Characterisation of residual açaí stone ash for addition to concrete

Abstract Environmental problems are a reality in today's world and are associated with urban and population growth, with little or no planning. The construction industry is one of the largest consumers of natural resources and generator of solid waste. Thus, it is interesting to think of a way to incorporate materials that are now considered waste, to the constructive process and reduce the consumption of natural materials. In this section, we have the ashes of açaí stone, residue of ceramic kilns, that today do not present an adequate destination. Thus, this research has the main objective to characterize residual ash of açaí (CCAR), in order to make possible its reuse as an input of the civil construction. In order to achieve this objective, a milling study was carried out in order to determine the optimum material processing time, characterization from the chemical, physical and mineralogical point of view, and the pozzolanic potential analysis to evaluate the residual ash reactivity. The results show that ash has physical characteristics that allow it to be used as an addition to concrete. There was a decrease in the axial compressive strength and an increase in the water absorption of concrete with additions, in relation to the reference concrete. In spite of these effects, a certain densification of the cementitious matrix was observed, probably due to the variation of the particle size that may provide greater compactness with optimization of grain packing.