Strength Degradation of Pre-Fatigued GFRP Composites under Hygrothermal Loading Conditions

Abstract

Composite materials are engineered materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct on a macroscopic level within the finished structure. Glass fibre-reinforced polymer (GFRP) have been used as an alternative to steel in concrete due to high strength-to-weight ratio, high stiffness-to-weight ratio, and corrosion and fatigue resistance. GFRP’s have been found attractive in the Asian region due to their cost competitiveness in comparison. Wide-spread use of fibre-reinforced polymers (FRP) in construction is hampered in this part of world due to lack of long-term durability and performance data, especially in a tropical environment. The main environmental factors for the deterioration of GFRP are temperature, sunshine, water/moisture, alkalinity and load. Most of the early durability tests were carried out with reference to application of FRP (Fibre Reinforced Polymer) in aerospace. With the consideration of the above points an experimental study was conducted to perform the pre-fatigue of GFRP specimen and then placing them in water at different temperatures i.e. 45°C and 55°C for one month and two month and observing the degradation in tensile strength for the specimen under investigation. Simultaneously macroscopic and microscopic behavior of the specimen were also studied at regular intervals and results were drawn graphically. In the end comparison for specimen exposed to different conditions of pre-fatigue load, time and temperature was done and different macroscopic and microscopic behaviors were observed and compared one on one in the graphical manner.