Mechanical properties of self-compacting coconut shell concrete blended with fly ash

The focus of this study is on the development of self-compacting lightweight concrete using local waste materials and investigation of its mechanical properties. Discarded fresh coconut shells were crushed mechanically and used as coarse aggregate with fly ash (FA) as partial replacement of Portland cement at 15% and 20% replacement levels by weight. Slump flow, T500, V-funnel, L-box, and wet sieve segregation tests were used to evaluate the self-compactibility of the developed mixes. For comparison purpose, self-compacting conventional concrete was also produced and tested for all the parameters experimentally. For the developed self-compacting concrete mixes, mechanical properties such as compressive, flexural, splitting tensile strengths, and impact resistance were tested and compared with the theoretical values as recommended by the standards and the literature references. Compressive, flexural, and splitting tensile strengths of 21.20 N/mm2, 4.50 N/mm2, and 2.56 N/mm2 with impact energy of 528.61 kN-mm were achieved for 15% FA and 20.10 N/mm2, 4.00 N/mm2, and 2. 52 N/mm2 with impact energy of 467.61 kN-mm achieved for 20% FA, respectively. This shows that the experimental values of all the parameters are high in performance compared to the theoretical values, and hence, coconut shell aggregate blended with fly ash is a promising local technology for structural lightweight concrete usage.