Boosting semi-flexible asphalt pavement sustainability and performance with rice husk biochar particle

Abstract

Developing low-carbon and carbon-sequestering pavement materials is significant for achieving the Paris Climate Agreement's “dual carbon” goals. The innovation of this study lies in the incorporation of rice husk biochar into semi-flexible pavements, which enhances rutting resistance, reduces the cement content in the grouting material, and contributes to energy conservation, emission reduction, and effective carbon sequestration. This forms the basis for the study's adherence to criteria for evaluating the performance of grouting materials with rice husk biochar, using tests for fluidity, flexural strength, compressive strength, and drying shrinkage. Comprehensive assessments were also conducted, including freeze-thaw splitting, immersion Marshall, immersion scattering, and rutting tests. These evaluations aimed to examine the effects of incorporating various amounts of rice husk biochar into the asphalt mixture matrix on water stability and high-temperature performance. Finally, the optimal content is determined from the above tests. The study shows that the internal blending ratio of rice husk biochar in grouting materials is 8 %. In the matrix of the asphalt mixture, the blending ratio is 12 %. The semi-flexible pavement performs best, with a 7.1 % improvement in high-temperature performance, a 15.0 % increase in shear strength, and improvements in residual stability, flexural stiffness modulus and freeze-thaw splitting tensile strength ratio.