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Cementitious paste samples proportioned with blended ordinary Portland cement, pulverised-fuel ash and condensed silica fume (CSF), with different water/cementitious materials ratios and varying superplasticiser (SP) dosages, were produced for packing density and flowability measurements. The results showed that increasing the SP dosage significantly increased the packing density and water film thickness (WFT) of the cementitious paste, and increases in SP dosage and WFT contributed to increasing the flowability of the cementitious paste. At the same SP dosage and WFT, cementitious pastes containing CSF tended to have higher flowability. It is postulated that this is because the finest portion of CSF and water flowed together as a slurry that coated the larger sized particles with a certain slurry film thickness (SFT). Regression analysis of the test data revealed a very good correlation of flowability to SP dosage and SFT. [ABSTRACT FROM AUTHOR]

Previous studies on the fresh properties of the mortar portion of concrete have revealed that the water film thickness (WFT) is the key factor governing the rheological performance of mortar. However, such studies were limited only to plain mortar containing no fibres. For mortar containing fibres, such as polypropylene (PP) fibres, there have been no similar studies. To investigate the combined effects of WFT and fibre content on the fresh properties of mortar, a number of mortar samples with various water/cement ratios and PP fibre contents were produced for measurements of packing density, flowability, cohesiveness and adhesiveness. It was found that the fibre content has certain effects on the packing density and WFT. Apart from the indirect effects through the change in WFT, the fibre content also has direct effects on the flowability, cohesiveness and adhesiveness. Overall, very good correlations of the fresh properties of mortar to the WFT and fibre content have been obtained and the concept of WFT has been extended to fibre-reinforced mortar. [ABSTRACT FROM AUTHOR]