Some Studies On Slab Panels Using Textile Fabrics As A Reinforcement And Mortar, Micro Concrete And Gfrp As A Repair Materials

Abstract

Repair of RC structures using different repair materials has a substantial growth in construction industry since last decade.Fewer efforts have been made to understand the effect of the repair of reinforced concrete slab with polymer modified mortar, micro concrete, GFRP cloth etc.Experimental studies provide results to predict the

exural behavior of RC slabs. During first phase of present investigation total four nos. of slabs of dimensions 2m*1m*0.1m have been cast.Three slabs are considered for repair.One slab is con- sidered as a control specimen.Slab is repaired with micro concrete and mortar.20mm layer of both material is provided on top tension surface of the slab.One slab is repaired using GFRP cloth.All the slabs are tested under four point bending.Comparative per- formance of all the slabs in case of load resistance,de ection,strain,failure modes and crack patterns are evaluated experimentally.Displacement at mid-span and at (1/3) span of the slab has been evaluated.Strain in concrete at six locations has been eval- uated for all the slabs.Experimental results show that as compared to the capacity of control slab,slab repaired with micro concrete gives the capacity of slab up to 60 %.Slab repaired with mortar gives the capacity of slab up to 47 % as compared to the capacity of the control slab.Slab repaired with GFRP cloth nearly doubles the load carrying capacity of the control slab.Except GFRP repaired slab,other three slabs show similar types of failure patterns with major cracks along central longer span and cracks propagating on all the sides. Many attempts have been made to find out the alternatives of replacement of steel bars as a reinforcing material for RC elements.For RC slabs, one available option is textiles consisting of fabrics of alkali resistant glass fibers,aramid,carbon etc.TRC- Textile Reinforced Concrete is an innovative composite material made from a con- crete matrix and textile reinforcement either by glass or carbon, which makes the production of extremely light and slender components permissible.This exible reinforcement makes it possible to create free forms and geometries. During second phase of present investigation phase, twelve slab panels each of dimensions of 500mm 250mm 35mm and 500mm 250mm 25mm have been cast.Two different concrete mixes such as micro concrete of grade M-50 and mor- tar mix are used to cast twelve slab panels respectively. Four slab panels each have been reinforced with grid patterns named by(2*2),(3*3) and (4*4) of steel bars re- spectively.Four panels each have been reinforced with textile fabrics one/two layers of biaxial grid and one layer of fibre mat respectively.Four slab panels are considered as control panels.Performance of the slab panels ,with steel reinforcement,with tex- tile reinforcement and without any reinforcement have been compared in three point bending.For each slab panel,load carrying capacity,cracking pattern, load vs.de ection characteristics etc. has been observed experimentally.Experimental result shows as compared to load carrying capacity of control panels,load carrying capacity of slab panels reinforced with steel grids is higher.Slab panels reinforced with textile fabrics show higher load carrying capacity as compared to load carrying capacity of control slab panels. Slab panels reinforced with (4*4) grid of steel bars gives the highest load carrying capacity.Results also show with increasing layers of biaxial grid, load carrying capacity of the slab panels increases.Plain concrete slab panels break into two pieces on the other hand,slab panel reinforced with steel bars show bending of the slab and results into smaller cracks.Slab panels reinforced with textile fabrics show brittle failure it as it breaks into two parts by tearing of the fibres.Failure mode and cracking patterns for all the slab panels are very similar in nature.From experimental results it can be concluded that though slab panels reinforced with textile fabrics give at par same load carrying capacity but failure of textile reinforced panels is brittle in nature,as compare to steel reinforced slab panels which shows ductile behavior.