Evaluation of Chloride Penetration in Fly Ash Concrete under Marine Environment by Ultrasonic Wave

Abstract

Abstract

This research, the ultrasonic wave was utilized for evaluation of chloride penetration of normaland fly ash concrete under marine environment. Fly ash concretes were cast by using fly ash from MeaMoh power plant to partially replace Portland cement type I at percentages of 15, 25, 35 and 50 by weightof binder. Water to binder ratios (W/B) were varied at 0.45, 0.55, and 0.65. (the same mix proportions ofconcrete exposed to marine site). The cylindrical specimen with 100-mm in diameter and 200-mm in heightwere cast for ultrasonic test at 28 and 90 days of curing. The concrete dense by ultrasonic test was usedto compare with chloride diffusion coefficient of concrete at 10-year exposure in marine site. The resultsshow that the ultrasonic wave velocity in 28 day concrete decrease with the increase of fly ash replacementof Portland cement type I, which is opposite trend with chloride diffusion coefficient. In the other hand, by90 days results, the increase of fly ash resulted in increase in ultrasonic wave velocity which is consistentwith chloride diffusion coefficient. In addition, the increase of curing age result in the increase of ultrasonicwave velocity which is more effective on increasing ultrasonic wave velocity in fly ash concrete than innormal concrete. The ultrasonic test developed in this study can be efficiently used to predict the chloridediffusion coefficient of normal concrete and concrete containingflyash of 15, 25, 35 and 50 by weight ofbinder.

Keywords : Chloride penetration; Durability; Fly ash; Marine environment; Ultrasonic wave