Effect of Clinker Phase Changes on Cement Performance and Its Reactivity with Super Plasticizer Additive

Based on various sources and experiences, the main phases of clinker have a significant impact on the technical characteristics of cement and its performance in the resulting concrete. The interaction of clinker phases with concrete admixtures is also obvious, but the effect of each of these phases and their optimal values for optimal concrete performance is complicate. Therefore, in this study, this issue was an extensive laboratory operation was designed. In the first phase, during three months, weekly sampling of two-kiln clinker of the cement factory was performed. Then, through 25 clinker samples taken, 11 samples were selected whose phase values were varied. During the second phase, laboratory cementation was performed under the same conditions using 11 clinker samples. A sample of high-consumption super plasticizer additive was also prepared. In the third phase, physical and chemical analysis of cement samples was performed. During the fourth phase, 22 concrete mixtures with 11 cement samples were prepared, so that 11 mixtures with the title of control (without additives) and 11 mixtures with the title of additives. Slump loss tests, air content, compressive strength of hardened concrete of 7, 28 and 90 days were performed on concrete mixtures and optical characteristics of fresh concrete mixtures were recorded for comparison. Based on the results, comparing the effect of C3S clinker on the compressive strength of standard mortar and concrete showed that there is no direct correlation between C3S and compressive strength (mortar and concrete), but it can be said that with each percentage increase of C3S clinker, about 1.5 unit (kg/cm2), 7 and 28 days strength of concrete increases. However, with the increase of C3S from about 57% onwards, the decrease in concrete strength is clearly seen, which can be referred to the negative effect of excessive C3S phase (due to the solubility of concrete and increasing the w/c ratio). Based on the results of air determination experiments of fresh concrete mixtures containing additives and its declining trend in this study, it was found that the optimal value of C3A is about 5-6%.