Preliminary Evaluation of Semiflexible Pavement Formed by Direct Mixing and Molding of an Asphalt Mixture and Grouting Material

Abstract

Semiflexible pavement (SFP) material is a rigid–flexible composite material with excellent overall road performance. However, traditional pouring semiflexible pavement (P-SFP) material suffers from problems such as an unreliable grouting rate, weak crack resistance, and complex molding process. To solve these problems, this paper tentatively proposes the mixing SFP (M-SFP) material using a simplified molding process, in which a loosely prewrapped asphalt mixture and cement grouting material (CGM) are mixed directly. Different CGM contents and asphalt–aggregate ratios were designed using the volume filling method, and low-temperature splitting tests and bending tests were carried out to evaluate the low-temperature crack resistance of M-SFP materials, and the area ratio of coarse aggregate in the cross section of the specimen was analyzed by digital image processing technology to evaluate the coarse aggregate homogeneity of the M-SFP material. The results showed that the low-temperature crack resistance of M-SFP material increases with the increase of the asphalt–aggregate ratio. Compared with the traditional P-SFP material, M-SFP material had an 18.9% reduction in the stiffness modulus and a 6.7% increase in the strain energy density. Analyzing the failure stiffness modulus and strain energy density of M-SFP materials with different CGM content indicated that when the stiffness-to-flexibility ratio of the composite material with SFAC-16 gradation is between 2.68 and 3.62, the low-temperature crack resistance is better. In addition, the aggregate homogeneity of M-SFP and P-SFP specimens is basically the same.