PERFORMANCE OF REINFORCED CONCRETE FERROCEMENT COMPOSITE BEAMS

Abstract

Composite construction have become one of the impressive reflection of today's development. The shortage of high grade raw-materials, rising prices and shortage of highly skilled labour has forced the architects and engineers for adopting various forms of composite construction to achieve strength economy and aesthetic appearance. Composite construction with ferrocement gives more versatility to the delicate looking thin walled construction mateial. The cracking in flexural member is undesirable from aesthetic point of view and also it is responsible for the corrosion of reinforcement. The R.C. ferrocement composite beam gives improved stiffness, strength and resistance to cracking loads with negligible change in the member dimensions and cracks are finer than the R.C. section. The present study deals with three objectives in view. The first being to investigate the efficacy of epoxy resins for repair and rehabilitation of distress structures and the possiblity of strengthening such rehabilitated beams with ferrocement jackets. The second objective was to study the performance of R.C. ferrocement composite beams and third was to verify the various ways to achieve full composite action in composite beams. • Four types of beams consist of four reinforced concrete and six composite beams were cast and tested upto ultimate load. In the second stage R.C. beams were repaired with epoxy and tested upto ultimate load. The purpose of this was to test the efficacy of epoxy repairing method as a rehabilitation technique. Again two beams of tested rehabilitated beams were repaired with epoxy and strengthened with 15 mm thick ferrocement jackets on the three sides of beams and tested upto ultimate failure. The experimental results showed 13%, 39.8%, 31.6%, 28.6% and 23.5% increase in ultimate strength for the epoxy repaired, epoxy repaired and ferrocement strengthened, composite with anchored transverse skeletal steel in R.C. infill, composite with skeletal steel in jackets only and bolted composite beams w.r.t R.C. beams repectively. The reduction in maximum crackwidth was of the order 13.9%, 38.5%, 38.5%, 24.6% and 40% for the above five group of beams. The bolted composite beams did not show any improvement in ulltimate loads compared to the without bolted composite beams implying that casting of R.C. beams in ferrocement jackets provides full composite action through friction only. In general, It was found, that by introducing mesh layers to R.C. beams, advantages of both R.C. and ferrocement were achieved.