The Effect of High Performance Super Plasticizer Admixture on the Strength of Concrete

Abstract

This Research outlines an experimental study that measures the effects of high performance superplasticizer admixture on the compressive strength of concrete and the workability of the fresh concrete. The study has focused on two mixes with compressive strength of 30 and 35 MPa at different ages. These mixes used Slag Cement as binder, maximum aggregate size of 16 and 32 mm and PCA® (I) as high performance superplasticizer. To investigate the effects of high performance superplasticizer admixture on concrete compressive strength, one control mix was prepared without addition of any admixture was used as a comparison and then seven mixes were prepared using superplasticizer admixture. The experimental works were carried out at the Dam Complex of Upper Atbara Project laboratory. The compressive strength tests were carried out on 150*150*150 mm concrete cubes at the ages of 7, 21 and 28 days. The test results were statistically analyzed to investigate the effect of addition of high performance superplasticizer admixture on the concrete compressive strength. The analysis have shown that the compressive Strength of concrete has increased by 25% when 1% dosage of superplasticizer admixture was used for the design compressive strength of 35 MPa, while for design compressive strength mixes of 30 MPa, it was found that the increase percent ranges from 38% to 90.33% for the same dosage of superplasticizer admixture. The results also have demonstrated the excellent relationship (R²=1) between the workability of concrete mix (measured using the flow test) and the superplasticizer content (in Kg/m3).