Effects of locally available burlap fiber on the mechanical and microstructural properties of concrete, Ethiopia

Innovative researches are increasingly becoming very important in construction industry in order to enhance concrete performance, reduce cost or/and contributing to environmental sustainability. This paper aims to experimentally investigate the effect of burlap fiber on mechanical and micro structural properties of concrete. Five levels of Burlap fiber contents: 0.1, 0.35, 0.60, 0.85%, and 1.1 (% wt) selected and investigated for their effect on concrete the properties of C25 concrete. The experiment was designed in completely randomized design with three replications for compressive strength, tensile strength, and water absorption of the concrete. Whereas descriptive statistics for workability and permeability tests and qualitative assessment for microstructural properties were employed. All the required tests for mechanical and microstructural properties were carried out according to AASHTO and ASTM procedures. It is found that all the burlap fiber content in the range 0.1%–0.85% (wt) can produce workable fresh concrete. In this range of burlap fiber, the fiber contents have showed no statistically significant effect on compressive strength but have showed statistically significant effect on tensile strength and water absorption. Among the different levels, 0.6% (wt) burlap fiber of has shown superior performance. At 0.6% (wt) burlap fiber, the compressive strength equivalent to control mix (0% fiber) is achieved but for tensile strength and water absorption statistically significant and highest improvement relative to the control mix are achieved. The results from the permeability test and microstructural analysis of images also further confirm that the fiber content of 0.6% (wt) can ensure more strong and durable concrete. Therefore, it is recommended to use 0.6% burlap fiber to enhance the tensile strength significantly (by about +3.8% relative to the control), yet maintaining similar compressive strength and water absorption with conventional C25 concrete.