Development of procedure for design and preparation of open-graded asphalt mixture used in semi-flexible pavement

Abstract

This study presents a procedure for design and preparing the open-graded asphalt (OGA) mixture used in the semi-flexible pavement (SFP) according to the principle engineering characteristics and performance. In this study, different aggregate gradations, cellulose and synthetic fibers, modified and neat asphalt binders, and air void contents were used to prepare the OGA mixtures. Furthermore, several experimental tests, including the Cantabro, Semi-circular bending (SCB), binder drainage, indirect tensile strength (ITS), wheel tracking, and permeability tests were conducted to assess the engineering properties of the OGA mixtures. According to the results of the mechanical tests (i.e., Cantabro, moisture sensitivity, semi-circular bending, and rutting), the increase of air void content in OGA mixtures causes a reduction in the failure resistance. However, considering the rutting and ITS test results, the performance of SFP (OGA mixture filled with grout) increases as the initial air void content of the OGA mixtures increases, which is because of the higher infiltration of grout inside of OGA mixture and higher internal integrity. The results of the mechanical performance tests on OGA mixtures indicate that the low and high ranges of the air void content to acquire most possible mechanical performance are 25% and 30–35%, respectively.