The importance of identifying d-cracking susceptible aggregates has led to a considerable number of aggregate identification test procedures. Unfortunately, the more reliable of the procedures may require 8 weeks or longer, expensive equipment, and highly skilled operators. In response to this problem, the strategic highway research program (shrp) has issued a research contract to develop a rapid, reliable test method for identifying aggregates susceptible to d-cracking. The new test method being developed is used to examine four aggregates: two that have produced d-cracking in the field, and two witha performance history of no d-cracking. The test method involves covering an oven-dried aggregate sample with water, and then pressurizing the water to 1, 150 psi (7, 930 kpa). The pressure is quickly released, and then the pressurization and release cycle is repeated. Tencycles per day are run for a total of 50 cycles. The amount of aggregate fracturing is determined and indicates d-cracking potential. The d-cracking susceptibility of the four aggregates tested was clearly identified even though the samples were different materials from diverse origins and locations. This paper appears in transportation research record no. 1301, Factors affecting properties and performance of pavements and bridges 1991.
Abstract