Experimental Study On The Carbonation Model Of Concrete With High Properties Using Of Large Dosage Fly Ash

At present,the fly ash is a kind of building material that has been applied extensively.When mix the fly ash in the concrete,on the one hand,the fly ash is used effectively and lessen air pollution;on the other hand,reducing and controlling construction cost.But a large number of researches indicate that the property of fly ash is unstable,and it effect to the durability of concrete.This paper based on previous studies,primary research the carbonation resistace of concrete by the theoretical and experimental analyses.In actrual enginerring,normally adopted the quick experiment to determine the carbonation depth,the experimental results is showed fast.But,there is less study on the carbonation of concrete in natural condition and its correlation with artificial accelerated carbonation.The article studies the same mix proportion through the accelerated carbonation experimental and the natural condition carbonation experimental,and it mainly analyzes their relationship from five aspects:water-binder ratio,addition of fly ash,CO₂ concentration,environment temperature,environment humidity,the main contents of the research can be summarized as follows:1.W/B ratio is one of significant factors affecting durability of concrete carbonation depth.Dynamic changes of the carbonation depth of different W/B ration were similarly during these two experimental:the carbonation depth of concrete increases with the water-binder ratio.2.The effect of the fly ash replacement on the carbonation depth is considerable than the water to binder ratio.So we couldn't judge the concrete carbonation model just by the water-binder ratio when mix the fly ash in concrete.3.According to analyes and compares the two experimental results,we find that when the quantity of fly ash amount to 60 percent,the carbonation depth changes bigger in the changed temperature and humidity environment.4.When the quantity of fly ash amount to 60 percen,the concrete will easily carbonized at low CO₂ concentrations.So we should be cautious to use the concrete with high properties using of large dosage fly ash.On the basis of analyzing the test results,analysis the existing concrete carbonation model,and through this time experimental,reformulate the existed models,get a new prediction model which is suitable to the concrete with high properties using of large dosage fly ash,when it has been proved in this experimental,we find that it has small error .