Experimental Investigation of the Thermal Resistance of Metal Dust Concrete Block

This paper discusses the thermal resistance of metal dust concrete block. The thermal insulation capacity of the block, coefficient of thermal expansion as well as mass loss of the blocks due to heating of the block were experimentally investigated. The effects of elevated temperature on the compressive strength of the block were discussed and compared with the unheated metal dust concrete block and conventional concrete blocks. The optimum compressive strength of the unheated metal dust block was 18.20N/mm<sup>2</sup> and its corresponding heated specimen was 17.5N/mm<sup>2</sup>, at a temperature of 200°C. The compressive strength of the controlled specimen was 16.5N/mm<sup>2</sup> and at a temperature of 200°C, the compressive strength was 15.3N/mm<sup>2</sup>. The coefficient of thermal expansion for the metal dust block with the optimum compressive strength was 14.12×10<sup>-6</sup> as against 10.51×10<sup>-6</sup> for the conventional block. The thermal insulation performance of the blocks was assessed by measuring the temperature rise on the unexposed side during a fire resistance test. The results suggest that metal dust increases the compressive strength of the block at a considerable replacement level, but when exposed elevated temperature of about 600°C, the block thermal properties deteriorated due to melting of the dust, evaporation of bound and free water in the block and other factors.