DTIC ADA185753: A Laboratory Study of Asphalt pdf

DTIC ADA185753: A Laboratory Study of Asphalt

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Effects of high-contact pressure F-4 and F-15 aircraft traffic in the 350-400 psi range on conventionally designed heavy-duty asphalt concretes were studied. Specimens of mix were prepared to current heavy-duty compactive efforts (75 blow per side with an impact hammer) and four other compactive efforts, using a modified gyratory compactor. The gyratory compactor was used to roughly simulate high-contact pressure traffic on some of the mixes. Two aggregate gradations recommended for high-pressure traffic were used to produce crushed limestone aggregate blends. Two grades of asphalt cement, AC 20 and AC 40, and a Chemkrete modified AC 20 asphalt cement were used as binders. Heavy-duty mix selection criteria were used to bracket optimum mixes for supplemental testing and analysis. testing consisted of indirect tensile tests (dynamic and static), direct shear tests. accelerated aging tests, and unconfined creep tests. Results indicated that current heavy-duty mix selection criteria can be used, but higher compactive effort is needed to prevent rutting and densification problems.

lower asphalt content mixes were selected when higher compactive efforts were used. Two modified methods of designing high-contact pressure asphalt concrete mixes were presented. The preferred method is based on the use of a gyratory compactor at a higher compactive is not effort. The second method, an approximate method for use when a gyratory compactor is not available, is based on use of the current 75-blow per side impact hammer Several mixes were recommended for use in a field test at Tyndall AFB, Florida

• Creator/s: Defense Technical Information Center
• Date: 7/1/1987
• Year: 1987
• Book Topics/Themes: DTIC Archive, Regan, George L, ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS GEOTECHNICAL LAB, *ASPHALT, *CONCRETE, *PAVEMENTS, ACCELERATED TESTING, AGING(MATERIALS), BINDERS, CEMENTS, CREEP TESTS, DYNAMICS, FIELD TESTS, HEAVY DUTY, HIGH PRESSURE, JET FIGHTERS, LABORATORIES, LIMESTONE, MIXTURES, RUNWAYS, SELECTION, SHEAR TESTS, STATICS, TENSILE PROPERTIES, TEST AND EVALUATION, TRAFFIC

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