Effect of gypsum on early hydration of amorphous C12A7 and its mechanism
-
摘要: 为推动非晶态C12A7在早强快凝工程材料中的高效应用，洞悉二水石膏对非晶态C12A7的影响作用机理，本文采用X射线衍射、微量热分析、扫描电子显微镜等测试手段研究了二水石膏对非晶态C12A7早期水化性能的影响。结果表明，适量二水石膏会延缓非晶态C12A7的水化进程，即随着二水石膏掺量增大，非晶态C12A7达到第一个水化放热峰的时间延迟，第二个放热峰值降低，放热峰持续时间延长；水化24 h时，二水石膏掺量为50 % 的试样水化放热总量最大，水化活性最高。在本实验的二水石膏掺量范围内，所有试样的水化产物均以钙矾石AFt和氢氧化铝AH3为主，二水石膏掺量和水化龄期可改变钙矾石的生成量和形貌特性，进而影响浆体的抗压强度。在相同水化龄期内，随着二水石膏掺量的增加，试样的抗压强度均呈先增后降趋势；本实验中最佳二水石膏掺量为50 %，其在水化龄期24 h、72 h和168 h时的抗压强度均为最高。Abstract: In order to promote the efficient application of amorphous C12A7 in early strength and rapid setting engineering materials, and understand the interaction mechanism between gypsum and amorphous C12A7, the influence of gypsum on the early hydration of amorphous C12A7 was studied by X-ray diffraction, scanning electron microscopy and isothermal calorimetry. The results show that proper dosage of gypsum can retard the hydration of amorphous C12A7, with the increasing dosage of gypsum, the time of the first exothermic peak is retarded, the second exothermic peak of hydration is reduced, and the duration of exothermic peak is prolonged; After 24 hours hydration, the accumulate heat of hydration of the sample with 50 % gypsum are the highest. In the experiment, ettringite and AH3 gel are the main hydration products. The content of gypsum and hydration ages can change the morphology of ettringite, and affect the compressive strength of the sample. At the same age, with the increase of the dosage of gypsum, the compressive strength of the hydrated pastes increases from 33 % to 50 % and then decreases from 50 % to 64 %. Amorphous C12A7 with 50 % gypsum system has the highest strength at day 1, day 3 and day 7.
-
Key words:
- gypsum /
- amorphous C12A7 /
- hydration products /
- ettringite /
- strength
-
图 2 掺有二水石膏的非晶态C12A7试样抗压强度
Figure 2. The evolution of the compressive strength for amorphous C12A7 and gypsum systems
图 3 掺有二水石膏的非晶态C12A7试样在不同养护龄期下水化产物的XRD图谱
Figure 3. XRD spectra of amorphous C12A7 and gypsum systems cured at different ages
图 4 掺有二水石膏的非晶态C12A7试样水化热曲线
Figure 4. Hydration heat evolution of amorphous C12A7 and gypsum systems
表 1 非晶态C12A7的主要化学成分质量分数
Table 1. The oxide composition of amorphous C12A7
% SiO2 Al2O3 Fe2O3 CaO MgO K2O Na2O 3.02 50.57 0.36 43.60 0.68 0.10 0.22 
下载: 导出CSV
表 2 二水石膏的主要化学成分质量分数
Table 2. The oxide composition of gypsum
% CaO SO3 Na2O Crystal water 32.60 46.37 0.12 20.2
下载: 导出CSV
表 3 非晶态C12A7和二水石膏质量分数
Table 3. The mass percent of amorphous C12A7 and gypsum in system
% 试样 非晶态C12A7 二水石膏 C1 67 33 C2 62 38 C3 58 42 C4 54 46 C5 50 50 C6 46 54 C7 36 64
下载: 导出CSV
-
[1] 汪卫华. 非晶态物质的本质和特性[J]. 物理学进展, 2013, 33(5): 177-351. https://www.cnki.com.cn/Article/CJFDTOTAL-WLXJ201305001.htmWang Weihua. The nature and properties of amorphous matter[J]. Progress in Physics, 2013, 33(5): 177-351. https://www.cnki.com.cn/Article/CJFDTOTAL-WLXJ201305001.htm [2] 王绪威. 非晶态材料及应用[M]. 高等教育出版社, 1992. [3] 李北星, 余其俊, 冯修吉. CaO-Al2O3系统铝酸钙矿物水化活性差异的SCC-DV-Xα方法研究[J]. 硅酸盐学报, 1998, 26(4): 411-416. doi: 10.3321/j.issn:0454-5648.1998.04.001Li Beixing, Yu Qijun, Feng Xiuji. SCC-DV-Xα studies on difference in hydration activity of calcium aluminate minerals of CaO-Al2O3 system[J]. Journal of the Chinese Ceramic Society, 1998, 26(4): 411-416. doi: 10.3321/j.issn:0454-5648.1998.04.001 [4] 张江涛, 王栋民, 王奕仁, 等. 非晶态铝酸钙基速凝剂的制备及其性能研究[J]. 混凝土与水泥制品, 2016(8): 1-4. doi: 10.3969/j.issn.1000-4637.2016.08.001Zhang Jiangtao, Wang Dongmin, Wang Yiren, et al. Research on preparation of amorphous calcium aluminate based accelerator and its performance[J]. China Concrete and Cement Products, 2016(8): 1-4. doi: 10.3969/j.issn.1000-4637.2016.08.001 [5] Watanabe T, Hosomi M, Yuno K, et al. Quality evaluation of shotcrete by acoustic emission[J]. Construction and Building Materials, 2010(24): 2358-2362. [6] Prudêncio L R. Accelerating admixtures for shotcrete[J]. Cement and Concrete Composites, 1998, 20(2/3): 213-219. [7] Park H G, Sung S K, Park C G, et al. Influence of a C12A7 mineral-based accelerator on the strength and durability of shotcrete[J]. Cement and Concrete Research, 2008, 38(3): 379-385. doi: 10.1016/j.cemconres.2007.09.016 [8] 李文平, 王栋民, 范德科, 等. 非晶态C12A7/CaSO4·2H2O体系对OPC早期性能的影响及作用机理[J]. 新型建筑材料, 2017(7): 104-107. doi: 10.3969/j.issn.1001-702X.2017.07.030Li Wenping, Wang Dongmin, Fan Deke, et al. Study on effects and mechanical performance of amorphous state C12A7/CaSO4·2H2O system on early properties of OPC[J]. New Building Materials, 2017(7): 104-107. doi: 10.3969/j.issn.1001-702X.2017.07.030 [9] 罗译. 日本化学外加剂发展的新趋势(下)[J]. 商品混凝土, 2007(3): 62-66.Luo Yi. New development trend of chemical admixtures in Japan (2)[J]. Commercial concrete, 2007(3): 62-66. [10] Majumbar A J, Singh B, Edmonds R N. Hydration of mixtures of C12A7 and granulated blastfurnace slag[J]. Cement and Concrete Research, 1989, 19(6): 848-856. doi: 10.1016/0008-8846(89)90097-5 [11] Nakagawa K, Terashima I, Asaga K, et al. Influence of Ca(OH)2 and CaSO4· 2H2O on hydration reaction of amorphous calcium aluminate[J]. Cement and Concrete Research, 1990, 20(5): 824-832. doi: 10.1016/0008-8846(90)90016-Q [12] 蔡剑育. 非晶质铝酸钙在砂浆中的应用研究[J]. 新型建筑材料, 2015, 42(4): 42-43, 72. doi: 10.3969/j.issn.1001-702X.2015.04.011Cai Jianyu. Application research of amorphous calcium aluminate on mortar[J]. New Building Materials, 2015, 42(4): 42-43, 72. doi: 10.3969/j.issn.1001-702X.2015.04.011 [13] Edmonds R N, Majumdar A J. The hydration of 12CaO. 7A12O3 at different temperatures[J]. Cement and Concrete Research, 1988, 18(3): 473-478. doi: 10.1016/0008-8846(88)90082-8 [14] Hewlett P C. Lea's chemistry of cement and concrete[M]. New York: Elsevier Butterworth Heinemann, 1988: 725-726. [15] 姚燕, 王宏霞, 刁桂芝, 等. 硝酸钙对铝酸盐水泥强度及水化性能的影响[J]. 硅酸盐学报, 2019, 47(2): 207-213. https://www.cnki.com.cn/Article/CJFDTOTAL-GXYB201902009.htmYao Yan, Wang Hongxia, Diao Guizhi, et al. Effect of calcium nitrate on strength and hydration of calcium aluminate cement[J]. Journal of the Chinese Ceramic Society, 2019, 47(2): 207-213. https://www.cnki.com.cn/Article/CJFDTOTAL-GXYB201902009.htm [16] Scrivener K L, Cabiron J L, Letourneux R. High-performance concretes from calcium aluminate cements[J]. Cement and Concrete Research, 1999, 29(8): 1215-1223. doi: 10.1016/S0008-8846(99)00103-9 [17] 盛冈实, 樋口隆行, 森泰一郎. 添加非晶质铝酸盐(ACA)的快硬水泥砂浆的特性[C]//第五届中国国际建筑干混砂浆生产应用技术研讨会论文集, 2012: 14-20. [18] 钟白茜. 石膏及碳酸钙对C12A7水化性能的影响[J]. 南京工业大学学报: 自然科学版, 1980, 2(1): 48-59. https://www.cnki.com.cn/Article/CJFDTOTAL-NHXB198001003.htmZhong Baiqian. Influence of gypsum and calcium on the hydration of C12A7[J]. Journal of Nanjing University of Technology: Natural Science Edition, 1980, 2(1): 48-59. https://www.cnki.com.cn/Article/CJFDTOTAL-NHXB198001003.htm [19] 张江涛, 王栋民, 王奕仁, 等. 不同掺量非晶态C12A7/CaSO4·2H2O体系对OPC早期性能的影响及作用机理[J]. 硅酸盐通报, 2017, 36(1): 1-7. https://www.cnki.com.cn/Article/CJFDTOTAL-GSYT201701001.htmZhang Jiangtao, Wang Dongmin, Wang Yiren, et al. Effects of different content of amorphous C12A7/CaSO4·2H2O system on early properties of OPC and mechanical performance[J]. Bulletin of the Chinese Ceramic Society, 2017, 36(1): 1-7. https://www.cnki.com.cn/Article/CJFDTOTAL-GSYT201701001.htm [20] 苏慕珍, 王燕谋, 张量硫铝酸盐水泥[M]. 北京: 北京工业大学出版社, 1999. [21] 徐玲琳, 周向艺, 李楠, 等. 石膏对硫铝酸盐水泥水化特性的影响[J]. 同济大学学报: 自然科学版, 2017, 46(6): 885-890. https://www.cnki.com.cn/Article/CJFDTOTAL-TJDZ201706016.htmXu Linglin, Zhou Xiangyi, Li Nan, et al. Impact of calcium sulfate on hydration features of calcium sulfoaluminate cement[J]. Journal of Tongji university: Natural science, 2017, 46(6): 885-890. https://www.cnki.com.cn/Article/CJFDTOTAL-TJDZ201706016.htm [22] Hayashi K, Hirano M, Hosono H. Thermodynamics and kinetics of hydroxide ion formation in 12CaO·7Al2O3[J]. The Journal of Physical Chemistry B, 2005, 109(24): 11900-11906. doi: 10.1021/jp050807j -
点击查看大图
图(5) / 表(3)
计量
- 文章访问数: 381
- HTML全文浏览量: 139
- PDF下载量: 25
- 被引次数: 0