Evaluation on properties of unired bricks containing red mud and stone dust

Abstract

Utilizing waste materials generated from the aluminum extraction process to produce unfired bricks provides multiple advantages, including land resource conservation, reduction of environmental pollution, and the creation of an alternative raw material supply. In this study, red mud (RM) obtained from an aluminum processing plant, combined with stone dust, served as the main ingredients for fabricating unfired bricks. Additionally, supplementary materials such as rice husk ash and fly ash were incorporated as additives in varying proportions within the brick formulation. The bricks were evaluated through a series of tests, including physical property assessments, compressive strength testing, water absorption analysis, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. The test results indicate the potential of combining red mud and stone dust in improving the properties of non-fired bricks. For example, a mixture containing 5% red mud (R05) achieved a compressive strength of up to 6.3 MPa after 28 days and a water absorption rate of 9.7%, meeting Vietnamese standards for concrete bricks.