Abstract:
Currently, large quantities of fly ash are being used in the concrete industry. However, some amount of fly ash dumped near the power plant area and exposed to humidity of the environment and rainwater has not been used yet. Therefore, it is possible to recycle this wet fly ash by studying the effect of wet fly ash on the properties of concrete.
The objective of this research is to study the durability of concrete mixed with wet fly ash to develop the utilization of wet fly ash. In this study, both dry and wet fly ashes from the BLCP power plant in Rayong province were partially replaced Portland cement type 1 (OPC) and the durability properties of concrete mixed with wet fly ash were investigated.
The study results revealed that the autoclave expansion of paste in both dry and wet fly ashes was not found, but a tendency to shrinkage was shown. The autogenous and drying shrinkages of fly ash mortar were less than those of OPC mortar. The autogenous and drying shrinkages of wet fly ash mortar were not different from those of dry fly ash mortar. However, the autogenous shrinkage of wet fly ash mortar at the moisture contact of 1 week was less than that of dry fly ash mortar. The wet fly ash with different moisture content and different moisture contact showed no effect on the autogenous and drying shrinkages of fly ash mortar. Furthermore, the carbonation depth of fly ash concrete was greater than that of OPC concrete. The carbonation depth of wet fly ash concrete was less than that of dry fly ash concrete. Moreover, the different moisture content and different moisture contact of wet fly ash had no effect on carbonation depth of concrete. Finally, the chloride penetration resistance of fly ash concrete was better than that of OPC concrete. The chloride penetration resistance of wet fly ash concrete at the moisture contact of 1 week was less than that of dry fly ash concrete, while that at the moisture contact of 1 month was not different. Besides, the wet fly ash with high moisture content resulted in lower chloride penetration resistance of concrete.