Use of bacterial silica precipitation to enhance strength and permeability of concrete

• Published in: Malaysian Construction Research Journal
• Main Author: Habulat A.; Saman H.M.; Kamarudin K.; Omar M.
• Format: Article
• Language: English
• Published: Construction Research Institute of Malaysia 2013
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84926357825&partnerID=40&md5=28bcc7caa97a26bee81968ea6b1039ec

Microbial treatments has led to the improvement of concrete but as of yet, few studies showed tangible evidence of using bacteria-induced silica precipitation to improve the strength of concrete. Therefore, this study investigated the effect of using Thermus Thermophilus (TT) to enhance the strength and permeability of concrete. The existing silica precipitation by TT was examined under X-Ray Diffraction. TT, in five concentrations of 103, 104, 105, 106 and 107 cell/ml, were incorporated with the concrete mixes. The properties of the concrete were then assessed by compressive strength and Rapid Chloride Permeability Test (RCPT) after 3, 7, 28, 60 and 180 days. Meanwhile, carbonation test was conducted after 3, 7 and 28 days of exposure in a carbonation chamber. The 106 cell/ml of TT was found to be optimum concentration for compressive strength and RCPT; however, there was no optimum concentration which could enhance the carbonation resistance. The maximum improvement in compressive strength, RCPT and carbonation resistance corresponding to that without TT were 27.9 %, 30.6 % and 62.5 % respectively. The microstructure examinations, conducted using Scanning Electron Microscope (SEM), showed significant differences in the microstructure texture compared to the control group (without TT). The results showed that having TT in the concrete mixes was able to enhance the concrete compressive strength, permeability and carbonation resistance characteristic.