Structural Lightweight PKS Concrete without the use of Supplementary Cementing Materials

Abstract

The depletion of coarse aggregate sources means there is the need to explore other sources of coarse aggregate to ensure sustainable construction. One such coarse aggregate source is palm kernel shell (PKS) which is obtained as a waste material from economic activities mostly in low income countries. This study sought to investigate whether large aggregates (2mm-18.5mm) of PKS could produce concrete of compressive strength of above 30 Mpa without the use of supplementary cementitious materials and also without the extra mechanical effort of reducing aggregate sizes below 9.5mm as demonstrated by other researchers. In this study, the PKS aggregates were generally inferior to granite aggregates in terms of strength, water absorption and density. The PKS aggregates were however better than the granite aggregates in terms of impact resistance, energy absorption and abrasion resistance. Plain concrete samples were prepared for PKS grades M20, M30 and M40 whilst for granite aggregates only M30 grade was prepared. Results on tests conducted on PKS plain concrete were consistent with those of normal concrete for modulus of elasticity, stressstrain relationship, flexural and compressive strength, and density and water absorption. Results showed that with the use of Ordinary Portland Cement of grade 42.5, the PKSC achieved the designed compressive strength for the target grade M20 and M30. The compressive strength of the granite concrete of grade 30 was however higher than those of the corresponding PKSC M30 and M40. The PKSC showed a progressive development of compressive strength with age just like the NWC, although at different rates.