Influence of Fly Ash and Fine Aggregates on the Characteristics of Pervious Concrete

摘要

The aim of this study is to investigate the effect of partial replacement of cement by 10% and 20% of fly ash, partial replacement of coarse aggregates by fine aggregates (ranging from 5 - 15%), on the characteristics of pervious concrete. Class C fly ash, coarse aggregates ranging in size from 19 mm to 9.5 mm and 9.5 mm to 4.75 mm blended in the ratio of 60:40 respectively, and a constant water/binder ratio of 0.34 were used and ACI method of mix proportioning, was adopted for various mixes. Altogether 32 mixes were designed. Compressive strength, flexural strength, split - tensile strength, total voids, permeable voids, density and permeability by falling head method, were determined. It is seen that the compressive strength range achieved for pervious fly ash - cement concretes with a minimum binder content of 300 kg/m~3, with fines (10% and 15%), has the potential application as a typical sub-base/base layer for flexible/rigid pavements. Further, replacement of cement by fly ash (up to 20%) has reduced the compressive strength only marginally, whereas, addition of fine aggregates (5 - 15%) has increased the above strength, ranging from 'marginal' to 'high'. Incorporation of fly ash has the effect of reduction in total voids in pervious concretes.