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Thesis. (M.Tech. (Dept. of Civil Engineering and Building, Faculty of Engineering and Technology)) -- Vaal University of Technology, 2011. / This research focused on the structural performance of Fibre Reinforced Polymer (FRP) re-bars in structural foundation compared to steel reinforcement re-bars. The corrosion of steel re-bars is the main reason of deterioration of reinforced concrete. However, use of FRP re-bars as alternative reinforcement will address the deterioration of reinforced concrete. Carbon and Glass Fibre Reinforced Polymer re-bars were used as reinforcing bars and traditional steel reinforced concrete was used as the reference. Thirty six specimens of reinforced concrete bases were tested for flexural capacity at different ages. The simulation of Soil Bearing Pressure of this study was derived from the model of beam finite length on elastic foundation. The foundation base was treated as a beam while the soil was modelled as series of timber elements acting as springs. The mathematical model to reflect the model was as documented by Timoshenko (1976:18) and Den Hartog (1952:160). Results showed that stress in the steel re-bars of reinforced concrete was higher than that of Carbon Fibre Reinforced Polymer (CFRP) and Glass Fibre Reinforced Polymer (GFRP) re-bars by 227 MPa (5.99 percent) and 284 MPa (7.61 percent), respectively. The stress in CFRP re-bars was 57 MPa or 1.53 percent higher compared to GFRP re-bars of FRP reinforced concrete. Furthermore, the experimental ultimate moments of CFRP and GFRP reinforced concrete foundation – bases on the 28th day were 23.917 kNm (79.0 percent) and 23.529 kNm (77.7 percent) higher than the theoretical ultimate moments, respectively. However, steel reinforced concrete foundation – bases had the higher calculated deflection than FRP reinforced concrete. With high resistance to corrosion as a property, FRP re-bars appeared to be a better alternative reinforcement to steel in corrosion in an aggressive environment. / Vaal University of Technology

In their service life, fibre reinforced plastics (FRP) face a variety of environmental conditions resulting from natural or artificial factors. These include variable temperature and humidity conditions, energetic radiations such as ultraviolet rays from the sun, and diverse chemical reactants such as liquid in storage tanks and pipes. These factors are always combined and negatively affect the material properties over the time. Therefore, optimized utilization of FRP material requires reliable methods for quantifying, controlling, and predicting environmental effects. This allows for optimal handling of issues related to component design, economic assessment and safety considerations, as well as the technical problems relating to equipment maintenance. Efforts worldwide are devoted to the modelling of FRP environmental degradation. However, modelling efforts have been hindered by the complexity of the process. This analysis presents a comprehensive model of the environmental degradation of FRP and a prediction method. The modelling method consists of a theoretical demonstration based on material science theories. An analytical approach is proposed. It resolves the complexity of the process into only three components: the chemical degradation, the physical degradation, and the stress state modification. A method to represent the real service environment as a constant environment in laboratory is also introduced. Then, the comprehensive model is expressed as a dynamic constitutive equation resulting from the combination of the historical variation in chemical link density and cohesive forces and the stress history of the material. It is shown that: • The average of the chemical and physical degradation as well as its upper and lower limits can be determined in a laboratory, in a constant environment, as exponential functions of the degradation time. • The environmental degradation can be comprehensively measured as a stress relaxation. • Acceleration of the predictive test can be obtained from a modified time temperature shift principle.

by Kwok Kin Wing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1990. / Bibliography: leaves 126-128. / Acknowledgement / Abstract / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- General Background --- p.1 / Chapter 1.2 --- Previous Studies on Injection Moulded Short Fibre Reinforced Composites --- p.4 / Chapter 1.3 --- Scope of the Present Work --- p.6 / Chapter 2. --- Theory --- p.8 / Chapter 2.1 --- Elastic Moduli of Injection Moulded Short Fibre Reinforced Composites --- p.8 / Chapter 2.1.1 --- Elastic Properties of an Anisotropic Solid --- p.10 / Chapter 2.1.2 --- Elastic Moduli of a Unidirectional Lamina --- p.12 / Chapter 2.1.3 --- Laminate Theory for the Elastic Moduli of Short Fibre Reinforced Composites --- p.21 / Chapter 2.1.4 --- Out-of-Plane Elastic Moduli of Injection Moulded Short Fibre Reinforced Composites --- p.31 / Chapter 2.2 --- Thermal Conductivity of Injection Moulded Short Fibre Reinforced Composites --- p.32 / Chapter 2.2.1 --- Thermal Conductivity of a Unidirectional Lamina --- p.32 / Chapter 2.2.2 --- Laminate Theory for the Thermal Conductivity of a Multidirectional Laminate --- p.35 / Chapter 2.2.3 --- In-plane Thermal Conductivity of Injection Moulded Short Fibre Reinforced Composites --- p.36 / Chapter 3. --- Expeirimental Techniques --- p.37 / Chapter 3.1 --- Determination of the Elastic Moduli by Ultrasonic Techniques --- p.37 / Chapter 3.1.1 --- Theory of Measurement --- p.37 / Chapter 3.1.2 --- Ultrasonic Measurement --- p.40 / Chapter 3.2 --- Determination of the Thermal Diffusivity by Laser Flash Radiometry --- p.49 / Chapter 3.2.1 --- Theory of Measurement --- p.49 / Chapter 3.2.2 --- Thermal Diffusivity Measurement --- p.51 / Chapter 3.3 --- Fibre Orientation and Length Measurements --- p.57 / Chapter 3.4 --- Density Measurement --- p.58 / Chapter 4 . --- Results and Discussion --- p.60 / Chapter 4.1 --- Composites and Polymers Studied in the Present Work --- p.60 / Chapter 4.2 --- Elastic Moduli and Thermal Conductivity of the Fibres and Polymer Matrices --- p.60 / Chapter 4.3 --- Fibre Orientation and Aspect Ratio --- p.67 / Chapter 4.4 --- Elastic Moduli of the Composites --- p.74 / Chapter 4.4.1 --- General Features --- p.74 / Chapter 4.4.2 --- Comparison between Theory and Experiment --- p.77 / Chapter 4.5 --- Thermal Conductivity of the Composites --- p.90 / Chapter 4.5.1 --- Thickness and Width Dependence of the Thermal Diffusivity of the Composites --- p.90 / Chapter 4.5.2 --- Comparison between Theory and Experiment --- p.104 / Chapter 5. --- Conclusion --- p.113 / Chapter Appendix A --- Tables of Data --- p.115 / References --- p.126