Effect of Fly Ash, Bottom Ash and Macro Synthetic Fiber on Dynamic Modulus of Elasticity of Concrete

Abstract

This research was aimed to study the dynamic elastic modulus (Ed) of cement-only concrete, fly ash concrete, bottom ash concrete and synthetic fiber concrete. The bottom ash was used as an internal curing material. Non-destructive testing by ultrasonic pulse velocity test (UPV) was used to determine the ultrasonic pulse velocity and to calculate Ed of concrete. The Ordinary Portland cement was used in this study as binder and the water to binder ratio was 0.55. In this study, the weight percentages of replacement of cement by fly ash were 0, 30 and 50%. The volume percentages of replacement of fine aggregate by the bottom ash were 10 and 30%. The content of synthetic fibers were 2 and 4 kilograms per cubic meter. The results showed that the Ed determined with the UPV method higher than the elastic modulus (Ec) about 13-39%. The cement-only concrete have Ec and Ed values nearly the same with synthetic fiber concrete. The fly ash concrete and bottom ash concrete have Ec and Ed lower than that of the cement-only concrete. The Ec and Ed decrease with the increase of fly ash or bottom ash content. The Ec and Ed have linear relationship while the compressive strength and UPV have exponential relationship.