jailcd2019-051: Study on Evaluation of Carbonation Resistance Properties of Fly Ash Concrete

Abstract

Fly ash is known as a useful concrete admixture. Its carbonation resistance property, however, is considered to be inferior to ordinary Portland cement concrete in the present circumstances where durability is generally evaluated in accelerated test. Admixture, such as fly ash, is used in place of cement, often shows that the hardening reaction is slow. As long as such an evaluation method is used, it is difficult to appropriately evaluate a long-term hardening reaction. Based on the above, we extracted and analyzed the evaluation results of accelerated tests from existing studies to understand the actual situation. As a result, it was revealed that the amount to which fly ash contributes to carbonation resistance in accelerated carbonation test may have been evaluated as almost zero. Then, we extracted and analyzed the evaluation results of carbonation resistance in actual environments. We took a contribution degree to the carbonation resistance property into consideration by derivation of the binder material contribution ratio. Based on the considerations, it was revealed that, the evaluated level of binding material contribution ratio under accelerated tests condition showed approximately a 12.5% than that of under the actual environment conditions.