摘   要：为防止液化天然气（Liquefied natural gas，LNG）储罐混凝土开裂失效，保障混凝土结构的安全性与耐久性能，对超低温作用下预应力混凝土的变形性能进行研究十分有必要。本文研究了超低温（-160 ℃）作用下不同初始预压应力（0.2、0.3、0.4、0.5、0.6、0.7）对不同含水率（正常、较高）预应力混凝土变形性能的影响。结果表明：超低温作用下，随着初始预压应力的提高，混凝土温降点和温均点时的预压应变差率均基本降低，而其降温阶段和恒温阶段的瞬态预压应变变化率基本呈先增后减的趋势；超低温作用下混凝土的变形性能与含水率密切相关，当初始预压应力不同时，含水率的影响程度也存在明显差异。研究成果可为LNG储罐结构设计及使用性能评判提供参考。Abstract: To prevent cracking and failure of concrete in liquefied natural gas (LNG) storage tanks and ensure the safety and durability of concrete structures, it is essential to investigate the deformation performance of prestressed concrete under ultra-low temperature conditions. In this paper, the effects of different initial precompressive stress (0.2, 0.3, 0.4, 0.5, 0.6, 0.7) on the deformation performance of prestressed concrete with different moisture contents (normal, high) at an ultra-low temperature of -160 ℃ were studied. The results show that under ultra-low temperature, with the increase of the initial precompressive stress, the difference rate of precompressive strain at both the cooling target point and the uniform temperature target point of concrete basically decreases, while the transient precompressive strain change rate during the cooling stage and the constant temperature stage generally increases first and then decreases. The deformation performance of concrete under ultra-low temperature is closely related to its moisture content, and the influence of moisture content varies significantly under different initial precompressive stresses. The findings can provide a reference for the structural design and service performance evaluation of LNG storage tanks.

时旭东,田在旭,韩源海.初始预压应力对不同含水率混凝土超低温预压变形性能的影响试验研究[J].混凝土与水泥制品,2026,53(9):1-5,12. Shi Xudong,Tian Zaixu,Han Yuanhai,et al.Experimental study on the effect of initial precompression stress on ultra-low temperature precompression deformation properties of concrete with different moisture contents[J].China Concrete and Cement Products,2026,53(9):1-5,12 (in Chinese).

摘   要：在水泥水化进程中，硅酸三钙（C3S）的水化行为对水泥基材料性能的发展至关重要，但其表面缺陷对水化过程的影响机理尚不明确。鉴于此，本文基于第一性原理研究了C3S表面点缺陷对其与水分子的相互作用及水化过程的影响。结果表明：C3S表面钙缺陷降低了局部结构密度，增强了水分子在缺陷位点的吸附能，并促进了水分子的解离、吸附；钙缺陷导致表面电荷分布不均，增强了吸附过程中的电荷转移；缺陷位点的轨道杂化程度提高，进一步调控了吸附过程中的键合性质；由于钙缺陷的形成，水分子与C3S表面的氢键相互作用增强，有助于加快水泥的初期水化反应，提高水泥基材料的早期强度和耐久性能。研究成果为理解C3S微观缺陷对宏观性能的影响提供理论依据，并为通过调控点缺陷优化水泥基材料的性能提供参考。Abstract: During the cement hydration process, the hydration behavior of tricalcium silicate (C3S) is critical to the property evolution of cement-based materials. Nevertheless, the mechanism underlying the effects of its surface defects on the hydration process remains unclear. In view of this, the first-principles calculations were performed in this work to investigate the influence of point defects on the C3S surface on its interaction with water molecules and the hydration process. The results show that calcium defects on the C3S surface reduce the local structural density, increase the adsorption energy of water molecules at defect sites, and promote the dissociation and adsorption of water molecules. Calcium defects lead to inhomogeneous surface charge distribution and enhance charge transfer during adsorption. The degree of orbital hybridization at defect sites is elevated, which further modulates the bonding characteristics during adsorption. Owing to the formation of calcium defects, the hydrogen-bond interaction between water molecules and the C3S surface is strengthened, which helps accelerate the early hydration of cement and improve the early strength and durability of cement-based materials. The findings provide a theoretical basis for understanding the influence of microscopic defects in C3S on macroscopic properties and offer a reference for optimizing the performance of cement-based materials by regulating point defects.

李中娟,张悦.基于第一性原理的钙空位缺陷对M3-C3S表面水化调控机理研究[J].混凝土与水泥制品,2026,53(9):6-12. Li Zhongjuan,Zhang Yue.Study on the regulation mechanism of calcium vacancy defects on M3-C3S surface hydration based on the first-principles calculations[J].China Concrete and Cement Products,2026,53(9):6-12 (in Chinese).

王盛年,谷雷雷,李晓鹏,等.水灰比和增黏早强剂掺量对喷射混凝土工作性的影响[J].混凝土与水泥制品,2026,53(9):13-17,26. Wang Shengnian,Gu Leilei,Li Xiaopeng,et al.Influence of water-cement ratio and dosage of viscosity-increasing early strength agent on the workability of shotcrete[J].China Concrete and Cement Products,2026,53(9):13-17,26 (in Chinese).

摘   要：硫铝酸盐水泥基材料因早强、快硬等性质常用于修补加固工程，但其延性差、易开裂、缺乏压敏性能等不足限制其智能化服役。碳纳米管因其卓越的力学、电学特性具备改善硫铝酸盐水泥基材料压敏性能的潜力。因此，本文研究了不同加载工况下多壁碳纳米管（MWCNTs）对硫铝酸盐水泥基材料力学、电学、压敏性能的影响，并采用SEM分析了MWCNTs的作用机理。结果表明：掺入0.6%的MWCNTs能提高试件的3 d力学性能，降低电阻率，提高导电性能；试件的压敏性能受MWCNTs掺量、加载方式、极限载荷的影响，其中，MWCNTs掺量的影响程度最大，抗压破坏载荷对压敏性能的影响程度大于劈裂抗拉破坏载荷；当MWCNTs掺量为0.6%、加载速率为0.4 mm/min、加载幅值为6 MPa时，MWCNTs通过桥连、填充作用抑制试件中裂缝的产生和发展，通过增加应力传递路径提升承载力，改善力学性能；MWCNTs互相搭接形成导电网络增加了MWCNTs接触导电和隧道导电的发生概率，改善了试件的电学性能和压敏性能。研究成果可为智能修补加固材料的研发及应用提供参考。Abstract: Sulphoaluminate cementitious materials are widely applied in repair and reinforcement engineering owing to their properties of early strength and rapid hardening. Nevertheless, their drawbacks including poor ductility, proneness to cracking and absence of pressure-sensing capability restrict their intelligent service performance. With outstanding mechanical and electrical properties, carbon nanotubes possess the potential to improve the pressure-sensitive performance of sulphoaluminate cementitious materials. Therefore, this paper investigated the effects of multi-walled carbon nanotubes (MWCNTs) on the mechanical, electrical and pressure-sensitive performance of sulphoaluminate cementitious materials under different loading conditions, and analyzed the modification mechanism of MWCNTs via SEM. The results show that adding 0.6% MWCNTs can improve the 3-day mechanical properties of specimens, reduce electrical resistivity and enhance electrical conductivity. The pressure-sensitive performance of specimens is affected by MWCNTs content, loading mode and ultimate load, among which MWCNTs content exerts the most significant influence. Compressive failure load has a greater impact on pressure-sensitive performance than splitting tensile failure load. With an MWCNT dosage of 0.6%, a loading rate of 0.4 mm/min and a loading amplitude of 6 MPa, crack generation and expansion within the specimens are suppressed by MWCNTs through bridging and filling mechanisms, while MWCNTs increase stress-transfer paths, thereby improving bearing capacity and mechanical properties. Meanwhile, MWCNTs overlap with each other to form a conductive network, which increases the probability of contact conduction and tunneling conduction, and improves the electrical and pressure-sensitive properties of specimens.The research findings can provide a reference for the research, development and engineering application of intelligent repair and reinforcement materials.

马硕,刘帅,夏雨,等.不同加载工况下多壁碳纳米管改性硫铝酸盐水泥基材料的压敏性能研究[J].2026,53(9):18-26. Ma Shuo,Liu Shuai,Xia Yu,et al.Research on the pressure-sensitive performance of sulphoaluminate cementitious materials modified by multi-walled carbon nanotubes under different loading conditions[J].China Concrete and Cement Products,2026,53(9):18-26 (in Chinese).

摘   要：为了研究泡沫混凝土在真三轴压缩状态下的力学特性，开展了泡沫混凝土试件在不同围压组合下的真三轴压缩强度试验，通过5种典型混凝土强度准则（过-王强度准则、Willam-Warnke五参数破坏准则、Drucker-Prager破坏准则、双剪统一强度准则、Mogi-Coulomb准则），采用均方根误差、平均绝对误差、平均绝对百分比误差评价各强度准则对试件真三轴压缩强度预测的适用性。结果表明：小主应力和中主应力均对试件的真三轴压缩强度存在强化效应，其中，小主应力的影响更显著；Willam-Warnke五参数破坏准则对试件真三轴压缩强度预测表现出更好的适用性，Mogi-Coulomb准则形式简洁且精度较高，过-王强度准则在高围压条件下具有优势。Abstract: In order to study the mechanical properties of foamed concrete under true triaxial compressive, the true triaxial compression strength tests of foamed concrete specimens under different confining pressure combinations were carried out. Through 5 typical concrete strength criteria (Guo-Wang strength criterion, Willam-Warnke five-parameter failure criterion, Drucker-Prager criterion, double shear unified strength criterion, Mogi-Coulomb criterion), the applicability of each strength criterion for the prediction of true triaxial compressive strength of specimens was evaluated by using root mean square error, average absolute error, and average absolute percentage error. The results indicate that both minor principal stress and intermediate principal stress have a strengthening effect on the true triaxial compressive strength of the specimen, with the influence of minor principal stress being more significant. The Willam-Warnke five-parameter failure criterion shows better applicability in predicting the true triaxial compressive strength of specimens, while the Mogi-Coulomb criterion is concise in form and highly accurate, and the Guo-Wang strength criterion has advantages under high confining pressure conditions.

文开艳,焦治霖,梁震,等.泡沫混凝土的真三轴压缩强度准则研究[J].混凝土与水泥制品,2026,53(9):27-33. Wen Kaiyan,Jiao Zhilin,Liang Zhen,et al.Research on true triaxial compressive strength criterion of foamed concrete[J].China Concrete and Cement Products,2026,53(9):27-33 (in Chinese).

摘   要：针对严寒地区大坝混凝土在冻融循环与疲劳荷载耦合作用下的性能劣化问题，本文通过冻融循环试验与四点弯拉疲劳试验，结合Weibull分布与可靠性理论，系统研究了冻融损伤对混凝土疲劳寿命的影响规律，得到了不同冻融循环次数（0~250次）和不同应力水平（0.75、0.80、0.85）下的性能指标值，并进行了可靠度分析。结果表明：随着冻融循环次数的增加，混凝土的质量损失率增大，相对动弹性模量与静态弯拉强度显著降低；冻融损伤混凝土的疲劳寿命服从两参数Weibull分布，其形状参数和标度参数均随着冻融循环次数的增加而下降，表明混凝土的疲劳寿命离散性增大，冻融损伤会加速寿命衰减；基于可靠度理论建立的冻融损伤混凝土的可靠性概率、应力水平与设计疲劳寿命关系图，量化了安全系数与冻融循环次数的关系；冻融循环250次后，可靠性概率为95%对应的安全系数需提高至3.7~3.8。研究成果弥补了传统模型的局限性，可为寒区大坝混凝土结构的抗疲劳设计提供基于概率统计的理论依据。Abstract: Aiming at the performance degradation of dam concrete in severe cold regions under the coupled action of freeze-thaw cycles and fatigue loading, this study systematically investigates the influence of freeze-thaw damage on the fatigue life of concrete through freeze-thaw cycle tests and four-point bending fatigue tests, combined with the Weibull distribution and reliability theory. Performance indicators are obtained under different freeze-thaw cycles (0~250 cycles) and different stress levels (0.75, 0.80, 0.85), and reliability analysis is conducted. The results show that with the increase of freeze-thaw cycles, the mass loss rate of concrete increases, while the relative dynamic elastic modulus and static flexural-tensile strength decrease significantly. The fatigue life of freeze-thaw damaged concrete follows a two-parameter Weibull distribution, and both its shape parameter and scale parameter decrease with the increase of freeze-thaw cycles, indicating greater dispersion in fatigue life and that freeze-thaw damage accelerates life degradation. Based on reliability theory, the relationship diagram among reliability probability, stress level, and design fatigue life of freeze-thaw damaged concrete is established, which quantifies the relationship between safety factor and freeze-thaw cycles. After 250 freeze-thaw cycles, the safety factor corresponding to a reliability probability of 95% needs to be increased to 3.7~3.8. The findings compensate for the limitations of traditional models, and provide a probability-statistics-based theoretical basis for the anti-fatigue design of dam concrete structures in cold regions.

胡义文,徐凌一,丁玲.冻融损伤下大坝混凝土的疲劳寿命预测与可靠度分析[J].混凝土与水泥制品,2026,53(9):34-39. Hu Yiwen,Xu Lingyi,Ding Ling.Fatigue life prediction and reliability analysis of dam concrete under freeze-thaw damage[J].China Concrete and Cement Products,2026,53(9):34-39 (in Chinese).