C25 High-performance Concrete Corrosion Resistance Of Acid Rain And Carbonation Environment

Along with the continuously spreading of acid rain areas and the rising of CO2 concentration in our country, the concrete structures, especially in medium-low strength grade of concrete structures are corroded and damaged by acid rain and carbon dioxide increasingly, which seriously affecting the concrete structure durability and service life. Therefore, the study on high-performance technology of ordinary concrete and its performance degradation eroded by acid rain and carbon dioxide have been a hot research topic in the field of Civil Engineering. In order to provide a theoretical basis and technical support for the effective way of the high-performance technology of ordinary, it's significant to carry out a corrosion resistant study with combined acid rain and carbon dioxide attack of C25 high-performance concrete.Based on the background of the C25 ordinary concrete of "Foshan Rapid trunk" bridge foundation and the simulated acid rain environment, the preparation techniques of C25 high-performance concrete by optimizing the mineral admixture was studied in this paper; and the corrosion resistance of C25 high-performance concrete, which eroded by four different patterns such as acid rain, carbonization, first acid rain then carbonization and first carbonization then acid rain, was analyzed; based on the test results, the service life of the C25 high-performance concrete was predicted by BP neural network way. The results showed that the performance such as the workability, the uniformity and the permeability resistance to chlorine of the C25 high-performance concrete prepared in this paper were excellent, and the 28d compressive strength met the regulation requirement (≥33.3MPa). In the four erosion mode, the compressive strength of C25 high-performance concrete increased with the erosion age and began a downward trend (five cycles later), but all greater than the initial strength; the neutralization depth increases with the erosion cycle; with the combined acid rain and carbon action, the neutralization of concrete is mainly caused by the carbonization and CaCO3 was the main product in the specimens'surface after erosion, the hydration products like C-S-H and Ca(OH)2 decreased with increasing age. The BP neural network prediction results showed that the service life of the C25 high-performance concrete structure prepared in this paper could meet the requirements of 100-years. These research efforts above all have important guiding significance and reference value to the application technology of C25 ordinary concrete in the acid rain area and amendment of related standards.