Yes / This paper presents an experimental investigation of demountable reinforced concrete slabs using dry connections between reinforced concrete slab elements. The test specimens comprised six full-scale reinforced concrete slabs; one control slab monolithically cast, while the other five slabs were produced with mid-span demountable dry connections. The slab elements were cast separately and assembled using top and bottom steel plates joined to each side of the slab element by high tensile steel bolts with or without a shear key and embedded steel block. Theoretical analysis of the behaviour of the demountable slabs tested in comparison with the control specimen was also conducted. The test results showed that using a dry connection consisting of a shear key at the assembled section is the most effective technique in terms of moment resistance, deflection, and flexural stiffness. On the other hand, the dry connection with embedded steel blocks failed prematurely because of stress concentration at the block edges. The moment capacity and deflection predictions of demountable slabs have reasonably correlated with the experimental results but required additional calibrated data from experiments. / This work was supported by an Institutional Links grant, ID 414633184, under the Newton-Kâtip Çelebi Fund partnership. The grant is funded by the UK Department for Business, Energy and Industrial Strategy and TÜBİTAK – Scientific and Technological Research Council of Turkey and delivered by the British Council. For further information, please visit www.newtonfund.ac.uk.

Yes / In the current practice, at the end of life of a reinforced concrete structure, it is destructively demolished and the demolition waste is landfilled or recycled. This approach is clearly wasteful of energy, creating serious environmental pollution and at high cost. However, design for demountability/deconstruction (DfD) of reinforced concrete structures would facilitate the future reuse of structural elements at the end of their life, potentially achieving a significant reduction in embodied energy of structures as well as giving the clients the benefit of retaining the value of their assets. In this paper, recent research developments and practical applications of DfD of reinforced concrete structures are reviewed and key technical issues are discussed. The main focus was on connections that should be designed in such a way to allow demounting. The main achievements are outlined, for each type of dry and semi dry connections, along with the aspects that still need to be developed. It is concluded that only semi-dry connections are currently implemented but information available in the literature on dry connections between structural elements is still very scarce. The paper concludes with an outline of some future opportunities and challenges in the application of DfD in concrete construction.

Yes / In the current practice, at the end of life of a reinforced concrete struc-ture, it is destructively demolished, and the demolition waste is limited to downcycling and low-tech applications, while the remaining is being landfilled. A recent report showed that construction and demolition waste (CDW) is the big-gest waste stream in the EU by weight, accounting for over 800 million tons in 2018, i.e. around 32% of the total waste generated. This approach is clearly wasteful of energy, jeopardizing the health of individuals and environments and at high cost. However, design for deconstruction (DfD) of reinforced concrete structures would facilitate the future reuse of structural elements at the end of their life, potentially achieving a significant reduction in embodied energy of structures and CO2 emission as well as giving the owners the benefit of retaining the value of their assets. In this paper, recent research developments and practical applications of DfD of reinforced concrete structures are reviewed and key technical issues are dis-cussed. The focus is on connections that should be designed in such a way to al-low demounting of precast reinforced concrete structural elements, including beam/column, wall/wall, column/column and segmental slab connections. The main achievements and progress to date are outlined for each type of dry connec-tions, along with the aspects that still need to be developed. The paper concludes with an outline of challenges in the application of DfD in concrete structures. / This project was supported by the Newton Prize 2020, UK-Turkey award, grant ref number NP2020PB\100026, funded by the Department for Business, Energy & Industrial Strategy. It has also received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 894100. / The full-text of this article will be released for public view at the end of the publisher embargo on 1 June 2024. / This paper is from the fib Symposium 2023, Building for the future: Durable, Sustainable, Resilient. 5-7 Jun, Istanbul, Turkey.

Yes / This paper presents an experimental investigation of a new dry connection for reinforced concrete slab elements. Seven full-scale slabs were tested; one slab was monolithic as control specimens, while the other six were assembled using top and bottom steel plates joined by high tensile steel bolts. Two scenarios were proposed for the connection, a simple bolted connection, and a connection with a shear key. The parameters studied were the use of stirrups at the connection section, the step size of the shear key as well as the bolt diameter and number. The test results showed that using a shear key at the assembled section in demountable slabs is more efficient than the simple bolted connection, providing higher flexural stiffness, load capacity, and less deflection. However, increasing the shear key step size improved the flexural performance of the demountable slabs. In addition, adding stirrups to the assembled section enhanced the flexural stiffness and the total load capacity of the demountable slabs. Furthermore, the predictions for the moment capacity and deflection demountable slabs have reasonably good agreement with the experimental results but require additional calibrated data from experiments to be generalized. / Department for Business, Energy and Industrial Strategy (BEIS) / The full text will be available at the end of the publisher's embargo: 27th June 2024.