INVESTIGATION OF THE EFFECTS OF DIFFERENT NATURAL FIBERS ON THE STRENGTH OF COMPRESSED STABILIZED EARTH BLOCKS (CSEB)

Abstract

This study investigates the most effective combination of natural fibers (namely coconut coir,abaca, and maguey) used as reinforcement for Compressed Stabilized Earth Blocks (CSEB). Portland cementand 0.25% fibers by weight were used to stabilize and reinforce CSEB, respectively. The blocks were madeprimarily with Manila soil and were formed using hand-pressed machine. CSEB without fibers were firsttested with varying cement contents of 6%, 8%, 10%, and 12% by weight. This was examined to determinethe practical cement content (PCC). Three strength tests namely dry compressive strength, wet compressivestrength, and flexural strength were conducted on CSEB at PCC with different fiber combinations of coir,abaca, and maguey fibers to determine the mix producing maximum strength. The highest dry compressivestrength was obtained with 100% maguey fiber; the highest wet compressive strength was obtained with100% abaca fiber; while the highest flexural strength was obtained with 17% coir fiber, 17% abaca fiber, and67% maguey fiber. Using the Response Surface Methodology (RSM), the maximum strengths were predictedas follows: 100% maguey for dry compressive strength, 100% abaca for wet compressive strength, and38.4% abaca and 61.6% maguey for flexural strength. However, the optimal mix of CSEB for three thestrength tests consists of CSEB with 42.5% abaca and 57.5% maguey. The fibers were found to improve theperformance of the block such as the strength and post-crack behavior. Furthermore, the performances of awall made of fiber-reinforced and unreinforced CSEB were investigated. The test results showed a 33.79%increase in load carrying capacity of the fiber-reinforced wall compared to unreinforced wall.