摘要
微生物诱导碳酸钙沉淀技术在土木工程材料领域应用日益广泛,近期研究表明该技术在自修复水泥基材料中具有广阔的应用前景。本实验采用一种能够矿化生产碳酸钙的固碳菌,将其与底物配制成自修复剂在水泥基成型阶段直接加入到基体中,对掺入后14 d内水泥基材料的力学性能和孔结构的发展进行探究。实验结果显示14 d后掺有微生物的水泥基材料的抗压、抗折强度均提高,孔结构更细化,通过DTA-TG和扫描电子显微镜发现水泥基材料表面及内部生成了方解石型碳酸钙晶体。此外,在标准养护7 d后制作宽度为0.1~0.2 mm的裂缝,模拟矿化环境探究修复效果。结果显示14 d后掺有微生物的试样即可实现接近100%的修复率,采用扫描电子显微镜和能谱仪检测发现裂缝内产生文石和方解石型的碳酸钙晶体。
Microbially induced calcium carbonate precipitation is a promising technology used in materials in civil engineering, recent researches have showed its broad application prospects in self-healing cement-based materials. One type of carbon-fixing bacteria which can catalyze mine-ralization reaction was adopted. Bacterial solution with nutrients and calcium sources was incorporated into cement-based materials before cas-ting. The results revealed that compressive strength and flexural strength of mortars with bacteria were improved after 14 d and the pore structure was denser, calcite was also found in the surface and inner of mortars by using DTA-TG and SEM. Besides, cracks with 0.1—0.2 mm width were made after 7 d standard curing and mineralization environment was imitated to investigate its healing effect. The results showed that cracks in mortars with bacterial solution were nearly completely repaired after 14 d. By using SEM and EDS, calcite and aragonite crystals were found in the cracks.
引文
1 Huang H,Ye G,Damidot D.Cement and Concrete Research,2013,52,71.
2 Wang R,Qian C.Journal of the Chinese Ceramic Society,2008 (4),457(in Chinese).王瑞兴,钱春香.硅酸盐学报,2008(4),457.
3 Qian C,Chen H,Ren L,et al.Frontiers in Microbiology,2015,6,1.
4 Wang J,Brecht V,Sam V,et al.Journal of Cleaner Production,2017.156,355.
5 Ghosh P,et al.Cement and Concrete Research,2005,35,1980.
6 De Muynck W,Debrouwer D,De B,et al.Cement and Concrete Research,2008,38(7),1005.
7 Van Tittelboom K,De Belie N,De Muynck W,et al.Cement and Concrete Research,2010,40(1),157.
8 Xu J,Yao W.Cement and Concrete Research,2014,64,1.
9 Li W,Chen W,Zhou P,et al.Chemical Engineering Journal,2013,218,65.
10 Li W,Chen W,Zhou P,et al.Colloids and Surfaces B:Biointerfaces,2013,102,281.
11 Li W,Liu L,Zhou P,et al.Current Science,2011,4(100),502.
12 Ghosh S,Biswaset M,Chattopadhyay B,et al.Cement and Concrete Composites,2009,2(31),93.
13 Shen W,Zhou M.Journal of Building Materials,2007,10(5),566 (in Chinese).沈卫国,周明凯.建筑材料学报,2007,10(5),566.
14 Fatma N,et al.HBRC Journal,2013(9),36.
15 Nicos S,Martys S,Chiara F.Cement and Concrete Research,1997,27(5),747.
16 Skubiszewska-Zi?ba J,Charmas B,Waniak-Nowicka H.Adsorption Science & Technology,2017,35(7-8),668.
17 Yokozeki K,Watanabe K,Sakata N,et al.Applied Clay Science,2004,26,293.
18 Yang Q,Analysis on microstructure and primary exploring of contact hardening mechanism of C-S-H superfine powder made with hydrothermal synthesis.Master’s Thesis,Chongqing University,China,2008(in Chinese).杨巧.水热合成C-S-H超细粉体微观结构分析及接触硬化机理初探.硕士学位论文,重庆大学,2008.
19 Young J,Berger R,Breese J.Journal of American Ceramic Society,1974,57(9),394.
20 Xu Q.The research on spatial and frequency distribution of the pore structure of cement-based materials.Master’s Thesis,Southeast University,China,2014(in Chinese).徐琼.水泥基材料孔结构空间分布与频率分布研究.硕士学位论文,东南大学,2014.
21 Konhauser K.Earth Science Reviews,1998,43(3),91.
22 Zhong S,Li J,Han D,et al.Journal of Building Materials,2012 (6),735(in Chinese).钟世云,李晋梅,韩冬冬,等.建筑材料学报,2012(6),735.
23 Rong H,Qian C,Li L.Journal of the Chinese Ceramic Society,2012(11),1564(in Chinese).荣辉,钱春香,李龙志.硅酸盐学报,2012(11),1564.