基于低场核磁共振的硫铝酸盐水泥砂浆孔结构演变研究

摘要/Abstract

摘要： 本文研究了不同水灰比(W/C)硫铝酸盐水泥(SAC)砂浆力学性能与毛细吸水性能随龄期的演化规律,基于低场核磁共振(LF-NMR)技术表征了SAC砂浆特定龄期孔结构与硬化过程中的动态孔结构,结合压汞法、吸水数据和理论模型讨论了LF-NMR测试中SAC砂浆表面弛豫速率的取值。结果表明,经0.5 d标准养护后,0.45、0.50和0.55水灰比SAC砂浆的抗压强度和抗折强度分别为23.5、20.8、16.2和4.2、3.9、3.6 MPa,基本可达28 d龄期的60%以上。0.5 d龄期时,不同水灰比SAC砂浆的毛细吸水系数为0.020~0.042 g·cm^-2·min^-0.5。3 d龄期时,毛细吸水系数下降了18.5%~25.0%,此后至28 d龄期时变化较小。加水拌和后的0.5 d内,SAC砂浆孔结构快速演化,孔隙率和孔径分布在0.5~3 d龄期间逐渐稳定。利用毛细吸水系数等数据和理论模型估算的代表性毛细管直径与基于LF-NMR T₂谱测定的SAC砂浆孔隙直径间存在密切关联,当快交换模型中表面弛豫速率取值范围为0.005 5~0.042 0 μm/ms时,二者较为接近。

关键词: 硫铝酸盐水泥, 低场核磁共振, 力学性能, 毛细吸水系数, 孔结构, 压汞法

Abstract: In this paper, the evolution of mechanical properties and capillary water absorption properties of sulfoaluminate cement (SAC) mortar with different water-cement ratios (W/C) with age was investigated. The pore structure of SAC mortar at specific age and dynamic pore structure during the hardening process were characterized based on low field nuclear magnetic resonance (LF-NMR), combined with mercury intrusion method, water absorption data and theoretical model, the value of the surface relaxation rate of SAC mortar was discussed. The results show that after 0.5 d of standard curing, the compressive strength and flexural strength of SAC mortar with W/C of 0.45, 0.50 and 0.55 are 23.5, 20.8, 16.2 and 4.2, 3.9, 3.6 MPa, respectively, which can basically reach more than 60% of those at 28 d age. At the age of 0.5 d, the capillary water absorption coefficients of SAC mortars with different W/C are 0.020~0.042 g·cm^-2·min^-0.5. At age of 3 d, the capillary water absorption coefficients decrease by 18.5%~25.0%. Thereafter, it changed little until age of 28 d. Within 0.5 d after adding water and mixing, the pore structure of SAC mortar evolves rapidly, and the porosity and pore size distribution gradually stabilize during 0.5~3 d age. The representative capillary tube diameters deduced from data such as capillary water absorption coefficients and theoretical models are closely related to the pore diameters of SAC mortar based on LF-NMR T₂ spectra. When the values of the surface relaxation rate in the fast exchange model are in the range of 0.005 5~0.042 0 μm/ms, the two are relatively close.

Key words: sulfoaluminate cement, low field nuclear magnetic resonance, mechanical property, capillary water absorption coefficient, pore structure, mercury intrusion porosimetry

中图分类号:

TU528

王丹, 薛善彬, 白如飞, 郭哲名. 基于低场核磁共振的硫铝酸盐水泥砂浆孔结构演变研究[J]. 硅酸盐通报, 2025, 44(3): 852-861.

WANG Dan, XUE Shanbin, BAI Rufei, GUO Zheming. Pore Structure Evolution of Sulfoaluminate Cement Mortar Based on Low Field Nuclear Magnetic Resonance[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2025, 44(3): 852-861.

参考文献

[1] 王培铭, 李楠, 徐玲琳, 等. 低温养护下硫铝酸盐水泥的水化进程及强度发展[J].硅酸盐学报, 2017, 45(2): 242-248.
WANG P M, LI N, XU L L, et al. Hydration characteristics and strength development of sulphoaluminate cement cured at low temperature[J].Journal of the Chinese Ceramic Society, 2017, 45(2): 242-248 (in Chinese).
[2] 齐秋霖, 周健, 葛仲熙, 等. 硫铝酸盐水泥抗酸侵蚀性能与机理研究[J].硅酸盐通报, 2021, 40(8): 2508-2514+2533.
QI Q L, ZHOU J, GE Z X, et al. Performance and resistance mechanism of calcium sulfoaluminate cement subjected to acids[J].Bulletin of the Chinese Ceramic Society, 2021, 40(8): 2508-2514+2533 (in Chinese).
[3] CHEN H, GUO Z H, HOU P K, et al. The influence of surface treatment on the transport properties of hardened calcium sulfoaluminate cement-based materials[J].Cement and Concrete Composites, 2020, 114: 103784.
[4] 何香香, 梅军鹏, 姜天华, 等. EVA对硫铝酸盐水泥净浆微观结构和力学性能的影响[J].硅酸盐通报, 2022, 41(8): 2628-2636.
HE X X, MEI J P, JIANG T H, et al. Effect of EVA on microstructure and mechanical properties of calcium sulfoaluminate cement paste[J].Bulletin of the Chinese Ceramic Society, 2022, 41(8): 2628-2636 (in Chinese).
[5] 邢秉元, 程鹏宇, 唐继朋, 等. 冻融循环作用下饱水砂浆孔结构的演变规律[J].硅酸盐学报, 2021, 49(2): 331-339.
XING B Y, CHENG P Y, TANG J P, et al. Pore structure evolution of water-saturated mortar under freeze-thaw cycles[J].Journal of the Chinese Ceramic Society, 2021, 49(2): 331-339 (in Chinese).
[6] 薛维培, 刘晓媛, 姚直书, 等. 不同损伤源对玄武岩纤维增强混凝土孔隙结构变化特征的影响[J].复合材料学报, 2020, 37(9): 2285-2293.
XUE W P, LIU X Y, YAO Z S, et al. Effects of different damage sources on pore structure change characteristics of basalt fiber reinforced concrete[J].Acta Materiae Compositae Sinica, 2020, 37(9): 2285-2293 (in Chinese).
[7] JI Y L, PEL L, SUN Z P. The microstructure development during bleeding of cement paste: an NMR study[J].Cement and Concrete Research, 2019, 125: 105866.
[8] MCDONALD P J, ISTOK O, JANOTA M, et al. Sorption, anomalous water transport and dynamic porosity in cement paste: a spatially localised ¹H NMR relaxation study and a proposed mechanism[J].Cement and Concrete Research, 2020, 133: 106045.
[9] QU Z Y, YAN Y, PEL L, et al. Quantifying early age hydration and micro-structure evolution of fast setting binder using ¹H NMR[J].Cement and Concrete Research, 2023, 174: 107343.
[10] SHE A M, LI G, TAN L Z, et al. Comprehensive analysis of early-stage hydration and microstructure evolution in sufflaminate cement: insights from low-field NMR and isothermal calorimetry[J].Journal of Building Engineering, 2023, 80: 108076.
[11] 薛善彬, 王丹, 马金元, 等. 内掺硅烷对硫铝酸盐水泥砂浆力学和吸水性能的影响[J/OL].复合材料学报, 1-12 (2024-10-30)[2024-11-26].https://doi.org/10.13801/j.cnki.fhclxb.20241030.001.
XUE S B, WANG D, MA J Y, et al. Effects of incorporated silane on mechanical and water absorption properties of sulphoaluminate cement mortar[J/OL].Acta Materiae Compositae Sinica, 1-12 (2024-10-30)[2024-11-26].https://doi.org/10.13801/j.cnki.fhclxb.20241030.001 (in Chinese).
[12] LOTHENBACH B, SCRIVENER K, SNELLINGS R. A practical guide to microstructural analysis of cementitious materials[M].Boca Raton: CRC Press, 2016.
[13] XUE S B, MENG F Q, ZHANG P, et al. Influence of water re-curing on microstructure of heat-damaged cement mortar characterized by low-field NMR and MIP[J].Construction and Building Materials, 2020, 262: 120532.
[14] 王茹, 周袁宇, 刘校荣, 等. 羟丙基甲基纤维素对硫铝酸盐水泥水化的影响[J].建筑材料学报, 2023, 26(5): 538-546.
WANG R, ZHOU Y Y, LIU X R, et al. Effect of hydroxypropyl methyl cellulose on hydration of calcium sulfoaluminate cement[J].Journal of Building Materials, 2023, 26(5): 538-546 (in Chinese).
[15] BLIGH M W, D'EURYDICE M N, LLOYD R R, et al. Investigation of early hydration dynamics and microstructural development in ordinary Portland cement using ¹H NMR relaxometry and isothermal calorimetry[J].Cement and Concrete Research, 2016, 83: 131-139.
[16] CAI J C, PERFECT E, CHENG C L, et al. Generalized modeling of spontaneous imbibition based on Hagen-Poiseuille flow in tortuous capillaries with variably shaped apertures[J].Langmuir, 2014, 30(18): 5142-5151.
[17] COMITI J, RENAUD M. A new model for determining mean structure parameters of fixed beds from pressure drop measurements: application to beds packed with parallelepipedal particles[J].Chemical Engineering Science, 1989, 44(7): 1539-1545.
[18] 蔡建超, 胡祥云. 多孔介质分形理论与应用[M].北京: 科学出版社, 2015.
CAI J C, HU X Y. Fractal theory in porous media and its applications[M].Beijing: Science Press, 2015: 106-109 (in Chinese).
[19] 杨振丽, 周春圣. 饱水水泥砂浆孔结构的低场磁共振测试分析[J].硅酸盐学报, 2022, 50(5): 1391-1400.
YANG Z L, ZHOU C S. Pore structure of water-saturated cement mortars by low-field nuclear magnetic resonance[J].Journal of the Chinese Ceramic Society, 2022, 50(5): 1391-1400 (in Chinese).
[20] NAGEL S M, STRANGFELD C, KRUSCHWITZ S. Application of ¹H proton NMR relaxometry to building materials-a review[J].Journal of Magnetic Resonance Open, 2021, 6: 100012.
[21] MA H Y. Mercury intrusion porosimetry in concrete technology: tips in measurement, pore structure parameter acquisition and application[J].Journal of Porous Materials, 2014, 21(2): 207-215.
[22] 周继凯, 潘杨, 陈徐东. 压汞法测定水泥基材料孔结构的研究进展[J].材料导报, 2013, 27(7): 72-75.
ZHOU J K, PAN Y, CHEN X D. Research advances in Mercury porosimetry study of pore structure in cement-based materials[J].Materials Review, 2013, 27(7): 72-75 (in Chinese).
[23] ZHOU C S, REN F Z, WANG Z D, et al. Why permeability to water is anomalously lower than that to many other fluids for cement-based material?[J].Cement and Concrete Research, 2017, 100: 373-384.
[24] REN F Z, ZHOU C S, ZENG Q, et al. Quantifying the anomalous water absorption behavior of cement mortar in view of its physical sensitivity to water[J].Cement and Concrete Research, 2021, 143: 106395.