Concrete mix design based on water film thickness and paste film thickness

In previous studies on the mortar portion of concrete, it has been found that the water film thickness (WFT) and paste film thickness (PFT) have major effects on the performance of mortar. The present study aims to extend the concepts of WFT and PFT to concrete. For this aim, a number of concrete mixes with various paste volumes, water/cement ratios and fine to total aggregate ratios were produced for slump, flow, strength and packing density measurements, and from the results, the combined effects of WFT and PFT on the deformability, flowability and strength of concrete were studied. It was found that whilst the WFT is the key factor governing the above properties of concrete, the PFT also has significant effects and thus is an important factor to be considered in concrete mix design. Lastly, based on the test results, two design charts for concrete mix design were produced.