Preliminary study on bricks drying process using microwave technology

Abstract

Clay brick is one of the essential materials in building construction. The demand for clay brick has been increased over the years as it goes along with the rise of world population and industrial building constructions. The current state of brick manufacturing process is still very traditional where drying of clay brick takes very long time and labour intensive. Adding to this problem, uneven heating during drying and firing affect a lot to bricks quality which often cause cracks. This research aims to evaluate the effectiveness of microwave energy source against the conventional methods for drying four different types of clay bricks. Green clay samples were pressed into a slab specimen at different compositions (%clay, %water, %lime, %fly ash). Later, the green samples were dried under four different mediums (natural, hot air, electric oven and microwave). The quality of dried bricks was compared in terms of water absorption, density, and porosity. It is found that microwave heating outperforms the three conventional heating methods by drying all types of brick samples without crack. Design of experiment (DOE) was utilized to evaluate significant factors (temperature (60-70-80oC), time (6-8-10 min) and percentage of charcoal (0-3-6%)) to dry red brick samples. Responses were crack density, brick density, water absorption and moisture contents. Analysis of variance indicates that all three factors are significant. Temperature is the most influential factors among the three affecting all responses. It is found that drying bricks at 70oC succeeding without any crack generation on the samples. It is also noted that a significant faster drying rate is seen when adding various percentages of charcoal contents in brick samples. From the results obtained, it is concluded that microwave technology has a great potential to be applied as a heating source in the production of bricks. The usage of this technology is foreseen able reduce the intensive labour dependent in brick manufacturing industry and this method is able to manufacture brick in a more sustainable environment.