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INFLUENCE OF CEMENT CONTENT ON THE PHYSICAL AND MECHANICAL PROPERTIES OF CONCRETE. By D.E. Ewa

ABSTRACT
The amount of cement in a concrete product is an important factor which determine the strength, workability and other properties that affect concrete quality. This study report on the influence of cement content on grade C20 concrete. Cement content evaluated were: 250kg/m3, 300kg/m3and 350kg/m3 using a designed mix ratio of 1:2.2:2.5 binder to fine aggregate to coarse aggregate. 150mm by 150mm concrete cubes specimen were prepared and cured in the laboratory in accordance with ASTM standards. The monitoring of concrete temperature histories was achieved by a digital thermometer, manufactured by BK Precision and Type-K thermocouple wires as temperature sensors. The results show that as cement content increases, water cement ratio and slump also increase as more water is required to achieve a specified workability. This resulted in a decrease in the total aggregate content. Temperature evolution was higher for mixes with more cement content at lower water-cement ratios. The richer mixes showed higher strength at lower water cement ratios. Slump increases rapidly to a water-cement ratio of 0.5, thereafter, no significant increase in slump is observed. This behaviour is true for all cement content. It is recommended that the minimum cement content of 235kg/m3 for grade 20 concrete specified by the Nigerian General Specifications for Roads and Bridges should be reviewed upwards to, say, 250kg/m3.

Keywords: Cement content, concrete, water cement ratio, temperature, slump, compressive strength

 

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