Evaluation of Different Fiber Reinforced Mortar as Retrofitting Materials for Rc Columns

Abstract

ABSTRACT:This study is about the use of fiber reinforced mortar (FRM) as a jacketing material for reinforced concrete (RC) columns. Presented in this paper are analyses of the test results of destructiveloading that were conducted to explore the applicability of different jacketing materials as retrofit to RC columns. The jackets used to wrap RC columns were built of mortar mixed with different fibers. The fibers considered were steel fibers and polymer fibers. A simple model based on material properties was used to simulate the axial strength of the columns. The numerical model calculation results as well as the experimental test results were used to assess the performance of the jacketing materials used. The experimental part consisted of testing two sets of column specimens. The first set is wrapped with mortar jackets reinforced with steel fibers and the second set is wrapped with mortar jackets reinforced with polymer fibers with and without fly ash. The efficacy of the different FRM jackets as retrofitting materials was assessed by calculating the effect of confinement. The calculation was accomplished by measuring the maximum load of the retrofitted columns with jackets and then subtracting the load that can be carried by the control specimens, that is, the column with the original cross section. The confining effect was used as the basis in determining the confined compressive strength of concrete and then used to establish a model that can simulate the axial strength of the columns. The results indicate that the FRM jackets are effective as retrofitting material for RC column.

Contribution of Steel Fibers on Ductility of Confined Concrete Columns

“…The effect of spiral reinforcement and square stirrup reinforcement combined with steel fiber has been shown to increase the stress-strain capacity of concrete [17][18][19]. In this study, it was seen that there was an increase in the capacity of the P h-max force due to the influence of the restraints and steel fiber and all of the P h-max occurred at around 3.5% drift.…”

“…Several researchers have carried out the need to increase displacement and curvature ductilities [3][4][5][6][7][8][9]. On the other hand, in research that seeks to increase the stress-strain in concrete, some of these researchers have attempted in various ways [10][11], including by applying reinforcement using steel fiber to the unconfined concrete members [12][13][14][15][16] and some to the confined concrete members [17][18][19] the results of this study indicate an increase in the stress-strain of concrete due to the use of steel fiber.…”