Effects of Firing Time and Temperature on Physical Properties of Fired Clay Bricks

Abstract

Brick is one of the most widely used conventional construction materials throughout the world. The production cost of clay brick is significantly affected by the cost of energy required for firing. The aim of this research is to investigate the effects of different firing temperatures on the compressive strength (CS), water absorption (WA) and saturation coefficients (SC) of fired clay bricks produced around Jimma Town and evaluate the effect of firing processes in brick manufacturing on the properties, color and appearance of the clay brick. During the production process, the effects of different heating rates on physical and mechanical properties of firing standard bricks were analyzed. In this study, different heating rates were used: slow heating rate and fast heating rate. Changes in the physical and mechanical properties of the fired clay brick were assessed with the increase in the firing temperature firing time. The results show that the CS increased with the increase in the firing temperature. On the contrary, WA and SC of the fired clay bricks decreased with the increase in the firing temperature. Increment in the duration of firing slightly increases the CS and lowers both the WA and WA of the clay brick. In the study area, traditional brick producers did not have firing temperature control device or mechanism in the fired clay brick production. The kiln operator decided the firing temperature and duration. The absence of the device frequently results in the over or under firing of bricks greatly affecting the engineering properties of this widely used contraction material. Therefore, the traditional clay brick producers should install the temperature control device on their kiln or at least needs to be trained how to approximately determine the optimum temperature.