Internal Curing Effect of Porous Ceramic Roof Tile Waste Fine Aggregate on Surface Quality of Steam-Cured Fly Ash Concrete

Steam curing, one of the methods to enhance the early-age strength of concrete, has a high possibility of deterioration of surface layer quality which strongly influences mass transfer resistance. On the other hand, it is reported that steam-cured fly ash concrete performance could be improved by using porous ceramic roof tile waste coarse aggregate as an internal curing material. However, there are few reports on the internal curing effect of the roof tile waste fine aggregate. Therefore, this study aims to clarify the internal curing effect of porous ceramic roof tile waste fine aggregate on surface layer quality in terms of surface air-permeability, surface moisture content, and pore size distribution. Furthermore, the relationship between the durability and the surface quality was investigated by conducting accelerated carbonation tests. The results showed that the steam-cured fly ash concrete with porous ceramic roof tile waste fine aggregate had a denser pore structure in the surface layer, lower air-permeability at the age of 364 days, and higher carbonation resistance than that without internal curing. It may indicate the internal curing is effective in improving the surface quality of steam-cured fly ash concrete at long ages.