Introduction Although different experiments on the co-corrosion of concrete vulcanization and carbonation are performed, the data are scattered and are not systematic. There are little reports on the mechanism of the performance degradation of cement-based materials due to the coupled effects of high temperature, high humidity, SO2 and CO2. It is thus of a great theoretical and practical significance to scientifically evaluate the durability of industrial building concrete structures and investigate the durability damage mechanism and performance degradation of industrial building concrete structures.In this paper, the neutralization process of cement-based materials under the coupling action of high temperature, high humidity, SO2 and CO2 was investigated with the three levels of cement paste, mortar and concrete. The appearance, neutralization depth, and quality change rules of cement-based materials with different water-cement ratios were analyzed. The porosity and pore solution of cement-based materials were determined by nuclear magnetic resonance (NMR) and electrochemical impedance (EIS). In addition, the neutralization mechanism of cement-based materials was discussed, and a prediction model for the neutralization depth of cement-based materials was also established.Methods The cement used was P.O 42.5. The fine aggregate was a natural river sand with a fineness modulus of 2.34, and the coarse aggregate was a granite crushed stone with a continuous gradation of 5-25 mm. Three types of samples were cement paste, mortar, and concrete. In the test, a prism-shaped sample of 100 mm×100 mm×400 mm was used to test the neutralization depth of the sample, and a cubic sample of 100 mm×100 mm×100 mm was used for quality and microscopic tests, with 3 samples in each group. The tests began after 28 d of standard curing of the samples.A concentration ratio of CO2 and SO2 in the workshop was approximately 20:1, and the temperature and humidity were at 50 ℃ and 70%, respectively. The rapid carbonation test method based on the Chinese National Standard GB/T50082—2009 was used. The ambient temperature of the vulcanization test box was 50 ℃, the relative humidity was 70%, and the SO2 concentration was 0.9% (the maximum concentration of SO2 in this test box was 0.9% due to the limit of the SO2 sensor). For the carbonization box, the ambient temperature was 50 ℃, the relative humidity was 70%, and the CO2 concentration was 20%. The samples were covered with epoxy, leaving only two sides. The sample was placed on a bracket in the vulcanization box, and the distance between each sample was not less than 50 mm. The sample was vulcanized for 1 d and carbonized for 1 d as one cycle. The samples were tested when the cycles reached 0, 2, 4, 7 and 14. The appearance, quality and neutralization depth of cement-based materials were examined. The pore characteristics and pore solution changes in the samples before and after corrosion cycles were analyzed by NMR and EIS.Results and discussion Based on the analysis of cement slurry, mortar, and concrete samples, the neutral depth of cement pure pulp is the largest, and the neutral depth after 14 cycles is approximately 35 mm. The neutral depth of the mortar sample after 14 cycles is approximately 13 mm. The overall neutralization depth of the concrete is the smallest, and the difference is not large. The neutral depths after 14 cycles are 6.42, 6.95 mm and 8.19 mm, respectively. The depth of the neutral depth of the ingredients on the cement base is obvious. The aggregate can reduce gas transmission in the sample. The maximum neutral depth of mortar and concrete is decreased by 59.85% and 77.52%, respectively, compared with cement paste.The pore rate for paste is increased by approximately 3%. For mortar, the pores increase slowly. After 7 cycles, the pore rate is increased rapidly by approximately 8%. For concrete, the pores decrease first and then increase slowly by approximately 1%. For different materials under the common action of carbonization and vulcanization, the pore rate of cement base materials is generally increased.The initial proportion of harmful pores in concrete is larger than that in paste and mortar. However, the increase in harmful pores in mortar and cement paste is significantly larger than that in concrete as corrosion cycle increases. The harmful pores of concrete increase slowly, and the harmful pores decrease significantly after the 14th cycle. Concrete harmful pores are increased by approximately 0.4%. The harmful pores of the mortar are increased by approximately 0.8%. The harmful pores of the cement paste are increased by approximately 0.6%.Conclusions In the early stage of the corrosion cycle, the concentration of CO2 was relatively high, and the reaction was mainly carbonization. In the middle of the corrosion cycle, CaCO3 filled in the pores of the sample so that the reaction slowed down and the mass increased slowly. SO2 could react with calcium-containing substances, resulting in expansion cracks. SO2 could also lead to decalcification of CSH, further increasing the porosity and accelerating the transmission of gas inside the sample. In the later stage, the carbonization reaction speed accelerated, and the sample mass began to increase again. The neutralization depth of different samples changed approximately in the same manner, i.e., firstly increasing rapidly and then increasing slowly as the number of corrosion cycle increases. The porosity changes in the sample at all levels were similar, and the less harmful pores gradually increased and decreased after 14 cycles. For harmful holes and more harmful holes, the cement paste and mortar samples increased gradually, while the concrete samples firstly increased and then decreased after 14 cycles.