STUDY ON CARBONATION OF FLY ASH CONCRETE WITH FREEZE-THAW CYCLE

Carbonation of high performance concrete under freeze-thaw cycles was studied with different fly ash proportion(0%,20%,40%,60%);the new rules to estimate carbonation of concrete under freeze-thaw cycles were defined.The influence of different fly ash proportion and different freeze-thaw damage on carbonation was analyzed quantitatively by image processing techniques.Experiment results showed that the carbonation of concrete after freeze-thaw cycles was different from the traditional carbonation of concrete.The traditional testing method using carbonation depth could not express new feature of carbonation after freeze-thaw damage.And the new testing method using carbonation area could better express the carbonation law.The carbonation area and fly ash proportion subject quadratic equation =45.12-1.35FA+0.035FA2;and the carbonation area and freeze-thaw damage degree linear equation =35+0.306x.The research on the carbonation of concrete under freeze-thaw cycles possesses the real meaning to the structure durability and life prediction of concrete in the freeze-thaw area.