高强混凝土抗冻性的研究

从宏观和微观两方面研究了Ｃ６０，Ｃ８０，Ｃ１００高强混凝土的抗冻性。宏观研究表明，Ｃ６０高强混凝土的抗冻性不能满足Ｆ３００的要求，而Ｃ６０引气高强混凝土的抗冻性能却很好，快冻可达Ｆ１２００以上。Ｃ８０，Ｃ１００高强混凝土具有非常高的抗冻性，快冻可达Ｆ１２００以上，但高强混凝土经过一定冻融循环后，抗折强度会出现明显的降低。微观研究表明，当高强混凝土的气泡平均半径小于０．０１ｃｍ左右时，混凝土将具有超抗冻的特性。Ｃ６０高强混凝土在冻融过程中微孔结构的破坏主要是毛细孔物破坏，而Ｃ８０，Ｃ１００高强混凝土在冻融过程中，可能是非常细的毛细孔和较大凝胶孔的破坏。

Study on Frost resistance of High strength Concrete

In this paper, frost resistance of high strength concrete of C60, C80 and C100 has been studied from both of macro and micro respects. The macro study results indicate that the frost resistance of the high strength concrete of C60 does not reach 300 cycles of freezing and thawing. But the frost resistance of the air entrained and high strength concrete of C60 is much better, and 1 200 freezing thawing cycles can be exceeded by rapid frosting method. The frost resistance of the high strength concrete of C80 and C100 is also so good that 1 200 freezing thawing cycles can be exceeded by rapid frosting method too. Meanwhile, after a certain freezing thawing cycles, the flexural strength of high strength concrete drops remarkably. The micro study results indicate that the high strength concrete has super high performance of frost resistance when its mean radius of air void is less than 0.01 cm. In the freeze thaw process, the destruction of micro void is mainly that of the capillary pores for the high strength concrete of C60, but may be that of the very small capillary pores and the bigger gel pores for the high strength concrete of C80 or C100.