Experimental Investigation of a Recyclable Fly-Ash Concrete Pavement Having Moderate Slump

Abstract

A high early strength concrete pavement incorporating a high volume of fly ash and a cement-replacement ratio of 0.4 has been developed. The pavement concrete consists of limestone aggregate and powder in addition to these cementitious materials. It was noteworthy that all components in the pavement concrete may be primary calcium materials for manufacturing Portland cement. The fly ash concrete was made of a low cementitious material ratio (w/cm=0.33) and very low water content (110 kg/m3) to improve strength development at an early age. The pavement concrete, therefore, has a very low slump value of 2 cm (or lower), so the concrete was not widely employed in the pavement application. This study aims to develop a new recyclable fly-ash concrete pavement having moderate workability. The foci of the experimental investigation are to confirm the recyclability for cement manufacturing and to examine strength properties applicable to the practical use of the concrete pavement. This paper demonstrates that chemical and physical properties of the recycled cement meet the Japanese criteria. The test result shows that the workable pavement concrete achieved the minimum strength for passable pavement at the age of 7 days, and the specified strength at 28 days.