Freeze–thaw of stabilised clay brick

This paper reports on freezing and thawing of stabilised clay brick incorporating a latent hydraulic binder. The latent hydraulic binder used for the stabilised clay bricks is an industrial by-product (slag) arising as an inherent consequence of iron production. Laboratory and industrial-scale masonry bricks were produced. In order to improve on the cementitious properties of the latent hydraulic binder, between 1·4 to 2·6% of lime was used as an activator. The brick specimens were moist cured at a room temperature of about 20°C for between 3 and 90 days before testing for compressive strength. Since the major factor influencing the durability of clay masonry units is the degree to which the clay masonry unit becomes saturated with water, the durability assessment of the unfired bricks was carried out by means of 24 h repeated freezing/thawing cycles. The results showed that the compressive strength values of the industrial-scale bricks were higher than those of the laboratory bricks. The results of the freeze–thaw suggest that both the laboratory and industrial unfired clay bricks were able to withstand 100 (24 h) repeated freeze–thaw cycles. These results gave an indication of the feasibility of a durable stabilised clay brick incorporating a lime-activated latent hydraulic binder.