Evaluation of sugarcane bagasse ash for lightweight aggregates production

Abstract

The present paper aims at researching the development of lightweight aggregates from sugarcane bagasse ash (SBA) sintering and binary mixtures of SBA and red clay (RC). Two different SBA were evaluated, which differ on their milling process: one was produced in a ball mill and the other in a knife mill. The average particle diameters of the resulting SBA were 2.99 µm and 20.47 µm, respectively. Each of these mills was evaluated in binary mixtures of SBA and RC, varying the SBA contents from 50% to 90%. Pure SBA and RC were also evaluated. Six different sintering temperatures were studied (1000 °C, 1050 °C, 1100 °C, 1150 °C, 1175 °C and 1200 °C). The precursor materials were characterized in terms of chemical, mineralogical composition, particle size distribution, specific surface area and thermal analysis, to be subsequently pelletized and sintered. After sintering, the bloating index, particle density, loose bulk density, water absorption, voids index, crushing strength and morphology analysis by scanning electron microscopy (SEM) were assessed. The results demonstrate that it is possible to obtain lightweight aggregates based on binary mixtures of SBA and RC in a wide range of particle densities, ranging from 1.03 to 1.67 g/cm3 and loose bulk densities ranging from 0.55 to 0.9 g/cm3. Bloating was observed only when smaller diameter SBA was used.