The use of pulverized fuel ash (pfa) as a partial cement replacement is growing as it improves many properties. However, its effect on key properties, such as compressive strength, drying shrinkage and porosity, remains to be dependant on the particular pfa utilized. It is necessary to routinely test for these key properties when pfa is to be employed. In this investigation a simple and rapid test scheme is proposed for this purpose. The scheme involves testing the flow of fresh pfa mortars. In addition, pfa mortars, with different w/c ratios and percentages of pfa, are tested for compressive strength at 7 and 28 days after curing in accordance with a number of curing regimes. Finally the drying shrinkage and porosity of the pfa mortar are tested at 28 days. An acceptance criteria for the proposed test scheme has also been set. One pfa was tested in accordance with this scheme as a demonstration. The results of the tested pfa were thoroughly analyzed in
order to gain insight into the action of pfa in cement based matrices. |
