Autoclaved Lime-Saline Soil Products: Reactivity Assessments and Effects of Quartz Sand

Abstract

Over the last few decades, the high growth rate in China’s construction industry has increased the demand for building materials. Thus, the sustainable use and conservation of quality clay soil for brick production has attracted much attention in recent years. This paper investigates the technical feasibility of using saline soil as a raw material for the production of autoclaved lime-saline soil products. The reactivity of lime-saline soil under different autoclave temperatures (12, 15, and 175°C), pressures (.1, .38, and .78 MPa), and times (1, 2, 3, and 6 h) was assessed. The experimental results indicate that saline soil’s reactivity increased with increasing lime content as well as autoclave temperature, pressure, and reaction time. However, the reaction process seemed to be significant only for the first 2 h. The mixture proportions were varied to further examine the effects of sand sizes and their replacement content for saline soil on the properties of autoclaved specimens. It was observed that specimens containing 25–85% saline soil possessed compressive strength ranging from 17 to 36 MPa with relatively low water absorption (4.–6.8%). Thermal analysis results indicate that tobermorite is responsible for the higher mechanical strength gain for the autoclaved specimens. The overall results have proved that it is feasible to produce an autoclaved lime-saline soil product with a lower environmental impact.