Effect of CR-Modified Binders on the Mechanical Properties of Semi-Rigid Pavements Prepared with Porous Asphalt Mixtures

In this study, experimental investigations were conducted to evaluate the fundamental engineering properties and performance of porous asphalt mixtures modified with CR (crumb rubber) for use in semi-rigid pavement structures. During the design of the porous asphalt mixtures, different aggregate gradations were used to determine air void contents. Two types of aggregates with different origins (basalt and limestone), 160/220 penetration grade pure bitumen, and CR-modified binder were utilized in the mixtures. The properties of the cement mortar used to fill the voids in the porous asphalt mixtures were also examined in detail for the production of semi-rigid pavement specimens. Flowability and compressive strength tests were performed on the cement mortar, while Cantabro loss, Marshall stability, compressive strength, and permeability tests were conducted on the semi-rigid composite specimens. The experimental results revealed that the use of CR-modified binders in porous asphalt mixtures significantly improved the mechanical performance of the semi-rigid pavement structures.