‘KARGO’ (POLIOSTIGMA THONNINGI) FRUITS POWDER AS ADMIXTURE IN CONCRETE
Publication Date : 01/02/2007
The paper presents the findings of an investigation into the admixture properties of ‘Kargo’ (poliostigma thonningi) fruits powder (KFP) in concrete. The investigation was conducted on grade 20 concrete and also on cement paste with varying percentage addition of KFP of 0%, 0.25%, 0.5%, 0.75% and 1.0% respectively. The results of the study show increase in compressive strength with increase in percentage addition of KFP up to 0.5% KFP, the strength then decreases with increase in percentage addition of KFP. The highest strength were obtained with 0.5% addition of KFP of 31.11 N/mm2, 33.48 N/mm2, 37.78 N/mm2 and 38.70 N/mm2 at 3 days , 7 days, 28 days and 56 days respectively. This represented 17.66%, 17.72%, 4.94% and 4.91% increase in strength from strength of control sample (0% addition of KFP) respectively. The study also shows that the use of KFP in cement paste decreases initial and final setting times with increase in percentage addition of KFP. The initial and final setting times obtained for cement paste with 0% addition of KFP were 75 minutes and 132 minutes, respectively. The mean percentage decreases of initial and final setting times from control samples of cement paste, (0% addition of KFP) were 31.42%, 68.95%, 89.65%, and 93.54% for cement paste with 0.25%, 0.5%, 0.75% and 1.0% addition of KFP, respectively. KFP concrete is susceptible to water absorption and drying shrinkage, hence not considered suitable for use in environment where it will be subject to ingress of water or chemicals. KFP could be considered as an accelerating admixture for up to 0.5% addition by weight of cement that is approximately 1.9 Kg per m3 of concrete.
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