The Research Of The Concrete's Frost Resistance

Concrete durability is a significant subject in concrete science at all times. The concrete freezing and thawing destruction is one of the primary causes of our country concrete structure aging and disease, which affects the long-term use and the safe operation of the concrete building seriously, for making these projects to continue working, we must consume large amount of maintenance cost every year. But led the invalidation of the concrete durability was the design at first, and the key of the design quality was the standard. Overall, the durable aspect in designs didn't arrange entirely and the standard is somewhat low. In particular the concrete frost resistance evaluation still had many unreasonable places, they could not appraisal the concrete life well. At present our country evaluates the frost resistance of the project component mainly is depends upon experiments, but it has neglected that the experiment concrete component and the project concrete component has greatly distinguishes. Therefore, it is very necessary to do further research on this problem.From whether concluding steel bar carried on and the different maintenance environment, this article divide concrete component according to the standard maintenance, the nature maintenance, the dry and moist maintenance into 3 groups. Each group of 3 test samples, divide the reinforced concrete according to the similar condition into 3 groups too. Puts them in the freezing and thawing box after the defined period to carry on the thaw-freeze cycle, we measured dynamic modulus of elasticity each 25 times, until the defined times.Through the analysis of the above series result, we know that the frost resistance of C20 concrete is changed by the maintain condition.the better maintain condition ,the better the frost resistance;the worse maintain condition,the worse the frost resistance. The reinforced concrete and plain concrete's frost resistance also presents the inconsistent characteristic, because of the existence of the steel bar ,the frost resistance of the reinforce concrete are lower than the plant concrete's. At present,the testing method of the frost resistance have not actually considered these factors,which is unreasonable place. And the mathmatical model between the maintain condition, the content of the steel bar and the frost resistance of the concrete waits for further studies.