Eco-friendly construction materials: new gypsum-based composite with dregs waste from the cellulose industry

The production of materials for civil construction is a process that imposes a significant environmental impact, due to factors, such as the extraction of raw materials and the high energy consumption required to obtain the final product. Consequently, the search for new materials has grown seeking more environmentally sustainable materials. An approach to address this issue is to incorporate industrial residues as fillers to replace traditional construction materials. In this study, dregs, a waste product generated by the cellulose-paper industry, were used as a filler in gypsum composites. Gypsum plasters were replaced with dregs in proportions of 5, 15, 30, and 45%, in nature (GDx) and Na2SO4-treated (GTDx). The compressive strength of the resulting composites was evaluated after 21 days. Compared to gypsum plaster (17.01 MPa), the incorporation of GD5 led to a reduction of 18.6% in compressive strength (13.84 MPa), while GTD5 demonstrated mechanical properties similar to those of gypsum plaster (17.02 MPa). Composites with incorporation of up to 30% of treated dregs presented mechanical resistance above the standard international recommendations. Thus, the gypsum/dregs composite has the potential alternative to the partial replacement of plaster in civil construction, providing a more sustainable solution to the current environmental challenges.