The Experimental Study Of The Hydraulic Concrete Permeability On The Condition Of Freeze-Thaw Damage

In our country,it is very serious that the problem of endurance of reinforced concrete structure,and there are a lot of factors influencing it.The corrosion of reinforcement is one of the main factors of reinforced concrete structure performance degradation.Freeze-thaw damage of concrete and chlorine ions’penetration into concrete acclerate the steel corrosion process.Some areas environment in our country is complicated.Concrete is often influenced by freeze-thaw and chlorine ion together.When these two kinds of determantal circumstances influence the concrete,freeze-thaw role will change the density of concrete,and then it will affect the permeability of concrete.Analyze the influence of freeze-thaw damage on the permeability of hydraulic concrete according to the experiment of freeze-thaw damage and chloride penetration on C30 air-entrained hydraulic concrete(add mineral admixture to enhance the concrete frost resistance).The main work includes the following several parts content:(1)Introduce the concrete natural freeze-thaw cycle and permeability research situation at home and abroad,the study of the hydraulic concrete permeability on the condition of freeze-thaw damage is necessity and feasibility.(2)Having tested the cube compressive strength and penetration performance,test result indicates that the strength drops sharply and presents a linear drop down along with the increase of freeze-thaw number,and the natural freeze-thaw cycle of concrete produces interior damage to concrete as for density falling,the concrete permeability increasing greatly.(3)On the basis of SEM test,observed the interior change of concrete pore before and after the freeze-thaw cycle,analyzed the causes of the interior micro-cracks.(4)Summarized the research work of this thesis and looked forward to this research in the future.