Assessment of the potential use of rubber tree endocarp as a reinforcement element in cementitious composites

Abstract

The increasing demand for sustainable practices in construction has driven the search for alternatives to conventional materials. The addition of natural fibers to cementitious matrices has proven to be a promising solution to improve the toughness and post-cracking strength of concrete. This study investigates the feasibility of using the rubber tree (Hevea brasiliensis) endocarp as a reinforcement in cementitious composites. The endocarp was treated with hot water washing, immersion in alkaline solution, or coating with carboxylated styrene-butadiene rubber (XSBR) to enhance adhesion to the cement matrix. Results indicated that treatments improved adhesion and contributed to increased post-cracking deformation in the reinforced composites. Furthermore, the endocarp showed potential as a bioaggregate, providing an environmentally sustainable disposal option for agroindustrial waste. Cementitious composites produced with XSBR-coated endocarp and steel and polypropylene fibers exhibited improved performance, with more favorable mechanical properties and enhanced durability. This study contributed to the development of more sustainable materials in the construction industry by utilizing agroindustrial residues and improving the characteristics of cementitious composites.