Influence of Fly Ash on Abrasion Resistance of Concrete for Roads Pavements

In Portugal, fly ash is often used as a cement replacement material on concrete for road pavements. The percentages of replacement generally range from about 30% in the top pavement layer up to 50% in the bottom layer. A study was carried out for evaluating to what extent such amounts of fly ash could affect concrete abrasion resistance. An attempt was also made to correlate the abrasion resistance with other concrete properties. For the purpose, abrasion tests, as well as determinations of compressive strength, capillary absorption, oxygen permeability and open porosity, were performed on concrete mixes with different cement and fly ash contents, using limestone coarse aggregate and a natural siliccous sand. Results obtained have shown that fly ash concrete can resist well to abrasion, even with large amounts of cement replacement. The other properties measured varied in such a way that concrete with lower permeability and higher strength has shown better abrasion resistance.