Study on the arch expansion characteristics of cement-stabilized macadam under the action of temperature and salt

Abstract

Environmental conditions, including temperature variations and salt erosion in desert areas, significantly affect the strength and arch expansion properties of cement-stabilized macadam materials. To reveal the effects of temperature, salt content, and cement dosage on the arch expansion deformation of cement-stabilized macadam, this study analyzes the strength performance, arch expansion characteristics, microscopic morphology, and pore structure characteristics of cement-stabilized macadam materials under different factors through strength tests, arch expansion tests, SEM, and CT techniques. The results show that the strength of cement-stabilized macadam increases with curing temperature and cement dosage, but decreases with salt content, exhibiting a significant abrupt change in both cases. During the heating process, the expansion coefficient first decreases, then increases, and decreases again, reaching its maximum value between 40–50°C. An arch expansion strain model is developed considering sulfate content, cement dosage, and temperature variations. The effect of cement dosage on the arch expansion failure of cement-stabilized macadam is greater than that of sulfate content. It is recommended to reduce the cement dosage while maintaining the mixture's strength. The arch expansion failure of cement-stabilized macadam under temperature and salt action can be divided into four stages, which are essentially the continuous increase of material porosity and pore quantity under stress accumulation.