Master of Science in Civil Engineering (MSCE)
Civil and Environmental Engineering
This research study is motivated by the need to reduce the costs of maintenance and repair of the aging transportation infrastructure in the US. The proposed approach is to use self-healing concrete. The objective of this study is to test the hypothesis that composite action due to fiber reinforced polymer (FRP) confinement of cylindrical concrete specimens may improve the self-repairing properties of self-healing concrete materials. Sodium silicate (Na2SiO3) is utilized as healing agent in this research. Concrete cylinders with 0.0%, 1.0%, 2.5%, and 5.0% of sodium silicate (SS) by weight of cement were cast and tested to evaluate the effectiveness of different content of SS on the self-healing capacities of concrete. Unconfined and FRP wrapped concrete cylinders were prepared for each different SS content level in order to investigate the effect of the FRP confinement on the self-repairing properties of concrete in terms of stiffness recovery and strength variation. The experimental results obtained from the stiffness tests were inconclusive. Several hypotheses were proposed and tested to explain the possible reasons why the self-healing mechanism was not activated. A second set of stiffness tests and a series of scanned electron microscopy (SEM) tests were designed and performed to investigate the different hypotheses proposed. The conclusions of this additional series of tests are: (1) Insufficient healing and poor SS microcapsule quality are not the reasons why the self-healing mechanism was not activated. (2) The results of the SEM tests suggest that the microcapsule shell may have had durability problems within the concrete environment and that the microcapsules may have been already broken and their content may have already solidified before the stiffness test was performed.
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Sui, Yueqiang, "Mechanical behavior of FRP-confined self-healing concrete" (2014). LSU Master's Theses. 402.