Semester

Spring

Date of Graduation

2012

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Civil and Environmental Engineering

Committee Chair

P.V.Vijay

Committee Co-Chair

Hota.V.S. GangaRao

Abstract

Wood railroad crossties resistance to current higher axle loads, speeds and frequency, along with the durability under harsh environments has proven to be inadequate. Additionally, defects such as decay, holes, splits, checks etc may further impair the strength and durability characteristics of the wood crossties. In this project, recycled polymer and discarded wood were used to increase the performance characteristics of the RR tie including resistance to higher axle loads, minimization of defects, and better performance under harsh environmental conditions. The objective of this study is to enhance and assess the strength characteristics of the timber crossties by using the glass fiber reinforced polymer (GFRP) composite shell. This research involved two different techniques for manufacturing the recycled composite ties, followed by laboratory testing of wood ties and GFRP recycled composite shell with wood core ties (thermoplastic) in WVU-CFC. The previous research program at WVU-CFC consisted of strengthening and evaluating the wood crossties by wrapping only the 12 inches wide steel plate embedment location using glass fiber fabrics saturated with resorcinol formaldehyde resin (thermoset).;In this research, over 200 recycled composite components were manufactured in the CFC laboratory that were used to mold 24 full-scale recycled composite ties with wood as a core material and GFRP composite as a shell material. The GFRP composite shell was manufactured using glass fabric reinforcement and Acrylonitrile Butadiene Styrene (ABS) resin. Two different fiber configurations were used in the manufacturing process-I (composite ties manufactured using twelve composite parts). Recycled composite ties produced under manufacturing process-I were tested under three point bending to evaluate the flexural rigidity. Test results of recycled composite ties from manufacturing process-I having fabric configuration-I were compared with those having fabric configuration-II. Further, recycled composite tie from manufacturing process-II (composite ties manufactured using two composite parts) along with wood crossties were tested under three point bending to evaluate the flexural rigidity, modulus of rupture, and static bending strength. Recycled composite ties showed higher static bending strength by approximately sixty percent than wood ties. Recycled composite ties also showed higher spike insertion and pullout strengths than the wood ties.;In order to study the dynamic response, a full-scale recycled composite tie produced through manufacturing process-II was embedded in gravel ballast and tested under flexural fatigue. The measured maximum deflection and applied bending moment values were compared with the theoretical values based on the classical beams on elastic foundation theory. The theoretical values were found to correlate well with the experimental values (within 10%). The research also included field testing of seven recycled composite ties on the South Branch Valley Railroad (SBVR) in Moorefield, WV. After three months of service, three ties with low fiber/fabric content showed localized horizontal cracking or some transverse cracks and the remaining four ties showed good field performance. Additional ties manufactured under this project are planned to be field-tested at TTCI, Pueblo, Colorado, test facilities. Conclusions and recommendations from this research work are summarized at the end of this report.

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