偏高岭土对活性粉末混凝土力学性能及微观结构的影响

硅酸盐通报 ›› 2021, Vol. 40 ›› Issue (4): 1162-1169.

偏高岭土对活性粉末混凝土力学性能及微观结构的影响

陈丽¹, 周长顺^2,3, 蒋晨辉⁴

1.绍兴职业技术学院建筑与设计艺术学院,绍兴 312000;
2.绍兴文理学院元培学院,绍兴 312000;
3.中南大学土木工程学院,长沙 430100;
4.绍兴文理学院土木工程学院,绍兴 312000

收稿日期:2020-12-08 修回日期:2021-01-25 出版日期:2021-04-15 发布日期:2021-05-11
通讯作者: 周长顺,博士,讲师。E-mail:3231677159@qq.com
作者简介:陈丽(1977—),女,高工。主要从事水泥基材料的研究。E-mail:49891594@qq.com
基金资助:
国家自然科学基金(41572305)

Effect of Metakaolin on Mechanical Properties and Microstructure of Reactive Powder Concrete

CHEN Li¹, ZHOU Changshun^2,3, JIANG Chenhui⁴

1. College of Architecture and Design Art, Shaoxing Vocational and Technical University, Shaoxing 312000, China;
2. Yuanpei College,Shaoxing University, Shaoxing 312000, China;
3. School of Civil Engineering, Central South University, Changsha 430100, China;
4. College of Civil Engineering, Shaoxing University, Shaoxing 312000, China

Received:2020-12-08 Revised:2021-01-25 Online:2021-04-15 Published:2021-05-11

摘要/Abstract

摘要： 活性粉末混凝土(RPC)具有优异的力学性能和耐久性能,应用前景广阔。为探讨偏高岭土(MK)对RPC的影响,通过MK火山灰活性指数测试,抗压强度、抗折强度和弹性模量试验,以及X射线衍射分析仪(XRD)、扫描电子显微镜(SEM)、压汞和纳米压痕分析,研究了0%、5%、10%、15%和20%的MK等质量取代胶凝材料对RPC力学性能和微观结构的影响。研究结果表明,MK在水泥水化早期就表现出较高的火山灰活性,其中MK掺量为10%时RPC的28 d抗压强度、抗折强度和弹性模量较基准组分别提高了20.1%、18.0%和11.4%,MK的最佳掺量为10%。微观结构分析显示,MK的掺入降低了RPC基体的孔隙率,并且通过“二次水化”反应生成更多额外的水化硅酸钙(C-S-H)凝胶填充基体的孔隙,改善了RPC的微观结构。纳米压痕试验研究表明,掺入质量分数为10%的MK增加了高密度C-S-H的含量,这可能归因于MK的火山灰活性和微集料填充效应。

关键词: 偏高岭土, 活性粉末混凝土, 力学性能, 微观结构, 纳米压痕

Abstract: Reactive powder concrete (RPC) is a promising material which exhibits extrordinary mechanical properties and durability. To investigate the effect of metakaolin (MK) on RPC, the effects of 0%, 5%, 10%, 15% and 20% mass ratio of cementitious materials replaced by MK on the mechanical properties and microstructure of RPC were studied, which included MK pozzolanic activity index test, and the compressive, flexural strength and elastic modulus tests, X-ray diffraction analyzer (XRD), as well as scanning electron microscope (SEM), MIP and nanoindentation measurements. The results show that MK exhibits high pozzolanic activity at the early stage of cement hydration, and the 28 d compressive strength, flexural strength and elastic modulus of RPC with 10% MK increase by 20.1%, 18.0% and 11.4%, respectively, comparing with the reference group. The optimal dosage of MK is 10%. It shows that the incorporation of MK reduces the porosity of RPC matrix, and more additional C-S-H gel filling the pores of RPC matrix is generated by the “secondary hydration” reaction, which improves the microstructure of RPC after the microstructure analysis. Nanoindentation investigation shows that the mass fraction of 10% MK increases the content of high density C-S-H to increase the mechanical properties of RPC. This may be attributed to the pozzolanic activity and the micro-aggregate filling effect of MK.

Key words: metakaolin, reactive powder concrete, mechanical property, microstructure, nanoindentation

中图分类号:

TU528

陈丽, 周长顺, 蒋晨辉. 偏高岭土对活性粉末混凝土力学性能及微观结构的影响[J]. 硅酸盐通报, 2021, 40(4): 1162-1169.

CHEN Li, ZHOU Changshun, JIANG Chenhui. Effect of Metakaolin on Mechanical Properties and Microstructure of Reactive Powder Concrete[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2021, 40(4): 1162-1169.

参考文献

[1] 李新星,杨才千,周泉,等.基于正交试验的活性粉末混凝土强度及流动性研究[J].硅酸盐通报,2019,38(4):1201-1210.
LI X X, YANG C Q, ZHOU Q, et al. Research on strength and fluidity of reactive powder concrete based on orthogonal test[J]. Bulletin of the Chinese Ceramic Society, 2019, 38(4): 1201-1210 (in Chinese).
[2] 邓明科,马福栋,张阳玺,等.活性粉末混凝土抗压强度试验研究[J].硅酸盐通报,2017,36(8):2731-2736.
DENG M K, MA F D, ZHANG Y X, et al. Experimental study on the compressive strength of reactive powder concrete[J]. Bulletin of the Chinese Ceramic Society, 2017, 36(8): 2731-2736 (in Chinese).
[3] 安明喆,李同乐.活性粉末混凝土损伤后的抗氯离子渗透性能研究[J].混凝土,2012(3):15-17.
AN M Z, LI T L. Resistance to chloride ion penetration of reactive powder concrete after injury[J]. Concrete, 2012(3): 15-17 (in Chinese).
[4] BROOKS J J, MEGAT JOHARI M A. Effect of metakaolin on creep and shrinkage of concrete[J]. Cement and Concrete Composites, 2001, 23(6): 495-502.
[5] POON C S, KOU S C, LAM L. Compressive strength, chloride diffusivity and pore structure of high performance metakaolin and silica fume concrete[J]. Construction and Building Materials, 2006, 20(10): 858-865.
[6] COURARD L, DARIMONT A, SCHOUTERDEN M, et al. Durability of mortars modified with metakaolin[J]. Cement and Concrete Research, 2003, 33(9): 1473-1479.
[7] LI Z J, DING Z. Property improvement of Portland cement by incorporating with metakaolin and slag[J]. Cement and Concrete Research, 2003, 33(4): 579-584.
[8] 席书娜.偏高岭土在高性能混凝土中的应用研究[D].焦作:河南理工大学,2009.
XI S N. Application research of metakaolin in high performance concrete[D]. Jiaozuo: Henan Polytechnic University, 2009 (in Chinese).
[9] 姜广.生态型偏高岭土超高性能水泥基复合材料的制备及机理分析[D].南京:东南大学,2015.
JIANG G. Study on preparation and mechanism analysis of ecological metakaolin UHPFRCC[D]. Nanjing: Southeast University, 2015 (in Chinese).
[10] 赵晓刚.水化硅酸钙的合成及其组成、结构与形貌[D].武汉:武汉理工大学,2010.
ZHAO X G. Synthesis of calcium silicate hydrate and its composition, structure and morphology[D]. Wuhan: Wuhan University of Technology, 2010 (in Chinese).
[11] 李阳.偏高岭土提高水泥性能及水化机理研究[D].武汉:武汉理工大学,2017.
LI Y. Research on improving the performance of cement and hydration mechanism of metakaolin[D]. Wuhan: Wuhan University of Technology, 2017 (in Chinese).
[12] YOUNG J F. Review of the pore structure of cement paste and concrete and its influence on permeability[J]. ACI Special Publication, 1988, 108(1): 1-18.
[13] SIDDIQUE R, KLAUS J. Influence of metakaolin on the properties of mortar and concrete: a review[J]. Applied Clay Science, 2009, 43(3/4): 392-400.
[14] HE Z H, ZHAN P M, DU S G, et al. Creep behavior of concrete containing glass powder[J]. Composites Part B: Engineering, 2019, 166: 13-20.
[15] HE Z H, QIAN C X, ZHANG Y, et al. Nanoindentation characteristics of cement with different mineral admixtures[J]. Science China Technological Sciences, 2013, 56(5): 1119-1123.