Reuse of grits waste for the production of soil–cement bricks

• Grits can be classified as a non-inert waste material.
• Grits waste as raw material for soil–cement brick was studied.
• Grits waste contains calcite as the major component.
• Grits waste influences the technological properties of soil–cement brick.

This investigation focuses on the reuse of grits waste as a raw material for replacing Portland cement by up to 30 wt.% in soil–cement bricks. The grits waste was obtained from a cellulose factory located in south-eastern Brazil. We initially characterized the waste sample with respect to its chemical composition, X-ray diffraction, fineness index, morphology, pozzolanic activity, and pollution potential. Soil–cement bricks were then prepared using the waste material and were tested to determine their technological properties (e.g., water absorption, apparent density, volumetric shrinkage, and compressive strength). Microstructural evolution was accompanied by confocal microscopy. It was found that the grits waste is mainly composed of calcite (CaCO3) particles. Our results indicate that grits waste can be used economically, safely, and sustainably at weight percentages of up to 20% to partially replace Portland cement in soil–cement bricks.