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- 2019
硫酸盐侵蚀溶液pH值对硅酸盐水泥浆体C-(A)-S-H凝胶结构的影响
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Abstract:
C-（A）-S-H凝胶的结构不仅受水泥基材料自身组成的影响，更受其所处环境的影响。本文利用固体核磁共振（NMR）并结合去卷积技术，探究硫酸盐侵蚀溶液pH值对硅酸盐水泥浆体中C-（A）-S-H凝胶结构的影响。结果表明：硫酸盐侵蚀过程中，前期进入凝胶中的Al3+后期又会脱出，使凝胶中四配位铝（Al[4]）/Si比值降低。侵蚀溶液pH值的降低促进了凝胶中Al[4]的脱出，使Al[4]的峰位向负值移动；同时也促进了[SiO4]（[AlO4]）四面体间的聚合，使C-（A）-S-H凝胶平均分子链长（MCL）增加。此外，侵蚀溶液pH值的降低，促进了浆体的水化，但抑制了浆体中钙矾石（AFt）的生成。 C-(A)-S-H gels are not only affected by the composition of cement-based materials, but also affected by the environment. The effect of pH-values of Na2SO4 solution on the structure of C-(A)-S-H gels was studied by solid-state nuclear magnetic resonance (NMR) with deconvolution technique. The results show that the Al[4]/Si value of C-(A)-S-H gels decreases in sulfate attack process, due to Al3+ entering into gel early and coming out later. The decrease of the erosion solution pH value promotes the migration of Al[4] from C-S-H gels, which leads to the peak position of Al[4] shifting to a negative value. It is found that the average molecular chain length (MCL) of C-S-H gel increases due to the polymerization among[SiO4] ([AlO4]) tetrahedra. In addition, the degree of hydration of the pastes is improved with the decrease of the pH-value, which is not favorable to formation of AFt. 安徽建筑大学先进建筑材料安徽省重点实验室开放课题（JZCL201601ZZ）；国家自然科学基金（51578004；51778513；51608004）；国家重点研发计划"重点基础材料技术提升与产业化"重点专项课题（2017YFB0310001
| [1] | DING Q J, ZHANG G Z, HU C G. Effect of sulfate attack on C-S-H microstructure in hardened Portland cement pastes[C]. The 14th International Congress on the Chemistry of Cement. Beijing, 2015:427-435. |
| [2] | LI Y, PENG W, GUAN Z Z, et al. Micromechanical properties of individual phases in cement pastes under brine solution using nanoindentation and scanning electron microscopy[J]. Journal of Nano Research, 2017, 46:31-44. |
| [3] | 何真, 王磊, 邵一心, 等. 脱钙对水泥浆体中C-S-H凝胶结构的影响[J]. 建筑材料学报. 2011, 14(3):293-298. HE Z, WANG L, SHAO Y X, et al. Effect of decalcification on C-S-H gel microstructure in cement paste[J]. Journal of Building Materials, 2011, 14(3):293-298(in Chinese). |
| [4] | 胡晨光, 丁庆军, 胡曙光, 等. 变温下SO42-对水泥硬化浆体中Al3+配位分布的影响[J]. 功能材料, 2014(2):142-146. HU C G, DING Q J, HU S G, et al. Effect of sulfate ions on distribution of Al3+ coordination in hardened cement pastes at variable temperature[J]. Journal of Functional Materials, 2014(2):142-146(in Chinese). |
| [5] | 丁庆军, 刘凯, 张高展, 等. MgSO4侵蚀条件下水泥浆体相组成及Al相转变[J]. 武汉理工大学学报, 2016, 38(5):1-7. DING Q J, LIU K, ZHANG G Z, et al. the composition and Al-bearing phases transition of cement paste subjected to MgSO4 attack[J]. Journal of Wuhan University of Technology, 2016, 38(5):1-7(in Chinese). |
| [6] | RICHARDSON I G, BROUGH A R, BRYDSO-N R, et al. Location of aluminum in substituted calcium silicate hydrate (C-S-H) gels as determined by 29Si and 27Al NMR and EELS[J]. Journal of the American Ceramic Society, 1993, 76(9):2285-2288. |
| [7] | ANDERSEN M D, JAKOBSEN H J, SKIBSTED J. Incorporation of aluminum in the calcium silicate hydrate (C-S-H) of hydrated Portland cements:A high-field 27Al and 29Si MAS NMR investigation[J]. Inorganic Chemistry, 2003, 42(7):2280-2287. |
| [8] | ANDERSEN M D, JAKOBSEN H J, SKIBSTED J. Characterization of white Portland cement hydration and the C-S-H structure in the presence of sodium aluminate by 27Al and 29Si MAS NMR spectroscopy[J]. Cement & Concrete Research, 2004, 34(5):857-868. |
| [9] | MANZANO H, DOLADO J S, GRIEBEL M, et al. A molecular dynamics study of the aluminosilicate chain structure in Al-rich calcium silicate hydrated (C-S-H) gels[J]. Physica Status Solidi, 2008, 205(6):1324-1329. |
| [10] | MANZANO H, DOLADO J S, AYUELA A. Aluminum incorporation to dreierketten silicate chains[J]. Journal of Physical Chemistry B, 2009, 113(9):2832-2839. |
| [11] | 方永浩. 固体高分辨核磁共振在水泥化学研究中的应用[J]. 建筑材料学报, 2003, 6(1):54-60. FANG Y H. Principles of high resolution solid-state nuclear magnetic resonance and its application in research of cement chemistry[J]. Journal of Building Materials, 2003, 6(1):54-60(in Chinese). |
| [12] | PARDAL X, POCHARD I, NONAT A. Experimental study of Si-Al substitutionin calcium-silicate-hydrate(C-S-H) pre-pared under equilibrium conditions[J]. Cement & Concrete Research, 2009, 39(8):637-643. |
| [13] | RICHARDSON I G. Tobermorite/jennite and tobermorite/calcium hydroxide-based models for the structure of C-S-H:Applicability to hardened pastes of tricalcium silicate, β-dicalcium silicate, Portland cement, and blends of Portland cement with blast-furnace slag, metakaol[J]. Cement & Concrete Research, 2004, 34(9):1733-1777. |
| [14] | PORTENEUVE C, ZANNI H, VERNET C. Nuclear magnetic resonance characterization of high-and ultrahigh-performance concrete[J]. Cement & Concrete Research, 2001, 31(12):1887-1893. |
| [15] | RICHARDSON I G, GROVES G W. The structure of the calcium silicate hydrate phases present in hardened pastes of white Portland cement/blast-furnace slag blends[J]. Journal of Materials Science, 1997, 91(32):4793-4802. |
| [16] | DING Q J, WANG H, HU C G, et al. Effect of corrosive solutions on C-S-H microstructure in portland cement paste with fly ash[J]. Journal of Wuhan University of Technology. 2016, 31(5):1002-1007. |
| [17] | 张彩文, 葛志, 杨克锐, 等. C-S-H表面对SO42-的吸附特性[J]. 硅酸盐学报, 2005, 33(8):926-929. ZHANG C W, GE Z, YANG K R, et al. Adsorption characteristic of calcium silicate hydrate surface for SO42- ions[J]. Journal of the Chinese Ceramic Society, 2005, 33(8):926-929(in Chinese). |
| [18] | HE Y, LU L, STRUBLE L J, et al. Effect of Ca/Si ratio on microstructure and nanostructure of calcium silicate hydrate synthesized by reaction of fumed silica and calcium oxide at room temperature[J]. Materials & Structures, 2014, 47(1-2):311-322. |
| [19] | KUNTHER W, LOTHENBACH B, SKIBSTED J. Influence of the Ca/Si ratio of the C-S-H phase on the interaction with sulfate ions and its impact on the ettringite crystallization pressure[J]. Cement & Concrete Research, 2015, 69(1):37-49. |
| [20] | PEREZ G, GUERRERO A, GAITERO J J, et al. Structural characterization of C-S-H gel through an improved deconvolution analysis of NMR spectra[J]. Journal of Materials Science, 2014, 49(1):142-152. |
| [21] | SUN G K, YOUNG J F, KIRKPATRICK R J. The role of Al in C-S-H:NMR, XRD, and compositional results for precipitated samples[J]. Cement & Concrete Research. 2006, 36(1):18-29. |
| [22] | WANG R, Li X G, WANG P M. Influence of polymer on cement hydration in SBR-modified cement pastes[J]. Cement & Concrete Research, 2006, 36(9):1744-1751. |
| [23] | WANG L, HE Z, ZHANG B, et al. Polymerization mechanism of C-S-H:Identified by FTIR and NMR[J]. Journal of Building Materials, 2011, 14(4):447-451. |
| [24] | LI X J. Study on the mechanism of magnesium sulfate to cement and C-S-H gel[J]. Advanced Materials Research. 2011, 243-249:4687-4690. |
| [25] | RICHARDSON I G. The nature of C-S-H in hardened cements[J]. Cement & Concrete Research, 1999, 29(8):1131-1147. |
| [26] | SUN G K, YOUNG J F, KIRKPATRICK R J. The role of Al in C-S-H:NMR, XRD, and compositional results for precipitated samples[J]. Cement & Concrete Research, 2006, 36(1):18-29. |
| [27] | RENAUDIN G, RUSSIAS J, LEROUX F, et al. Structural characterization of C-S-H and C-A-S-H samples-Part Ⅱ:Local environment investigated by spectroscopic analyses[J]. Journal of Solid State Chemistry, 2009, 182(12):3320-3329. |
| [28] | 马惠珠. 硫酸盐侵蚀过程中钙矾石的形成及碱的影响[D]. 南京:南京工业大学, 2007. MA H Z. Ettringite formation in sulfate attack process and effect of alkali[D]. Nanjing:Nanjing Tech University, 2007(in Chinese). |
| [29] | LIU K W, MO L W, DENG M et al. Influence of pH on the formation of gypsum in cement materials during sulfate attack[J]. Advances in Cement Research, 2015, 27(8):1-7. |
