ABSTRACT
This research work was carried out to investigate the effects and suitability of Cassava starch as an admixture in cement paste and concrete. A standard consistency test was carried out on the cement paste with concentrations of the cassava starch at 0%, 0.5%, 1%, 2%, 3%, 4% and 5% by weight of the cement used in the paste. A prescribed concrete mix ratio of 1:2:4 concrete cubes (150mm by 150mm) and water-cement ratio of 0.5 were cast with the same concentrations as above. A total of eighty four (84) cubes were cast and cured for 3, 7, 14 and 28 days and compressive strength subsequently determined in comparison with the relevant specifications. Consistency test on the cement paste at the various concentrations exhibited an increase in the setting time as the concentration increases with the highest value recorded at 5% cassava starch concentration as 219 minutes for the initial setting time and 275 minutes for the final setting time as against the control specimen of 159 minutes and 234 minutes for both initial and final setting times respectively. The 28 days compressive strength of the concrete cubes; compared with that of the control; showed a slight increase in both strength values and strength gain at 0.5% and 1% starch concentrations with compressive strength of 21.24N/mm2 and 21.63N/mm2 and strength gain of 4% and 6% respectively. Also, the rate of strength development within the same concentration in terms of test ages was also realized to be higher at starch concentrations of 0.5%, 1% and 2% with the highest recorded as15% at 1% from 7 to 14 days.