408Prime Coat

Prime Coat

408.1DESCRIPTION

1 This section describes the requirements for preparing and coating an existing surface with prime coat and, if required, blotter.

408.2MATERIALS

1 Provide materials in accordance with the following:

Material Subsection Aggregate for Blotter 803 Emulsified Asphalt 804.3

2 Provide either emulsified cutback asphalt, AEP, or penetrating emulsion prime (PEP).

3 Provide blotter material from a specified department-furnished or contractor-furnished source.

408.3EQUIPMENT

1 Provide tank trucks, asphalt distributor, and on-site storage tanks in accordance with Subsection 407.3, Equipment.

2 Provide mechanical spreading equipment for applying blotter material; do not use hand tools unless approved by the engineer.

408.4CONSTRUCTION

408.4.1 General

1 Ensure the application surface is shaped to the required grade and section, free of ruts, corrugations, segregated material, and other irregularities and uniformly compacted. Reprocess or reshape damaged areas. Obtain the engineer’s approval of the surface before applying prime coat.

2 Provide samples and certification documents for emulsified asphalt in accordance with Materials Testing Manual, Section 840.0, Liquid Asphalt Sampling.

3 When using PEP, pre- wet surface with water in accordance with Subsection 209.4.2, Prewetting, to reduce surface tension of fine particles and maximize penetration of prime coat. Apply prime coat when the application surface is damp and both the air and surface temperatures are above 50 °F [10 °C].

Prime Coat SECTION 408

4 Emulsified asphalt used for prime coat must be diluted, either in the field or by supplier, at a ratio in accordance with manufacturer's recommendations depending on gradation of base aggregate. Minimum dilution ratio is 1:1 which is 1 part emulsified as phalt to 1 part water. When using PEP and base aggregate meets requirements of Grading "L" in Table 803.4.4-1, Gradation Requirements: Subbase and Base, dilution ratio may be as much as 1 part PEP to 4 parts water (1:4, 20% emulsion) to ensure penetration of prime coat. Before mixing, heat dilution water and emulsified asphalt to minimum temperature specified by manufacturer. Dilute by introducing water into emulsified asphalt.

5 Apply emulsified asphalt in accordance with T able 408.4.1-1, Application Temperatures for Emulsified Asphalt.

Table 408.4.1-1 Application Temperatures for Emulsified Asphalt Emulsified Asphalt Temperature (°F [°C]) AEP 70 to 160 [20 to 70] PEP 120 to 160 [50 to 70]

6 Apply prime coat the full top width of the crushed base plus 6 in [150 mm] beyond the toes of the bituminous pavement so there is uniform, complete coverage at rate specified or approved. Correct deficiencies and areas not covered.

7 When traffic is present in construction areas, apply prime coat on one half of the application surface at a time. Do not allow traffic on the surface until the prime coat has been sufficiently absorbed to prevent pick -up or tracking. When using PEP and before allowing traffic, post-wet surface with water after emulsion has cured (color is black; stops bubbling). Cover unabsorbed quantities with blotter material; spread the material without operating the equipment’s tires on the exposed, newly applied liquid asphalt.

408.4.2 Acceptance

1 The engin eer will accept emulsified asphalt in accordance with Subsection 113.2, Acceptance of Asphalt Material.

408.5MEASUREMENT and PAYMENT

408.5.1 General

1 The engineer will measure:

Measurement Methods. Quantities of water to dilute the emulsified asphalt for application will not be measured and paid for as Prime Coat.

Prime Coat SECTION 408

2 The engineer will not measure for payment quantities exceeding those specified or approved.

3 The department will pay as follows:

Pay Item

Pay Unit Measure to the Nearest Pay Nearest to Nearest Prime Coat TON [t] 0.01 ton [0.01 t] 0.01 TON [0.01 t] Blotter TON, CY [t, m3] 0.01 ton, ft [0.01 t, 0.5 m]

0.01TON, CY

[0.01 t, m3]

408.5.2 Referenced Sections for Direct Payment

1 When specified, the engineer will measure and pay for Haul in accordance with Section 204, Haul.

408.5.3 Payment Adjustment

1 The engineer may reduce the payment for liquid asphalt that does not meet specifications but is accepted in accordance with Subsection 113.2, Acceptance of Asphalt Materials.