325 Page 193325 ASPHALT CONCRETE – CLASS S
325.1DESCRIPTION
This work consists of constructing a course of asphalt concrete on a prepared surface.
325.2MATERIALS
The materials for asphalt concrete Class S and their use will conform to Section 320.2 with the following additional requirements: Stabilizing Additive for Asphalt Concrete: The Contractor will use cellulose fibers only as the stabilizing additive for asphalt concrete. The cellulose fibers will conform to the following requirements and be accompanied with certified test results for each batch delivered to the project. Fiber Length: 0.25 inch max Sieve Analysis: Alpine Sieve Analysis Passing #100 sieve 60-80% Ash Content: 13-23% non-volatiles pH: 7.5 (±1.0) Oil Absorption (times fiber weight): 5.0 (±1.0) Moisture Content: 5.0% max (by weight)
325.3CONSTRUCTION REQUIREMENTS
The construction requirements will be as prescribed in Section 320.3 with the following modifications: A.Weather and Seasonal Limitations: Asphalt concrete will not be placed when the underlying surface is wet or frozen. Asphalt concrete will not be placed when weather conditions prevent proper handling, compaction, or finishing. The placement of asphalt concrete will only be permitted between June 1 and September 15, inclusive, and when the air and surface temperatures are 60°F or greater in the shade. B.Rollers: Substitute the following for the first paragraph of Section 320.3 B.6: There will be at least three steel faced tandem rollers for each paver in use. The self-propelled steel faced tandem rollers (two steel drums operating in the same track) will furnish a minimum rolling weight (mass) of 325 pounds per inch of roller width. Vibratory rollers will be operated in the static mode unless otherwise ordered by the Engineer. Pneumatic tired rollers are not allowed. The rollers will be capable of being reversed smoothly, without shoving or tearing the asphalt concrete. C.Breakdown Rolling: Substitute the following for Section 320.3 G.2: Self-propelled tandem smooth steel rollers (two steel drums operating in the same track) will furnish a minimum rolling weight (mass) of 325 pounds per inch of roller width. Breakdown 325 Page 194rolling, consisting of a minimum of two complete coverages with at least two self-propelled tandem smooth steel rollers, will proceed on the mat as soon as laydown is completed. Operations will be scheduled so breakdown rolling is completed on a segment within 300 feet of the laydown. Final or finish rolling will consist of a minimum of one complete coverage with at least one self-propelled tandem smooth steel roller. Completion of rolling will not lag behind the laydown by a distance of more than 600 feet. During periods of cool weather this maximum distance between laydown and final rolling will be reduced as ordered by the Engineer. Compaction to a specified density will not be required. However, additional roller coverage may be required in order to obtain a smooth surface finish. D.Stabilizing Additive for Asphalt Concrete: Add the following to Section 320.3 C: 5.The asphalt concrete mixture will meet the 0.3% maximum drain down percent in uncompacted bituminous paving mixtures requirement when tested in accordance with SD 306. If the asphalt concrete mixture drain down percent exceeds the maximum allowed, the Contractor will be required to add a stabilizing additive to the mixture to prevent drain down of the asphalt binder and mineral aggregate according to the following: Stabilizing additives will be introduced into the mixture using a stabilizer supply system recommended by the manufacturer of the additive. The supply system will be a separate system that proportions the required amount of stabilizer in a uniform distribution. The system will include low level and no-flow indicators and a printout of status of feed rate in lbs/min. The stabilizer supply line will include a section of transparent pipe for observing consistency of flow or feed. Stabilizing additive will be added at a dosage rate between 0.2% and 0.4% by weight of the total mix as determined by the mix designer. If the stabilizing additive content falls outside a tolerance of ±10% by total weight of desired stabilizing additive from the job mix formula target, the Contractor will stop production until corrective measures are taken.
325.4METHOD OF MEASUREMENT
Measurement as prescribed in Section 320.4 with the following addition: G.Stabilizing Additive for Asphalt Concrete: Stabilizing additive for asphalt concrete, when provided, will be measured to the nearest 0.1 ton.
325.5BASIS OF PAYMENT
Payment as prescribed in Section 320.5 with the following addition: G.Stabilizing Additive for Asphalt Concrete: Stabilizing additive for asphalt concrete will be paid for at the contract unit price per ton including all cost for labor, equipment, and materials associated with the addition of the stabilizing additive for asphalt concrete complete in place. 326 Page 195326 ASPHALT CONCRETE – CLASS HR
326.1DESCRIPTION
This work consists of constructing one or more courses of asphalt concrete with RAP on a prepared surface.
326.2MATERIALS
The materials for asphalt concrete Class HR and their use will conform to Section 320.2 except as modified by the following: Asphalt concrete aggregates will consist of RAP and virgin aggregate. The proportions of materials in the mixture will be determined by the job mix formula. The virgin mineral aggregate for asphalt concrete Class HR will conform to Section 321 - Class E, Type 1. The virgin aggregates will meet the specifications of the class and type specified. The combined virgin aggregate and RAP will not be further tested for gradation or quality control purposes.
326.3CONSTRUCTION REQUIREMENTS
The construction requirements will be as prescribed in Section 320.3 with the following modifications: A.The compacted thickness of each lift will not exceed 3 inches. B.The minimum density requirement will be 92% of the maximum specific gravity of the test specimens prepared in the field in accordance with SD 312. The compacted density of asphalt concrete will be determined according to SD 311. C.The RAP, virgin aggregate materials, and asphalt cement will be mixed by a conventional hot mix batch plant or a drum mix type hot plant.
326.4METHOD OF MEASUREMENT
Measurement as provided in Section 320.4 .
326.5BASIS OF PAYMENT
Payment as provided in Section 320.5 .