2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference

Bond Behavior of Structural Concrete using Recycled Coarse and Fine Aggregates

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Mr. Charles Rockson (Presenter)
Dr. Shahria Alam, University of British Columbia
Mrs. Kishoare Tamanna, UBC
Dr. Ahmad Rteil, The University of British Columbia

Concrete remains the most demanding material in the construction industry and requires the extraction of natural reserves which destabilizes the ecosystem through emissions. The global challenge in the 21st Century of reducing CO2 emissions in the construction industry is paramount in contributing to the sustainability initiatives and development strategy within the industry. One advantage is the use of recycled coarse and fine aggregates which is gaining attention in research and is also being added to international standards. Using recycled aggregates has been limited in proportion and application due to varied engineering reasons (low density, high water absorption, reduced modulus of elasticity, reduced bond strength, etc), and in some instances, eliminating its use for structural elements such as beams, slabs and columns. The bonding properties of using recycled concrete can give credence to expanding the current limitations and application of structural members. In this research the elemental form of beam behaviour (using beam-end specimens based on ASTM A944-2015) to determine the relative bond strength between reinforcements and structural recycled concrete strengths of 30-35MPa is investigated. The beam-end specimens containing 0%, 25%, 50%, 75% and 100% recycled fines and 100% coarse recycled aggregates, were tested to determine the effect of using recycled aggregates. The bond behaviour of 15M&25M bars, with bond lengths of 250mm and a cover of 2*db was investigated in this research. The experimental results are analyzed and discussed in this paper, and its effect in the provision of appropriate bond length is recommended as part of this research. The recommendations in this research can be applied to the use of recycled coarse and fine aggregates in structural elements which can be adopted safely to expand and promote sustainability, and thereby reduce the extraction and consumption of natural aggregates.