Effect of the Fiber Type and Axial Stiffness of FRCM on the Flexural Strengthening of RC Beams

Abstract

Abstract:The use of externally-bonded fiber-reinforced polymer (FRP) sheets has been successfully used in the repair and strengthening of both the shear and flexural capacities of reinforced concrete (RC) beams, slabs and columns since the 1990s. However, the externally-bonded FRP reinforcements still present many disadvantages, such as poor performance in elevated temperature and fire, lack of permeability and strength degradation when exposed to ultraviolet radiation. To remedy such drawbacks, the fiber-/fabric-reinforced cementitious matrix (FRCM) has been recently introduced. The FRCM system consists of a fiber mesh or grid embedded in a cementitious bonding material. The present research investigates the flexural strengthening of reinforced concrete (RC) beams with FRCM. The experimental testing included eight large-scale concrete beams, 150 mm × 250 mm × 2400 mm, internally reinforced with steel bars and strengthened in flexure with FRCM. The investigated parameters were the internal steel reinforcement ratio and the FRCM systems. Two steel reinforcement ratios of 0.18 and 0.36 of the balanced reinforcement ratio, as well as three FRCM systems using glass, carbon and PBO fibers were investigated. Test results are presented in terms of load-deflection, load-strain and load-crack width relationships. The test results indicated that the PBO FRCM significantly increased the ultimate capacity of the strengthened RC beams with both low and moderate internal reinforcement ratios compared to the glass and carbon FRCM.

Repair of Heavily Damaged RC Beams Failing in Shear Using U-Shaped Mortar Jackets

“…The aforementioned literature review reveals that the majority of the conducted research is focused on the application of nonconventional jackets in strengthening methods of original RC structural members [17][18][19]21,22,24,[26][27][28][30][31][32][33][34]36,[38][39][40][41][42][43][44][45][48][49][50]56]. Significantly fewer studies investigate such jackets for the repair of preloaded and slightly damaged RC specimens [20,23,25,29,35,37,46,47,[51][52][53][54][55].…”

“…These reasons have led researchers to switch to new jacketing techniques with alternative materials such as steel [17][18][19], advanced materials such as fiber reinforced polymer (FRP) [20][21][22][23][24][25], textile reinforced concrete or mortar [26][27][28][29] and shape memory alloys [30][31][32], cement-based materials such as ferrocement [33][34][35][36], steel fibrous concrete or mortar [37][38][39][40], high-performance fiber reinforced concrete [41][42][43][44][45][46][47][48], self-compacting concrete (SCC) [49][50][51][52][53][54], and thin slightly reinforced flowable mortar [55,56]. Many of these jacketing techniques have been proved successful substitutes to common RC jacketing.…”

Experimental Investigation of Four-Point Flexural Behavior of Textile Reinforcement in Geopolymer Mortar

“…Then, the specimens continue to undergo a multi-cracking process, in which all o f the stresses are transferred fro m matrix to textile. At this stage, the textile is only carrying until it fails by rupturing or by slipping [13]. In Fig.…”

Flexural Performance Evaluation of Various Carbon Fibre Fabric Reinforced Geopolymer Composite

“…This is due to the favourable properties offered by TRC, such as its resistance to corrosion, its high strength to weight ratio, its ease and speed of application and the minimum change in geometry. Furthermore, TRC composites are also considered when manufacturing lightweight concrete structures or prefabricated sandwich panels with outstanding mechanical performance, and high-performance concrete construction with free-form designs [7][8][9][10][11][12][13][14][15] A textile reinforced geopolymer (TRG) is a relatively new composite material. To date, many works have been performed to evaluate the effectiveness of the use of a textile reinforced geopolymer matrix composite for the external strengthening layer of existing structure members [16][17][18][19][20][21][22][23][24].…”