The Performance Evaluation of Crack Resistance in Cement Stabilized Macadam Base Reinforced with Polypropylene Fibers Based on DIC Technology

In order to enhance the crack resistance durability of cement stabilized macadam base layers, aiming for a long service life of road surfaces, varying amounts of polypropylene fibers were introduced into the cement stabilized macadam base. Through conducting split tensile strength tests at different curing ages, the optimal dosage of polypropylene fibers was determined. Subsequently, macroscopic mechanical property tests were employed to assess the impact of added polypropylene fibers on compressive strength, split tensile strength, and flexural tensile strength. Finally, a semi-circular bending test was conducted on two groups of specimens to obtain their displacement-time curves. The entire loading process was continuously monitored and compared using Digital Image Correlation (DIC) for full-time domain observation. Experimental findings demonstrate that the incorporation of 0.1% polypropylene fibers can enhance the macroscopic mechanical performance of the water-stable base layer, with the most pronounced improvement observed in the splitting strength, approximately around 20%. Furthermore, by leveraging its inherent bridging effect, the bearing capacity of the semi-circular specimens increased from 3.71kN to 3.92kN. The duration from loading to the appearance of macroscopic cracks extended from 1.92s to 3.92s, mitigating stress concentration and abrupt displacement increases through stress transmission. Through experimentation, the optimal dosage of polypropylene fibers in water-stable crushed stone base layers has been determined.