Eco-efficient construction has emerged as a distinct new field. The reuse or recycling of residues for production of building materials has the potential to avoid incorrect disposal, decrease the volume of waste in landfills and reduce the extraction of natural resources, which deplete the environment. This study proposes a new approach to reuse lime mud (LM), mainly composed of calcium carbonate, as filler in gypsum plaster to replace gypsum in proportions of 5, 15 and 25%, tested after 7, 14 and 21 days. An elemental analysis of the residue showed calcium-rich composition and that the particle distribution was between 1 and 11 μm with a mean particle diameter around 6 μm. The density of gypsum/lime mud (G/LM) composites was reduced from gypsum (1244.9 kg/m3) to G/LM25 (1132.1 kg/m3) in 21 days. The flexural strength of gypsum after 21 days was 5.7 MPa compared to 5.4 MPa for G/LM5 (LM at 5%), the latter being a reduction of only 5.3% from the former. Even with incorporation of 25% of LM, after 21 days composites presented mechanical resistance above the standard international recommendations: compressive strength of 9.6 MPa (≥8.3 MPa recommended), axial compression strength of 8.5 MPa (≥6.0 MPa) and flexural strength of 3.7 MPa (≥2.0 MPa).

The reuse of industrial waste plays a crucial role in avoiding environmental impacts caused by incorrect disposal. The industrial production commonly generates huge volumes of wastes and also, increase costs associated to waste management and landfills maintenance. This study investigates the reuse of Grits waste, from cellulose kraft industry, as filler on gypsum plaster. The samples were prepared in proportions of 100/0, 85/15, 75/25 and 50/50 Gypsum/Grits and, tested at 7, 14, 21, 28 days. The mechanical resistance with incorporation until 25wt% of Grits as filler is over than the regulatory standards recommendations. Flexural and compression strength tests for 15wt% of gypsum replaced achieving 4.5 MPa and 8.3 MPa, respectively. The manufacture of Gypsum/Grits became a viable solution for waste management and, has a great potential of enabling fabrication of gypsum plaster board, a low cost and more sustainable new material.