TY - JOUR
T1 - Crack healing in cementitious mortars using enzyme-induced carbonate precipitation
T2 - Quantification based on fracture response
AU - Dakhane, Akash
AU - Das, Sumanta
AU - Hansen, Hannah
AU - O'Donnell, Sean
AU - Hanoon, Farouq
AU - Rushton, Aimee
AU - Perla, Carlos
AU - Neithalath, Narayanan
N1 - Funding Information:
The authors gratefully acknowledge support for this study from the U.S. National Science Foundation (NSF) under the Engineering Research Centers (ERC) program, Grant No. EEC-1449501. Hannah Hansen acknowledges the Fulton Undergraduate Research Initiative (FURI) program at ASU for support. Farooq Hanoon acknowledges the NSF REU program and Carlos Perla acknowledges the NSF RET program for support. Any opinions or positions expressed in this paper are those of the authors only and do not reflect the opinions or positions of the NSF.
Publisher Copyright:
© 2018 American Society of Civil Engineers.
PY - 2018/4/1
Y1 - 2018/4/1
N2 - This paper evaluates a nonmicrobial means of carbonate precipitation to heal cracks in concrete. 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 in which precracking is induced are subjected to EICP solutions with different CaCl2 concentrations and a fixed molar ratio of urea: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 approximately 33% is observed for mortars treated with an EICP solution made using 0.5 M CaCl2 compared with the mortars that are just moist cured, and 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.
AB - This paper evaluates a nonmicrobial means of carbonate precipitation to heal cracks in concrete. 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 in which precracking is induced are subjected to EICP solutions with different CaCl2 concentrations and a fixed molar ratio of urea: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 approximately 33% is observed for mortars treated with an EICP solution made using 0.5 M CaCl2 compared with the mortars that are just moist cured, and 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.
KW - Carbonate precipitation
KW - Crack healing
KW - Digital image correlation
KW - Fracture
KW - Strain energy release
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U2 - 10.1061/(ASCE)MT.1943-5533.0002218
DO - 10.1061/(ASCE)MT.1943-5533.0002218
M3 - Article
AN - SCOPUS:85040967804
SN - 0899-1561
VL - 30
JO - Journal of Materials in Civil Engineering
JF - Journal of Materials in Civil Engineering
IS - 4
M1 - 04018035
ER -