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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Showing 1-5 of 923 Abstracts search results
November 1, 2018
Wassim M. Ghannoum, Nawaf K. Alotaibi, Jose Garcia, Chang Hyuk Kim, Yungon Kim, Douglas Pudleiner, Kevin Quinn, Neil Satrom, William Shekarchi, Wei Sun, Helen Wang, and James O. Jirsa
Strengthening using carbon fiber reinforced polymers (CFRP) provides a valuable addition to available structural preservation and life extension techniques. Damaged bridges can be repaired efficiently while structurally deficient bridges can be effectively retrofitted to higher load capacities using CFRP materials. A large research program has been ongoing since 2008 in Texas to demonstrate the effectiveness of using anchored CFRP sheets in shear strengthening of reinforced concrete bridge beams and girders. The research program has encompassed three main thrusts: 1) over 70 large-scale tests of concrete bridge sections strengthened using externally applied anchored CFRP sheets, 2) small-scale tests aimed at developing CFRP anchor design criteria as well as a simple test procedure for quality control of materials and installation, and 3) developing design specifications for CFRP anchors and sheets in shear strengthening applications. An overview of the experimental findings of the program is presented.
Cristian Sabau, Cosmin Popescu, Gabriel Sas, Thomas Blanksvärd and Björn Täljsten
This paper summarizes the state-of-the-art on the topic of structural wall panels strengthened using fabric reinforced cementitious matrix composites (FRCM) composites. A systematic review of the literature is carried out to identify gaps in the available literature. A database of experimental tests, relevant for structural panels, was created and used to assess the influence of parameters such as test method, fiber type and material compressive strength, on the performance of FRCM strengthening. Since experimental investigations on walls strengthened with FRCM composites is still limited and mostly focused on shear, further investigations on walls as compression members can be considered timely, especially walls with openings, which have been overlooked. Experimental tests performed by the authors on reinforced concrete walls with openings are presented and assessed relative to the complete database. It was shown that FRCM composites are suitable repair solutions when new openings need to be created in existing walls.
Trevor N. S. Billows and Ahmad Rteil
The current state of North America’s infrastructure system is in dire straits. The cost of repair is estimated at over $3.6 trillion in the United States alone. As an alternative to the current strengthening methods, fabric reinforced cementitious mortar (FRCM) is proposed to aid the civil engineering industry in removing the infrastructure spending gap. This research initiative set out to determine the flexural strength improvement on RC beams with different textile ratios, different fabric materials and different anchorage methods. Five full-scale (200 x 300 x 4000 mm) (8 in x 12 in x 13 ft) reinforced concrete beams (1 control, 4 strengthened) were cast and tested under monotonic four-point bending conditions. Ultimate flexural capacity, pseudo-ductility, stiffness, and failure mode were taken as performance indicators. The study found that flexural strength was improved by up 81% over the control value.
Salah Altoubat, Abdul Saboor Karzad, Mohamed Maalej
This paper is part of an on-going research project on the behavior of damaged Reinforced Concrete (RC) beams repaired and strengthened with Externally Bonded Fiber Reinforced Polymer (EB-FRP). A total of seven full-scale rectangular beams; fully-damaged in a previous study, were repaired and retested to failure. The repair methodology consists of filling the cracks with epoxy, and then wrapping the beams with FRP discrete strips with two different thicknesses (1 layer and 2 layers). Out of the seven beams, four beams were strengthened using 2 layers of EB-FRP discrete strips; two beams were strengthened with 1 layer of EB-FRP; and the remaining beam was only repaired by crack injection with epoxy without wrapping with FRP. The beams were instrumented and tested to failure in three-points loading setup. The measured test parameters were the beams deflection and the maximum load-carrying capacity. Furthermore, the mode of failure was also observed and reported in this study. The test results revealed that the use of EB-FRP strips along with epoxy injection is an effective repair method that not only recovers the original strength (strength of the beams tested in previous study, considered as the reference beams), but also significantly increases their shear capacity. Comparing the shear capacity of the repaired beams to that of the reference beams, revealed that 2 layers of EB-FRP increased the shear strength by up to 95%, while the use of 1 layer of EB-FRP increased the shear strength by up to 66%. Moreover, comparison of the test results with existing predictive models (ACI 440.2R and fib TG-9.3) showed that both models reasonably predict the EB-FRP contribution to the shear strength of repaired and strengthened damaged beams.
Ruo-Yang Wu and Chris P. Pantelides
A rapid repair or replacement method is developed for severely damaged concrete bridge columns due to cyclic loading. A carbon fiber-reinforced polymer (CFRP) shell and headed steel bars are used to relocate the column plastic hinge. The technique employs a steel collar with steel studs to increase bond of the original column to repair concrete inside the CFRP shell. Two bridge columns were damaged including concrete crushing and longitudinal steel bar pullout under quasi-static cyclic loads. One of the specimens required additional epoxy injection of the cracks; for the other specimen, the column and cap beam were decoupled before repair to simulate replacement of a column which sustained unrepairable damage. The technique successfully relocated the plastic hinge and restored strength and displacement capacity. Failure of the repaired specimens included concrete crushing and bar fracture. The technique is an accelerated bridge construction method and could be used to repair columns with repairable damage or replace columns with unrepairable damage.
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