Study On The Carbonization Of High Performance Concrete With Different Compressive Stress Levels

Reinforced concrete materials play an important role in engineering construction.The first factor that causes the damage of reinforced concrete structure is the corrosion of steel reinforcement.Concrete carbonization is the main factor that causes the corrosion of reinforcement,and is also one of the main evaluation indexes of concrete durability.Nowadays,the research on concrete carbonization mainly stays in the "pure material" stage,and there is less research on the carbonization of damaged concrete in the service state."Pure material" stage achievements of concrete carbonation regularity of carbonization of concrete structure,it is difficult to accurately reflect service served the results applied to concrete structures,may cause the destruction of concrete structure early,endanger the safety of the people's property,bring incalculable economic loss to the country.In this article,using prestressed concrete damage experiment to study the carbonation resistance of damaged high performance concrete.The model of predicting damaged concrete carbonation depth is modeled through the experiment.It is of great significance to predict the service concrete structure carbonation depth,residual life and the maintenance and reinforcement.According to the current high performance concrete application technical regulations and speciation for mix proportion design of ordinary concrete,the high performance concrete specimen of C35,C40,C45 and C50 is prepared.100×100×300 specimens of 5 sets and 100×100×100 specimens were prepared for each mix proportion.The following contents were studied by accelerated carbonization test method according to the 40%,50%,60% and 70% of the compressive strength of the axial compressive strength of each strength grade.According tothe40%,50%,60% and 70% of the compressive strength of the axial compressive strength are used as precast concrete damage.The following contents are studied by means of accelerated carbonization test:Compared with normal concrete with different compressive stress levels,the carbonization performance of high performance concrete with different compressive stress levels was studied.Compared with non-compressive stress concrete,the carbonization performance of concrete with different compressive stress levels was studied.Through the analysis of the test results,the concrete carbonation depth and the phase correlation of concrete under different stress levels were returned.Through the above research,the conclusions are drawn as following:The accelerated carbonization depth of high performance concrete with different compressive stress is consistent with the same strength grade.For the damaged concrete,the higher the strength grade,the greater the increase of carbonation depth in each phase.Compared with no compressive stress accelerated carbonation depth of concrete damage,when the compressive stress level is 70%,C35 and C50 concrete,C40 concrete,C45 concrete 28 d accelerated carbonation depth of concrete increased respectively by 29.56%,36.19%,37.6% and 36.19%,an average of 37.18%.