Date of Award

12-2018

Level of Access

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Civil Engineering

Advisor

Eric N. Landis

Second Committee Member

Roberto Lopez-Anido

Third Committee Member

Todd S. Rushing

Abstract

Recent studies investigating the impact performance of ultra-high performance concrete (UHPC) reported a quasi-brittle flexural failure that transitioned to a brittle punching-shear failure as the size of the impact head was reduced. A potential technology to increase the flexural strength and impact resistance of concrete is applying fiber reinforced polymer (FRP) composites to the exterior faces of the beam or slab. In this work, E-glass fiber reinforced thermoplastics were utilized in two different systems to apply reinforcement to UHPC. Thermoplastic materials were chosen over traditional thermoset materials for their unique advantages, such as rapid fabrication, automated manufacturing and the ability to weld to the material. These advantages could create an ideal system for large scale production of UHPC panels with thermoplastic reinforcement for use in protective systems. The two systems investigated were stamped thermoforming and vacuum infusion. For stamped thermoforming, the UHPC, fiber reinforced prepreg tapes and an additional layer of thermoplastic resin were heated then consolidated. Upon cooling the multiple prepreg layers of thermoplastic tapes were formed into a complete laminate, which was completely bonded to the UHPC core. The second system to reinforce the UHPC was vacuum infusion using a two-part liquid thermoplastic resin-system and a woven roving fabric. The impact performance of the thermoplastic composite reinforced UHPC panels was characterized using a combination of drop-weight impact testing and quasi-static testing. After testing it was confirmed that the application of thermoplastic composite skins to UHPC panels improved the impact resistance of the UHPC. Preliminary results showed little or no performance differences between the thermoplastic tapes and the vacuum infused panels. Thermoplastic tape reinforcement may have a fabrication method well suited for automated production, which is an advantage over the labor intensive vacuum infusion procedure. More work must be performed in order to optimize the thermoplastic composite reinforced UHPC panel design for impact resistance.

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