A Case Study: Bacterial Surface Treatment of Normal and Lightweight Concrete - Biotechnologies and Biomimetics for Civil Engineering - page 361

Fig. 16.6 CaCO 3 crystal filled in pore of aggregate on top surface of lightweight concrete
treated by cell-free medium. Reprinted from Kim et al. ( 2013 ), Copyright (2013), with permission
from Elsevier
specimens and were loosely connected to each other. On the other hand, in the
lightweight concrete, the assembly of many small-sized calcium carbonate crystals
of a size of about 10 lm was noted (point 1 in Fig. 16.8 b); these were connected to
each other by web-shaped crystals (Point 2 in Fig. 16.8 b). The chemical compo-
sition of these web-shaped crystals differed slightly from that of bulk calcium
carbonate crystals (Fig. 16.8 c, d). It is important to note that the EDS spectra of
the pure calcium carbonate crystals should show 20 % of calcium ions, 20 % of
carbon ions, and 60 % of oxygen ions. It is assumed that the web-shaped crystals
Fig. 16.7 SEM images of top surface of normal concrete treated by the medium with S. pasteurii
measured in 10 lm(a), 400 nm (b), and EDS spectra at point 1 (c). Reprinted from Kim et al.
( 2013 ), Copyright (2013), with permission from Elsevier