2014 Volume 68 Issue 1 Pages 337-344
The utilization of fly ash for concrete as a supplementary cementitious material has been required in order to reduce an environmental impact, which can contribute to creating a sustainable society. If sufficient wet curing is conducted, fly ash is well known to produce a dense structure and to contribute to developing the strength in the long term.
On the other hand, the porous ceramic waste aggregate（hereafter, PCWA）, which is made of waste from porous ceramic roof tiles in western Japan, has been applied to concrete as one of the internal curing agents, because it has a higher water absorption than general aggregates and a lower crushing value than existing internal curing agents such as artificial lightweight aggregates. It is reported that the internal curing using PCWA is effective in reducing the autogenous shrinkage and increasing the compressive strength of concrete. However, it has not been investigated on high strength fly ash concrete.
This study aims at investigating the effects of PCWA as an internal curing agent on the durability of concrete containing fly ash. In the experiments, the compressive strength, length change, carbonation and chloride penetration were investigated.
As a result, autogenous shrinkage of concrete at the early age was decreased by using fly ash and PCWA. However, the drying shrinkage of concrete containing fly ash and PCWA was larger than the reference concrete. In the case where the replacement ratio of fly ash was 40％, PCWA was effective in developing compressive strength and reducing carbonation and diffusion coefficient of chloride ions.
