Synergistic valorization of rice straw and red brick demolition in development performance of lightweight cement mortars

Abstract

This work deals with upgrading the undesirable agro- and industrial wastes, such as rice straw (RS), red brick demolition (RBP), and polystyrene foam (PSF), for construction purposes, as an excellent strategy to protect the environment. In this respect, the RS and its pulp fibers are modified by PSF, followed by their incorporating individually or in hybrid with RBP, in cement mortar formulation. As a substitute for fine aggregates. Six rice straw pulps used in this study were prepared from alkali, neutral, acidic, and kraft pulping agents. The effective performance of this investigated route is assessed from the mechanical properties, density, moisture resistance (thickness swelling and water absorption), measurements of the resulting mortar composites, as well as how the investigated treatment effects on behavior of RS fibers. The finding results show that the modified RS fibers, especially those results from KOH–NH4OH and neutral RS-pulping reagents, in hybrid with red brick waste provide motors with better mechanical and water resistance properties. These treated fibers have a synergistic role for including the RBP in mortar formulation to 30 %. The produced mortar has compressive strength 6.2 MPa and flexural strength 4.4 MPa, which is convenient to apply as load-bearing wall. Moreover, they provide improvement in resistance to thickness swelling and water absorption after 24-h exposure to water. The reduction in thickness swelling and water resistance reached 36.7 and 52.8 %, respectively. From the TGA measurements and SEM, it is interesting to notice that the investigated route accepts the RS fibers thermal stability and hydrophobic surface character.