Aci Method of Concrete Mix Design: a Parametric Study
نویسندگان
چکیده
Concrete mix design by the ACI method requires various material properties as the input. The effect of variation of these input parameters on mix proportions has been studied here, with reference to strength attainment in few cases. The sensitivity of the mix has been expressed by volume ratios of fine aggregate to coarse aggregate and cement to fine aggregate. It is found that inter-particle voids of coarse aggregates, a function of gradation, plays a significant role in the prediction of mix proportions. The study reveals that ACI method fails to rationally predict the proportion of the ingredients when coarse aggregates of higher voids is used in making the concrete. In such cases, the amount of fine aggregate is over estimated. This over estimation leads to a higher surface area to be covered by the same amount of cement, which is determined without any reference to aggregate grading. As a result, the mix fails to attain the design strength. Test results have confirmed these findings.
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