{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T05:21:45Z","timestamp":1788326505669,"version":"build-2803163510"},"reference-count":43,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T00:00:00Z","timestamp":1788134400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100014103","name":"Key Research and Development Program of Shandong Province","doi-asserted-by":"crossref","award":["2024TSGC0668"],"award-info":[{"award-number":["2024TSGC0668"]}],"id":[{"id":"10.13039\/100014103","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>Unsaturated polyester resin concrete (UPC) exhibits high strength and corrosion resistance, and it has been widely used in hydraulic engineering structures. However, the diffusion of water molecules inevitably induces matrix plasticization and debonding at the aggregate\u2013resin interface, which leads to progressive degradation of mechanical performance under long-term aqueous service conditions. To elucidate the water-induced mechanical deterioration mechanism of UPC and to develop a temperature-adaptive model for long-term compressive strength prediction, we prepared UPC specimens using graded quartz sand aggregate, an unsaturated polyester binder, V388 curing agent, and KH570 coupling agent at a fixed mass mixing ratio, followed by 7 days of natural curing after demolding. Accelerated water aging tests were conducted at three temperature levels (25 \u00b0C, 40 \u00b0C, 60 \u00b0C) and four immersion durations (15 d, 30 d, 45 d, 60 d), including water absorption, compressive, splitting tensile, and flexural tests. Based on Fick\u2019s second diffusion law and the Arrhenius equation, we quantitatively analyzed moisture diffusion behavior and the evolution of mechanical degradation. The results indicate that the water absorption of UPC strictly follows Fickian diffusion, and that elevated temperature increases both the water absorption rate and the saturated water absorption capacity. The saturated water absorption ratios reached 0.15%, 0.16%, and 0.22% at 25 \u00b0C, 40 \u00b0C, and 60 \u00b0C, respectively, corresponding to apparent diffusion coefficients of 1.13 \u00d7 10\u22126, 1.67 \u00d7 10\u22126, and 4.52 \u00d7 10\u22126 mm\/s. Long-term water aging progressively degrades the mechanical properties of UPC; after 60 d of immersion at 60 \u00b0C, the retention rates of compressive, splitting tensile, and flexural strength decreased to 88%, 85%, and 78%, respectively. We developed a physically coupled compressive strength prediction model based on moisture erosion depth and the associated reduction in effective bearing area. The ratio of model predictions to experimental data ranged from 0.93 to 0.98, indicating favorable conservative accuracy for engineering applications. When further combined with the Arrhenius relationship, the model enables extrapolation of the long-term mechanical properties of UPC under arbitrary service temperatures. This work provides theoretical support and a quantitative calculation framework for assessing the durability and predicting the service life of UPC hydraulic structures.<\/jats:p>","DOI":"10.3390\/polym18172112","type":"journal-article","created":{"date-parts":[[2026,8,31]],"date-time":"2026-08-31T09:21:19Z","timestamp":1788168079000},"page":"2112","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Degradation Law of Mechanical Properties and Long-Term Compressive Strength Prediction Model of Unsaturated Polyester Resin Concrete in Aqueous Environments"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4238-6007","authenticated-orcid":false,"given":"Wenchao","family":"Li","sequence":"first","affiliation":[{"name":"College of Civil and Architectural Engineering, Taishan University, Taian 271000, China"},{"name":"Shandong Engineering Research Center of High-Durability and Corrosion-Resistant New Building Materials, Taian 271000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"given":"Fusheng","family":"Wen","sequence":"additional","affiliation":[{"name":"College of Civil and Architectural Engineering, Taishan University, Taian 271000, China"},{"name":"Shandong Engineering Research Center of High-Durability and Corrosion-Resistant New Building Materials, Taian 271000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"}]},{"given":"Bin","family":"Han","sequence":"additional","affiliation":[{"name":"College of Civil and Architectural Engineering, Taishan University, Taian 271000, China"},{"name":"Shandong Engineering Research Center of High-Durability and Corrosion-Resistant New Building Materials, Taian 271000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"software","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"}]},{"given":"Wenming","family":"Cao","sequence":"additional","affiliation":[{"name":"Changjiang Water Conservancy and Hydropower Engineering Construction (Wuhan) Co., Ltd., Jinan 250100, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"investigation","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"}]},{"given":"Kai","family":"Liu","sequence":"additional","affiliation":[{"name":"College of Civil and Architectural Engineering, Taishan University, Taian 271000, China"},{"name":"Shandong Engineering Research Center of High-Durability and Corrosion-Resistant New Building Materials, Taian 271000, China"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"validation","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,31]]},"reference":[{"key":"ref_1","first-page":"7249743","article-title":"A review on epoxy and polyester based polymer concrete and exploration of polyfurfuryl alcohol as polymer concrete","volume":"2016","author":"Kumar","year":"2016","journal-title":"J. Polym."},{"key":"ref_2","first-page":"e06257","article-title":"Assessment of different classes of polymer concrete: Comparative mechanical properties and new empirical equations for behavior modeling","volume":"25","author":"Pokharel","year":"2026","journal-title":"Case Stud. Constr. Mater."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"125771","DOI":"10.1016\/j.conbuildmat.2021.125771","article-title":"Polymer modified concrete impact on the durability of infrastructure exposed to chloride environments","volume":"317","author":"Mohammed","year":"2022","journal-title":"Constr. Build. Mater."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"100225","DOI":"10.1016\/j.nxmate.2024.100225","article-title":"Polymer-enhanced concrete: A comprehensive review of innovations and pathways for resilient and sustainable materials","volume":"4","author":"Salami","year":"2024","journal-title":"Next Mater."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"103922","DOI":"10.1016\/j.tafmec.2023.103922","article-title":"Fracture mechanics of polymer concretes: A review","volume":"125","year":"2023","journal-title":"Theor. Appl. Fract. Mech."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"128813","DOI":"10.1016\/j.conbuildmat.2022.128813","article-title":"Identification of damage mechanisms of polymer-concrete in direct shearing tests by acoustic emission","volume":"351","author":"Qin","year":"2022","journal-title":"Constr. Build. Mater."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1016\/j.conbuildmat.2012.01.010","article-title":"Investigation of mechanical properties of thin epoxy polymer overlay materials upon orthotropic steel bridge decks","volume":"33","author":"Mo","year":"2012","journal-title":"Constr. Build. Mater."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"449","DOI":"10.1016\/S0958-9465(99)00032-3","article-title":"Polymers in concrete: A vision for the 21st century","volume":"21","author":"Fowler","year":"1999","journal-title":"Cem. Concr. Compos."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"767","DOI":"10.1016\/j.conbuildmat.2017.12.115","article-title":"Investigating fracture mechanics and flexural properties of unsaturated polyester polymer concrete (UP-PC)","volume":"163","author":"Hashemi","year":"2018","journal-title":"Constr. Build. Mater."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"336","DOI":"10.1016\/j.conbuildmat.2017.02.116","article-title":"Flexural fatigue life analysis of unsaturated polyester-methyl methacrylate polymer concrete","volume":"140","author":"Yeon","year":"2017","journal-title":"Constr. Build. Mater."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"117229","DOI":"10.1016\/j.conbuildmat.2019.117229","article-title":"Optimal design for epoxy polymer concrete based on mechanical properties and durability aspects","volume":"232","author":"Ferdous","year":"2020","journal-title":"Constr. Build. Mater."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"539","DOI":"10.1016\/j.conbuildmat.2016.10.056","article-title":"Optimal mix and freeze-thaw durability of polysulfide polymer concrete","volume":"127","author":"Hong","year":"2016","journal-title":"Constr. Build. Mater."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"167","DOI":"10.2472\/jsms.74.167","article-title":"Study of test method for direct tensile strength of polymer concrete","volume":"74","author":"Kasahara","year":"2025","journal-title":"J. Soc. Mater. Sci. Jpn."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1016\/j.conbuildmat.2019.06.144","article-title":"Effective resin content and its effect on the overall performance of polymer concrete for precision machine tools","volume":"222","author":"Yin","year":"2019","journal-title":"Constr. Build. Mater."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"126","DOI":"10.1016\/j.mechmat.2017.11.004","article-title":"Micromechanics based damage model for predicting compression behavior of polymer concretes","volume":"117","year":"2018","journal-title":"Mech. Mater."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"117907","DOI":"10.1016\/j.conbuildmat.2019.117907","article-title":"Durability of polyester polymer concretes based on metallurgical wastes for the manufacture of construction and building products","volume":"240","author":"Seco","year":"2020","journal-title":"Constr. Build. Mater."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"469","DOI":"10.1016\/j.conbuildmat.2019.01.085","article-title":"Mechanical and durability performance evaluation of crumb rubber-modified epoxy polymer concrete overlays","volume":"203","author":"Wang","year":"2019","journal-title":"Constr. Build. Mater."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"146383","DOI":"10.1016\/j.conbuildmat.2026.146383","article-title":"A comprehensive approach for lightweight polymer concrete production: Determination of the effect of resin and perlite types on high temperature, freeze-thaw behavior and damage mechanisms of polymer concrete","volume":"526","author":"Bulut","year":"2026","journal-title":"Constr. Build. Mater."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"117887","DOI":"10.1016\/j.conbuildmat.2019.117887","article-title":"Durability of epoxy polymer and ordinary cement concrete in aggressive environments","volume":"234","author":"Ghassemi","year":"2020","journal-title":"Constr. Build. Mater."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"119853","DOI":"10.1016\/j.conbuildmat.2020.119853","article-title":"Effect of polymer content and temperature on mechanical properties of lightweight polymer concrete","volume":"260","author":"Heidarnezhad","year":"2020","journal-title":"Constr. Build. Mater."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"116709","DOI":"10.1016\/j.conbuildmat.2019.116709","article-title":"Unsaturated polyester resin concrete: A review","volume":"228","author":"Yang","year":"2019","journal-title":"Constr. Build. Mater."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"119318","DOI":"10.1016\/j.conbuildmat.2020.119318","article-title":"Laboratory research on road performances of unsaturated polyester concrete at medium-high temperature","volume":"254","author":"Zhang","year":"2020","journal-title":"Constr. Build. Mater."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"173","DOI":"10.2472\/jsms.74.173","article-title":"Experimental and reproduction analysis on the time-dependent characteristics of strength and deformation properties of polymer concrete subjected to humid environment","volume":"74","author":"Kasahara","year":"2025","journal-title":"J. Soc. Mater. Sci. Jpn."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"100","DOI":"10.1002\/cepa.2959","article-title":"Performance of manhole under severe condition in Japan","volume":"6","author":"Ishitsuka","year":"2023","journal-title":"ce\/Papers"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"115224","DOI":"10.1016\/j.compstruct.2022.115224","article-title":"Enhancing hygrothermal mechanical properties stability of polymer composite based on the concrete structure","volume":"285","author":"Yin","year":"2022","journal-title":"Compos. Struct."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"539","DOI":"10.1007\/s10338-021-00234-y","article-title":"Experimental Study of Hygrothermal and Ultraviolet Aging on the Flexural Performance of Epoxy Polymer Mortar","volume":"34","author":"Li","year":"2021","journal-title":"Acta Mech. Solida Sin."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"04014058","DOI":"10.1061\/(ASCE)CC.1943-5614.0000517","article-title":"Prediction of Long-Term Performance and Durability of BFRP Bars under the Combined Effect of Sustained Load and Corrosive Solutions","volume":"19","author":"Wu","year":"2015","journal-title":"J. Compos. Constr."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"4960","DOI":"10.1016\/j.matdes.2010.04.037","article-title":"Degradation of compressive properties of pultruded kenaf fiber reinforced composites after immersion in various solutions","volume":"31","author":"Nosbi","year":"2010","journal-title":"Mater. Des."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"798","DOI":"10.1016\/j.conbuildmat.2013.03.081","article-title":"Flexural, shear and bond strength of polymer concrete utilizing recycled resin obtained from post consumer PET bottles","volume":"44","author":"Mahdi","year":"2013","journal-title":"Constr. Build. Mater."},{"key":"ref_30","unstructured":"Crank, J. (1975). The Mathematics of Diffusion, Clarendon Press."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"810","DOI":"10.1016\/j.polymertesting.2012.06.001","article-title":"Effect of water absorption on the mechanical properties of n-SiC filled recycled cellulose fibre reinforced epoxy eco-nanocomposites","volume":"31","author":"Alamri","year":"2012","journal-title":"Polym. Test."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"382","DOI":"10.1016\/j.cja.2022.11.022","article-title":"Effect of hygrothermal aging on moisture diffusion and tensile behavior of CFRP composite laminates","volume":"36","author":"Du","year":"2022","journal-title":"Chin. J. Aeronaut."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"2","DOI":"10.1177\/002199837601000101","article-title":"Moisture Absorption and Desorption of Composite-Materials","volume":"10","author":"Shen","year":"1976","journal-title":"J. Compos. Mater."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"123766","DOI":"10.1016\/j.conbuildmat.2021.123766","article-title":"Micro-structure characteristics of unsaturated polyester resin modified concrete under fatigue loads and hygrothermal environment","volume":"296","author":"Zhang","year":"2021","journal-title":"Constr. Build. Mater."},{"key":"ref_35","first-page":"e06257","article-title":"Long-term moisture-induced strength degradation of unsaturated polyester polymer concrete manholes: Laboratory acceleration, predictive modeling, and field validation","volume":"25","author":"Kasahara","year":"2026","journal-title":"Case Stud. Constr. Mater."},{"key":"ref_36","first-page":"1359","article-title":"Mechanical properties and water diffusion in polyester polymer concrete","volume":"121","author":"Mebarkia","year":"1995","journal-title":"J. Eng. Mech."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"683","DOI":"10.2472\/jsms.26.683","article-title":"Degradation of polyester resin mortar in boiling water","volume":"26","author":"Tamura","year":"1976","journal-title":"J. Soc. Mater. Sci. Jpn."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"161","DOI":"10.3323\/jcorr.69.161","article-title":"Strength reduction mechanism and strength estimation of unsaturated polyester resin concrete deteriorated in outdoor soil","volume":"69","author":"Miwa","year":"2020","journal-title":"Zairyo-to-Kankyo"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"546","DOI":"10.1016\/j.conbuildmat.2005.09.003","article-title":"Comparative assessment of isophtalic and orthophtalic polyester polymer concrete: Different costs, similar mechanical properties and durability","volume":"21","author":"Gorninski","year":"2007","journal-title":"Constr. Build. Mater."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"279","DOI":"10.1061\/(ASCE)1090-0268(2006)10:4(279)","article-title":"Durability prediction for GFRP reinforcing bars using short-term data of accelerated aging tests","volume":"10","author":"Chen","year":"2006","journal-title":"J. Compos. Constr."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"455","DOI":"10.1016\/0008-8846(81)90117-4","article-title":"The Use of Accelerated Aging Procedures to Predict the Long-Term Strength of GRC Composites","volume":"11","author":"Litherland","year":"1981","journal-title":"Cem. Concr. Res."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"04020170","DOI":"10.1061\/(ASCE)MT.1943-5533.0003243","article-title":"Comparative Investigation on Tensile Performance of FRP Bars after Exposure to Water, Seawater, and Alkaline Solutions","volume":"32","author":"Lu","year":"2020","journal-title":"J. Mater. Civ. Eng."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"191","DOI":"10.1061\/(ASCE)0899-1561(2002)14:3(191)","article-title":"Use of fiber reinforced polymer composites as reinforcing material for concrete","volume":"14","author":"Uomoto","year":"2002","journal-title":"J. Mater. Civ. Eng."}],"container-title":["Polymers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4360\/18\/17\/2112\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T04:40:46Z","timestamp":1788324046000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4360\/18\/17\/2112"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,31]]},"references-count":43,"journal-issue":{"issue":"17","published-online":{"date-parts":[[2026,9]]}},"alternative-id":["polym18172112"],"URL":"https:\/\/doi.org\/10.3390\/polym18172112","relation":{},"ISSN":["2073-4360"],"issn-type":[{"value":"2073-4360","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,31]]}}}