EFFECT OF TREATED BORASSUS AETHIOPUM MART FIBERS ON THE PHYSICAL AND MECHANICAL PROPERTIES OF HOLLOW BLOCK-MORTAR

Abstract

Borassus aethiopum mart is a woody monocotyledon plant and a renewable resource that comes from sub-Saharan Africa. In Benin, the transformation of its trunk in strips produces some fibrous waste unused due to the lack of fiber upgrading process in the manufacture of cementitious composite. These wastes cause problems in terms of environmental management. As an illustration, these wastes were also used as household fuels, producing CO2 which is one of the main greenhouse gases responsible for global warming. In addition, these fibrous wastes were dumped in pits behind Sourou Bayayé's hullers acquired on a subsidy from Millennium Challenge Account Benin. In order to protect the environment and valorize the availability of this local material, borassus aethiopum mart fiber (BAMF) were used in mortar to produce hollow blocks for hollow-core-slab which the most used in Benin. This present study focused on the effect of treated borassus aethiopum mart fiber on the physical and mechanical properties of hollow block-mortar. For this purpose, alkaline treatment of BAMF was done using different concentration of NaOH and at different immersion period . For this reason, Scanning electronic microscopy (SEM) was employed to examine the effect of NaOH concentration on the surface morphology of BAMF including its effect on the mechanical properties. A change in fiber surface was observed from the untreated to the treated BAMF, as well as an increase in tensile strength of BAMF treated with was respectively observed as compared to untreated BAMF . Then treated BAMF with vi NaOH at 1-hour were used in mortar. For this purpose, the mechanical behavior in flexion (three-point by bending) and compression of composites were studied at 28 days of age. The composites offer not only good mechanical performance in three-point bending up to but also compressive strengths up to as compared to the controls used and respectively. In addition, the performance of the composites after exposure in H2SO4 medium at 90 days using pH3 was evaluated by loss in compressive strength as durability test. Finally, the flexural (three-point) and compressive strength at of the hollow blocks used as an application to the mortar were evaluated according to EN 1537-02. Keywords: Alkaline treatment, tensile strength, flexural strength, compressive strength, durability.