Influence of composition of curing agent and sand ratio of engineering excavated soil on mechanical properties of fluidized solidified soil

Abstract With the continuous expansion of the urban scale, the development of engineering construction has been accelerated. In this process, excavated engineered soils produced in the construction process are facing the problem of difficult treatment. In this work, the influence of the composition ratio of different curing agents on the strength of fluidized solidified soil was studied. It was found that when the proportion of fly ash and quicklime in the curing agent was 1:1, and the percentage of the curing agent in the soil was 15%, the 28 days unconfined compressive strength of fluidized solidified soil reached the maximum value. When the composition and content of the curing agent and the slump of the fluidized solidified soil remained unchanged, the strength and water stability of the fluidized solidified soil increased with the increase of the sand ratio of the excavated engineered soil. X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) showed that with the increase of sand in the soil ratio, more needle-like ettringite crystals were produced in the fluidized solidified soil, which were more compact, had fewer voids, and had higher overall compactness. The carbon emissions of the prepared fluidized solidified soil and the common backfill materials were calculated, and it proved that the carbon emissions of the fluidized solidified soil were the lowest. Therefore, this work offers a new method for resource utilization of excavated soil and provides a carbon emission reference for green low-carbon building materials. Finally, it was recommended to choose engineered excavation soil with high sand content to obtain higher performance from fluidized solidified soil.