Flexural Strength of Pavement Concrete with High Volume Fly Ash

Abstract

This paper describes flexural strength characteristics of concrete with high volume fly ash. Coal-fired power plants have produce about 9,200,000tons coal ashes per year in Japan. The number of coal-fired power plants has been increasing, and amount of coal ash will increase gradually in future. About 90 percent of coal ashes is fly ash and the other bottom ash. Concrete with high volume fly ash may decrease the workability and strength. Short-term strength becomes low due to late reaction of fly ash. Slump as the pavement concrete with high volume is less than the half of the slump of the normal concrete. This results in a suitable pavement concrete. This study aims to investigate the feasibility of pavement concrete with high volume fly ash. Pavement concrete is designed based on the flexural strength. Flexural strength is determined by the failure at the weakest location in the tensile side of the specimen, and is determined by the amount of defects in the mortar and transition zone around aggregates. This may be verified by the distance of two loads over the flexural test specimen. Resultantly, high volume fly ash concrete is affected by the defect based on fly ash. In order to investigate variation of concrete strength, several tests have herein conducted. The strength variation is also analyzed by the Monte Carlo Simulation, which is based on the weakest-link-model. The numerical analysis agrees well with experimental results.