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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 97 Abstracts search results
Document:
SP188
Date:
August 1, 1999
Author(s):
Editors: Charles W. Dolan, Sami H. Rizkalla, and Antonio Nanni
Publication:
Symposium Papers
Volume:
188
Abstract:
SP-188 This volume presents 24 papers from the Fourth International Symposium and represents a significant expansion in the state of knowledge that has occurred since the First Symposium in 1993.
DOI:
10.14359/14223
SP188-43
J. O’Connor, H. Hoyos, A. Yannotti, S. Alampalli, and K. Luu
The New York State Department of Transportation is evaluating the use of innovative materials for bridge repair. One application being investigated is the strengthening of cracked reinforced concrete cap beams using fiber reinforced polymer (FRP) composites. In-house maintenance crews repaired two piers with FRP as part of a demonstration project with industrial partners to evaluate the benefits. One of two repair systems used is described in detail and is evaluated in terms of additional strength gained, cost-effectiveness, ease and speed of installation, impact on traffic flow during the repair, and long term durability. For comparison, data from a past project that employed conventional repair techniques are provided. This paper describes the project scope, subsequent repairs using FRP, and long term plans for monitoring.
10.14359/5647
SP188-44
E. Ferrier and P. Hamelin
With their strength and their specific stiffness, composite materials present a significant interest in the conception of bearing structures. The influence of combined effects "time-temperature-loading" on composite reinforcement adhesive layer was studied to identify the long-term mechanical behavior of RC beam reinforced with FRP. A set of tests were conducted on reinforced concrete structures with carbon epoxy composites. The tests consist of applying a tensile shear stress during six months to obtain the long-term creep data and to carry out thermo-stimulated test to assess short-term creep data. The master curves set up with this method predicts with reasonable accuracy the long-term creep test data. The time-temperature superposition method is used to determine several master curves with several levels of shear stress. This method permits an evaluation of the long-term shear stress to apply in the adhesive layer to minimize the creep. The durability of repaired or reinforced structure depends on the adhesive behavior. We have assessed that the identification of the long-term creep can be done with a thermo-stimulated test. This test allows setting up the safety factor for any polymer to guaranty the structure durability.
10.14359/5648
SP188-45
K. Sekijima, Y. Otsuka, and T. Konno
Many pretensioning prestressed concrete (PC) beams using the grid glass fiber reinforced polymer (GFRP) reinforcements as prestressing tendons were manufactured. The initial prestressing forces were selected at various levels, namely from 0 to 52.5 % of the tensile capacity of the grid GFRP reinforcement. Then, the PC beams were left outdoors for a long time, namely from seven to eight years. Thereafter, they were demolished to take the grid GFRP reinforcements out. First, the tests on tensile properties of the grid GFRP reinforcements were carried out. Their residual tensile capacities decreased only a little, and moreover, their residual tensile rigidities did not change. Then, the cross sections of the glass fibers of the grid GFRP reinforcements were observed with a scanning electron microscope (SEM). The cross sections remained real circular and the glass fibers were not attacked by alkali of concrete.
10.14359/5649
SP188-46
T. Uomoto and T. Nishimura
This paper clarifies, experimentally, the degradation of aramid fiber, glass fiber and carbon fiber, used as reinforcement for concrete, in various solutions (alkaline solution, hydrochloric acid aqueous solution and pure water) at different temperatures. A calculation model is proposed to estimate the progress of the degradation by the solution. The accelerated degradation test, immersing fibers in several solutions, was carried out at the temperatures of 20, 40 and 60 degrees Celsius and the strength of the fiber after the immersion test was examined. Observation of the fibers was carried out by scanning electron microscope (SEM) in order to clarify the degradation of the fibers. As a result of this study, the strength changes of Kevlar 49 and Technora were quantitatively estimated using the weakest link theory of Weibull.
10.14359/5650
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