Improvement of mechanical strength of recycled blend concrete with secondary vibrating approach

摘要

To achieve construction sustainability, the use of demolished concrete as substitution of fresh concrete (FC) in recycled blend concrete (RBC) has gained significant attention. RBC is a concrete mix made of FC and coarsely-crushed demolished concrete blocks (DCBs) which are distinctly larger than the conventional aggregates. It is a simple and economical approach to recycling demolished concrete and has been implemented in many projects. However, some mechanical strength of RBC including the cylindrical compressive strength, tensile strength and flexural strength are inferior, limiting its acceptance by the construction industry. This paper proposes a remedial vibrating approach, namely "secondary vibrating approach (SVA)", intending to improve the mechanical strength of the RBC. Experimental results show that using SVA can significantly increase the mechanical strength of the RBC. Applying SVA helps to fill some of the voids and cracks and to meliorate the hydration, resulting in denser and stronger interfaces, and subsequently improves the mechanical strength of RBC. (C) 2019 Elsevier Ltd. All rights reserved.