Roles of water film thickness and fibre factor in workability of polypropylene fibre reinforced mortar

For plain mortar without fibres, it has been found that its fresh properties are governed mainly by the water film thickness (WFT). For fibre reinforced mortar with fibres added, it has been suggested that the effects of the fibres may be evaluated in terms of a fibre factor (FF) combining the fibre volume and aspect ratio together. In two previous studies on the workability of polypropylene (PP) fibre reinforced mortar, the combined effects of WFT and fibre volume and the combined effects of WFT and fibre length have been separately studied. Herein, additional tests with both the fibre volume and fibre length varying simultaneously have been carried out to generate more data for evaluating the combined effects of WFT, fibre volume and fibre length. Based on the test results, a new model is developed whereby the workability attributes are each expressed as a single-variable function of the product of a linear function of WFT and an exponential function of FF. By this model, the roles of WFT and FF are revealed and the workability may be estimated for preliminary design of PP fibre reinforced mortar.