Isoresponses for strength, permeability and porosity of high performance mortar

This investigation is aimed at developing high performance-low environmental impact concrete utilising blends of pozzolanic by-product materials as cement replacing materials. Pulverised fuel ash (PFA) and Silica fume (SF) were used in ternary systems with the aim of exploiting the potential synergy between these materials, thus reducing or eliminating limitations inherent in individual materials. Compressive strength, oxygen permeability and porosity results at various ages are reported. Mortar containing 0%, 20%, 30% and 40% PFA to which 0%, 5%, 10% and 15% SF were incorporated as partial cement replacements, for the preparation of various combinations of ternary blended cement. A water-binder ratio of 0.27 was used throughout. Based on the experimentally obtained results, prediction models were developed. These enabled the establishment of isoresponse contours showing the interaction between the parameters investigated. It was found that the incorporation of 8–12% SF as cement replacement yielded the optimum performance, resulting in the lowest permeability and porosity values for all levels of PFA.