The resilient modulus of a laboratory-compacted asphalt concrete specimen is dependent on many factors, including the test system used, the test operator, the method of compaction, the level of compaction, and parameters or conditions in the test procedure such as temperature, load frequency, load duration, and load-induced diametral strain level. The results of a parametric study involving resilient modulus testing of two dense-graded hot-mix asphalt concrete mixtures compacted to two levels of air voids are presented. Three replicated test specimens were prepared for each mix at each air void level using the Marshall method of compaction. The concern was to select one combination of test temperature, load frequency, load duration, and induced diametral strain that would lead to repeatable modulus results among the replicated specimens within each group while being sensitive enough to detect differences between the two mix types and levels of air void contents of similar mix types. A pneumatic test system was used to measure resilient modulus. On the basis of a statistical analysis of the test results, it was concluded that the test conditions consisting of 0.1-sec load duration, 0.33 Hz load frequency, 50 to 75 x 10-4 percent induced strain at 60 degrees F would best satisfy the repeatability criteria. (Author/publisher)
Samenvatting