Investigation of Preparation and Shrinkage Characteristics of Multi-Source Solid Waste-Based Cementitious Materials

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.

Investigation of Mechanical and Shrinkage Performance for Large-Size Cement-Stabilized Aggregates

“…The presence of cracks in the base layer serves as a critical prerequisite for the emergence of reflective cracks. Scholars, through extensive research on semi-rigid base materials, have identified two primary factors contributing to the formation of shrinkage cracks [ 4 , 5 , 6 ]. The first factor involves stress induced by temperature fluctuations, while the second factor is stress resulting from the reduction in moisture content within the semi-rigid base material.…”

Mechanical Properties and Hydration Mechanism of Iron Tailings–Cement-Based Supplementary Cementitious Materials

“…Therefore, it is imperative to research and develop new cement-based supplementary cementitious materials to meet the needs of the concrete industry, increase the amount of cementitious materials, and reduce CO 2 emissions from the concrete industry [41][42][43]. Industrial solid wastes of different natures can produce optimal complementary advantages during hydration reactions and structure formation in different systems [44,45]. Therefore, it is important to study the synergistic effect and hydration between solid wastes, which can provide a theoretical basis for their effective utilisation [46,47].…”