section 2.1:
Earthworks Definitions and Classifications. Nevertheless where, in these circumstances, such backfill has to be deposited below standing water, the Contractor shall use only sand as defined in Section 2.6:
Embankment. Such material may be deposited below water without the associated use of compaction plant.
(iv) Where shown in the drawings, rock fill or suitable material shall be placed directly on naturally occurring weak material. The backfill material shall be deposited in accordance with the requirements of Section 2.5: Excavation and Backfill for Structures and Section 2.6:
Embankment for the compaction of fill.
(v) If, after the removal of unsuitable material the Contractor allows the material so exposed as to reach a condition where compaction of backfilling complying with Section 2.6: Embankment is impracticable he shall make good at his own expense, either by additional excavation and filling in the manner specified, or by waiting until the condition of the exposed material is fit to receive the approved backfill.
(vi) The work shall be carried out by the Contractor in such a way as to avoid disturbance to the surrounding ground. Particular care shall be taken to maintain stability when excavating in close proximity to existing works.
(vii)The work shall be carried out in a careful manner to ensure that the exposed surfaces are as sound as the nature of the material permits and that no point shall protrude inside the lines shown on the Drawings. In soft excavations which are to remain open permanently, exposed faces shall be formed accurately to the required slopes and profiles.
(2)Excavation in cut
(i) Where cuttings having two or more different slopes are identified on the Outline Design Drawing s, excavation shall commence at the slope
indicated for the underlying strata. The depth at which a change of slope occurs shall be established when sufficient depth has been excavated to enable the full depth of the layer of soft to stiff material to be identified. The Contractor shall then re-excavate to the upper slope as indicated on the drawings.
(ii) Erosion protection measures shall be carried out immediately after trimming of the excavated slope.
(iii)Where materials having a CBR value (when compacted to 95 % of the maximum dry density determined by AASHTO Test Method T99 and CBR shall be tested in accordance with AASHTO Test Method T193) lower than 5 % are found in the 150 mm underlying the sub-grade layer, such materials shall be excavated and replaced by materials (which will be paid as embankment fill) having a CBR value of 5 or more.
(iv) In cut areas, the "final surface" on which sub-base is to be placed shall be processed as necessary and compacted to a minimum depth of 300 mm to not less than 95 % of the maximum dry density of the materials as determined by AASHTO Test Method T180.
(v) The sub-grade is the soil on which the sub ballast is placed. It must have the following characteristics for a layer of at least 300 mm:
bearing strength CBR 8 % and compacted to 95 % of the maximum dry density determined by AASHTO Test Method T180. The sub- grade layer shall be essentially granular.
(vi) The sub-grade shall be capable of supporting an imposed local stress due to live load of not less than 100 kPa.
(vii)Any excess depth excavated below the formation level shall be made good by backfilling with suitable material of similar characteristics to that removed and compacted in accordance with Section 2.6:
Embankment.
(viii)Hauling of materials from cuttings or the importation of fill material to embankments or other areas of fill shall proceed only when sufficient compaction plant is operating at the place of deposition to ensure compliance with the requirements of Section 2.6:
Embankment.
(ix) Construction traffic shall not use the surface of the bottom of a cutting unless the cutting is in rock or the Contractor maintains the level of the bottom surface at least 300 mm above formation level (top of sub-grade).
(3)Channel excavation
(i) Where indicated on the Outline Design Drawings ditches and streams sha ll be widened, trained or permanently diverted.
(ii) Interception ditches at the top of slopes in cuts, as well as outlet ditches from railway ditches and culvert outlets, shall be excavated as shown on the Drawings.
(iii)Channels shall be excavated by methods which will not endanger the stability of the side slopes.
(iv) Existing channels, which are to be reshaped, cleared and trimmed, shall be cleared of all weeds and grow1h and the beds graded to the required levels. The sides of channels shall be trimmed to the required slope so as to provide widths not less than those shown on the Drawings.
(v) Side banks of channels shall be trimmed to a neat appearance and even surfaces.
(vi) Any channels, streams, drains or pipes taking water to or from cultivated land shall be diverted so as to maintain their flow before being moved or broken into.
(vii)The Contractor shall control the rates of filling and drawdown of water in channels so as not to endanger the stability of earthworks.
(4)Control of water
(i) The Contractor shall arrange for the rapid dispersal of water, shed on to earthworks or completed formation during construction, or which enters the earthworks from any source, and when practicable the water shall be discharged into a permanent outfall of the pipe drainage system. Adequate means of trapping silt shall be provided on temporary systems discharging into existing drainage systems.
The arrangements shall be made in respect of all earthworks including excavations whether for pipe trenches, foundations or cuttings.
(ii) The Contractor shall provide, where necessary, temporary watercourses, ditches, drains, pumping or other means of maintaining the earthworks free from water. Such provision shall include carrying out the work of forming the cuttings and embankments in such a manner that their surfaces have at all times a sufficient minimum cross fall and, where practicable, a sufficient longitudinal gradient to enable them to shed water and prevent ponding.
(iii)Pumping shall not be regarded as meeting the provisions of this Clause where a blockage temporarily obstructs the free drainage of a cutting. In such circumstances the Contractor shall construct temporary drains with a suitable out-fall or install the permanent drainage through the blockage.
(iv) The Works related to the control of water shall be considered as incidental to earthworks and shall not be measured or paid for.
(5)Disposal of excavated material (i) General
All suitable excavated materials shall be used insofar as practicable in the construction. Waste or any excavated material in excess, is the property of the Contractor which he shall remove and dispose of outside the Site.
(ii) Suitable Material
Suitable materials will be used for embankment fill or filling stream beds outside of embankment areas.
(iii)Unsuitable Material
Unsuitable fill may be placed in the former stream bed out with the embankment areas or disposed of off-site.
(6)Surface finishes (i) Slopes
All slopes shall be finished in a neat and workmanlike manner and to an accuracy appropriate to the material, and care shall be taken that no material is loosened below the required slopes. Surplus materials shall be removed and disposed of.
(i) Sub-grade
(ii) The surface of the finished sub-grade shall be neat and workmanlike and shall have the required form, supe r-elevation, levels, grades and cross-section. The deviation from design level should not exceed 20 mm on the top surface, and the design shape and drainage falls must be constructed correctly.
(7)Other right-of-way
At locations where the construction is close to irrigation canals and power transmission lines which have their own right-of-way, the Contractor must not, without receiving the consent of the relevant authorities remove any materials from the right-of-way of other authorities.
2.4Fill
2.4.1 General (1) Scope
This section specifies the execution of fill by providing, placing, compacting and shaping suitable material of acceptable quality obtained from compliant sources in accordance with these Specifications and forming to the lines, levels, grades, dimensions and cross sections shown on the Drawings.
(2) Backfill – General
Except around structures, excavations shall be backfilled with suitable excavated material compacted in layers of 300 mm maximum thickness to
achieve a density of at least 95 % of the maximum dry density determined in accordance with AAS HTO T1 80 or equivalent.
2.4.2 Materials (1) Fill Material
(i) Fill mate rial, other than that for road works, shall be evenly graded granular material. Clods or large lumps of earth over 75 mm in greatest dimension shall be broken up before compacting. All fill materials shall be free from roots, sods or other deleterious material.
(ii) The Contractor shall carry out the following initial tests on the proposed material to confirm that fill materials comply with the design.
- Wet sieve analysis
- Dry density/moisture content relationship in accordance with AASHTO Test Method T180 or equivalent
(iii) Thereafter, one set of tests shall be carried out for each 200 m3 of fill, supplied to Site.
(2) Materials for capping layer of fill
(i) In addition to the general requirements for fill material, the material in the top layer shall not exceed the following test values:
Plasticity index: 6 Liquid Limit (LL): 35
(ii)The laboratory CBR value, at 95 % of the maximum dry density achieved in AASHTO T180 or equivalent after soaking for 96 hours, shall not be less than 30%.
2.4.3 Execution (1) Test
(i) Testing of fill – General
Classification tests shall be carried out to ensure that true comparisons can be made between in -situ densities, laboratory compaction densities and field trial densities i.e. that variation in the properties of materials being used in the tests are not affecting the results.
Tests shall be carried out on fill to determine the degree of compaction achieved, at the rate of one test for either each 1,200 m3 or each layer whichever is the more frequent. Compacted layers shall not be covered without approval as identified in the Test and Inspection Plan.
The density of individual compacted layers shall be determined by a method detailed in AASHTO T1 91 or equivalent.
The in-situ dry density of fill shall average 95 % of the maximum reached in AASHTO Test Method T180 or equivalent. No single result shall be less than 92 % and no more than 25 % of the results on
anyone layer sha ll fall between 92 % and 95 %. The average shall be computed from the total number of tests
on anyone layer where the extent of the layer is defined by the Contractor.
(ii) Testing of Top Layer
Tests shall be carried out on the capping layer of fil l as follows:
(a) Laboratory tests to monitor the consistency of the specified material during construction:
Test Test frequency
(not less than one test per…) Maximum dry density
1500 m2 Optimum moisture content
Grading
Plasticity index Linier shrinkage
CBR 3500 m2
(b)In-situ tests to confirm that the required degree of compaction is being achieved during construction:
Test Test frequency
(not less than one test per…)
Dry density 500 m2
CBR 2500 m2
Tests shall be carried out in accordance with AASHTO T180 or equivalent, using 4.5 kg rammer methods where applicable or AASHTO T191.
2.5Excavation and Backfill for Structures 2.5.1 General
(1) Scope
This section shall cover the excavation for structures and subsequent backfilling. Works include:
(i) Excavation of foundations for structures and under drains.
(ii)Constructing and removing cofferdams and sheeting.
(iii)Pumping, dewatering and bailing.
(iv) Backfilling around completed structures.
(v)Disposal of excavated material.
2.5.2 Material
(1)Material for foundation fill
Material for foundation fill shall consist of suitably graded sand, gravel, or stone or concrete as described below.
(2)Concrete for foundation fill
Concrete shall be Grade 15 and conform to the requirements of Section 5:
Concrete for Structures.
(3)Backfill material (i)General
Backfill shall be obtained from the structure excavation if suitable. Any additional suitable material shall be obtained from excavation or borrow.
(ii)Culverts
Culverts shall be sand complying with the requirements of Selected Material Type B of Section 2.6: Embankment or consented well graded granular material.
(iii)Porous Backfill
Porous Backfill shall be hard durable material composed of gravel, crushed rock or sand, free from organic material, clay balls and other deleterious material. Laterite or concretionary materials shall not be used. Poro us materials to be used shall conform to the following:
- Sand
Shall confirm to the following particle-size gradation:
Excavated material suitable for use as backfill may be deposited by the Contractor in storage pi les at points convenient for re- handling of the material during the backfilling operation.
Excavated material shall be deposited in such places and in such a manner as not to cause damage to the highway, roads, services or property either within or outside the right-of-way and so as to cause no impediment to the drainage of the site or surrounding area. The location of storage piles, their formation and protection, so as not to cause a nuisance, shall comply with the local authority requirements.
(4)Cofferdam
(i) The term "cofferdam" denotes any temporary' or removable structure, constructed to hold the surrounding earth, water, or both, out of the excavation, whether such structure is constructed of earth, timber, steel, concrete or any combination of these. The term includes earth dikes and timber cribs, sheet piling, removable stee l shells and all bracing; and it shall be understood to include excavation enclosed by pumping wells and well points.
(ii) The interior dimensions of cofferdams sha ll be such as to give sufficient clearance for the construction and removal of any required forms and the inspection of the interior and to permit pumping outside the forms.
(iii) If practicable, cofferdams shall be so designed that no cross bracing shall be left in place. If this is not practicable, bracing left in place shall be of structural steel. The end of such structural members that would be exposed when the structure is completed
shall be boxed back at least 150 mm behind the concrete face. The resulting holes shall be completely filled with concrete.
(iv) In general, sheet piling cofferdams shall extend well below the bottom of the footing and sha ll be well braced and as watertight as practicable.
(v) When foundation piles are to be driven inside a cofferdam and it is judged impracticable to dewater the cofferdam before placing a concrete seal, the excavation may be extended below the designed level to a depth sufficient to allow for swell of the material during pi le driving operations. Any material that rises to a level above the design level shall be removed.
(vi) Where it is possible to dewater the cofferdam the foundation materials shall be removed to exact grade after the foundation piles are driven.
(vii) Backfilling in a foundation to compensate for excavation which has been extended below the required design level shall be at the expense of the Contractor. Backfilling shall be with suitable concrete or foundation fill material. If no material is indicated, backfilling shall be concrete Grade 15 to comply with the requirements of Section 5: Concrete. No excavation sha ll be made outside of cofferdams or sheet piling and a natural stream bed adjacent to the structure shall not be disturbed. Material deposited within the stream area from foundations or other excavations or from the filling or cofferdams shall be removed and the stream area freed from obstruction.
(viii) Cofferdam which tilt or move laterally during construction shall be corrected as necessary at the expense of the Contractor.
(ix) Unless otherwise provided cofferdams shall be removed after the completion of the sub-structure. The removal shall be effected in such a manner as not to disturb or mar the finished work.
(x) When conditions are encountered where it is impracticable to dewater the foundation before placing the footing, the Contractor shall consider the construction of a concrete foundation or seal of such dimensions as he may consider necessary, and of such thickness as to resist any possible uplift. The concrete for such a seal shall be placed. The foundation shall then be dewatered and the footing placed. When weighted crib s are used, and the weight is used to overcome partially the hydrostatic pressure acting against the bottom of the foundation seal, special anchorages such as dowels or keys shall be provided to transfer the entire weight of the crib to the foundation seal. When a foundation seal is placed under water, the cofferdam shall be vented at low water as approved. Cofferdams shall be constructed so as to protect newly cast concrete from a sudden rising of the water and to prevent damage to the foundation by erosion.
(5)Pumping and bailing
(i) Pumping or bailing to dewater a sealed cofferdam shall not be started until at least 36 after the final set of sealing concrete.
(ii) Pumping and bailing from the interior of any foundation enclosure shall be done in such a manner as to preclude the possibility of the movement of water through, or alongside, any concrete being placed. No pumping or bailing will be permitted during the placing of concrete or for a period of at least 24 hours thereafter unless it is done from a suitable sump separated from the concrete work by a watertight wall.
(iii) Excavations shall be as dry as possible prior to, and during, placing concrete. Placing concrete under water will only be permitted if indicated on the Drawings.
(6)Backfilling
(i) All spaces excavated under these Specifications and not occupied by the permanent structure shall be backfilled. Backfilled material shall be free from large lumps, wood and other extraneous material.
(ii) The Contractor shall not backfill around structures until the structural elements have attained adequate strength.
(iii) Backfill, not within the embankment area, shall be placed in layers not more than 300 mm in depth (loose measurement) and shall be compacted to a density comparable with the adjacent undisturbed material.
(iv) Backfill within the embankment areas shall be made with suitable material placed in uniform layers not to exceed 300 mm in depth (loose measurement) and each layer shall be constructed and compacted in accordance with Section 2.6: Embankment.
(v) Backfill for culverts shall be placed in layers not exceeding 300 mm and shall be compacted to at least 95 % of the maximum dry density according to AASHTO Test Method T99. The in -place dry density shall be tested in accordance with AASHTO Test Method T1 91.
(vi) In placing backfill in a cutting, the material shall be placed insofar as possible to approximately the same height on both sides of the structure. If it conditions require backfilling appreciably higher on one side; the Contractor shall instigate a design check.
(vii) Backfill against an embankment shall not be placed behind walls of bridges or box culverts until the top slab has been placed for the concrete to achieve adequate strength and not less than three days. Backfill and embankment behind abutments, held at the top by superstructure, shall be carried up simultaneously behind opposite abutments and side walls.
(viii) Jetting of fill or other hydraulic methods involving, or likely to involve, liquid or se mi -liquid pressure shall be prohibited.
(ix) Special care shall be taken to prevent any unduly high pressures against the structures.
(x) The placing of embankment and the benching of slopes shall continue in such a manner that at all times there will be a horizontal berm of thoroughly compacted material for a distance at least equal to the height of the abutment or wall to be backfilled.
(xi) Adequate provision shall be made for drainage and to allow for porous backfill material to be placed in accordance with Sub- Clause 2.5.2 herein.
2.6Embankment 2.6.1 General
(1) Scope
This work shall consist of the construction of embankment and backfill not specified elsewhere by furnishing, placing, compacting and shaping suitable material of acceptable quality obtained from approved sources in accordance with these Specifications, and to the lines, levels, grades, dimensions, and cross-sections of depot as shown on the Drawings.
2.6.2 Materials
(1)Embankment shall be constructed of materials with a CBR value not lower than the design values stated on the Specification.
(2)These required CBR values shall be on soaked samples compacted to 95
% of the AAS HTO Test Method T99. The use of materials with a CBR value of less than 2% shall not be considered suitable.
(3)Embankment materials classified as Selected Material Type A and Selected Material Type B, if required, shall be constructed to the thicknesses shown on the Drawings and shall meet all the following material requirements. Selected Material Type A - shall consist of naturally occurring soil aggregate free of topsoil and all other organic matter. The soil aggregate shall consist of sound durable particles which do not breakdown under compaction or repeated wetting/drying cycles.
All sizes greater than 50 mm shall be handpicked and removed from the working layer.
The fraction of material passing the No. 40 sieve shall have a liquid limit, as determined by AASHTO Test Method T89, of not greater than 40 % and a plasticity index, as determined by AAS HTO Test Method T90, of not greater than 20 %. The fraction passing the No. 200 sieve shall be more than 10 % but not greater than 30 %. Shale material and sand shall not be used for Selected Material Type A. The minimum required CBR values indicated on the Drawings shall be on soaked samples compacted to 95 % of the maximum dry density in a moisture range of 3% as determined in AASHTO Test Method T99.
Selected Material Type B - shall consist of naturally occurring soil aggregate, sand or other materials free from topsoil and all other organic matter. The material shall consist of sound durable particles which do not
breakdown under compaction or repeated wetting/drying cycles. All sizes greater than 50 mm shall be handpicked and removed from the working layer.
The fraction passing the No. 200 sieve shall not be greater than 35 %. The minimum required CBR values indicated on the Drawings shall be on soaked samples compacted to 95 % of the AAS HTO Test Method T99.
(4)Where sand embankment is specified on the Drawings, such materials shall consist of river or pit-run sand whose properties shall meet the following requirements:
- Gradation:
Maximum particle Size: 3/8 inch.
Material finer than No.200 sieve: 25 % maximum - Plasticity:
Material shall be generally non -plastic and free from clay lumps.
- CBR strength:
When compacted to 95 % of AASHTO Test Method T99 density, the material shall have minimum soaked CBR of 10 %.
(5)Materials for earth fill, landscaping and is lands shall consist of clay, laterite, land deposit sand or river or beach sand, unless otherwise shown on the Drawings, shall comply with the requirements of Section 2.4: Fill of these Specifications.
2.6.3 Execution
(1) Preparation of foundation for embankment
(i) Prior to placing any embankment upon any area, all clearing and grubbing operations shall have been completed in accordance with Section 2.2: Clearing and Grubbing of these Specifications.
(ii) Natural ground (including slopes of existing road) situated less than 1.5 m below surface of the road or side slopes shall, after proper clearing and grubbing or scarifying of existing road surface, be compacted to a depth of 150 mm, measured from the original ground as shown on the cross-section sheet, to not less than 95 % of the maximum dry density of the material as determined by AASHTO Test Method T99. Compression of existing so il which may result from this compaction will not be measured and backfilling of the corresponding volume of earth fill is considered incidental to other items of work and will not be separately paid for.
(iii) Where embankments are to be constructed on slopes or existing embankments are to be widened or included in a new embankment, the existing slopes (or slope of the existing embankment) shall be loosen by scarifying to a depth of not less than 100 mm, to ensure a good bond between the embankment and the embankment foundation, or where this is impracticable, steps in vertical and
horizontal face shall be cut in the existing slopes and the embankment built up in successive layers. Material which has been loosened shall be re-compacted simultaneously with the first level of embankment material placed.
(iv) Unless otherwise shown on the Drawings, where existing unpaved roads are to be covered with less than 300 mm of fill, excluding pavement, the top of the old road bed shall be scarified and re- compacted with the next layer of the new embankment. The total depth of the scarified and added material shall not exceed the permissible depth of layer.
(v) Embankment in swamps or water shall be constructed with sand.
The Contractor shall excavate or replace swamp ground and backfill with suitable material. Backfill will be in accordance with the same provisions as for embankment.
(vi) If unsuitable materials occur in some areas under the embankment or in existing embankments, such materials shall be removed and the bottom of the excavation shall be compacted, as described above, and the areas backfilled and compacted layer by layer with suitable material.
(vii) All compaction shall conform to the requirements in (3) below;
"Compaction of embankment other than rock embankment", of this Specification. Where an existing surface of a road is situated at sub- grade level or lower, the surface shall be scarified, except where otherwise shown on the Drawings, to a depth of 150 mm, graded, spread and compacted, to the density prescribed for layers at the depth concerned below sub-grade, in the full width of the new embankment.
(viii)Where the surface of an existing road is above the required sub- grade, the existing road shall be removed to new sub-grade level, except where otherwise shown on the Drawings, where after shaping and compaction shall be carried out in accordance with following "(3) Compaction of embankment other than rock embankment" of this Specification.
(ix) On pavement rehabilitation, where selected material and/or sub- base layers are to be placed directly on an existing pavement surface which is in a good condition, the existing surface shall not be scarified and re-compacted.
(x) In landscape areas, topsoil shall be removed in accordance with these Specifications. Fill shall be placed in the same manner as for embankments.
(xi) Clay berm or dike placed next to the ditch or channel as indicated on the Drawings shall be constructed by the excavated clay from the
ditch or from the borrow pit. The suitable material shall be specified on the Standards.
(2) Placing embankment
Embankment shall be placed in accordance with the following requirements:
(i) General
All embankments shall be constructed in layers approximately parallel to the finished grade of the road bed. During construction of embankment, a smooth grade having an adequate crown or super- elevation shall be maintained to provide drainage. Embankment shall be constructed to the required grade, and completed embankment shall correspond to the shape of the typical sections shown on the Drawings.
(ii) Earth Embankment
Earth embankment shall be defined as those principally of material other than rock, and shall be constructed of consented material from designated or other consented sources. Except as specified for embankment in swamps, earth embankment shall be constructed in successive layers, for the full width of the cross-section and in such lengths as are suited to the compaction and watering methods used.
Prior to compaction the layers shall not exceed 200 mm in depth.
(iii) Placing over Swamp Ground
Embankment in or over swamps or in water shall be placed as specified in the Special Provisions.
(iv) Adjacent to Culverts and Bridges
Embankment adjacent to culverts and bridges which cannot be compacted by use of equipment used in compacting the adjoining section of embankment shall be compacted in the manner prescribed under the Section 2.5 : Excavation and Backfill for Structures. Embankment placed round spill through type abutments shall be compacted in 150 mm layers (measured before compaction) of uniform suitable material placed in such a manner as to maintain approximately the same elevation on each side of the abutment and each layer of material shall be mixed, wetted and compacted as specified herein. Material placed adjacent to any portion of any structure shall be Selected Material Type A or Type B.
(v) Preparation od Sub-grade
- The surface of the finished sub-grade shall be neat and workmanlike and shall have the required form, super elevation, levels grades, and cross-section. The surface shall be constructed to sufficient accuracy to permit the construction of subsequent
layers of material to the thickness, surface tolerance, and compaction specified.
- As far as is practicable the Contractor shall construct bridge approach fills as early in the Contract period as possible to allow for consolidation of the embankment during the remainder of the Contract period.
- Where new embankment is to be compacted against existing embankment with side slopes as specified on the Outline Construct Specifications or where embankment is built one-half width at a time, the slopes of old or new embankment shall be cut into a minimum of 2 m horizontally to provide a working platform as the work is brought up in layers.
- Material thus cut out shall be re-compacted along with the new embankment material at the Contractor's expense.
- Clods or large lumps of earth over 150 mm in greatest dimension shall be broken up before compacting the material in embankment.
- Where streams or ditches are to be diverted, or abandoned, their beds should be filled up to a level. Within the limits of earthwork, such fill shall be placed and compacted to the requirements as specified in this Section. Filling shall be performed well ahead of the construction of roadway embankments, and all other works involved such as pumping, damming, etc. Embankment fill placed against the sides of pipe culverts shall be placed in such manner as to maintain the same elevation on both sides of the culvert.
- All settlement occurring in embankment construction shall be corrected by the Contractor by providing additional layers of embankment or selected material. The Contractor shall be fully responsible for the stability and integrity of the embankment during the Contract and Maintenance periods.
- If a so il failure either occurs or becomes imminent during the construction of the embankment, the Engineer shall have the authority to suspend all embankment construction in the affected area until corrective measures can be determined and implemented. Any delay in the embankment construction schedule and any other effects caused by implementation of the above clause shall not constitute grounds on the part of the Contractor for a claim for extension of the Contract and/or financial compensation.
(3) Compacting of embankment other than rock embankment
(i) Before compaction, each layer shall be processed as required to bring the moisture content to within + 1 % and - 2 % of optimum
moisture content as determined in AASHTO Test Method T99 with respect to the type and size of the compactors being utilized. The material shall be so worked as to have uniform moisture content throughout the layer. Full compensation for any additional work involved, wetting or drying embankment material to the required moisture content, shall be considered as included in the contract price paid for embankment and no additional compensation will be allowed.
(ii) Each layer of material shall be compacted uniformly by use of adequate and appropriate compaction equipment. The compaction shall be done in a longitudinal direction along the embankment and shall generally begin at the outer edges and progress toward the centre in such a manner that each section receives equal compactive effort. Hauling equipment shall be operated over the full width of each layer in so far as practicable.
(iii) Embankments shall be constructed in layers of uniform thickness not to exceed 150 mm in thickness after compaction and compacted to the requirements of this Section. Each layer of the embankment shall be compacted to a dry density equal to at least 95 % of the maximum dry density of the material as determined by AASHTO Test Method T99, except the top 150 mm of the embankment shall be compacted to 95 % of the maximum dry density as determined by AASHTO Test Method T1 80. The in-place dry density shall be tested in accordance with AASHTO Test Method T191.
(iv) Embankments shall be maintained to the grade and cross-section shown on the Drawings throughout the contract period.
(v) The Contractor shall protect the prepared sub-grade from both his own and public traffic. The Contractor shall maintain the sub-grade by watering and rolling as frequently as necessary to preserve the sub-grade in a completely satisfactory condition as specified above.
(vi) The compaction of the sub-grade shall, in cut areas, including areas of existing road where surface layer have been removed, extend to a minimum depth of 150 mm and the compaction shall attain not less than 95 % of the maximum dry density determined by AASHTO Test Method T1 80. The in -place dry density shall be tested in accordance with AASHTO Test Method T191.
(vii) Attention is drawn to the fact that the genera l compaction requirements shall at any level apply to the full width of the embankment. Slopes to be covered with topsoil and grassing shall have a firm surface before topsoil is placed.
(4) Preparation of sub-grade surface
The sub-grade shall be shaped to correct line and level and the Contractor shall at all times ensure that the sub-grade is well drained and protected against damage from public as well as construction traffic. The finished sub-grade surface shall at no point deviate more than 15 mm from the cross-section shown on the Drawings. The surface shall be maintained in this state, with a regular light sprinkling of water to prevent a dusty condition until the pavement layers are spread.
3. ROAD WORKS 3.1Method Statement
Prior to commencing Roadworks, the Contractor shall prepare a Method Statement comprehensively detailing how he shall progress such works, showing his sources of materials, their composition, test requirements, handling, compaction, marking, temporary traffic measures, etc. additionally he shall produce the Test and Inspection Plans associated with this work.
3.2Subbase and Base 3.2.1 Description
This work shall consist of supplying, processing, hauling, spreading, watering and compacting graded aggregate on a prepared and accepted surface, in accordance with the Contractor's Construction Technical Drawings.
Processing shall include, where necessary, crushing, screening, separation, blending, and any other operation necessary to produce a material conforming to the requirements of this Specification.
3.2.2 Sample and Certification
The Contractor shall obtain, at least 21 days prior to the proposed date of first using any materials, such as Aggregate sub-base and Aggregate base:
(1) Two samples of 50 kg weight of each of the materials, that shall be retained for reference throughout the Contract Period
(2)a statement of the origin and composition of any material proposed for use as Aggregate Subbase and Aggregate Base, together with laboratory test data verifying that the material properties specified in this Section are met.
3.2.3 Material Requirements (1)Aggregate Base Classes
The two different qualities of base course are specified as Class A and Class B. Generally, Aggregate Base Class A is base course quality for use in the layers immediately below a bituminous surfacing, while Aggregate Base Class B is for sub-base layers.
(2)Coarse Aggregate Fraction
The coarse aggregate retained on the 4.75 mm sieve sha ll consist of hard, durable particles or fragments of rock and gravel. Material which breaks up when alternately wetted and dried shall not be used. When produced
from gravel, not less than 100% by weight of the coarse aggregate shall be particles having at least one fractured face for Aggregate Base Class A.
(3)Fine Aggregate Fraction
Fine aggregate passing the 4.75 mm sieve shall consist of natural or crushed sand and fine mineral particles. The fraction passing the 0.075mm sieve sha ll not be more than two-thirds the fraction passing the 0.425mm sieve. Grading requirements for Aggregate Sub-Base and Base (AASHTO M147)
SIEVE DESIGNATION
(mm) Mass Percentage Passing
Class A Class B
50 100
37.5 100 88 - 95
25 79 - 85 70 -85
19 -
9.5 44 - 58 30 - 65
4.75 29 - 44 25 - 55
2.0 17 - 30 15 - 40
0.425 7 - 17 8 - 20
0.075 2 - 8 2 - 8
Physical-mechanical properties of stones aggregate for the sub-base are specified as follows:
Aggregate Sub-base and Base properties
Property Class A Class B
Los Angeles Abrasion of the aggregate (LA), % (AASHHTO T96- 94)
0 – 40% 0 – 40%
Plastic limit (lp), % (with the sieve passing 0.425 mm) (AASHTO T90- 02)
0 - 6 0 - 10
PP index = Plastic limit Ip x % of the quantity of sieve passing 0.075 mm
Max. 25 -
Liquid limit (WL), % (with the sieve passing 0.425 mm) (AASHTO T89-02)
0 - 25 0 - 35
Soft Fragments (AASHTO T112 –
87) 0 -5 % 0 -5 %
CBR (AASHTO T 193 -81) Min. 90% Min. 35%
3.2.4 Construction
Aggregate sub-base and aggregate base shall not be placed, spread or compacted while rain is falling, and no compaction shall be carried out when the moisture content of the material falls outside the specification range. In locations were sub-base or base materials are to be placed on a prepared sub-grade, the sub-grade shall be prepared in accordance with this Specification: Section 2 prior to base and/or sub-base placement.
(1)Trial section
(i) Before either sub-base or base construction is started, the Contractor shall spread and compact trial sections. The purpose of the trial sections is to check the suitability of the materials and efficiency of the equipment and construction method which is proposed to be used by the Contractor. Therefore, the Contractor must use the same materials, equipment and procedures he proposes to use for the main work. One trial section about 50m shall be made for every type of material and/or construction equipment/procedure proposed for use.
(ii) Density tests and other tests required as AASHTO T180 – 90 and AASHTO T191-86.
(iii) Should the materials not be suitable for sub-base or base as appropriate to the trial, the material shall be removed at the Contractor's expense, and a new trial section shall be constructed.
(iv) If the basic conditions regarding the type of material or procedure change during the execution of the work, new trial sections shall be constructed.
(2)Spreading
Spreading shall be carried out by the use of spreader boxes.
(i) Spreader boxes shall be self-propelled wheel type or tracked vehicles and adjustable to place the material in layers of the specified thickness without undue disturbance to the prepared surface.
(ii) The granular material shall be placed in uniform layers so that the compacted depth does not exceed 18cm for sub-base and 15cm for base.
(3)Compacting
(i) Immediately following final spreading and smoothing, each layer shall be compacted to full width by means of smooth-wheel power rollers, pneumatic tyre rollers or other approved compaction equipment. Rolling shall progress gradually from the low to the high point of the cross section parallel to the center line of the road, and shall continue until the entire surface has been rolled.
Generally, light rollers with low speed shall be used for first compaction, and then heavy rollers shall be used for continuous compaction to the required compaction density.
(ii) Any irregularities or depressions that develop shall be corrected by loosening the material at these places and adding or removing material until the surface is smooth and uniform. At all places not accessible to the roller, the material shall be compacted thoroughly with tampers or compactors. The material shall be both bladed and rolled until a smooth, even surface has been obtained. Where surfaces fail to meet the tolerance requirements the Contractor shall remove and replace the material.
(iii) Granular material shall be compacted to produce the required density through the full depth of each layer of at least 98 percent of the maximum density determined in accordance with AASHTO T1 80 - 90. In place field density determinations shall be made in accordance with AASHTO T1 91-86. Test holes at random, during progress of the work, shall be made for measurement to confirm compliance with the Specification and to determine the depth of un-compacted layers required to produce the designated nominal depth of material placed.
Cutting the test holes and refilling with materials properly compacted shall be done by the Contractor.
3.2.5 Checking the Quality of the Sub-Base and Base Construction
The sub-base and base, after completed to the required compaction, shall be tested regarding geometric dimensions and roughness prior to acceptance of the construction. The density and specific requirements are specified in the following table:
Tolerance for Aggregate Sub-base and Base
Testing index Permitted limit Testing density
Sub-base Base - For straight
section: 40 – 50 m
- For sections of horizontal curves or vertical
curves: 20 – 25 m.
Elevation - 10
mm - 5 mm
Cross slope ±0.5% ±0.3%
Thickness ± 10mm ± 5 mm
Width - 50mm - 50mm
Roughness: Max.
joint under straightedge 3 m
≤ 10mm ≤ 5mm At 100m
intervals.
3.3Bituminous Prime Coat 3.3.1 Description
This work shall consist of furnishing and applying bituminous material to a previously prepared sub-grade, sub-base or base course surface in accordance with these Specifications.
3.3.2 Material
Bituminous Material
Bituminous material shall be of a type and grade called for in the Contractor's Construction Technical Drawing s and shall conform to the requirements of the specifications listed below:
Medium-curing cut back AASHTO M82
Rapid-curing cut back asphalt AASHTO M81
The grade and temperatures shall be MC-70 (43 - 8S°C) or RC-250 (60- 100°C).
3.3.3 Construction
(1) Weather Limitations
A primer coat shall only be applied when the surface to be treated is dry or only slightly damp and when the weather is dry.
(2) Preparation of Surface to be Treated
Immediately before applying the bituminous material, all loose dirt and other objectionable material shall be removed from the surface with a power broom and! or blower as required.
(3) Application of Bituminous Material
Bituminous material shall be applied to the width of the section to be primed by means of a bitumen distributor in a uniform, continuous spread. The rate of application will usually be in the range of 1.0 to 2.0 liters/sq.m. Care shall be taken that the application of bituminous material at the junction of spreads is not in excess of the specified amount. Excess bituminous material shall be sponged from the surface. Skipped areas or deficiencies shall be corrected. Building paper shall be placed over the end of the previous applications and the joining application shall start on the building paper position after the building paper has been removed.
3.4Bituminous Tack Coat 3.4.1 Description
This work shall consist of preparing and treating an existing bituminous or concrete surface with bituminous material in accordance with these Specifications.
3.4.2 Materials
Bituminous material shall conform to the requirements of the Specification listed below:
Rapid-curing cut back asphalt: AASHTO M81
The grade and the temperatures shall be RC-250 (60 - 100°C).
3.4.3 Construction
(1)Preparation of Surface to be Treated
The existing surface shall be patched and cleaned and shall be free of irregularities to provide a reasonably smooth and uniform surface to receive the treatment. Unstable, corrugated or damaged areas shall be removed and replaced or repaired. The edges of existing pavements, which are to be adjacent to a new pavement, shall be cleaned to permit the adhesion of bituminous materials.
(2)Application of Bituminous Material
The bituminous material shall be uniformly applied with a pressure distributor within the 24 hours preceding placement of the covering course. The rate of the application will usually be in the range of 0.4 to 0.8 liters / sq.m. Care shall be taken that the application of bituminous material at the junction of spreads is not in excess of the specified amount.
Excess bituminous material shall be sponged from the surface.
Skipped areas or deficiencies shall be corrected.
The surface shall be allowed to dry until it is in a proper condition of tackiness to receive the covering course. Tack coat shall be applied only so far in advance of covering course placement as is necessary to obtain this proper condition of tackiness. Until the covering course is placed, the Contractor shall protect the tack coat from damage.
3.5Bituminous Plant-Mix Material 3.5.1 Description
This work shall consist of aggregate and bituminous material mixed in a central plant and spread and compacted on a prepared surface in accordance with these Specifications.
(1) Composition of Mixtures
The bituminous material shall be composed of a mixture of aggregate, filler and hydrated lime, if required, and asphalt cement. The several aggregate fractions shall be sized, uniformly graded and combined in such proportions that the resulting composite blend meets the job- mix formula as determined in accordance with AASHTO T 245.
In calculating the void characteristics of the mixture the Contractor shall allow for the bitumen absorbed by the aggregate and use the effective specific gravity of aggregate and the maximum specific gravity of the loose paving mixture (AASHTO T209).
The several aggregate and filler fractions for the mixture shall be sized, graded, and combined in such proportions that the resulting composite blend meets one of the grading requirements of Table 3.4 (1).
Grade A shall be used for asphalt base course. Grade B shall be used for asphalt binder course. Grade C shall be used for asphalt surface course Table 3.4 (1)
Table 3.4 (1) Requirements for Grade A, Grade B and Grade C
Before stockpiling aggregate, the Contractor shall submit a proposed job-mix formula. The formula submitted shall propose definite single values for:
- The percentage of aggregate passing each specified sieve
- The percentage of bituminous material to be added, on the total aggregate basis
- The temperature of the mixture leaving the mixer - The temperature of the mixture delivered on the road - The grade of bituminous material
- Values shall be proposed within the limits specified for the particular type of bituminous concrete called for. The mixture furnished by the Contractor shall conform to this job-mix formula, within the following range of tolerances and within the grading ranges of Table 6.05(1).
Aggregate passing the 4.75 mm and larger sieve:!:.7 percent
Aggregate passing the 2.36 mm through the 0.150 mm sieve:!:.4 percent
Aggregate passing the 0.075 mm sieve
Bituminous material: !:. 0.4 percent
Temperature leaving the mixer:!:. 6 DC
Temperature delivered on the road.:!:. 6 DC
Should a change in sources of material be proposed, a new job-mix formula will be established before the new material is used. The plant mixed material will be tested after blending or mixing at the plant or prior to final incorporation in the work.
(2)Coarse Aggregate
The coarse aggregate (retained on the 2.36 mm sieve) shall consist of clean, tough, durable fragments free from any excess of flat, elongated, soft or disintegrated pieces and free from stone coated with dirt or other objectionable material. The percentage of wear when tested according to AASHTO T96, shall be as follows:
Los Angeles Abrasion:
For use in asphalt base course - not more than 40%
For use in asphalt binder and surface course - not more than 30% loss.
The sodium sulphate soundness loss shall not exceed 9 percent and the magnesium sulphate soundness loss shall not exceed 12 percent.
When crushed gravel is used, not less than 50 percent of the particles by weight retained on the 4.75 mm sieve shall have at least one fractured face.
(3)Fine Aggregate
The fine aggregate (passing a 2.36 mm sieve), shall have General Characteristics and Soundness in accordance with AASHTO M29.
(4)Filler
Mineral filler, when required, shall consist of limestone dust, portland cement or other non-plastic mineral matter from sources approved by the Engineer. Mineral filler shall be dry, free from flowing, free from lumps and other objectionable material and when tested by means of laboratory sieve, shall meet the following gradation requirements:
(5)Asphalt Cement
Asphalt Cement shall be of penetration grade 60-70, and shall conform to the requirements of AASHTO M20.
4. CONCRETE
This section refers to the production of concrete, including concrete mix design, trial mix, testing and workmanship for concreting. The materials and workmanship standards shall include:
- Indonesian Standards equivalent to appropriate Japanese Standards - Japanese Industrial Standards (JIS)
