Influence of Plastic Aggregate Geometry on Strength Properties of Cement-Stabilized Macadam

Abstract In order to improve the toughness and flexibility of cement-stabilized macadams and inhibit crack formation and propagation, the influence of plastic aggregate geometry on the strength properties of cement-stabilized macadam is studied. The surface roughness of plastic aggregate was designed into Ra 12.5 and Ra 25. When the content of plastic coarse aggregate was gradually increased from 4–8%, 12%, 16%, 20%, and 24%, the compressive strength, splitting strength, and the tensile-compression ratio of the cement-stabilized macadam made of aggregate with rough surface texture were found higher than those of aggregate with smooth surface texture. The rough cylindrical, spherical, spindle, and dumbbell-shaped plastic coarse aggregates were designed and prepared for testing. The test results showed the maximum compressive strength, splitting strength, and tensile-compression ratio of cement-stabilized macadam with the dumbbell-shaped plastic coarse aggregate. The tensile-compression ratio increased by 15.2% compared to natural aggregate cement-stabilized macadam. The results show that under the same conditions, the plastic aggregate with different geometry can improve the compressive and splitting strengths of cement-stabilized macadam and significantly improve the toughness and flexibility, with dumbbell-shaped plastic coarse aggregate having the greatest improvement, especially compared with natural aggregate cement-stabilized crushed stone. This research provides insights for improving pavement engineering quality and new ideas for utilizing waste plastics.