利用微生物诱导成矿实现混凝土的开裂自修复，面临的首要问题是对菌体进行负载保护，而载体材料是关键。该文选取了掺入质量分数20%硅灰的硫铝酸盐水泥作为低碱性胶凝负载材料，通过对胶凝材料的pH值以及凝结时间的优化，并评价负载后细菌芽孢的活性，探索出了一个有效的负载体系。混凝土开裂自修复的测试结果表明：借助该负载体系，28 d可使最大约322 μm宽的混凝土裂缝得以完全修复。修复后，混凝土抗压强度恢复到损伤前的84%，水密闭性恢复至未损伤时的水平。
关键词：
混凝土; 裂缝; 微生物; 自修复; 载体
The primary issue for self-healing of concrete cracks by microbially induced mineralization is protection of the bacteria and the key to protecting the bacteria is the carrier material selection. This paper used calcium sulphoaluminate cement with 20% silica fume as a low-alkali binder type carrier material. An effective loading method was developed by regulating the binder pH and setting time through evaluations of the bacterial spore activity in this carrier. The concrete crack self-healing was successful up to a maximum crack width of about 322 μm that could be healed after 28 days. After the self-healing, the concrete compressive strength recovered up to 84% of the original strength with the water tightness completely restored.
[1] BOQUET E, BORONAT A, RAMOS-CORMENZANA A. Production of calcite (calcium carbonate) crystals by soil bacteria is a general phenomenon[J]. Nature, 1973, 246(1):527-529.
[2] DEJONG J T, SOGA K, KAVAZANJIAN E, et al. Biogeochemical processes and geotechnical applications:Progress, opportunities and challenges[J]. Géotechnique, 2013, 63(4):287-301.
[3] MACLEOD F A, LAPPIN-SCOTT H M, COSTERTON J W. Plugging of a model rock system by using starved bacteria[J]. Applied and Environmental Microbiology, 1988, 54(6):1365-1372.
[4] GOLLAPUDI U K, KNUTSON C L, BANG S S, et al. A new method for controlling leaching through permeable channels[J]. Chemosphere, 1995, 30(4):695-705.
[5] YANG Z, CHENG X. A performance study of high-strength microbial mortar produced by low pressure grouting for the reinforcement of deteriorated masonry structures[J]. Construction and Building Materials, 2013, 41(4):505-515.
[6] DE MUYNCK W, VERBEKEN K, DE BELIE N, et al. Influence of urea and calcium dosage on the effectiveness of bacterially induced carbonate precipitation on limestone[J]. Ecological Engineering, 2010, 36(2):99-111.
[7] 李沛豪, 屈文俊. 生物修复加固材料在土木工程中的应用研究进展[J]. 材料科学与工程学报, 2008, 26(5):810-815. LI P H, QU W J. State of arts in application of bioremedying and bioreinforceing materials in civil engineering[J]. Journal of Materials Science and Engineering, 2008, 26(5):810-815. (in Chinese)
[8] JONKERS H M. Bacteria-based self-healing concrete[J]. HERON, 2011, 56(1-2):1-12.
[9] JONKERS H M, THIJSSEN A, MUYZER G, et al. Application of bacteria as self-healing agent for the development of sustainable concrete[J]. Ecological Engineering, 2010, 36(2):230-235.
[10] TZIVILOGLOU E, WIKTOR V, JONKERS H M, et al. Bacteria-based self-healing concrete to increase liquid tightness of cracks[J]. Construction and Building Materials, 2016, 122(3):118-125.
[11] XU J, YAO W. Multiscale mechanical quantification of self-healing concrete incorporating non-ureolytic bacteria-based healing agent[J]. Cement and Concrete Research, 2014, 64(6):1-10.
[12] 钱春香, 任立夫, 罗勉. 基于微生物诱导矿化的混凝土表面缺陷及裂缝修复技术研究进展[J]. 硅酸盐学报, 2015, 43(5):619-631. QIAN C X, REN L F, LUO M. Development of concrete surface defects and cracks repair technology based on microbial-induced mineralization[J]. Journal of the Chinese Ceramic Society, 2015, 43(5):619-631. (in Chinese)
[13] LORS C, DUCASSE-LAPEYRUSSE J, GAGNÉ R, et al. Microbiologically induced calcium carbonate precipitation to repair microcracks remaining after autogenous healing of mortars[J]. Construction and Building Materials, 2017, 141(5):461-469.
[14] WANG J Y, DE BELIE N, VERSTRAETE W. Diatomaceous earth as a protective vehicle for bacteria applied for self-healing concrete[J]. Journal of Industrial Microbiology & Biotechnology, 2012, 39(4):567-577.
[15] WANG J Y, SNOECK D, VAN VLIERBERGHE S, et al. Application of hydrogel encapsulated carbonate precipitating bacteria for approaching a realistic self-healing in concrete[J]. Construction and Building Materials, 2014, 68(8):110-119.
[16] WANG J Y, SOENS H, VERSTRAETE W, et al. Self-healing concrete by use of microencapsulated bacterial spores[J]. Cement and Concrete Research, 2014, 56(6):139-152.
[17] ALAZHARI M, SHARMA T, HEATH A, et al. Application of expanded perlite encapsulated bacteria and growth media for self-healing concrete[J]. Construction and Building Materials, 2018, 160(5):610-619.
[18] BUNDUR Z B, AMIRI A, ERSAN Y C, et al. Impact of air entraining admixtures on biogenic calcium carbonate precipitation and bacterial viability[J]. Cement and Concrete Research, 2017, 98(9):44-49.
[19] ERŞN Y, HERNANDEZ SANABRIA E, BOON N, et al. Enhanced crack closure performance of microbial mortar through nitrate reduction[J]. Cement & Concrete Composites, 2016, 70(10):159-170.
[20] DOUGLAS L A, BREMNER J M. Extraction and colorimetric determination of urea in soils[J]. Soil Science Society of America Journal, 1970, 34(6):859-862.
[21] DE MUYNCK W, DEBROUWER D, DE BELIE N, et al. Bacterial carbonate precipitation improves the durability of cementitious materials[J]. Cement and Concrete Research, 2008, 38(7):1005-1014.
