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Prediction of frost resistance and multiobjective optimisation of low-carbon concrete on the basis of machine learning

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MATERIALS TODAY COMMUNICATIONS 2024年 40卷

作者： Dai, Jinpeng Zhang, Zhijie Dong, Xuwei He, Jie Yang, Xiaoyuan Wang, Qicai Lanzhou Jiaotong Univ Natl & Prov Joint Engn Lab Rd & Bridge Disaster Pr Lanzhou 730070 Peoples R China Jiangsu Res Inst Bldg Sci CO LTD State Key Lab High Preformance Civil Engn Mat Nanjing 210008 Peoples R China Southeast Univ Sch Mat Sci & Engn Nanjing 211189 Peoples R China Lanzhou Jiaotong Univ Civil Engn Dept Lanzhou 730070 Peoples R China Lanzhou Jiaotong Univ Key Lab Optoelect Technol & Intelligent Control Minist Educ Lanzhou 730070 Peoples R China

The use of Portland cement is a major source of carbon dioxide emissions, causing considerable environmental pollution worldwide. Therefore, reducing carbon emissions in concrete is of paramount importance. This study presents a multiobjective optimisation method for low-carbon concrete mix design, combining the use of optimal machine learning models for prediction, with the aim of minimising the cost and carbon emissions of concrete. Several optimisation models, including SVR, CatBoost, RF, XGBoost, DBO-RF and VMD-DBO-RF, were employed to predict the frost resistance of low-carbon concrete. The research findings demonstrate that the VMD-DBO-RF optimisation algorithm achieves high prediction accuracy in terms of RDEM and MLR. For RDEM prediction, R2 = 0.9346, MSE = 0.0508, MAE = 0.1686, and RMSE = 0.2253. For MLR prediction, R2 = 0.9557, MSE = 0.0245, MAE = 0.1042, and RMSE = 0.1565. Furthermore, the model's interpretability was improved by combining SHAP and PDP analyses.

关键词： Low -carbon concrete Machine learning relative dynamic elastic modulus Mass loss rate Optimisation algorithm Mix ratio optimisation design Optimisation model

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Study of entropy Weight-Grey theory-BP Network life prediction Model of unit silica fume concrete lining under the influence of carbonation-sulfate freeze-thaw cycle erosion

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Research in Cold and Arid Regions 2025年第2期17卷 127-135页

作者： ZhiMin Chen MingYang Yi Meng Zhang ZhiQiang Yang JunHui Liu QianLong Yuan DianQiang Wang Hui Long HaoYong Zhang PengJi Zheng HongYan Shang ShengYi Xie Lanzhou jiaotong university School of Civil Engineering China Construction Second Engineering Bureau Co. Ltd

To address the challenges posed by tunnel construction in the alpine region, silica fume mixed concrete is commonly used as a construction material. The correlation between silica fume content and the lining life requires immediate investigation. In view of this phenomenon, the durability of unit lining concrete is predicted by analyzing three key indicators: carbonation depth, relative dynamic elastic modulus, and residual quality. This prediction is achieved by integrating the Entropy Weight Method, Grey theory life prediction model and BP artificial neural networks using data from tests and predictions of these indicators. Then, the Entropy Weight-Grey theory-BP Network Model is compared with other methods to analyze the predicted life. Finally, verify the scientificity of this model, and the optimum silica fume content of unit concrete lining is verified. The results showed, 1) The addition of silica fume will accelerate the carbonization of unit concrete lining, and slow down the freeze-thaw cycle and sulfate erosion. 2) The utilization of artificial neural networks is essential for enhancing the realism of the data, as it emphasizes the significance of silica fume content. 3) Silica fume content of 10% results in the longest life and is the most suitable for lining construction. 4) A comparison between single-factor and multi-factor predictions indicates that the multi-factor approach yields a longer maximum life. This improvement can be attributed to the inclusion of additional factors, such as freeze-thaw cycles and carbonation, which enhance the predicted life when employing these methods. In conclusion, the Entropy Weight-Grey Theory-BP Network life prediction Model is well-suited for tunnel lining in the alpine sulfate area of northwest China.

关键词： Lining life prediction Carbonation depth relative dynamic elastic modulus Freeze-thaw cycle erosion Residual mass Sulfate attack

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Damage Prediction of Hydraulic Concrete in Severe Cold Region Based on FOTP-GM (1,1) Model

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KSCE JOURNAL OF CIVIL ENGINEERING 2023年第7期27卷 2993-3005页

作者： Gong, Li Liang, Yuting Yu, Xingbo Liang, Ying Du, Qiangye Lanzhou Jiaotong Univ Dept Civil Engn Lanzhou 730070 Peoples R China

In winter, hydraulic concrete is often under the synergistic destruction of the freeze-thaw cycle, dry-wet alternation, and salt erosion. The special climate in cold and arid areas has adverse effects on the safe operation and economic benefits of hydraulic buildings. The durability of polypropylene fiber-modified concrete under multiple working conditions was studied. Combined with the FOTP-GM (1,1) model, damage prediction of modified concrete under different working conditions was carried out. The results show that a certain amount of polypropylene fiber significantly increased the corrosion resistance of specimens. The fitting degree between the measured sequence and the model increased with increasing order 'h' of the time power term. Under different working conditions, the time power term corresponding to the optimal model structure was different. The correlation coefficient R-2 between the established prediction model and the original sequence was above 0.9. Through error analysis, it was proved that the FOTP-GM (1,1) model can effectively predict the number of cycles when the concrete reaches the failure standard. The optimal model structure can be used in practical engineering to establish a prediction model to calculate the safe 0service life of engineering structures.

关键词： Polypropylene fiber concrete relative dynamic elastic modulus Damage prediction FOTP-GM (1 1) Multi-factor coupling

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Experimental Study and Analytical Modeling on Properties of Freeze-Thaw Durability of Coal Gangue Pervious Concrete

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MATERIALS 2023年第22期16卷 7104-7104页

作者： Wang, Yujing Xia, Junwu Li, Pengxu Yu, Linli Yang, Han Chen, Yidong China Univ Min & Technol State Key Lab Geomech & Deep Underground Engn Xuzhou 221116 Peoples R China Jiangsu Vocat Inst Architectural Technol Jiangsu Collaborat Innovat Ctr Bldg Energy Saving Xuzhou 221116 Peoples R China China Univ Min & Technol Sch Mech & Civil Engn Xuzhou 221116 Peoples R China

To assess the freeze-thaw (F-T) durability of coal gangue pervious concrete (CGPC) in different F-T cycle media (water, 3.5 wt% NaCl solution), experimental studies on 36 groups of cube specimens and 6 groups of prismatic specimens were carried out, with designed porosity, F-T cycling media, and F-T failure times as variables. The changes in apparent morphology, mass, compressive behavior, relative dynamic elastic modulus, and permeability coefficient have been analyzed in detail. To predict the compressive strength after F-T cycles, a GM (1,1) model based on the grey system theory was developed and further improved into a more accurate grey residual-Markov model. The results reported that the cement slurry and coal gangue aggregates (CGAs) on the specimen surface continued to fall off as F-T cycles increased, and, finally, the weak point was fractured. Meanwhile, the decrease in compressive behavior and relative dynamic elastic modulus was gentle in the early phase of F-T cycles, and they gradually became faster in the later stage, showing a parabolic downward trend. The permeability coefficient increased gradually. When F-T failure occurred, specimen mass dropped precipitously. The F-T failure of CGPC was more likely to occur in 3.5 wt% NaCl solution, and the F-T failure times of samples were 25 times earlier than that of water. This study lays the foundation for an engineering application and provides a basis for the large-scale utilization of CGPC.

关键词： pervious concrete coal gangue aggregates relative dynamic elastic modulus permeability grey theory Markov process

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Durability and mechanical properties of rubber concrete incorporating basalt and polypropylene fibers: Experimental evaluation at elevated temperatures

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CONSTRUCTION AND BUILDING MATERIALS 2023年第1期368卷

作者： Su, Qiang Xu, Jinming Shanghai Univ Dept Civil Engn Shanghai 200444 Peoples R China

Waste tires cause serious environmental problems, such as pollution, which can be reduced by mechanically grinding rubber tires into powder to obtain rubber particles. These components are then used in equal mass (20%) to replace fine aggregate to manufacture rubber concrete (RC), a new type of environmentally friendly building material. This study explored the performance of RC and different volume fractions (0.5%, 1.0% and 1.5%) basalt-polypropylene fiber-reinforced rubber concrete (BPRC) under elevated temperatures through a series of experiments on mass, relative dynamic elastic modulus, static compressive strength, and dynamic compressive strength. The experimental results showed that with increasing temperature, mass loss in RC and BPRC gradually increased, their relative dynamic elastic moduli slowly decreased. Their static compressive and dynamic compressive strengths reflected different degrees of loss, the strength loss temperature node of pure rubber concrete is earlier and the loss degree is more. The best performance was shown by the BPRC with 1% and 1.5% volume ratios of basalt and polypropylene fibers, respectively. Mixing basalt and polypropylene fibers into RC is beneficial to improvements in its performance after an increase in temperature.

关键词： Elevated temperature Rubber concrete Mass loss relative dynamic elastic modulus Static compressive strength dynamic compressive strength

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Freeze-thaw damage model for concrete considering a nonuniform temperature field

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JOURNAL OF BUILDING ENGINEERING 2023年 72卷

作者： Rong, Xian-Liang Li, Lei Zheng, Shan-Suo Wang, Feng Huang, Wei-Yuan Zhang, Yi-Xin Lu, Dong Tongji Univ Coll Civil Engn Shanghai 200092 Peoples R China Xian Univ Architecture & Technol Sch Civil Engn Xian 710055 Peoples R China Huaqiao Univ Coll Civil Engn Xiamen 361021 Peoples R China Hong Kong Polytech Univ Dept Civil & Environm Engn Kowloon Hong Kong 999077 Peoples R China

Studies show the temperature field inside the concrete under freeze-thaw cycling is not uniformly distributed. However, the existing indicators of freeze-thaw damage do not take into account the effect of nonuniform temperature field distribution. This study uses the loss of relative dynamic modulus of concrete D as a physical index to characterize the degree of freezethaw damage. Starting from the concrete freeze-thaw damage mechanism, a widely applicable freeze-thaw damage model that considers the nonuniform temperature field distribution inside the concrete structure is established based on Cai's model, theoretical derivations and experimental research. The accuracy and reliability of the model are verified through design tests. Finally, the application of the freeze-thaw damage model considering nonuniform temperature field distribution is determined for reinforced concrete (RC) beam-column joints under freezethaw cycle (FTC) action. The results show that the value for D is sensitive to the material coefficient & lambda;. The value of & lambda;tends to be a constant according to hydrostatic pressure theory and damage mechanics. The water-cement ratio significantly affects the temperature of the maximum freezing rate for concrete under FTC action, and the freezing rate for concrete under FTC action shows a linearly related with the quadratic power of the water-cement ratio. The freeze-thaw damage model considering nonuniform temperature field distribution can be used to accurately quantify the freeze-thaw damage of RC structures and members.

关键词： Freeze-thaw damage model Unevenly distributed temperature field relative dynamic elastic modulus Maximum freezing rate Maximum hydrostatic pressure

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Reliability Study of Magnesium Oxychloride-Coated Reinforced Concrete Based on Gumbel Distribution

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MATERIALS 2023年第6期16卷 2521-2521页

作者： Li, Yuanke Qiao, Hongxia Yang, An Lanzhou Univ Technol Sch Civil Engn Lanzhou 730050 Peoples R China Gansu Adv Civil Engn Mat Engn Res Ctr Lanzhou 730050 Peoples R China

The constant current accelerated corrosion test was used to study the durability of magnesium oxychloride-coated reinforced concrete (MOCRC) in order to solve the problem of MOCRC's durability. The relative dynamic elastic modulus was utilized as the failure threshold to evaluate the concrete durability, and the collected life data of concrete under different cover thickness were acquired. On the basis of the Gumbel distribution, the probability analysis can be used to study and foretell the life data. The results show that when the durability is evaluated by the relative mass and the relative dynamic modulus of elasticity, the durability of MOCRC with a larger protection layer thickness is better;the relative dynamic modulus of elasticity can better reflect the durability change in MOCRC than the relative mass. When the Gumbel distribution is used for durability analysis, the calculated value of the model and the life data have a relatively high degree of fit, which can provide a reference basis for the durability evaluation of concrete.

关键词： accelerated corrosion relative dynamic elastic modulus gumbel distribution life prediction

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Estimation of rubberized concrete frost resistance using machine learning techniques

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CONSTRUCTION AND BUILDING MATERIALS 2023年第1期371卷

作者： Gao, Xifeng Yang, Jian Zhu, Han Xu, Jie Tianjin Univ Key Lab Coast Civil Struct Safety China Minist Educ Tianjin 300350 Peoples R China Tianjin Univ Sch Civil Engn Tianjin 300350 Peoples R China

Utilizing waste rubber in concrete has effectively reduced global environmental pollution and carbon emission. It is essential to accurately evaluate and predict the evolution of its frost resistance in a complex environment to promote its engineering application. The traditional experimental modeling method is difficult to overcome the complex nonlinearity and environmental sensitivity among concrete components. Therefore, this study employed three classical single ML models, including RG, ANN, and SVR, and three new ensemble learning models (RF, XGBoost, and Stacking) to predict the two indexes of frost resistance of rubberized concrete, i.e., RDEM and MLR. Before modeling, the LOF detection algorithm was used to process the initial dataset to reduce the training bias. In addition, the performance statistics of the above six ML models show that the XGBoost ensemble learning algorithm based on Boosting has the best prediction performance for the frost resistance of rubberized concrete, with more than 95 % of the predictions distributed within the +/- 20 % confidence interval (R2 = 0.96, MAE = 0.15, RMSE = 0.27). According to the SHAP and the partial dependence analysis, adding an appropriate amount of rubber can improve the frost resistance of concrete. The recommended RC and RS ranges are 15 to 25 kg/m3 and 0.1 to 0.5 mm, respectively. These findings revealed that ML algorithms are an efficient and robust model for predicting rubberized concrete's frost resistance.

关键词： Machine learning Rubberized concrete relative dynamic elastic modulus Mass loss rate

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Durability of Concrete with Different Improvement Measures and Its Ser-vice Life Prediction in Island and Reef Environment

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China Ocean Engineering 2022年第6期36卷 947-958页

作者： GONG Wei YU Hong-fa MA Hai-yan WANG Nan ZHU Hai-wei School of Civil Engineering and Architecture Jiangsu University of Science and TechnologyZhenjiang 212100China Department of Civil and Airport Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China School of Civil Engineering University of Science and Technology LiaoningAnshan 114051China Key Laboratory of Harbor and Marine Structure Durability Technology of the Ministry of Communications CCCC Forth Harbor Engineering Institute Co.Ltd.Guangzhou 510230China

To solve the durability of island and reef concrete engineering in the harsh environment of high temperature,high salt,high humidity and windy,the strength grade of concrete and the type of corrosion inhibitor were used as the influence factors,while the relative dynamic elastic modulus was used as the evaluation *** addition,the law and time variability of the deterioration of concrete,the size effect,environmental similarity and the service life model were *** results showed that improving the strength grade of concrete could improve the durability of concrete,and corrosion inhibitor could slightly improve the durability of ***-varying law of the deterioration of concrete conformed to the univariate quadratic *** with the concrete damage equivalent theory,a size effect model based on the relative dynamic elastic modulus was proposed and verified,and the size effect coefficient was also *** environmental similarity model between simulated and practical island and reef environment was *** with the reliability theory and the first order second moment method,a new service life model of concrete structure was *** authors were convinced that the research will be advantageous to researchers.

关键词： island and reef environment relative dynamic elastic modulus size effect environmental similarity service life model

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Study on Durability and Piezoresistivity of Cement-Based Piezoelectric Materials Mixed with Carbon Fiber and Iron Tailings under Salt-Freezing Erosion

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BUILDINGS 2022年第8期12卷 1150页

作者： Xu, Jin Wang, Sheliang Bai, Jiaojiao Li, Yifan Quan, Xiaoyi Xian Univ Architecture & Technol Sch Civil Engn Xian 710055 Peoples R China Xijing Univ Sch Civil Engn Xian 710123 Peoples R China Shaanxi Key Lab Safety & Durabil Concrete Struct Xian 710123 Peoples R China

Under the complex working conditions in cold areas, in order to achieve health monitoring of engineering structures, carbon fiber and iron tailings sand were added to ordinary cement-based materials to prepare cement-based piezoelectric composites, and the deterioration of their pressure-sensitive properties and mechanical properties under the action of the sulfate-freeze-thaw cycle was studied. Six groups of specimens and a set of benchmark specimens were prepared according to different contents of carbon fiber and iron tailings sand, and the specimens of each group were analyzed qualitatively and quantitatively after 50, 100, and 150 freeze-thaw cycles. Based on the external damage analysis, it was concluded that with the increase in the number of freeze-thaw cycles, the apparent morphology of the specimens in each group continued to deteriorate. After 150 freeze-thaw cycles, the addition of a certain proportion of carbon fiber and iron tailings can improve the compactness of cement-based composites, effectively inhibit the development of cracks, maintain the integrity of the apparent morphology of the specimen, and the quality loss rate of the specimen does not exceed 5%. Based on the internal damage analysis, it is concluded that the specimen mixed with carbon fiber and iron tailings has undergone the freeze-thaw cycles, and its relative dynamic elastic modulus generally shows a trend of first rising and then falling, and after 150 freeze-thaw cycles, the relative dynamic elastic modulus of C04T30 specimen is 85.5%, and its compressive strength loss rate is 20.2%, indicating that its freeze resistance is optimal. The compressive stress and resistivity change rate of each group of cement-based piezoelectric composite specimens that have not undergone freeze-thaw cycles are approximately consistent with the linear attenuation relationship. Those that have undergone 150 freeze-thaw cycles approximately conform to the polynomial attenuation relationship. The correla

关键词： cement-based piezoelectric composites relative dynamic elastic modulus compressive strength loss rate resistivity change rate pressure sensitivity coefficient

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