Experiment And Research Of High Frost-Resistance Concrete

With the rapid economy development of our country, we are enlarging investment in water Resources and hydropower engineering to build more dams. Because these dams have the significant economy and social efficiency to our construction, and to our utility of water as well as flood prevention, they must be of high durability for longer operation time. The freezing-thawing destruction phenomena of concrete are universal in northern area of our country and this question has obtained our scientists'enormous attention. With heightening the durability of concrete; our scientists are starting to research its failure mechanism of freezing-thawing.After reviewing results about freezing-thawing destruction research of concrete inland and outseas, the paper points out the are three directions about research in frost-resistance of concrete inland in recent.1 ) Microscopically, Researchers macroscopically and microscopically analyzed the failure mechanism of freezing-thawing and the main influence factor t other than water/cement ratio about frost-resistance of concrete.2 ) High frost-resistance, Someone have researched to abstain the main technical parameters requested for making high frost-resistance concrete.3)High-strength, Scientists have researched the causes why the high-strength concrete has high frost-resistance ability.Through summarizing the conclusion of above researches, the paper analyzes the realities and cause of freezing-thawing destruction in northern area of our country, suggest that we must make high frost-resistance concrete F300 to ensure the safe age limit of hydropower engineering. Aim to the request of high frost-resistance concrete F300, based on the utility in construction of ordinary hydropower engineering. Using the theory of mix proportion ABOUT hydraulic concrete, comparing the frost-resistance capabilities with different volume of water reducing admixture, air entraining admixture and fly ash , elect the best volume, such as air entraining admixture 2/万,water reducing admixture0.75%,fly ash 20%,such concrete has 28d strength 38.1 MPa, number of freezing-thawing cycles 300.With the complex function of water reducing admixture, air entraining admixture and fly ash, the paper firstly researches and analyzes how to make the non-high strength but high frost-resistance concrete step by step with the help of experiments. More ever, the paper firstly analyzes the relations between the frost-resistance ability and water absorption of hardened concrete in different situations with the help of using water absorption to represent compactness of hardened concrete.Through above studies, conceiving that we can use the relation between the concrete compactness and frost-resistance ability of concrete to build a mathematical model of water absorption ,strength ,air content and the number of freezing-thawing cycles to estimate the concrete capability of frost- resistance in advance which will achieves twice the result with half the effort.