Bond characteristics of carbon fiber reinforced polymer strengthened concrete member exposed to acidic solution

Abstract

Deterioration of construction materials due to aggressive environments is becoming a serious issue nowadays. Concrete is a widely used construction materials however, due to its alkaline nature, it is highly susceptible to acidic corrosion. Therefore, the concrete structures lose the aesthetic appearance and become structurally unsafe even before it’s intended service life. In order to rehabilitate these deteriorated structures fiber composites were introduced in the civil engineering industry. Several types of fiber composites are available for the civil engineering application, however, due to the superior engineering properties Carbon Fiber composites are commonly used to strengthen buildings which may experience aggressive environments. Carbon Fiber Reinforced Polymer (CFRP) composites consist of carbon fibers which are relatively immune to the aggressive environmental conditions and epoxy resin matrix which is highly susceptible to environmental degradation. Extensive researches were conducted all around the world to investigate structural strengthening and load transfer mechanisms of CFRP strengthened system however, environmental degradation of these systems were studied comprehensively. Especially, very minimum research studies were conducted to investigate the degradation of CFRP to concrete strengthened system in acidic environment. This study aims to address the lacuna regarding the deterioration behaviour of CFRP to concrete strengthened system in acidic environmental conditions. Extensive literature review was conducted to identify available research studies and limitations in CFRP to concrete strengthened system in aggressive environmental conditions. At the beginning, a case study was conducted at Awissawela wastewater treatment, which was renovated from a near collapse condition by CFRP composite. Later experimental studies were conducted to study the degradation behaviour of CFRP, concrete and CFRP-Concrete interface under various acidic condition. These acidic conditions were simulated in order to achieve actual conditions identified in several locations. Series of accelerated environmental exposure were conducted and several tests were carried out. Finally, the obtained results were statistically analysed and conclusions were presented.