Theory and application of cement-based materials remediation by carbonate precipitation (MCP) induced by microorganism

Title: Theory and application of cement-based materials remediation by carbonate precipitation (MCP) induced by microorganism
Author(s): C. Qian, L. Cheng, R. Wang, J. Wang
Paper category : conference
Book title: The 50-year Teaching and Research Anniversary of Prof. Sun Wei on Advances in Civil Engineering Materials
Editor(s): C. Miao, G. Ye and H. Chen
Print-ISBN: 978-2-35158-098-1
e-ISBN: 978-2-35158-099-8
Publisher: RILEM Publications SARL
Publication year: 2010
Pages: 81 - 98
Total Pages: 18
Nb references: 23
Language: English

Abstract: Bacterial induced carbonate mineralization has been demonstrated as a new potential method for restoration of limestones in historic buildings and monuments. We claim here the formation of calcium carbonate was controlled by extracellular polymeric substances (EPS) isolated from Bacillus pasteurii. The process of crystallization nucleation was accelerated in the presence of cells and inhibited in the presence of EPS. The CaCO3 film deposited on cement paste surface was about 100µm after 7 days treatment. The results of various restoring methods showed that higher decrease of water absorption of cement paste was gained in brushing application in the presence of agar, which could maintain urease with high activity in long term compared to spraying method. The coefficient of capillary suction of cement paste treated with brushing method was reduced by 90%. Mixed media consisted of sands, urea, Ca2+ and concentrated biomass, was injected into artificial cracks of cement paste followed by continual nutrient supplement, and CaCO3 particles were precipitated gradually between sands particles which were combined with cement matrix. The results showed that the compressive strength of recovered specimens was restored to 84%, which demonstrated that this kind of bio-restoration method is effective in repairing surface defects of cement-based materials.

Online publication: 2010-04-22
Publication type : full_text
Public price (Euros): 0.00