The Durability Of Water-permeable Concrete In Acid Rain Environment Study

In order to study the durability of water-permeable concrete in acid rain environment, long time immersion test is carried out in this paper. The mixes are firstly designed through uniform design based on which the concrete specimens are made according to the corresponding test methods. After 28 days, the permeability coefficient and the anti-compressive strength indexes of the material are tested. The relationship between the mix parameters and the strength and permeable coefficients are processed by using non-parametric regression. The results provide empirical correlation between permeable coefficients & strength and the mix parameters. The study also confirms the effectiveness of the uniform design and non-parametric regression. Secondly, a long time immersion test in sulfuric acid is carried out to study the durability of the specimen. The immersion periods are two months, four months, six months respectively. The pH value of the soak solution of the dilute sulfuric acid is 4.00. The changes of the pH value in the soak solution are recorded by portable acidity meter. In order to maintain the pH value of the soak solution, the dilute sulfuric acid of 0.125mol/l is used as titrating solution. The acid consumption rate is then determined by the titration. The theoretical formula of the acid consumption rate and immersion time is put forward combination with the experiment results and the concentration boundary layer theory. The results with theoretical model has a good consistency. The results show that water-cement ratio and cement dosage is an important factor affecting the strength of water-permeable concrete, and permeability coefficient has a negative linear relationship between water-cement ratio and a proportional relationship between the set ash ratio & the amount of acid consumption. With the increase of immersion time and the dilute sulfuric acid, the calcium vanadium stone and plaster are produced by the continuous reaction between the hydration products Ca(OH)2 in concrete and SO42-, which lead to the increase of the weight but the continuous reduction of the strength of the specimens. At the same time, based on the above-mentioned results and theoretical analysis, the aging law of water-permeable concrete is obtained and the corresponding measures of anti-acid corrosion are put forward.