ABSTRACT
Disck et al. 2006) ornamental stones (Carlos et al. 2003) and monumental stones.(Tiano et al. 1999) Deposition reduces the water absorption rate of limestone. A reduction of water absorption by about 60% by the samples treated with MICP was observed. (Dick et al 2006, Tiano et al. 1999). Cracks in granite were effectively remediated by MICP using microorganisms mixed with a filling material such as silica fume and sand. (Gollapudi et al. 1991) The potential for bioclogging in micro fractured aquifers was demonstrated by stimulation of ground water microbes.(Ross et al. 2001). To reduce the harmful effects of the environment on the microbial metabolism some researchers used polyurethane to immobilize the bacterium or the enzyme. (Klein & Kluge 1981, Wang & Ruchenstein 1993, Bang et al 2001)
The strength improvement in cement mortar due to MICP was studied using Bacillus pasteurii (Ramachandran et al. 2001) and Shenwalla in a tropical environment. (Ghosh et al 2005) Strength as well as durability properties of concrete with MICP were studied.(Ramakrishnan et al. 2003)They not only observed improvement in strength, modulus of rupture and stiffness but also observed better resistance to alkali aggregate reaction, resistance to sulfate and freeze thaw. MICP on cementitious materials using Bacillus Sphaericus was attempted. (Muynck et al. 2008) They observed that the surface deposition of calcium carbonate crystals decreased the water absorption by 65 to 90% depending on the porosity of the specimens.
