Design for Disassembly of Concrete Slabs with Mortar Joints

A sustainable future is required for precast concrete structures, and the reuse of concrete elements will be an essential part of the solution. Design for disassembly is currently conducted with costly and time-consuming mechanical joints. Now, mortar joints with much weaker mortar types are propose...

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Main Author: Philip Skov Halding
Format: Article
Language:English
Published: MDPI AG 2023-07-01
Series:Buildings
Subjects:
Online Access:https://www.mdpi.com/2075-5309/13/8/1957
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author Philip Skov Halding
author_facet Philip Skov Halding
author_sort Philip Skov Halding
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description A sustainable future is required for precast concrete structures, and the reuse of concrete elements will be an essential part of the solution. Design for disassembly is currently conducted with costly and time-consuming mechanical joints. Now, mortar joints with much weaker mortar types are proposed for new buildings, enabling easier disassembly by new methods: removal by direct pulling and removal by use of a system of flat jacks. Different weak mortar types were tested in the lab to achieve the properties required to check the transfer of wind loads and the level of resistance to separation during disassembly. Using a modelled case study building, the results showed that weak lime cement-based mortars had the required properties to substitute regular cement-based mortar in joints between slabs and a stabilising wall during a critical wind load. Regarding disassembly, pulling concrete slabs out with a mobile crane would be possible if hydro demolition systems could be implemented to remove parts of the mortar joint beforehand. Using a system of flat jacks to push the slab apart showed that the method’s weakness was the punching failure of the thin wall to the hollow cores. Solutions were proposed to overcome the challenge.
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spelling doaj.art-a3185c03b7164e4e999842b00373fa2b2023-11-19T00:28:57ZengMDPI AGBuildings2075-53092023-07-01138195710.3390/buildings13081957Design for Disassembly of Concrete Slabs with Mortar JointsPhilip Skov Halding0Department of Civil and Mechanical Engineering, Technical University of Denmark, 2800 Kongens Lyngby, DenmarkA sustainable future is required for precast concrete structures, and the reuse of concrete elements will be an essential part of the solution. Design for disassembly is currently conducted with costly and time-consuming mechanical joints. Now, mortar joints with much weaker mortar types are proposed for new buildings, enabling easier disassembly by new methods: removal by direct pulling and removal by use of a system of flat jacks. Different weak mortar types were tested in the lab to achieve the properties required to check the transfer of wind loads and the level of resistance to separation during disassembly. Using a modelled case study building, the results showed that weak lime cement-based mortars had the required properties to substitute regular cement-based mortar in joints between slabs and a stabilising wall during a critical wind load. Regarding disassembly, pulling concrete slabs out with a mobile crane would be possible if hydro demolition systems could be implemented to remove parts of the mortar joint beforehand. Using a system of flat jacks to push the slab apart showed that the method’s weakness was the punching failure of the thin wall to the hollow cores. Solutions were proposed to overcome the challenge.https://www.mdpi.com/2075-5309/13/8/1957wet jointsDfD methodsdirect reusehollow core slabssustainabilityshear testing
spellingShingle Philip Skov Halding
Design for Disassembly of Concrete Slabs with Mortar Joints
Buildings
wet joints
DfD methods
direct reuse
hollow core slabs
sustainability
shear testing
title Design for Disassembly of Concrete Slabs with Mortar Joints
title_full Design for Disassembly of Concrete Slabs with Mortar Joints
title_fullStr Design for Disassembly of Concrete Slabs with Mortar Joints
title_full_unstemmed Design for Disassembly of Concrete Slabs with Mortar Joints
title_short Design for Disassembly of Concrete Slabs with Mortar Joints
title_sort design for disassembly of concrete slabs with mortar joints
topic wet joints
DfD methods
direct reuse
hollow core slabs
sustainability
shear testing
url https://www.mdpi.com/2075-5309/13/8/1957
work_keys_str_mv AT philipskovhalding designfordisassemblyofconcreteslabswithmortarjoints