| 12. |
- Suchorzewski, Jan, et al.
(author)
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Quality assurance for reused concrete building elements
- 2023
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Reports (other academic/artistic)abstract
- This report describes work performed by RISE within Återhus project funded by the Swedish Innovation Agency Vinnova within Challenges-Driven Innovation program. The project aimed for developing new tools for accelerating the transition to circular construction understood as reusing building parts in new buildings. The key part of that process was identified as quality assurance and tackling the challenges concerning legal regulations, certification processes, determination of material quality by non-destructive and destructive testing, as well as calculation of remaining service-life. The report discussed also the most common deterioration mechanisms affecting service-life based on the pilot cases from the project. The calculation tool included carbonation and chloride ingress as two main mechanisms leading to risk of corrosion. Additionally theoretical relation of environment relative humidity to corrosion rate was embedded in the calculation to give an estimate of the remaining propagation period after corrosion initiation. The calculation tools were applied to estimate the residual service-life of slab elements of four pilot buildings based on empirical data gathered during inventory and condition assessment using both non-destructive methods and laboratory testing. A simple classification of concrete elements was proposed with a clear link to three main factors: remaining calculated service-life, observed cracking and the target environment.
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| 13. |
- Suchorzewski, Jan, et al.
(author)
-
Reusing of concrete building elements – Assessment and quality assurance for service-life
- 2023
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In: Materials Today. - : Elsevier. - 2214-7853.
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Journal article (peer-reviewed)abstract
- Strategic reuse of demounted concrete elements in new buildings may be one of the solutions that will support the transition to circular construction. To ensure wider application of concrete reuse, RISE developed a methodology for the assessment of the structural condition of existing buildings, and the selection of elements suitable for reuse, including guidelines for their disassembly, storage, and installation. However, one of the main obstacles for wide application of concrete reuse is the uncertainty concerning the remaining service-life of concrete elements and evaluation of quality over the future service-life in a new building. This paper describes a methodology for material and structural assessments which combine non-destructive, on-site testing with traditional laboratory tests of samples extracted from the structures. The results are intended to support the decision-making process on reuse and give a technical basis for the design of new buildings. Great consideration is put on various deterioration mechanisms for concrete and steel corrosion affecting structural condition of housing and office buildings. To assess the impact of degradation processes, theoretical models are considered, while the remaining service life is estimated by means of a simplified approach that provides the basis for evaluation of likelihood and severity of consequences entailed by material degradation on the structural performance. The proposed approach was validated on the results from three pilot projects, where real buildings in Stockholm and Uppsala, Sweden, were reused or prepared for reuse to different extent. The analysed buildings had different functions (housing, office, parking) and structures (prefabricated elements and in-situ casted concrete), being representative for Swedish building stock. One of the buildings has been already dissembled and the prefabricated, where prestressed hollow-core slabs have been successfully reused for a new office building construction. Based on these experiences, a simple classification system for quality of concrete elements for reuse was proposed with three main parameters, namely calculation of remaining service-life, extent of cracking and the target exposure class. The proposed system is not complete and must be further validated for various types of elements and structures by wider group of market actors.
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