Shrinkage Cracking Potential & Petrographic Analysis of Concrete with MgO Expansive Admixture
Open Access
- Author:
- Bazer, Abdulsamed
- Graduate Program:
- Civil Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- December 13, 2018
- Committee Members:
- Aleksandra Z Radlinska, Thesis Advisor/Co-Advisor
Shelley Marie Stoffels, Committee Member
Patrick Joseph Fox, Committee Member - Keywords:
- shrinkage
restrained ring test
MgO expansive admixture
MgO concrete
petrography
thin sections
concrete
cementitious admixtures
shrinkage cracking
cracking potential
microstructure of concrete
fluorescence microscopy
polarized light microscopy
scanning electrom microscopy
SEM
EDS
concrete petrography - Abstract:
- Shrinkage cracking is one of the main engineering problems that reduce the durability of concrete infrastructure. MgO expansive admixture is a technology designed to diminish shrinkage cracking in various applications of concrete, to decrease the cost of maintenance and project timeline as well as to increase the service life of the material. Ordinary portland cement (OPC) concrete with MgO expansive admixture is tested by two sets of restrained ring instruments standardized by ASTM C1581 and AASHTO PP-34. Results of restrained ring tests of plain and MgO concrete specimens with 0.42 w/c showed that 5% addition of MgO expansive admixture to the OPC delayed shrinkage cracking in concrete. Petrographic analyses of plain and MgO concrete showed that fewer shrinkage microcracks are observed in the MgO concrete specimens. SEM/EDS analyses showed that hydrated MgO expands in concrete and reduces shrinkage microcracks. Fresh properties of MgO concrete showed insignificant difference from that of plain concrete while MgO admixture reduced the slump of concrete predominantly.