Potential of ceramic waste aggregate to improve the engineering performance of hollowed masonry units

Due to their inherent brittleness, ceramic materials are prone to breakage, a condition that leads to significant waste stream. This has driven research into repurposing the waste material for various applications. Processed ceramic waste has been extensively studied in the past as a substitute for cement or sand to produce cementitious composites. However, its applications have primarily been limited to solid mortars and concrete. Here, the influence of ground ceramic tiles as a fine aggregate for hollowed masonry units (HMU) was investigated. Ceramic waste aggregate (CWA) was introduced at 0%, 25%, 50%, 75%, and 100% of the total aggregate volume, and their compressive strength, densities at various moisture states, moisture characteristics, and sustainability were evaluated. Results showed that adding CWA improved the strength (by as much as three times), reduced the density (by 13.9%), minimally affected the absorption capacity, and lowered the material cost (by up to 21.3%) of HMU, with the 100% replacement achieving the most favorable results. X-ray fluorescence analysis revealed that CWA contained higher levels of amorphous silica than river sand, which may explain the improved engineering performance. While partial estimates of carbon emission suggested favorable results for CWA, further research is needed to refine the analysis for greater accuracy. Moreover, all HMUs were found to satisfy the required strength for nonloadbearing blocks. The block with 100% CWA was classified as medium weight while all other blocks were classified as normal weight. In summary, this study demonstrated the significant potential of ceramic tile waste as an aggregate alternative for nonloadbearing masonry construction.