Effect of fine aggregate composition on moisture susceptibility of hot mix asphalt

Abstract

This paper discusses how the moisture susceptibility is influenced by the angularity characteristic and the composition of the fine aggregates. The results indicate that the composition of fine aggregate affects the moisture susceptibility of asphalt mixture in certain degree. By reviewing the results of the split strength ratio of bituminous mixture, the mass (in percent %) of natural sand in the fine aggregate (N/FA) ratio has an optimal value. This value is propitious to improve the workability of the asphalt mixture and enhance the compaction of mixture, and thus reduce the percent of air voids in asphalt mixture and reduce the moisture susceptibility. From the study, it was found that the optimal value of N/FA is 30%, approximately being equal to 13% (in weight) of the total weight of the mineral aggregates. Further increase in N/FA ratio may cause a lower adhering ability between the bitumen and aggregate. Furthermore it is considered that by viewing the FAA alone is not sufficient to justify or conclude on the possible performances of the subsequent bituminous mixtures formed.