Experimental Investigation on Shear Strength and Microstructure of Chemically Treated Sisal Fiber-Reinforced Concrete

The incorporation of sisal fiber into the concrete matrix reduces waste disposal, which has negative environmental impacts. The aim of this study was to perform an experimental investigation on shear strength and microstructure of chemically treated sisal fiber-reinforced concrete (SFRC). In order to accomplish the aim of the study, physical, shear, and mechanical properties of concrete reinforced with chemically treated sisal fiber have been performed. 0.50%, 1.00%, 1.25%, 1.50%, 1.75%, and 2.00% of sodium hydroxide (NaOH) and sulfuric acid (H2SO4) treated sisal fiber were used as an addition to the dry weight average with the help of the American Concrete Institute (ACI) mix design procedure. After the 7th and 28th days of curing, shear strength according to the ASTM D5379M standard and the mechanical properties of concrete have been conducted. For microstructural properties, scanning electron microscopy (SEM) and X-ray diffraction (XRD) were conducted after the concrete was cured for 28 days. Forty-six percent and 20% compressive strength enhancement at the 7th and 28th days of curing was compared to the control mix. Twenty-seven percent enhancement was recorded in the split tensile strength of 1.5% SFRC as compared to the control mix at 28 curing days. A shear strength of 1.5% SFRC was improved by 95% at the 7th curing days and 28% at the 28th curing days as compared to the control mix. As compared to conventional concrete, SFRC shows a denser microstructure. In addition to this, portlandite, quartz, calcium aluminum silicate, and C─S─H crystal are the available phases in the concrete matrix.