International Concrete Abstracts Portal

Corrosion of steel reinforcement is a major cause of deterioration problems in reinforced concrete structures exposed to harsh environmental conditions. The expansion of highway systems increased the need to provide corrosion-free reinforced concrete components for highway bridges. An extensive research program to investigate the behavior of two types of bridge barriers—PL-2 and PL-3—reinforced with glass fiber-reinforced polymer (GFRP) bars has been ongoing for the last 4 years at the Université de Sherbrooke, Sherbrooke, Quebec, Canada, in collaboration with the Ministry of Transportation of Quebec (MTQ). The geometry, concrete dimensions, and reinforcement of both PL-2 and PL-3 barriers were based on the new Canadian Highway Bridge Design Code. Sand-coated GFRP bars and conventional steel bars were used. A new detailing for connecting the wall to slab by extending the main reinforcement of the wall through the slab was introduced. This program included two parts. Part I involved laboratory tests on barriers under static loading conditions where four full-scale, 2 m-long barrier prototypes—2 PL-2 and 2 PL-3—were constructed and tested. Part II involved the behavior of barriers subjected to impact loads by performing a pendulum crash test using a 3.0 ton pear-shaped iron ball on eight full-scale 10 m-long barrier prototypes—4 PL-2 and 4 PL-3. The performance of barriers reinforced with GFRP bars was evaluated and compared with that of their counterparts reinforced with steel. Based on the results of this investigation, it is concluded that the behavior of PL-2 and PL-3 concrete bridge barriers reinforced with GFRP bars is very similar to their counterparts reinforced with conventional steel in terms of cracking, deflections, strains, energy absorption, integrity, and ultimate strength.

Failure modes and ultimate strengths of existing solid concrete gate walls in hydropower plants are not well understood in the present engineering practice. A continuum fracture simulation model, corroborated with exper-imental model studies, is considered in this paper for the safety assessment of tailgate walls of Beauharnois Power station in Quebec. Numerical simu-lation of the structural fracture response needs a priori experimental investigations to determine the material fracture parameters. However; fracture properties of concrete in existing structures are often not known, and experimental procedures for the determination of in situ fracture properties are also not well developed. In this paper, fracture properties of concrete are determined from the measured compress strengths by using the empirical relationships proposed in the literature. A smeared fracture analysis model, specifically developed for the fracture simulation studies of mass concrete structures, is applied to corroborate the reduced scale model test results. The validated tool is subsequently applied to assess the ultimate strength of an idealized finite element model of a tailgate wall. Effects of retrofitting measures that may be applied in similar structures to enhance the fracture resistance are also investigated in this paper.

Describing concrete setting time control applicatble by set-controlling admixtures based on author's experience. Studies conducted on projects such as Gentily Nuclear Center, Gentiliy, Quebec; International Nickle stack, Sudbury, Ontario Husky Tower, Calgary, Alberta, and numerous others.