Mechanical strength and durability performance of autoclaved lime-saline soil brick

The growing demand of building materials in China has intensified the search for a greener and more environmental friendly substitute for conventional clay brick. One of the proposed alternatives is the use of brick incorporating saline soil as replacement for conventional siliceous sand. Saline soil is available in abundance in China but because saline soil contains high content of soluble salts, it is unsuitable for agricultural use. It is therefore interesting to explore the utilization of saline soil in the production of autoclaved brick for both economic and environmental benefits. As part of research project in producing lime-saline soil bricks, this paper presents an investigation of the mechanical strength and durability properties of the bricks with varying amount of fine sand replacements (10%, 20%, 30% and 40%) for saline soil. The results revealed that in general, the lime-saline soil bricks had good water resistance in terms of softening coefficient and drying-wetting durability as no reduction in compressive strength was observed. Incorporation of fine sand, particularly at 40%, also resulted in improvement in the drying-wetting and freeze-thaw durability properties of the autoclaved lime-saline soil bricks. In addition, autoclaved lime-saline soil sample exhibited enhanced salt fixing ability compared to raw saline soil sample. Overall, it can be said that the autoclaved lime-saline soil brick exhibit good properties in terms of mechanical strength and durability performances, and further improvement can be achieved through the incorporation of up to 40% fine sand.