Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-48712 Zeitschriftenartikel Shamsuddoha, Md; Hüsken, Götz; Schmidt, Wolfram; Kühne, Hans-Carsten; Baeßler, Matthias Long-term mechanical and shrinkage properties of cementitious grouts for structural repair Grouts have numerous applications in construction industry such as joint sealing, structural repair, and connections in precast elements. They are particularly favoured in rehabilitation of structures due to penetrability and convenience of application. Grouts for repair applications typically require high-performance properties such as rapid strength development and superior shrinkage characteristics. Sometimes industrial by-products referred as supplementary cementitious materials (SCM) are used with neat cement due to their capabilities to provide binding properties at delayed stage. Micro silica, fly ash and metakaolin are such SCMs, those can modify and improve properties of cement products. This study aims at investigating long-term mass loss and linear shrinkage along with long-term compressive and flexural strength for grouts produced from ultrafine cement and SCMs. A series of mixtures were formulated to observe the effect of SCMs on these grout properties. Properties were determined after 365 days of curing at 23oC and 55% relative humidity. The effect of SCMs on the properties are characterised by statistical models. Response surfaces were constructed to quantify these properties in relation to SCMs replacement. The results suggested that shrinkage was reduced by metakaolin, while micro silica and fly ash had positive effects on compressive and flexural strength, respectively. 4 avenue du Recteur Poincaré, 75016 Paris, France RILEM Publications SARL 2019 RILEM Technical Letters 4 International Conference on Sustainable Materials, Systems and Structures (SMSS 2019) Rovinj, Croatia 20.03.2019 22.03.2019 9 15 10.21809/rilemtechlett.2019.82 2019-08-19 OPUS4-48796 Beitrag zu einem Tagungsband Hüsken, Götz; Shamsuddoha, Md; Thiele, Marc; Baeßler, Matthias; Kühne, Hans-Carsten Comparison of cracks formed in scaled grouted connection of offshore energy structures under static and cyclic loads Global energy consumption will increase in the future necessitating both fossil fuels and renewable energy choices - especially wind energy. Such high energy demand requires installation of offshore energy structures, rigs, platforms and towers, which are susceptible to adverse environmental conditions along with maintenances. Due to their large size and remote locations, cylindrical grouted joints are often adopted between substructure and foundation in these offshore platforms and wind structures such as monopiles. However, these connections are composite structures with exterior sleeve, interior pile and infill mortar. Degradation and settlements were reported inside similar connections, which were installed in last three decades. Besides, grouting in the offshore sites were proven difficult to obtain ideal load bearing capacity. In-situ loading conditions were also found to be affecting the failure mechanism inside such connections. This study aims at characterizing the nature of cracks generated in these grouted connections under both static and cyclic loading. Scaled grouted joints were manufactured using a novel reusable mold, and connections were loaded to failure to visualize the main failure patterns. An assessment between failure under these two types of load is drawn along with comparison to previously available literature. 2019 Proceedings of SMAR 2019 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures Potsdam, Germany 27.08.2019 29.08.2019 Th.2.A.1-1 Th.2.A.1-9 urn:nbn:de:kobv:b43-487961 https://creativecommons.org/licenses/by/4.0/deed.de 2019-09-02 OPUS4-52059 Zeitschriftenartikel Hüsken, Götz; Shamsuddoha, Md; Pirskawetz, Stephan; Hofmann, Detlef; Baeßler, Matthias; Kühne, Hans-Carsten Potential of a Repair System for Grouted Connections in Offshore Structures: Development and Experimental Verification Grouted connections are intensively used in offshore rigs, platforms as well as jacket and monopile offshore wind turbine structures. Being located in remote offshore conditions, these connections can experience considerable adverse loading during their lifetimes. Degradation was reported inside similar connections, which were installed in the last three decades. Grouting in the offshore sites may often be proven difficult, which eventually leads to reduced load-bearing capacity of connections in the long run. Thus, repair and rehabilitation of such connections should be planned ahead to minimize operational delays and costs. In this study, scaled grouted connections were manufactured using a novel mould, whose integrity were monitored using digital image correlation (DIC). The connections were loaded under static load to visualize the main failure pattern using distributed fibre optic sensors and acoustic emission (AE) analysis. Grouted connections were then repaired using a cementitious injectable grout. The effectiveness of the grout injection was monitored using dye penetration technique. Finally, specimens are reloaded to identify the potential of such repair for grouted connections. Elsevier Ltd. 2021 Marine Structures 77 102934 10.1016/j.marstruc.2021.102934 2021-02-03 OPUS4-39914 Beitrag zu einem Tagungsband Shamsuddoha, Md; Baeßler, Matthias; Hüsken, Götz; Pirskawetz, Stephan; Kühne, Hans-Carsten; Thiele, Marc Banjad Pecur, Ivana; Baricevic, Ana; Stirmer, Nina; Bjegovic, Dubravka Identification of failure pattern in cylindrical grouted connection for wind structures - a pilot study At present, Wind Turbine Generators (WTGs) operating in onshore and offshore wind farms are primary sources of renewable energy around the world. Cylindrical grouted sleeve connections are usually adopted in these WTG structures to connect the upper structure and foundation for ease of installation. These structures including grouted connections experience considerable adverse loading during their lifetimes. Settlements were reported inside similar connections used in energy structures especially oil and gas platforms, which were installed in last three decades. Thus, repair and rehabilitation of such connections in existing wind structures should also be planned ahead to keep them operating in the future. The nature of failure and crack generation in grouted connections are crucial prior to adopt a strengthening strategy. This pilot study is carried out to actualize the failure mechanism in the grouted connection, when subjected to axial loading. A novel reusable scaled cylindrical grouted connection with shear keys was designed and tested for its load bearing behaviour. The mechanical test was accompanied by classical measuring techniques (e.g. displacement transducer) as well as non-destructive measuring techniques (e.g. digital image correlation (DIC), acoustic emission analysis (AE)). The failure mechanism incorporating slippage of the shear keys and cracking of the grout was investigated. The capacity and applicability of such test mould were also discussed. The knowledge is expected to pave way towards repair of deteriorated grouted connections with similar geometry and failure pattern. University of Zagreb, Faculty of Civil Engineering, Zagreb, Croatia 2017 Proceedings of the 1st International Conference on Construction Materials for Sustainable Future 978-953-8168-04-8 1st International Conference on Construction Materials for Sustainable Future (CoMS_2017) Zadar, Croatia 19.04.2017 21.04.2017 544 551 2017-04-25 OPUS4-42387 Beitrag zu einem Tagungsband Shamsuddoha, Md; Hüsken, Götz; Baeßler, Matthias; Kühne, Hans-Carsten; Thiele, Marc Critical factors affecting the capacity of cylindrical grouted connections in offshore energy structures Current trend suggests that global energy consumption will increase in the future. This growing energy demand and advancement of technology lead to explore all potential offshore fossil and non-fossil energy sources, necessitating erection of exploration and production structures, rigs, platforms and towers, which are susceptible to adverse environmental conditions along with their maintenances. Cylindrical grouted joints provide suitable connections between steel substructure and foundation in these offshore platforms and wind structures especially monopiles for ease of installation. However, these are composite connections with exterior sleeve, interior pile and infill grout. The capacity of these connections is affected by number of factors. The literature over last four decades by numerous researchers has shown the development of these connections with increasingly higher capacities and influences on these capacities due to various factors. This paper provides a comprehensive review on the factors affecting the connection capacity along with technical challenges for the future. Critical aspects and shortcomings of the current connection systems and potential solutions may be sought after for these issues are also discussed. American Society of Mechanical Engineers (ASME) 2017 Structures, Safety and Reliability - Proceedings of the ASME 3B 978-0-7918-5766-3 36th International Conference on Ocean, Offshore and Arctic Engineering Trondheim, Norway 25.06.2017 30.06.2017 UNSP V03BT02A037, 1 10 10.1115/OMAE2017-62510 2017-10-09 OPUS4-45922 Zeitschriftenartikel Shamsuddoha, Md; Hüsken, Götz; Schmidt, Wolfram; Kühne, Hans-Carsten; Baeßler, Matthias Ternary mix design of grout material for structural repair using statistical tools Repair is an indispensable part of the maintenance of structures over their lifetimes. Structural grouting is a widely used remediation technique for concrete components, trenches, mine subsidence, dam joints, restoration of masonry structures, and geological stabilizations. A structural grout system should be injectable in narrow spaces and hence include ingredients with finer particles. Ultrafine cements are ideal for these type of demanding grouts due to their superior properties compared to that of the less expensive, but coarser ordinary Portland cement (OPC). Supplementary cementitious materials (SCMs) are often used to replace OPC clinker based binder in order to modify certain properties and to reduce costs. The most commonly used SCMs are fly ash (FA), and ground granulated blast furnace slag (GGBS). For various special applications microsilica (MS), and metakaolin (MK) are also used. Identifying the optimum replacement contents of OPC by SCMs are a challenge during the design of such grouts. The aim of this experimental study is to investigate the effect of the selected SCMs (FA, MS and MK) on the slump flow, time of efflux, viscosity, shrinkage, and compressive and flexural strength of ultrafine cement based grouts with constant water-binder ratio and superplasticizer content. The test program was formulated using Box-Behnken design principles. Maximum percentages of replacement with ultrafine cement was 6% by volume of cement for MS and 16% for FA, and MK. The results suggest that most investigated grouts have the potential to be used for structural applications. The appropriate quadratic models are then formulated through statistical tools and presented as response surfaces. The trends indicate that fly ash improves the rheological properties, whereas microsilica and metakaolin positively affect shrinkage and mechanical properties to some extent. Based on the influence of SCMs and priorities among the properties, Decision Matrix Analysis (DMA) is carried out to select the most suitable ones among the SCMs. The analysis suggests that microsilica and fly ash are more suitable as SCMs than metakaolin without affecting the properties. Elsevier Ltd. 2018 Construction and Building Materials 189 170 180 10.1016/j.conbuildmat.2018.08.156 2018-09-13 OPUS4-46476 Beitrag zu einem Tagungsband Shamsuddoha, Md; Hüsken, Götz; Schmidt, Wolfram; Kühne, Hans-Carsten; Baeßler, Matthias Alexander, M.G.; Beushausen, H.; Dehn, F.; Moyo, P. Workability and mechanical properties of ultrafine cement based grout for structural rehabilitation: A parametric study on the partial replacement with SCMs Grouting is a universal repair and strengthening technique, which is constantly used for structural remediation of concrete components, trenches, mine subsidence, dam joints, restoration of masonry structures, and geological stabilizations. Having an extremely small particle size of only few microns, ultrafine cements are ideal for grouting applications due to their superior permeability and compressive strength properties of the hardened cement paste compared to that of the less-expensive, but coarser ordinary Portland cements. Supplementary cementitious materials (SCMs) are often used to replace ultrafine cement in order to modify certain properties and to reduce costs. The aim of this experimental study is to investigate the effect of three supplementary materials: microsilica (MS), fly ash (FA), and metakaolin (MK) on the workability, and mechanical properties of an ultrafine cement based grout with a constant water-binder ratio and constant superplasticizer content. Maximum percentages of replacement with ultrafine cement were 6% by volume of cement for MS and 16% for FA, and MK. In general, results suggest that the workability is improved by addition of FA, whereas is reduced, when modified with MS and MK. The compressive strength of grout after cement replacement remains comparable to that of pure cement grout. However, there is a tendency of the MS to positively affect the compressive strength opposite to FA, whereas flexural strength is positively affected by FA. Based on the results, it is evident that grouts with Hägerman cone flow more than 500 mm and compressive strength of more than 90 MPa after 28 days can be produced. MATEC Web of Conferences 2018 Proceedings of the International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018) 199 International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018) Cape Town, South Africa 19.11.2018 21.11.2018 07006-1 07006-7 urn:nbn:de:kobv:b43-464769 10.1051/matecconf/201819907006 https://creativecommons.org/licenses/by/4.0/deed.de 2018-11-07 OPUS4-47831 Beitrag zu einem Tagungsband Shamsuddoha, Md; Hüsken, Götz; Schmidt, Wolfram; Kühne, Hans-Carsten; Baeßler, Matthias Superplasticizer and Shrinkage Reducing Admixture Dosages for Microfine Cement in Grout Systems Grouts have numerous applications including crack repair as maintenance in construction industries. Microfine cements are intensively used for high strength mortar and grout products. They are ideal for injection grouting in structural repair. Such grouts should have suitable rheological properties to be injectable, especially those used in repair and rehabilitation. The use of superplasticizers (SP) in these products is thus becoming increasingly crucial to achieve favorable workability and viscosity properties. A difficulty in such grouts is the plastic shrinkage due to finer particles used. It is thus necessary to determine optimum SP and shrinkage reducing admixture (SRA) dosages for a microfine cement based grout. In this study, a saturation dosage was decided from two Polycarboxylate ether (PCE) based SPs in relation to neat cement using slump flow and rheological parameters. A range of grout mixtures was formulated containing micro silica (MS) and fly ash (FA), and tested for suitable rheological and mechanical parameters. Based on the results, a grout mixture with MS and FA was selected to determine optimum SRA content. According to the results, a SP dosage of 3% by weight of neat cement is sufficient to achieve saturation. The grout material including MS and FA can produce comparable properties to neat cement grout. MS is found to improve compressive strength within the range considered, whereas a higher FA content provides favourable rheological properties. Finally, a SRA dosage of 4%, which could reduce the shrinkage by about 43% after 28d days, is determined for the grout system. EDP Sciences 2019 MATEC Web of Conferences 278 2nd International Conference on Building Materials and Materials Engineering (ICBMM 2018) University of Lisbon, Portugal 26.09.2018 28.09.2018 Article Number 01001 urn:nbn:de:kobv:b43-478319 10.1051/matecconf/201927801001 https://creativecommons.org/licenses/by/4.0/deed.de 2019-04-17