Reuse of sugarcane bagasse ash to produce a lightweight aggregate using microwave oven sintering

Abstract

This work evaluated the influence of sugarcane bagasse ash addition on the performance of red ceramics that are used to produce lightweight aggregates in Portland cement concrete. Two sintering methods were evaluated, namely conventional sintering in an electric oven and microwave sintering. The sintering in a microwave oven was the most energy efficient alternative. The raw materials were subjected to granulometric, X-ray fluorescence and X-ray diffraction analyses. The ceramic masses were prepared with addition of 44% by mass of sugarcane bagasse ash that was extruded and sintered between 700 °C and 1000 °C. The sintering in the electric oven had a heating rate of 5 °C/min and a burning time of 60 min. In the microwave oven, the heating rate was 50 °C/min and the burning times were 10 and 20 min. After sintering, the samples were characterized for water absorption, apparent density, compressive strength and microstructure. The results indicate that microwave oven sintering, when compared to sintering in an electric oven, promoted an increase in the compressive strength and reduction in water absorption for the ceramic masses, probably due to the microstructure refinement. The addition of sugarcane bagasse ash led to a reduction in the density of the samples, especially those sintered in the microwave oven.