@article{YANG2026, 
author = {Bin YANG and Yue LI and Hui LIN and Wei LI and Tianlong QIAO},
title = {Prediction of Damage Degree of Underground Concrete Under Load-Ion-Temperature Interaction},
year = {2026},
journal = {Journal of the Chinese Ceramic Society},
volume = {54},
number = {2},
pages = {653-665},
keywords = {concrete, damage degree, multi-factor coupling, life prediction},
url = {https://www.sciopen.com/article/10.14062/j.issn.0454-5648.20250177},
doi = {10.14062/j.issn.0454-5648.20250177},
abstract = {IntroductionThe underground concrete structure is in a complex and changeable service environment for a long time, and it is often affected by the combined effects of load, corrosive ions and temperature changes. There is a significant nonlinear coupling relationship among these three factors, which makes the concrete show a completely different damage evolution law from the single effect during the service process. Especially in the underground environment, chloride ions and sulfate ions will accelerate pore dissolution and micro-crack propagation, and temperature changes will vary the hydration rate and ion migration ability. Under external loads, the generation and propagation of microcracks further promote ion penetration and chemical erosion, resulting in a rapid degradation of material properties. Conventional durability tests are often difficult to quantitatively describe the damage law under the combined action of multiple factors, and it is difficult to accurately predict the service life of underground concrete. It is thus of great significance to reveal the deterioration mechanism and service life evaluation of underground concrete via constructing a method that can comprehensively reflect the damage degree of concrete under multi-factor coupling and realize a life prediction.MethodsIn the experiment, ordinary Portland cement was used to prepare concrete specimens, and the mix ratio of each group was kept consistent. The test was carried out under the accelerated conditions of simulated underground environment, and the service environment of different load, ion and temperature combinations was set up to investigate the damage evolution law under the coupling of three factors. During the test, the five indexes of concrete failure load, ultrasonic wave velocity, dynamic elastic modulus, rebound value and quality change were tested regularly. These indexes could reflect the mechanical properties, internal compactness, surface hardness and mass loss of concrete, respectively, as the important indexes for comprehensive evaluation of damage degree. In addition, the evaluation system of concrete damage degree was also established based on the entropy weight method, and the weight was automatically assigned by the dispersion of index changes, so that the damage degree evaluation could be more objective and comparable.For the life prediction, four models were selected for comparison, including Even Grey Model (EGM), Even Discrete Grey Model (EDGM), Optimized Discrete Grey Model (ODGM) and Discrete Grey Model (DGM), based on the grey system theory. The grey model has a good prediction performance under the condition of small sample and weak information, and is suitable for durability research with limited test period and small data volume. The accuracy of the model could be improved by cumulative generation and parameter analysis, and the prediction performance of each model was evaluated by various error indexes, and the optimal model was selected for the life prediction.Results and discussionThe damage degree of concrete under four different conditions firstly increases and then decreases. The failure load, ultrasonic wave velocity, dynamic elastic modulus, rebound value and mass change trend under the same conditions are similar. However, the turning points of damage attenuation under the four conditions are not consistent due to the difference of hydration reaction and internal pore structure. At 50 ℃, the faster early reaction rate can result in the faster pore filling, thus improving the compactness.Based on the entropy weight method, the weight coefficient of each index to the damage degree of concrete is obtained. The influencing degree from large to small is failure load, dynamic elastic modulus, rebound value, ultrasonic wave velocity, and quality change. Also, the accuracy ranking of the four prediction models is obtained based on the comprehensive score ranking method. The prediction accuracy from high to low is ODGM > EGM = EDGM > DGM.ConclusionsUnder the combined action of load-ion-temperature, the failure load, ultrasonic wave velocity, dynamic elastic modulus, rebound value and mass of concrete all firstly increased and then decreased, but the turning points of damage under various environmental effects were inconsistent. In addition, the hydration products under chloride erosion environment were mainly filled with micropores (i.e., ≤ 0.1 mm3) and small pores (i.e., 0.1-1.0 mm3), and the pores of concrete at 50 ℃ in the early stage were more dense than those at 20 ℃. The damage degree of each index was quantified by the entropy method, i.e., failure load (i.e., 80%-90%), dynamic elastic modulus (i.e., 5%-8%), rebound value (i.e., 1%-6%), ultrasonic wave velocity (i.e., 1%-4%), and mass change (i.e., < 1%). The ODGM model had the highest accuracy in predicting the service life of concrete under the combined action of load-ion-temperature. The service life of concrete was 82 months, 29 months, 24 months and 20 months under the four environments (i.e., 0.2Fmax, 3%NaCl, 20 ℃ and 0.2Fmax, 3%NaCl, 50 ℃ and 0.2Fmax, 5%Na2SO4, 20 ℃ and 0.2Fmax, 5%Na2SO4, 50 ℃), respectively.}
}