STUDY OF REINFORCED CONCRETE FERROCEMENT COMPOSITE -BEAMS

Abstract

Composite construction gives more versatility to,, ferrocement, the delicate looking thin wall construction material. The basic idea behind this technique is that mortar can undergo large strains• in the neighbourhood of the reinforcement and the magnitude of strains depends on the distribution and subdivision of reinforcement throughout the mass of the mortar. The cracking in flexural member is undesirable from aesthetic point of view and also it is responsible for the corrosion of reinforcement. The ferrocement elements can act as formwork for composite construction of beams, lintels, columns and other structural elements. The composite construction gives improved stiffness, strength and resistance to cracking loads with negligible change in the member dimensions. The distressed beams can be repaired and strengthened by applying a thin layer of ferrocement. In the present study, R.C. ferrocemert composite beams were tested in flexure. Also R.C. Beams were tested in flexure, repaired with epoxy and then rehabilitated/strengthened by ferrocement jacketing. The jacket was not connected to R.C. beam by any mechanical means. There was only friction between the surfaces. A comparative study showed that the composite beam strength is increased by 44% with respect to original beams. Strength of rehabilitated beams increased by 39%, cracking load goes .up by 11% and 33% for two types of composite beams. Rehabilitated beams show 11% increase in cracking load. Deflection reduced by about 37% in composite beams and 29% in rehabilitated beams. The average decrease in crackwidth for composite beam was 42% and for rehabilitated beams 36%. The study shows that casting R.C. beams in this ferrocement jacket and casting jacket on distressed R.C. beams can substantially increase their stiffness and strength, reduce cracking and structural deformation at all load levels. The jacketed beams showed beam action and composite behaviour upto failure. With the increasing cost of timber and shuttering the use of f.errocement as formwork for strengthening structural elements is' gaining importance- day by day. It is not only economical method but also environment friendly.