Progressive collapse of reinforced rubberised concrete: Experimental study Ibrahim M.H. Alshaikh a , B.H. Abu Bakar a,⇑ , Emad A.H. Alwesabi a , Hazizan Md Akil b a School of Civil Engineering, Universiti Sains Malaysia, Engineering Campus, Nibong Tebal, Penang, Malaysia b School of Materials & Mineral Resources Engineering, Universiti Sains Malaysia, Engineering Campus, Nibong Tebal, Penang, Malaysia highlights  This study experimentally investigated the progressive collapse of reinforced rubberised concrete frames.  A mitigation scheme is proposed for resisting progressive collapse by using rubberised concrete.  Adding crumb rubber increased the structural ductility by well over 50%. article info Article history: Received 16 March 2019 Received in revised form 9 July 2019 Accepted 22 July 2019 Keywords: Progressive collapse Rubberised concrete Reinforced concrete frame Structural ductility abstract This paper discusses on the efficiency of partial replacements of fine aggregate (sand) by waste crumb rubber for improving the deformability and structural ductility of the reinforced concrete (RC) frame and thus resisting progressive collapse. This research experimentally tested the behaviour of four RC frames at one-third-scale under the middle column removal scenario. For comparison, two frames were prepared for 0% crumb rubber as the controlled specimens. The remaining frames were prepared for 20% crumb rubber replacements by volume for sand. The mechanical properties, failure mode, the crack pat- tern, the load-displacement behaviour, and structural ductility are analysing herein for normal and RuC frames. Results indicated that there was enhanced in structural ductility induced by the addition of crumb rubber in conventional concrete. Meanwhile, the RuC frames showed more deflection than the NC frames. Therefore, RuC is an eco-friendly building material that can be used for enhancing the ductil- ity of RC elements as a new design strategy for preventing progressive collapse. Ó 2019 Published by Elsevier Ltd. 1. Introduction Progressive collapse is the ‘‘spread of an initial local failure from element to element, resulting eventually in the collapse of an entire structure or a disproportionately large part of it” [1]. Abnor- mal loads, such as design or construction error, accidental over- load, vehicular collision, foundation failure and explosions, lead to progressive collapses [2]. Given the growing number of terrorist attacks and the serious consequences of the progressive collapse of buildings due to sudden column loss, research on the best way to prevent such seriousness events must be conducted. In such events, the fundamental solution is to design structures with ductile components. Ductility of reinforced concrete (RC) members is defined as the capability of concrete to withstand large deformations without crashing before failure. Therefore, a ductile member can absorb energy without critical failure increases and reduce the probability of progressive collapse. In addition, rub- berised concrete (RuC) has advantages and disadvantages. The first advantage is RuC is the environmental solution to the disposal of waste tires. Second, the addition of waste tires as crumb rubber (appropriate rubber content replacement of sand) in concrete mixtures improves the deformability, ductility and strain capacity [3–10]. According to the authors (e.g. [3,11–14]), the mechanical prop- erties of RuC (compressive strength and splitting tensile) decrease with the increasing replacement ratio of rubber content and the decreasing rubber particle size. In addition, replacement ratios that exceed 20% are unsuitable for use in RC members. Few studies have been carried out on the possibilities of using RuC for structural applications in large-scale specimens. For exam- ple, Son et al. [10] investigate the strength and deformability of reinforced RuC by testing 12 columns. Xue and Shinozuka [15] investigated the seismic performance of RuC columns. Ganesan et al. [9] studied the effect of self-consolidating rubberised https://doi.org/10.1016/j.conbuildmat.2019.07.270 0950-0618/Ó 2019 Published by Elsevier Ltd. ⇑ Corresponding author. E-mail address: cebad@usm.my (B.H. Abu Bakar). Construction and Building Materials 226 (2019) 307–316 Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat