Experimental Study On Mechanical Properties Of Concrete In Acid Rain Environment

The corrosion of concrete structure during the service period will cause its deterioration of the bearing capacity and the durability will fail in advance.The structural durability degradation caused by acid rain has become a major problem in civil engineering and has become the focus of research.Therefore,it is of great theoretical significance and practical value to study the damage law of concrete mechanical properties in acid rain environment.According to the composition and characteristics of acid rain in our country,the sodium sulfate solution with different concentration(10%,15%,20%)and different acidity(pH value of 3,5,7)was formulated to simulate acid rain environment.Using dry-wet alternate method to periodic soak specimen in the laboratory,the concrete mechanics test was carried out on the basis of the analysis of the mechanism of acid rain erosion of concrete.To observe the color change,surface exfoliation and apparent changes in the form of concrete holes in the corrosion process,the deteriorating law of the concrete corroded by acid rain are analyzed from the concrete quality,failure pattern and the compressive strength and so on.At the same time,using the CT scanner to analyze the microstructure of the concrete specimens before and after corrosion,and reveal the change of the internal structure of corroded concrete by analyzing the change of CT value.On the basis of CT image processing and 3D reconstruction technology,the porosity of concrete under different conditions was measured and the relationship between the porosity and the various factors change was analyzed.Finally,orthogonal experiment was designed on the basis of analyzing the principle of orthogonal test,and the method of range analysis and variance analysis was adopted.The sensitivity of the three factors:The concentration,the pH value and the corrosion time,was analyzed with the quality and compressive strength as the index.