Publication Date

2016-07-15

Availability

Open access

Embargo Period

2016-07-15

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Civil, Architectural and Environmental Engineering (Engineering)

Date of Defense

2016-06-17

First Committee Member

Wimal Suaris

Second Committee Member

Antonio Nanni

Third Committee Member

Francisco J. De Caso y Basalo

Fourth Committee Member

Stefano Mariani

Abstract

Glass fiber reinforced polymer (GFRP) bars are emerging as concrete reinforcements especially in applications where corrosion resistance properties are required. This dissertation focuses on bond properties, microstructure and post-fire behavior of GFRP bars. First, the bond of three GFRP bars with different surface characteristics was investigated by performing pull-out tests. A parametric bond-slip relationship was proposed for the GFRP bar with sand coated surface. The parameters were found by performing sensitivity analysis. The proposed bond-slip law was employed in an FEM model to predict the failure mode. Additionally, the model was employed in a GFRP-RC slab to replace the unrealistic perfect-bond assumption and led to more accurate results. Next, the microstructural patterns of four different GFRP bars were investigated using SEM analysis. Each bar demonstrated a unique defect/void pattern due to experiencing different manufacturing process. In order to investigate the effect of microstructure on GFRP durability, two of the bars were exposed to accelerated conditioning in an alkaline solution. The difference in microstructural patterns significantly affected the GFRP durability-related properties. Finally, the post-fire behavior of two different GFRP bars was investigated. GFRP-RC slabs were exposed to standard fire tests while being loaded at the service load. After the cooling phase, the GFRP bars were extracted for investigation of their residual mechanical properties. GFRP bars maintained the mechanical properties and no microstructural degradation was observed. Additionally, a thermomechanical model was developed to predict the temperature distribution and investigate the effect of the fire on the structural response and concrete cracking.

Keywords

Glass fiber reinforced polymer; Reinforced concrete; Bond modeling; Pull-out test; FEM modeling; Scanning electron microscopy; Microstructure; Fire behavior

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