Use of bacterial binder in repair mortar for micro-crack remediation

Sırt Çıplak, Elif
Bilecen, Kivanc
Akoglu, Kiraz Goze
Guchan, Neriman Sahin
Micro-cracks are one of the types of stone deterioration which can propagate and lead to surface detachments and larger cracks in the long run. The present study developed a sustainable and environmentally friendly infill material—biological mortar (BM), as an alternative to conventional approaches. Using a biomineralization approach, this BM was explicitly designed for healing micro-cracks (less than 2 mm) in historic travertines. To this end, the mortar was prepared using a calcifyingBacillussp. isolated from thermal spring water resources in Pamukkale Travertines (Denizli), stone powder gathered from travertine quarries in the vicinity, and a triggering solution specifically designed to set off calcium carbon- ate precipitation reaction. After setup, BM was applied to micro-cracks of artificially aged test stones for testing. Scanning electron microscopy revealed calcium carbonate-coatedBacillussp. bodies in the BM matrix, optical microscopy showed secondary calcite minerals throughout the BM applied micro-cracks, and stereomicroscopy and nanoindentation analyses demonstrated bonding of BM with stone due to microbial calcification activities. Furthermore, BM and original material contact showed a continuous and coherent structure in all samples. Within this context, BM could be considered a promising and alternative approach for the remediation of micro-cracks of historic stones.
Citation Formats
E. Sırt Çıplak, K. Bilecen, K. G. Akoglu, and N. S. Guchan, “Use of bacterial binder in repair mortar for micro-crack remediation,” APPLIED MICROBIOLOGY AND BIOTECHNOLOGY, vol. 108, pp. 1–15, 2023, Accessed: 00, 2023. [Online]. Available: