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APPENDIX B ASPHALT CONCRETE SPECIMEN PREPARATION B -1
APPENDIX B: ASPHALT CONCRETE SPECIMEN PREPARATION Watsonville granite aggregate and Valley AR-4000 grade asphalt were used for the asphalt concrete mix. Two different gradations, medium and coarse, were used during the course of this study and are descnbed in Table B.~. Table B. ~ . Medium and Coarse Gradations Percent Retained on Each Sieve by Weight Sieve Size Medium Gradation Coarse Gradation ~ in. 0 0 3/4 in. 5 10 I/2 in. 16 iS 3/S in. 12 12.5 No. 4 20 20 No. ~14 13 No. 16 I} 10 No. 30 ~9 , No. 50 5 2 No. 100 5 3 Pan (passing No. 100) 4 2.5 , . The aggregates were heated overnight at the mixing temperature of 284°F. The asphalt was heated until the mixing temperature was achieved, the maximum allowable time of heating not exceeding 3.5 hours. Mixing time of 4 minutes was used. Optimum asphalt contents of 4.9 and 4.7 percent were used for mixing for medium and coarse gradation samples, respectively. After mixing the specimen was cured at 140°F for 15 hours and then stored at room temperature. Before compaction the mix was placed at a temperature of 240°F until it reached uniform temperature (normally within 1.5 hours). The mix was discarded if it was not used within 3 to 3.5 hours. Specimens were compacted by a Gyratory Testing Machine (GTM) to achieve 4 + 0.5 percent air voids. B-2