Part D Report

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Item 200 AGGREGATE SUBBASE COURSE:

Item 200 AGGREGATE SUBBASE COURSE

200.1 Description:

200.1 Description The item shall consist of furnishing, placing and compacting an aggregate subbase course on a prepared subgrade in accordance with this Specification and the lines, grades and cross-sections shown on the Plans, or as directed by the Engineer.

200.2 Material Requirements :

200.2 Material Requirements Aggregate for subbase shall consist of hard, durable particles or fragments of crushed stone, crushed slag or natural gravel and filler of natural or crushed sand or other finely divided mineral matter. The composite shall be free from vegetable matter and lumps or balls of clay, and shall be of such nature that it can be compacted readily to form a firm, stable subbase.

200.2 Material Requirements :

200.2 Material Requirements The subbase material shall conform to Table 200.1, Grading Requirements. TABLE 200.1 Grading Requirements Sieve Designation Standard (mm) Alternate US Standard Mass Percent Passing 50 2” 100 25 1” 55-85 9.5 3/8 ” 40-75 0.075 No. 200 0-12

200.2 Material Requirements:

200.2 Material Requirements The fraction passing 0.075 mm (No. 200) sieve ≤ 2/3 of the fraction passing 0.425 mm (No. 40) sieve. The fraction passing 0.425 mm (No. 40) sieve shall have: LL ≤ 35 and PI ≤ 12 as determined by AASHTO T 89 and T 90, respectively.

200.2 Material Requirements:

200.2 Material Requirements The coarse portion retained on a 2.00 mm (No. 10) sieve: mass percent of wear ≤ 50 by the Los Angeles Abrasion Tests as determined by AASHTO T 96. The material shall have a soaked CBR value ≥ 25% as determined by AASHTO T 193. The CBR value shall be obtained at the maximum dry density and determined by AASHTO T 180, Method D.

200.3 Construction Requirements:

200.3 Construction Requirements

200.3.1 Preparation of Existing Surface:

200.3.1 Preparation of Existing Surface The existing surface shall be graded and finished as provided under Item 105, Subgrade Preparation, before placing the subbase material.

200.3 Construction Requirements:

200.3 Construction Requirements

200.3.2 Placing:

200.3.2 Placing The aggregate subbase material shall be placed as a uniform mixture on a prepared subgrade in a quantity which will provide the required compacted thickness. When more than one layer is required, each layer shall be shaped and compacted before the succeeding layer is placed.

200.3.2 Placing:

200.3.2 Placing The placing of material shall begin at the point designated by the Engineer. Placing shall be from vehicles especially equipped to distribute the material in a continuous uniform layer or windrow. The layer or windrow shall be of such size that when spread and compacted, the finished layer will be in reasonably close conformity to the nominal thickness shown on the Plans.

200.3.2 Placing:

200.3.2 Placing When hauling is done over previously placed material, hauling equipment shall be dispersed uniformly over the entire surface of the previously constructed layer, to minimize rutting or uneven compaction.

200.3 Construction Requirements:

200.3 Construction Requirements

200.3.3 Spreading and Compacting:

200.3.3 Spreading and Compacting When uniformly mixed, the mixture shall be spread to the plan thickness, for compaction. Where the required thickness is 150 mm or less, the material may be spread and compacted in one layer.

200.3.3 Spreading and Compacting:

200.3.3 Spreading and Compacting Where the required thickness is more than 150 mm, the aggregate subbase shall be spread and compacted in two or more layers of approximately equal thickness, and the maximum compacted thickness of any one layer shall not exceed 150 mm. All subsequent layers shall be spread and compacted in a similar manner.

200.3.3 Spreading and Compacting:

200.3.3 Spreading and Compacting Immediately following final spreading and smoothening, each layer shall be compacted to the full width by means of approved compaction equipment. Rolling shall progress gradually from the sides to the center, parallel to the centerline of the road and shall continue until the whole surface has been rolled.

200.3.3 Spreading and Compacting:

200.3.3 Spreading and Compacting 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. Along curbs, headers and walls, and at all places not accessible to the roller, the subbase material shall be compacted thoroughly with approved tampers or compactors.

200.3.3 Spreading and Compacting:

200.3.3 Spreading and Compacting If the layer of subbase material, or part thereof, does not conform to the required finish, the Contractor shall, at his own expense, make the necessary corrections. Compaction of each layer shall continue until a field density of at least 100% of the maximum dry density determined in accordance with AASHTO T 180, Method D has been achieved. In-place density determination shall be made in accordance with AASHTO T 191.

200.3 Construction Requirements:

200.3 Construction Requirements

200.3.4 Trial Sections:

200.3.4 Trial Sections Before subbase construction is started, the Contractor shall spread and compact trial sections as directed by the Engineer. The purpose of the trial sections is to check the suitability of the materials and the efficiency of the equipment and construction method which is proposed to be used by the Contractor. Therefore, the Contractor must use the same material, equipment and procedures that he proposes to use for the main work.

200.3.4 Trial Sections:

200.3.4 Trial Sections One trial section of about 500 m² shall be made for every type of material and/or construction equipment/procedure proposed for use. After final compaction of each trial section, the Contractor shall carry out such field density tests and other tests required as directed by the Engineer.

200.3.4 Trial Sections:

200.3.4 Trial Sections If a trial section shows that the proposed materials, equipment or procedures in the Engineer’s opinion are not suitable for subbase, the material shall be removed at the Contractor’s expense, and a new trial section shall be constructed. If the basic conditions regarding the type of material or procedure change during the execution of the work, new trial sections shall be constructed.

200.3 Construction Requirements:

200.3 Construction Requirements

200.3.5 Tolerances:

200.3.5 Tolerances Aggregate subbase shall be spread with equipment that will provide a uniform layer which when compacted will conform to the designed level and transverse slopes as shown on the Plans. The allowable tolerances shall be as specified in the following table.

200.3.5 Tolerances:

200.3.5 Tolerances

200.4 Method of Measurement:

200.4 Method of Measurement Aggregate Subbase Course will be measured by the cubic metre (m³). The quantity to be paid for shall be the design volume compacted in-place as shown on the Plans, and accepted in the completed course. No allowance will be given for materials placed outside the design limits shown on the cross-sections. Trial sections shall not be measured separately but shall be included in the quantity of subbase herein measured.

200.5 Basis of Payment:

200.5 Basis of Payment The accepted quantities, measured as prescribed in Section 200.4, shall be paid for at the contract unit price for Aggregate Subbase Course which price and payment shall be full compensation for furnishings and placing all materials, including all labor, equipment, tools and incidentals necessary to complete the work prescribed in this Item.

200.5 Basis of Payment:

200.5 Basis of Payment Payment will be made under:

Item 203 LIME STABILIZED ROAD MIX BASE COURSE:

Item 203 LIME STABILIZED ROAD MIX BASE COURSE

203.1 Description:

203.1 Description Consist of: Foundation for surface course Soil aggregate Lime Water Road mixed Constructed on a prepared subgrade / subbase

203.2 Material Requirements :

203.2 Material Requirements Soil Aggregate Consist of any combination of Gravel, sand, silt and clay or other approved combination of materials free from any objectionable matter Crushed or Uncrushed granular material In-situ soil may be used if the quality is satisfactory

203.2 Material Requirements :

203.2 Material Requirements Grading Requirements. TABLE 203.1 Grading Requirements Sieve Designation Mass Percent Passing Standard (mm) Alternate US Standard Grading A Grading B 50 2” 100 100 4.75 No. 4 45-100 55-100 2 No. 10 37-80 45-100 0.425 No. 40 15-20 25-80 0.075 No. 200 0-25 11-35

203.2 Material Requirements:

203.2 Material Requirements Materials passing the 4.75mm (No. 4) sieve must have a plasticity index not less than 4 and no more than 10. The aggregate shall have a mass percent of wear not exceeding 50 (AASHTO) Salvaged Soil-Aggregate Where soil aggregate is already in place Contractor shall not be responsible for its grading

203.2 Material Requirements:

203.2 Material Requirements Hydrate Lime Shall conform to the requirements of item 701, Construction Lime Water Shall conform to the requirements of item 714, Water

203.2 Material Requirements:

203.2 Material Requirements Proportioning of Mixture Amount of lime to be added to the soil-aggregate shall be from 3 – 12 mass percent of the dry soil

203.2 Material Requirements:

203.2 Material Requirements Strength Requirements CBR Test for Gravelly soils Test according to AASHTO T 193 and CBR value determined by AASHTO T 180, Method D Unconfined Compression Test for Finer Textured soils, 7-day compressive strength obtained by AASHTO T 134 Method B

203.3 Construction Requirements:

203.3 Construction Requirements

203.3 Construction Requirements:

203.3 Construction Requirements

203.3.1 Weather Limitation:

203.3.1 Weather Limitation Not be applied during windy, rainy or impending bad weather. In the event rain occurs during the operation work shall be promptly stopped Entire section shall be reconstructed

203.3.2 Construction Equipment:

203.3.2 Construction Equipment Scarifying Pulverizing Mixing Spreading Hauling Watering Finishing and Compacting Equipment Slurry lime Distributor

203.3.2 Construction Equipment:

203.3.2 Construction Equipment Distributor Tachometer pressure gauge Accurate volume measuring device or calibrated tank Equipped with power unit for the pump Full circulation spray bars Agitator to prevent setting of lime solids

203.3.3 Preparation of Soil-Aggregate:

203.3.3 Preparation of Soil-Aggregate Case 1 (New Soil Aggregate) Existing roadbed shall be scarified lightly Rolled or watered and rolled At least 1 day shall be allowed for measuring, sampling and testing Case 2 (Salvaged Soil Aggregate) Material in the existing roadbed is to be used for mixing Shall be scarified to the depth ordered by the engineer to leave a foundation undisturbed material

203.3.4 Application of Lime:

203.3.4 Application of Lime Hydrated lime shall be uniformly spread at specified percent. Mixing equipment shall follow immediately behind the distributor to partially mix lime with soil aggregate Dry lime should not be spread under windy condition to avoid excessive dustings Lime slurry, the facilities should be approved Slurry ratio is 1 tonne lime to 2 m 3 of water

203.3.5 Mixing:

203.3.5 Mixing Entire mass of the mixture shall be windrowed Mixed by blading the mixture from side to side Until whole mass has uniform color and free from fat or lean spot or balls of unmixed particles Avoid cutting into underlying course Should the mixture show any inaccurate distribution of lime, shall be corrected by addition of soil aggregate or lime

203.3.5 Mixing:

203.3.5 Mixing If mixture contains excessive moisture or volatile content, it shall be manipulated until it is satisfactory Surface should be in satisfactory condition Mixture shall be formed into a windrow of uniform cross section

203.3.6 Spreading, Compacting and Finishing:

203.3.6 Spreading, Compacting and Finishing Spread by self-propelled pneumatic-tire blade grader Rolled parallel to the road center line Compaction shall conform to AASHTO T 180 Method D Field density test is in accordance to AASHTO T 191

203.3.7 Protection, Curing and Maintenance:

203.3.7 Protection, Curing and Maintenance The contractor shall be required to maintain at his own expense the entire work within the limits of his contract in good condition From start until the work have been completed

203.3.7 Protection, Curing and Maintenance:

203.3.7 Protection, Curing and Maintenance The surface shall be protected against rapid drying. Sprinkling with water (maintain moisture) Cover the surface with a 50mm layer of earth Apply on surface an asphalt membrane of the type and quality approved by the Engineer Apply on surface liquid membrane curing compound approved by the Engineer

203.3.8 Trial Sections:

203.3.8 Trial Sections Shall be constructed at least 2 weeks before actual base construction. These shall conform to the applicable requirements of Subsection 200.3.4

203.3.9 Tolerances:

203.3.9 Tolerances Shall be laid to the designed level and transverse slopes shown on the Plan.

203.3.9 Tolerances:

203.3.9 Tolerances

203.3.10 Traffic:

203.3.10 Traffic The Contractor will not be permitted to drive heavy equipment over completed portions prior to the end of 5 days curing period Turning areas on completed portion shall be protected by a layer of stable granular materials. Not less than 50mm compacted depth

200.4 Method of Measurement:

200.4 Method of Measurement will be measured by the cubic metre (m³). quantity to be paid for the design volume compacted in-place as shown on the Plans No allowance will be given for materials placed outside the design limits shown on the cross-sections. Trial sections shall not be measured separately but shall be included in the quantity of subbase herein measured.

200.5 Basis of Payment:

200.5 Basis of Payment The accepted quantities, measured as prescribed in Section 203.4, shall be paid for at the contract unit price for Lime Stabilized Road Mix Base Course which price and payment shall be full compensation for furnishings and placing all materials, including all labor, equipment, tools and incidentals necessary to complete the work prescribed in this Item.

200.5 Basis of Payment:

200.5 Basis of Payment Payment will be made under:

SUMMARY:

SUMMARY

SUMMARY:

SUMMARY Item No Description Material Requirement Construction Requirement Method of Measurement Basis of Payment

SUMMARY:

SUMMARY Item 200 Aggregate Subbase Course Item 201 Aggregate Base Course Grading requirement tolerances Item 202 Crushed Aggregate Base Course Material Requirement Item 203 Lime Stabilized Road Mix Base Course

SUMMARY:

SUMMARY Item 204 Portland Cement Stabilized Road Mix Base Course Proportioning of mixture Item 205 Asphalt Stabilized Road Mix Base Course Material requirement Item 206 Portland Cement Treated Plant Mix Base Course

SUMMARY:

SUMMARY Item 206 Portland Cement Treated Plant Mix Base Course Construction Requirement Item 207 Aggregate Stockpile Construction requirement

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Thank You 

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