Effect of water content of sawdust ash/clay mix on the strength of unfired clay bricks with varied sawdust ash replacement ratios.

Abstract

Studies on the use of waste materials in the construction industry is not an uncommon area of research. A number of wastes such as fly ash, rice husk ash, sawdust have been investigated for suitability for use as partial replacements of concrete and clay in construction. This paper presents the results of a study on the use of sawdust ash as a partial replacement of clay in the manufacture of clay bricks. The effect of water content of sawdust ash/clay mix on the compressive strength of bricks with varied sawdust ash replacement ratios was investigated. Bricks of 5%, 10%, 15%, 20% and 25% ash replacement ratios were molded and cured for 28 days. Tests on compressive strength showed a general decrease in the compressive strength of the bricks with increase in water/clay ratio. The results also showed an increase in strength of the bricks at low ash replacement ratios whereas at high replacement ratios, the compressive strength decreased. The optimum sawdust ash content and water content were determined to be 10% and 15% respectively and the corresponding 28-day compressive strength of the bricks was dtermined as 10 MPa. The bricks with optimum sawdust ash and water contents were also tested for flexural strength and found to be 5.4 MPa.