Identifier

etd-11122008-194055

Degree

Master of Science in Mechanical Engineering (MSME)

Department

Mechanical Engineering

Document Type

Thesis

Abstract

The purpose of this study was to find the optimum mixing technique that leads to maximum gain in mechanical, thermal, and fire-retardant properties of vinyl ester based nanocomposites. Specifically, five combinations of incremental mixing intensity were applied to five groups of samples that were made of vinyl ester resin reinforced by 1 wt. % of montmorillonite (MMT). Changes in mechanical properties associated with each mixing combination were examined through a variety of tests, which were low velocity impact test, bending test, compression test, and dynamic mechanical analysis (DMA). Additionally, changes in thermal properties (e.g., thermal diffusivity, glass transition temperature) and fire-retardant properties associate with each mixing combination were also evaluated. The result was compared with pure vinyl ester resin. Finally, an optimum mixing combination was proposed. In order to additionally approve the effect of exfoliated MMT/VE, it was introduced to Advanced Grid Stiffened Fiber Reinforced Polymer (AGS-FRP) tube encased concrete cylinders and to improve their fire resistant behavior and mechanical property. MMT reinforced AGS-FRPC cylinders was fabricated and tested. This paper presents test results of temperature distributions and residual strength of 2 groups of AGS-FRPC cylinders with or without MMT reinforced (Groups A and B), which were exposed to a jet fire of 982oC for a time period of 5 minutes. The temperature distribution of the AGS-FRPC cylinders under fire was recorded by the embedded thermocouples. After fire test, uniaxial compression tests were conducted to evaluate the residual strength. The results were compared with that from a group of AGS-FRPC cylinders without fire exposure (Group E and F). To improve the fire resistance of the confined concrete cylinders, a fireproof additive was also applied to 2 other groups of specimens (Group C and D) and these specimens were also fire tested for 5minutes. And the results were compared with that from a group of AGS-FRPC cylinders without fire exposure (Group G and H). The final results show that the fire exposure has a significant effect on reducing the residual strength of the confined concrete cylinders. The introduced MMT increased the fire resistance and compression strength of AGS-FRPC cylinders. The fireproof additive used is effective in minimizing the effect of the fire hazard, but reduce some compression strength.

Date

2008

Document Availability at the Time of Submission

Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.

Committee Chair

Guoqiang Li

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