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Title: Shear-Friction Behavior of Recycled and Natural Aggregate Concrete—An Experimental Investigation

Author(s): Khaldoun N. Rahal and Abdul-Lateef Al-Khaleefi

Publication: Structural Journal

Volume: 112

Issue: 6

Appears on pages(s): 725-733

Keywords: recycled aggregates; reinforced concrete; shear; slip; strength

DOI: 10.14359/51687748

Date: 11/1/2015

The results of an experimental investigation of the shear-friction behavior of recycled and natural coarse aggregate concrete are reported. Eighteen non-precracked pushoff specimens were tested. The percentages of replacement of coarse aggregates with recycled aggregates in the concrete mixtures were 0%, 50%, or 100%. The specimens made of the same concrete had different amounts of clamping reinforcement across the shear-transfer plane. It is shown that all specimens with clamping reinforcement resisted significant post-ultimate strengths, in addition to relatively large slips along the shear-transfer planes. It is also shown that the full replacement of conventional aggregate with recycled aggregate had a limited effect on the ultimate and post-ultimate reserve shearing strength, while partial replacement (50%) caused a more significant reduction in the ultimate shearing strength. The results also showed that the ultimate strength was reached as soon as the clamping steel yielded. The nominal strength calculated using the shear friction model of the ACI Code, using a coefficient of friction suitable for monolithic construction, was significantly lower than the observed ultimate strength. The calculated strength was closer to the post-ultimate strength.