Research On The Influence Of Antifreeze Mixture On Properties Of Concrete And Proportion Optimization

The winter is at a low temperature for a long time in high-latitude area, and the concrete application is limited. To ensure the smooth construction of concrete in cold seasons, mixing antifreeze admixture in concrete is a more convenient and economical means. But mostly compound antifreeze admixture have complex compositions, which is difficult for a clear understanding of the low of influence on concrete properties of antifreeze admixture, which even serious impact on product application and promotion. With the current chaotic situation of antifreeze admixture applications, systematically investigate the influence of antifreeze components on properties of concrete, revealing the influence mechanism of antifreeze components for concrete, to provide technical reference for seasonal frozen application.Firstly, we discussed the influence of different antifreeze components on the concrete mix workability, mechanical properties and resistance to freeze-thaw durability. The results showed slump loss increases and reduced the initial slump with CaCl₂. Ca（NO₂）₂ and Ca （NO₃）₂ has increased on the concrete initial slump, but the slump lost increased. Glycol slump loss is reduced and the initial slump improves. CaCl₂, Ca （NO₂）₂, Ca （NO₃）₂ and ethylene glycol can play a certain effect for antifreeze. At-10 ℃, the freezing effect of contrast is CaCl₂> Ca （NO₃）₂> ethylene glycol> Ca（NO₂）₂ .With CaCl₂ and Ca （NO₂）₂ dosage increasing, concrete frost resistance decreasing significantly. Ethylene glycol also can improve the frost resistance of concrete when it at a lower dosage.Secondly, through research superplasticizer concrete workability with antifreeze components, the results show that the performance of antifreeze component has little effect on water reducer. Its impact is mainly manifested in superplasticizer concrete slump loss increases.Then create a exponential decay model which characterize the result of cement slurry bubble in the bubble shaking, it can fit bubble volume variation with time preferably, and its parameters can characterize different characteristic parameters of air entraining agent. Applications of this model study the antifreeze composition on two different air-entraining agent bubble stability. Then we measured air content of concrete mix. The results show that for spanning air entraining agent, CaO₂ reduces bubble stability and concrete mixture gas content, Ca（NO₂）₂, Ca（NO₃）₂ solution reduces foaming ability leaving the gas content is reduced. Glycol on foam stability has increased, but decreased significantly foaming ability, fresh concrete air content is also reduced. Entraining agent for acid salts, CaCl₂ decreased ability to make bubbles,Ca（NO₂）₂ is mainly reduced the foam stability, Ca（NO₃）₂ adverse effect was not significant, but gas are reduced which three kinds of salts mixed concrete batching material containing. Ethylene glycol is improved bubble stability and air content of fresh concrete.Finally, based on response surface methodology antifreeze ratio between the various components to determine the methods, results show that response surface regression equation can be used to predict the negative temperature strength, slump and air content of concrete. Best ratio is that calcium nitrate content is 4.79%, superplasticizer is 0.21%, air entraining agent is 0.31%. The difference of experimental results and predicted value is very small, indicating that the response surface methodology can be used to optimize antifreeze admixture ratio.