Abstract
Cement-stabilized macadam (CEM-SM) base layers on highways are prone to early shrinkage cracking in extremely cold and arid regions, mainly caused by the large drying shrinkage of traditional cement-stabilized base materials. A multi-component solid waste cementitious material (SWCM) was designed based on the response surface method. The synergistic reaction mechanism of SWCM was analyzed using X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TG). A shrinkage testing system was developed to evaluate the anti-cracking characteristics of stable macadam using multiple solid waste cementitious materials (SWCM-SM), and the strength growth law and frost resistance were analyzed. The results show that the Box-Behnken response surface model was used to obtain the optimal parameter combination for SWCM, including 60% slag, 30% steel slag, and 10% desulfurization gypsum. The compressive strength and flexural strength of SWCM-SM were 24.1% and 26.7% higher than those of CEM-SM after curing 180 days. The frost resistance of SWCM-SM was basically equivalent to that of CEM-SM, and the dry shrinkage strain of SWCM-SM was reduced by 30.7% compared to CEM-SM. It can be concluded that steel slag and desulfurization gypsum stimulate the hydration reaction of slag, thereby improving the bonding strength. Compared to CEM-SM, SWCM-SM exhibits slower hydration reaction and longer hydration duration, exhibiting characteristics of low early strength and high later strength. The early microstrain of the semi-rigid base layer is mainly caused by the occurrence of early water loss shrinkage, and the water loss rate of SWCM-SM is lower than that of CEM-SM. This study concludes that SWCM has good early crack resistance performance for stabilized crushed stones.