2019 Volume 73 Issue 1 Pages 266-271
The properties of concrete surface which influence the durability of concrete structures will be greatly affected on mix proportions and curing conditions. In this study, the effects of nominal strength, type of cement, demolding timing and curing method on air permeability of concrete were investigated. As a result, curing method supplying water from outside of the concrete was most effective to do the coefficient of air permeability small in case of the normal portland cement. Curing method which didn’t make water dry from the concrete surface was effective to do the coefficient of air permeability small in case of the portland-blast furnace slag cement typeB. And then appropriate curing was effective for air permeability small than increase of concrete strength. Therefore, there was no clear correlation between the coefficient of air permeability and the concrete strength. However, there was correlation between the coefficient of air permeability and the sound speed of concrete surface. The coefficient of air permeability tended to be small that the sound speed of concrete surface became speedy. And the coefficient of air permeability tended to be small that the water content of concrete became high.
