Laboratory investigation of solid wastes combined with tunnel slag in cement stabilized base of asphalt pavement

Abstract

To coordinate the disposal and resource utilization of bulk solid waste iron ore tailings sand (IOTS) and hazardous solid waste phosphogypsum (PG), this paper has carried out the research of using the two and the tunnel slag in the pavement base, including unconfined compressive strength, splitting strength, compressive resilience modulus, frost resistance, temperature shrinkage, and dry shrinkage tests. According to the characteristics of phosphogypsum (PG), the water stability, delayed compaction, and leaching of toxic substances were studied, and the mechanism was analyzed by SEM and XRD. It is concluded that tunnel slag and IOTS are great filling materials; The inclusion of PG inhibited the hydration of cement, which results in the reduction of unconfined compressive strength and splitting strength in the early stage, and the higher mean coefficient of thermal contraction; When the content of PG did not exceed 6%, the frost resistance, water stability, and drying shrinkage coefficient performed well, and the delayed forming strength had almost no loss, providing support for the continuous construction technology of the road base and the inhibition of reflective cracks. Applying a large number of solid wastes to road engineering can not only efficiently handle various waste buildup problems but also produce a new form of road materials with important social, economic, and environmental benefits.