2018 Volume 72 Issue 1 Pages 285-292
In this research, the study of the relationship between pozzolanic reaction rate of fly ash and durability of fly ash concrete was conducted to evaluate the change in durability over time. This study was based on the analysis of fly ash concrete specimens exposed to various parts of Japan since 2009. The pozzolanic reaction rate of fly ash in the exposed specimens was indirectly estimated from the accumulated temperature, based on the mock test paste analysis, using the same fly ash as in the exposure test. As a result, the pozzolanic reaction rate of fly ash demonstrated an exponential relationship with the accumulated temperature, when the basis temperature was set to 13 degrees Celsius. A sufficient correlation between the pozzolanic reaction rate of fly ash was found by estimating the relationship, observing the progressive change of the specific electrical resistance, and obtaining the carbonation coefficient of fly ash concrete. The result of the relationship is due to the densification of the microstructure of fly ash concrete, which is superior in the consumption of Portlandite from the pozzolanic reaction of fly ash. Additionally, when the specimens are exposed to a marine environment, the permeability of chloride ions was analyzed, which revealed that fly ash concrete contains higher resistance to chloride ion penetration than OPC concrete even when subjected to carbonation.
