ITEM 305 - BITUMINOUS PENETRATION MACADAM PAVEMENT

305.1 Description

This Item shall consist of furnishing and placing one or more courses of graded aggregate and one or more application of bituminous material, followed by a seal coat with cover aggregate constructed on a prepared base in accordance with this Specification and in conformity with the lines, grades and typical cross-sections shown on the Plans.

305.2 Material Requirements

305.2.1 Quantities of Materials

The approximate amounts of materials per square meter and sequence of operations shall be provided in Table 305.1, whichever is called for in the Bill of quantities. The weights given in the Table are those of aggregates having a bulk specific gravity of 2.65 as determined by AASHTO T 84 and T 85. Proportionate corrections will be made when the aggregates furnished on the job have a bulk specific gravity above 2.75 or below 2.55. In such case, the corrected amount will be the product of the weight given in the Table and the ratio of the bulk specific gravity of the aggregate to 2.65.The amounts in the Table are approximate and the exact quantity will beset by the Engineer. Total amount of bituminous material per square meter maybe varied by the Engineer as necessary to fit conditions, but the total amount of aggregate per square meter, after adjusting for specific gravity will not be changed.

Table 305.1 – Quantities of Materials and Sequence of Operations

Type of Aggregate and Sequence of Operations	Type of Bituminous Material
	Asphalt Cement or Rapid Curing (RC)	Emulsified Asphalt
First Layer:    Spread Aggregates:      Coarse Aggregate, kg/m2      Choker Aggregate, kg/m2      Apply bituminous material, L/m2 Second Layer:   Spread Aggregate:      Key Aggregate, kg/m2     Apply bituminous material, L/m2 Third Layer:    Spread Aggregate:       Key Aggregate, kg/m2      Apply bituminous material, L/m2 Fourth Layer:   Spread Aggregate:     Cover Aggregate, kg/m2 Total Quantities:     Bituminous Material, L/m2      Aggregate, kg/m2	90 - 40 13 1.8 11 1.4 8 7.2 122	90 10 5.5 10 3.5 8 2 8 11 126

305.2.2 Bituminous Material

The bituminous material shall be either Asphalt Cement, Rapid Curing (RC), Cut-back Asphalt or Emulsified Asphalt, whichever is called for in the Bill of Quantities. It shall conform to the requirements of Item 702, Bituminous Materials. The Penetration Grade Number of asphalt cement and type and/or grade of cut-back or emulsified asphalt will be specified in the Special Provisions.

305.2.3 Aggregate

  The coarse aggregate shall be crushed stone, crushed slag or crushed gravel. The choker material, key rock, and cover aggregate shall be crushed or broken stone, crushed gravel, or crushed boulders or screened gravel or coarse sand. All aggregate shall consist of clean, tough, durable fragments, free from excess of flat, soft or disintegrated pieces and free from stone coated with dirt or other objectionable matter which will prevent adherence of the asphalt to the aggregate. Natural gravel may be used for cover material. Gradation shall conform to Table 305.2.

Table 305.2 – Aggregate Grading Requirements

Sieve Designation		Mass percent Passing
Standard, mm	Alternate US Standard	Coarse Aggregate	Choker Aggregate	Key Aggregate	Cover Aggregate
63 50 37.5 25 19 12.5 9.5 4.75 2.36 1.18	2 – ½” 2” 1 – ½” 1” ¾” ½” 3/8” No. 4 No. 8 No. 16	100 90 – 100 35 – 70 0 – 15 - 0 – 5 - - - -	- - - - 100 90 – 100 40 – 70 0 – 15 0 – 5 -	- - - 100 90 – 100 20 – 55 0 – 15 0 – 5 - -	- - - - - 100 85 – 100 10 – 30 0 – 10 0 - 5

The aggregate shall have a mass percent of wear not exceeding 40 when tested by AASHTO T 96.

When the crushed gravel is subjected to five cycles of the sodium sulfate soundness test (AASHTO T 104), the weighted loss shall not exceed 12 mass percent.

When crushed slag is used, it must be of uniform density and quality and shall have a density not less than 1120 kg/m³ as determined by AASHTO T 19.

305.3 Construction Requirements

305.3.1 Weather Limitations

Application of bituminous material shall be made only when the aggregate is dry and the atmospheric temperature in the shade is 150 C or above and when the weather is not foggy or rainy.

305.3.2 Equipment

The equipment to be used shall include hand or power operated brooms, shovels, rakes, self-powered bituminous material distributors or hand or power-operated spray pumps, broom dragging equipment and self-powered rollers. A sufficient number of stiff-fiber or steel-bristle push brooms shall be included. Application of the bituminous material by any means other than a pressure spray will not be approved and the equipment used shall be of such nature that the temperature of application of the bituminous material can be accurately controlled within the limits specified and such that the rates of application can be accurately controlled.

The rollers shall be self-propelled steel wheel, vibratory or pneumatic type. The number and weight of rollers shall be sufficient to compact the layer to the required condition.

305.3.3 Conditioning of Existing Base

Before spreading the aggregate, the base shall be cleaned of all loose foreign materials. The existing base shall be swept until the embedded large aggregate is exposed, or in the case of a previously constructed asphalt surface, until the surface is free of mud or other covering.

If shown on the Plans and called for in the Bill of Quantities, a prime coat shall be applied to the prepared untreated base in accordance with the Item 301, Bituminous Prime Coat, or in case of previously constructed asphalt or cement surface tack coat shall be applied in accordance with Item 302, Bituminous Tack Coat.

305.3.4 Spreading and Compacting of Aggregate Layers

The number of layers in which the macadam pavement is to be constructed and the order and rates the bituminous material and mineral aggregates are to be spread shall be as indicated in Table 305.1.

The type of aggregate required in the order of spreading shall be placed in the required amount of approved aggregate spreaders, or by other approved mechanical methods. All areas with non-uniformly graded aggregate shall be removed and replaced with suitable materials before the rolling begins. These corrections shall be made by hand picking whenever necessary and shall be continued after initial rolling until the appearance and texture of the aggregate are uniform and all irregularities are corrected.

The aggregate shall be dry-rolled until it is compacted and keyed. Rolling shall progress gradually from the sides to the center, parallel with the center line of the road and overlapping uniformly each preceding rear wheel track by one-half the width of such track and shall continue until the aggregate does not creep or displace ahead of the rollers.

Materials which are crushed excessively under the roller or becomes segregated in such a manner as to prevent free and uniform penetration of the bituminous material shall be removed and replaced with suitable aggregate. The compacted aggregate shall have a firm and even surface.

Dry rolling shall be stopped when the surface of the aggregate will support the distributor and before the voids are closed sufficiently to prevent the free uniform penetration of the bituminous material.

Along curbs, headers and walls, and at all places not accessible to the roller, the aggregate shall be tamped thoroughly with mechanical tampers or with hand tampers. Each hand tamper shall have a mass of not less than 25 kg and a face area of not more than 250 mm by 250 mm.

Aggregate in any layer that becomes coated or mixed with dirt or clay prior to the application of the bituminous material shall be removed and replace with clean aggregates and the area shall be rerolled.

Prior to application of the bituminous material, the surface of the aggregate layer will be tested by the Engineer using a 3-m straight-edge at selected locations. The variation of the surface from the testing edge of the straight-edge between any two contacts with the surface shall at no point exceed 10 mm. All humps or depressions exceeding the specified tolerances shall be corrected by removing defective work and replacing it with new materials as specified.

Each layer of aggregate shall be spread so that the bituminous material is covered before wheels or tracks pass over it.

305.3.5 Application of Bituminous Material

The bituminous material shall be uniformly applied at the rate specified in Table 305.1. Building paper shall be placed over the end of the previous application and the joining application shall start on the building paper. Building paper so used shall be removed and disposed off in a satisfactory manner. During the application of the bituminous material, care shall be taken to prevent spattering of adjacent pavements, structures and trees.

The distributors shall not be cleaned or discharged into ditches, borrow pits or shoulders along the right-of-way.

305.4 Method of Measurement

Bituminous Materials, and Aggregate for Bituminous Penetration Macadam Pavement will be measured by the tonne (t). The quantity to be paid for shall be the number of tonnes of bituminous material and aggregate used and accepted in the completed work.

305.5 Basis of Payment

The accepted quantities, measured as prescribed in Section 305.4, shall be paid for at the contract unit price for Bituminous Penetration Macadam Pavement, which price and payment shall be full compensation for furnishing and placing all materials and for all labor, equipment, tools, and incidentals necessary to complete this Item.

Payment will be made under:

Pay  Item Number	Description	Unit of Measurement
305 305 (1) 305 (2) 305 (3) 305 (4)	Bituminous Penetration Macadam Pavement Aggregates Asphalt Cement RC ___ Cut-back Asphalt Emulsified Asphalt	Tonne Tonne Tonne Tonne