Assessment of Workability and Compressive Strength of Rice Husk Ash-Blended Palm Kernel Shell Concrete

Abstract

The evaluation of agro-industrial by-products as alternative construction materials is becoming more significant as the demand for environmentally friendly construction materials increases. In this study, the workability and compressive strength of concrete produced by combining Palm Kernel Shell (PKS) and Rice Husk Ash (RHA) was investigated. Concrete mixes using a fixed content of 15% RHA as replacement for cement and 20, 40, 60, 80 and 100% PKS as replacement for crushed granite by volume with the mix ratios of 1:1½:3, 1:2:4 and 1:3:6 were produced. The water-to-cement ratios of 0.5, 0.6 and 0.7 were used for the respective mix ratios. Concrete without PKS and RHA served as control mix. The fresh concrete workability was evaluated through slump test. The concrete hardened properties determined were the density and compressive strength. The results indicated that the workability and density of PKSC were lower than control concrete, and they decreased as the PKS content in each mix ratio was increased. The compressive strength of concrete at 90 days decreased from 27.8-13.1 N/mm2, 23.8-8.9 N/mm2and 20.6-7.6 for 1:1½:3, 1:2:4 and 1:3:6, respectively as the substitution level of PKS increased from 0-100%. However, the compressive strength of concrete increased with curing age and the gain in strength of concrete containing RHA and PKSC were higher than the control at the later age. The concrete containing 15% RHA with up to 40% PKS for 1:1½:3 and 20% PKS for 1:2:4 mix ratios satisfied the minimum strength requirements for structural lightweight aggregate concrete (SLWAC) stipulated by the relevant standards. It can be concluded that the addition of 15% RHA is effective in improving the strength properties of PKSC for eco-friendly SLWAC production..

Insight Into the Microstructural Properties of Bio-Engineered Concrete Matrices & Analysis by Scanning Electron Microscopy

“…It ultimately proved that the spores of bacteria were still alive inside the concrete and due to the increment of alkaline ambience they were germinating spores and making the microstructure denser and more compacted. The primary reason behind it is that the hydration rate is relatively low at initial curing ages with bacterial solution and faster at the later ages (Oriola et al, 2018).…”

“…Inclusion of Bacillus Megaterium resulted in 24% increment of compressive strength than the conventional concrete samples. Oriola et al (2018) directly applied Bacillus Pumilus bacterial culture in concrete mix as well as used the bacterial culture as a curing agent. The bacterial concrete developed in that study showed a 6.3% increment in compressive strength and also about 4.5% less weight loss than the conventional concrete.…”