Evaluation of the influence of the addition of bean residue in gypsum matrices

Abstract

In order to reduce the production of cement, several alternatives have been studied. Among them, gypsum presents itself as a viable option, since it is already used in internal finishing; however, this material can still be improved. The objective was to improve the physical and mechanical efficiency of gypsum by developing a material with the incorporation of natural fibers from bean residues. For this, the lignocellulosic material was first characterized in natura. Subsequently, different contents of bean fiber residues (0.0%, 2.5%, 5.0%, 7.5% and 10.0%) were added in replacement to gypsum in matrices with a constant 0.6 gypsum-to-water ratio. In order to evaluate the influence of the addition of bean residue in the gypsum matrix, mechanical tests of bending and compression and physical tests of moisture on dry basis, apparent density, water absorption, thermal conductivity and acoustic insulation were carried out. Scanning electron microscopy (SEM) images were also taken. In general, the satisfactory results were obtained with the incorporation of bean fiber residues; as an example, the physical characteristics of the composite with 10.0% incorporation can be cited, which demonstrated a decrease in apparent density, improvement in acoustic insulation and stability of thermal conductivity. As for the mechanical characteristics, the incorporation of 5.0% of bean residue stood out, obtaining the best results in the bending tests. Therefore, given the initial positive results, further studies are needed in order to confirm the prospect of this composite as a viable option for application in civil construction.