Crack Healing in Cementitious Mortars Using Enzyme-Induced Carbonate Precipitation: Quantification Based on Fracture Response

Authors

Akash Dakhane
Sumanta Das, University of Rhode IslandFollow
Hannah Hansen
Sean O'Donnell
Farouq Hanoon
Aimee Rushton
Carlos Perla
Narayanan Neithalath

Document Type

Article

Date of Original Version

2018

Department

Civil and Environmental Engineering

Abstract

A non-microbial means of carbonate precipitation to heal cracks in concrete is evaluated in this paper. Enzyme induced carbonate precipitation (EICP) that relies on plant-derived urease enzyme is used to catalyze the reaction between calcium chloride and urea to precipitate calcium carbonate. The faster rate of carbonate precipitation and the absence of microbes makes this method attractive for surface applications for crack healing of concrete. Notched mortar beams, where pre-cracking is induced, are subjected to EICP solutions with different CaCl₂ concentrations and a fixed molar ratio of urea-to-CaCl₂ of 1.2. X-ray diffraction and thermal analysis of samples collected from the vicinity of the notch clearly demonstrate the presence of calcium carbonate in the cracks. A flexural strength enhancement of about 33% is observed for mortars treated with an EICP solution made using 0.5 M CaCl₂ as compared to the mortars that are just moist cured, while the fracture toughness doubled. The strength and fracture parameters (fracture toughness, and critical crack tip opening displacement) scale well with the carbonate content. Digital image correlation (DIC) is used to quantify the reduction in crack extension after the beams are treated with the EICP solution.

Citation/Publisher Attribution

Dakhane, A., Das, S., Hansen, H., O'Donnell, S., Hanoon, F., Rushton, A., Perla, C., Neithalath, N. (2018). Crack Healing in Cementitious Mortars Using Enzyme-Induced Carbonate Precipitation: Quantification Based on Fracture Response. Journal of Materials in Civil Engineering, 30(4), 04018035. doi: 10.1061/(ASCE)MT.1943-5533.0002218

Available at: https://doi.org/10.1061/(ASCE)MT.1943-5533.0002218