Bacteria for Concrete Surface Treatment - Biotechnologies and Biomimetics for Civil Engineering - page 333

Fig. 15.1 Top view of an untreated crack (a), crack repaired with BS + CaCl 2 (b) or BS in sol-
gel + Ca(CH 3 COO) 2 (c), cross-section of cracks repaired with grout (d), epoxy (e), sol-gel (g),
Sol-gel + BS + CaCl 2 (h) and cross-section of the tip of a 10 mm (f) and 20 mm (i) deep crack
repaired with BS in sol-gel + Ca(CH 3 COO) 2 (upper surface of sample is indicated with an
arrow) (Van Tittelboom et al. 2010 )
emphasis of the studies on the comparison of the characteristics of calcium car-
bonate precipitation on concrete by two types of ureolytic bacteria, S. pasteurii and
B. sphaericus. The present treatment methods can also be applied on horizontal
and vertical surfaces. Both the normal and lightweight concrete specimens treated
by the medium with B. sphaericus showed the lowest weight increases per unit
area. It was considered that the denseness of the calcium carbonate crystals of the
medium with B. sphaericus was higher than that of the cases with other treatments
(Kim et al. 2013 ).