Abstract: Low-heat Portland (LHP) cement is a new type of Portland cement that has been widely used in recent years due to its low heat of hydration, which makes it exceptional in temperature control for mass concrete construction. However, limited studies have investigated the impact of temperature and magnesium oxide (MgO) content on LHP cement-based materials. This study utilizes thermodynamic simulations to study the hydration process, pore structure, and autogenous shrinkage of LHP cement pastes with different water-to-cement ratios (0.3, 0.4, and 0.5), curing temperatures (5, 15, 20, and 30 °C), and MgO contents (mass fractions of 2%, 4%, and 5%). Higher curing temperature is found to promote the hydration reactions in cement paste. Moreover, the incorporation of 4% MgO moderately decreases both porosity and dimensional shrinkage in pastes. The microstructural evolution of different LHP pastes is examined through a comparative analysis, lending insights into LHP cement-based material applications.

低热硅酸盐水泥水化反应及外加氧化镁产生补偿效应的热力学模拟

[1]Abdel-GawwadHA, Abo El-EneinSA, HeikalM, et al., 2018. Synergistic effects of curing conditions and magnesium oxide addition on the physico-mechanical properties and firing resistivity of Portland cement mortar. Construction and Building Materials, 176:676-689.

[2]BentzDP, 2006. Influence of water-to-cement ratio on hydration kinetics: simple models based on spatial considerations. Cement and Concrete Research, 36(2):238-244.

[3]BentzDP, JensenOM, 2004. Mitigation strategies for autogenous shrinkage cracking. Cement and Concrete Composites, 26(6):677-685.

[4]BernardE, NguyenH, KawashimaS, et al., 2023. MgO-based cements‍–‍current status and opportunities. RILEM Technical Letters, 8:65-78.

[5]BrouwersHJH, de KorteACJ, 2016. Multi-cycle and multi-scale cellular automata for hydration simulation (of Portland-cement). Computational Materials Science, 111:116-124.

[6]BullardJW, JenningsHM, LivingstonRA, et al., 2011. Mechanisms of cement hydration. Cement and Concrete Research, 41(12):1208-1223.

[7]ChenT, WangZH, BaiEL, et al., 2023. Effect of nano admixtures on the engineering properties and microstructure of sulphoaluminate cement mortar at -‍10°C. Construction and Building Materials, 402:133015.

[8]ChenX, YangHQ, LiWW, 2016. Factors analysis on autogenous volume deformation of MgO concrete and early thermal cracking evaluation. Construction and Building Materials, 118:276-285.

[9]CuestaA, AyuelaA, ArandaMAG, 2021. Belite cements and their activation. Cement and Concrete Research, 140:106319.

[10]DengM, CuiXH, LiuYZ, et al., 1990. Expansive mechanism of magnesia as an additive of cement. Journal of Nanjing Institute of Chemical Technology, 12(4):1-11 (in Chinese).

[11]FangK, FallM, 2018. Effects of curing temperature on shear behaviour of cemented paste backfill-rock interface. International Journal of Rock Mechanics and Mining Sciences, 112:184-192.

[12]GongJW, JiangCM, TangXJ, et al., 2020. Optimization of mixture proportions in ternary low-heat Portland cement-based cementitious systems with mortar blends based on projection pursuit regression. Construction and Building Materials, 238:117666.

[13]HilpertM, MillerCT, 2001. Pore-morphology-based simulation of drainage in totally wetting porous media. Advances in Water Resources, 24(3-4):243-255.

[14]HuangKJ, ShiXJ, ZollingerD, et al., 2019. Use of MgO expansion agent to compensate concrete shrinkage in jointed reinforced concrete pavement under high-altitude environmental conditions. Construction and Building Materials, 202:528-536.

[15]JawedI, GotoS, KondoR, 1976. Hydration of tetracalcium aluminoferrite in presence of lime and sulfates. Cement and Concrete Research, 6(4):441-453.

[16]KarpovIK, ChudnenkoKV, KulikDA, 1997. Modeling chemical mass transfer in geochemical processes; thermodynamic relations, conditions of equilibria and numerical algorithms. American Journal of Science, 297(8):767-806.

[17]KarpovIK, ChudnenkoKV, BychinskiiVA, et al., 2001. Minimization of Gibbs free energy in geochemical systems by convex programming. Geochemistry International, 39(11):1108-1119.

[18]KjellsenKO, DetwilerRJ, 1992. Reaction kinetics of Portland cement mortars hydrated at different temperatures. Cement and Concrete Research, 22(1):112-120.

[19]KjellsenKO, DetwilerRJ, 1993. Later-age strength prediction by a modified maturity model. ACI Materials Journal, 90(3):220-227.

[20]KotsayG, JaskulskiR, 2019. Belite cement as an ecological alternative to Portland cement—a review. Materials Structures Technology, 2(1):70-76.

[21]KulikDA, WagnerT, DmytrievaSV, et al., 2013. GEM-Selektor geochemical modeling package: revised algorithm and GEMS3K numerical kernel for coupled simulation codes. Computational Geosciences, 17(1):1-24.

[22]KuriharaR, MaruyamaI, 2022. Revisiting Tennis-Jennings method to quantify low-density/high-density calcium silicate hydrates in Portland cement pastes. Cement and Concrete Research, 156:106786.

[23]LiZH, ZhangW, WangRL, et al., 2019. Effects of reactive MgO on the reaction process of geopolymer. Materials, 12(3):526.

[24]LothenbachB, KulikDA, MatscheiT, et al., 2019. Cemdata18: a chemical thermodynamic database for hydrated Portland cements and alkali-activated materials. Cement and Concrete Research, 115:472-506.

[25]MaHY, LiZJ, 2013. Realistic pore structure of Portland cement paste: experimental study and numerical simulation. Computers and Concrete, 11(4):317-336.

[26]MoLW, DengM, TangMS, 2010. Effects of calcination condition on expansion property of MgO-type expansive agent used in cement-based materials. Cement and Concrete Research, 40(3):437-446.

[27]MoLW, DengM, WangA, 2012. Effects of MgO-based expansive additive on compensating the shrinkage of cement paste under non-wet curing conditions. Cement and Concrete Composites, 34(3):377-383.

[28]MoLW, DengM, TangMS, et al., 2014. MgO expansive cement and concrete in China: past, present and future. Cement and Concrete Research, 57:1-12.

[29]MoLW, LiuM, Al-TabbaaA, et al., 2015. Deformation and mechanical properties of the expansive cements produced by inter-grinding cement clinker and MgOs with various reactivities. Construction and Building Materials, 80:1-8.

[30]MoLW, FangJW, HouWH, et al., 2019. Synergetic effects of curing temperature and hydration reactivity of MgO expansive agents on their hydration and expansion behaviours in cement pastes. Construction and Building Materials, 207:206-217.

[31]NobreJ, AhmedH, BravoM, et al., 2020. Magnesia (MgO) production and characterization, and its influence on the performance of cementitious materials: a review. Materials, 13(21):4752.

[32]ParkS, MaJ, YunTS, et al., 2020. Pore-scale swelling mechanism of magnesium oxide granules during hydration. Construction and Building Materials, 251:119101.

[33]PengHY, LinP, XiangYF, et al., 2022. Effects of carbon thin film on low-heat cement hydration, temperature and strength of the Wudongde dam concrete. Buildings, 12(6):717.

[34]Pérez-BravoR, Morales-CanteroA, BruscoliniM, et al., 2021. Effect of boron and water-to-cement ratio on the performances of laboratory prepared Belite-Ye’elimite-ferrite (BYF) cements. Materials, 14(17):4862.

[35]QianZ, SchlangenE, YeG, et al., 2010. Predicción de las propiedades mecánicas del cemento en la micro-escala. Materiales de Construcción, 60(297):7-18 (in Spanish).

[36]RijfkogelLS, GhanbarianB, HuQH, et al., 2019. Clarifying pore diameter, pore width, and their relationship through pressure measurements: a critical study. Marine and Petroleum Geology, 107:142-148.

[37]ShiJY, LiuBJ, HeZH, et al., 2020. Properties evolution of high-early-strength cement paste and interfacial transition zone during steam curing process. Construction and Building Materials, 252:119095.

[38]ShiraniS, CuestaA, Morales-CanteroA, et al., 2021. Influence of curing temperature on belite cement hydration: a comparative study with Portland cement. Cement and Concrete Research, 147:106499.

[39]SinyoungS, KunchariyakunK, AsavapisitS, et al., 2017. Synthesis of belite cement from nano-silica extracted from two rice husk ashes. Journal of Environmental Management, 190:53-60.

[40]SongSB, DingQL, WeiJN, 2019. Improved algorithm for estimating pore size distribution from pore space images of porous media. Physical Review E, 100(5):053314.

[41]VahedifardF, NiliM, MeehanCL, 2010. Assessing the effects of supplementary cementitious materials on the performance of low-cement roller compacted concrete pavement. Construction and Building Materials, 24(12):2528-2535.

[42]van DammeH, 2018. Concrete material science: past, present, and future innovations. Cement and Concrete Research, 112:5-24.

[43]WagnerT, KulikDA, HingerlFF, et al., 2012. GEM-Selektor geochemical modeling package: TSolMod library and data interface for multicomponent phase models. The Canadian Mineralogist, 50(5):1173-1195.

[44]WallingSA, ProvisJL, 2016. Magnesia-based cements: a journey of 150 years, and cements for the future? Chemical Reviews, 116(7):4170-4204.

[45]WangQH, LiuRX, LiuPY, et al., 2022. Effects of silica fume on the abrasion resistance of low-heat Portland cement concrete. Construction and Building Materials, 329:127165.

[46]XieJ, WuZM, ZhangXH, et al., 2023. Trends and developments in low-heat Portland cement and concrete: a review. Construction and Building Materials, 392:131535.

[47]YangHQ, WangYC, ZhouSH, 2007. Anti-crack performance of low-heat Portland cement concrete. Journal of Wuhan University of Technology (Materials Science Edition), 22(3):555-559.

[48]YangY, YaoJK, LiuJT, et al., 2024. Evaluation of the thermal and shrinkage stresses in restrained concrete: new method of investigation. Construction and Building Materials, 411:134493.

[49]YiST, MoonYH, KimJK, 2005. Long-term strength prediction of concrete with curing temperature. Cement and Concrete Research, 35(10):1961-1969.

[50]ZhangJ, 2022. Recent advance of MgO expansive agent in cement and concrete. Journal of Building Engineering, 45:103633.

[51]ZhangMZ, YeG, van BreugelK, 2010. A numerical-statistical approach to determining the representative elementary volume (REV) of cement paste for measuring diffusivity. Materiales de Construcción, 60(300):7-20.

[52]ZhongWL, FanLF, ZhangYH, 2022a. Experimental research on the dynamic compressive properties of lightweight slag based geopolymer. Ceramics International, 48(14):20426-20437.

[53]ZhongWL, ZhangYH, FanLF, et al., 2022b. Effect of PDMS content on waterproofing and mechanical properties of geopolymer composites. Ceramics International, 48(18):26248-26257.

[54]ZhongWL, ZhangYH, FanLF, 2023a. High-ductile engineered geopolymer composites (EGC) prepared by calcined natural clay. Journal of Building Engineering, 63:105456.

[55]ZhongWL, QiuB, ZhangYH, et al., 2023b. Mesoscopic damage characteristics of hydrophobicity-modified geopolymer composites under freezing-thawing cycles based on CT scanning. Composite Structures, 326:117637.

[56]ZhongWL, SunYH, ZhaoX, et al., 2024. Study on synthesis and water stability of geopolymer pavement base material using waste sludge. Journal of Cleaner Production, 445:141331.

[57]ZhouSB, ShenAQ, LiangXY, et al., 2014. Effect of water to cement ratio on autogenous shrinkage of pavement cement concrete and its mechanism analysis. Journal of Highway and Transportation Research and Development, 8(1):7-12.

[58]ZhouYF, LiWW, PengYX, et al., 2023. Hydration and fractal analysis on low-heat Portland cement pastes using thermodynamics-based methods. Fractal and Fractional, 7(8):606.