TY - CONF A1 - Geißler, Peter A1 - Cuéllar, Pablo A1 - Hüsken, Götz A1 - Kühne, Hans-Carsten A1 - Baeßler, Matthias T1 - Insights into compaction grouting for offshore pile foundations N2 - The authors are currently investigating the possibility to apply compaction grouting for offshore pile foundations (Jacket piles as well as monopiles) as a possible retrofitting technique for an optimised foundation concept. In this research project, we are developing a design approach aiming to predict the ideal amount and properties of a grout for a specific soil situation and desired improvement of pile bearing capacity after Installation and during service time. Both numerical and experimental tests have been carried out to investigate the injection process during which a highly viscous grout is injected into the soil under high pressure to displace and compact the surrounding soil without fracturing it. The implicit Material Point Method (MPM) based on a mixed formulation is the numerical technique chosen to deal with the expected large deformations and the arbitrary shape of the developing grout bulb. The usage of MPM prevents both the need of remeshing and the numerical instability induced by extensive mesh distortion. For validation with experimental results, we have constructed a testing chamber with one transparent sidewall. This chamber enables us to observe the injection process directly at the transparent vertical window and to measure the in-plane soil displacements and strains by means of the Digital Image Correlation (DIC) technique. The results already reveal the interrelation of soil and grout properties for a successful usage of this common ground improvement technique. T2 - ASME 2018 37th International Conference on Ocean, Offshore and Arctic Engineering (OMAE 2018) CY - Madrid, Spain DA - 17.06.2018 KW - Offshore Pile Foundation KW - Compaction Grouting KW - Material Point Method KW - Digital Image Correlation PY - 2018 AN - OPUS4-45352 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shamsuddoha, Md A1 - Hüsken, Götz A1 - Pirskawetz, Stephan A1 - Baeßler, Matthias A1 - Kühne, Hans-Carsten A1 - Thiele, Marc T1 - Remediation of Cracks Formed in Grouted Connections of Offshore Energy Structures under Static Loads N2 - The future energy demand necessitates the exploration of all potential energy sources both onshore and offshore. Global trend has shifted towards offshore energy, which can be obtained from either carbon intensive or renewable options, hence requiring structures such as rigs, platforms, and monopiles. Most of these structures adopt easily installable construction techniques, where lower foundation need to be connected with the super structure by mean of grouted composite joints. Generally, these composite connections have exterior sleeve, interior pile and infill grout. Being located in remote offshore conditions, connections can experience considerable adverse loading during their lifetimes. Degradations were reported inside similar connections, which were installed in last three decades. Besides, grouting in the offshore sites may often be proven difficult, which eventually leads to reduced 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 the future. This study aims at characterizing the nature of crack generation in grouted connections and thereby identifying the potential of repair using suitable repair material. Scaled grouted joints were manufactured using a novel mold, and connections were loaded under static load to visualize the main failure pattern. The failure mechanism and loading capacity are found compatible to previous results from earlier literature. Grouted connection was then repaired using cementitious injectable grout. The effectiveness of the repair system is also discussed. T2 - Twenty-eighth (2018) International Ocean and Polar Engineering Conference CY - Sapporo, Japan DA - 10.06.218 KW - Offshore KW - Energy KW - Grouted Connection KW - Cracks KW - Repair KW - Rehabilitation PY - 2018 AN - OPUS4-45226 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hüsken, Götz A1 - Shamsuddoha, Md A1 - Thiele, Marc A1 - Baeßler, Matthias A1 - Kühne, Hans-Carsten T1 - Comparison of cracks formed in scaled grouted connection of offshore energy structures under static and cyclic loads N2 - 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. T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures CY - Potsdam, Germany DA - 27.08.2019 KW - Grouted connection KW - Crack formation KW - Crack pattern KW - Static load KW - Cyclic load PY - 2019 AN - OPUS4-48797 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geißler, Peter A1 - Schwarz, Johannes A1 - Cuéllar, Pablo A1 - Hüsken, Götz A1 - Baeßler, Matthias A1 - Kühne, Hans-Carsten A1 - Morrone, C. T1 - Compaction grouting to improve the pile bearing capacity in non-cohesive soil N2 - The increasing use of renewable energies leads to a constant search for optimised foundation concepts aiming to reduce the costs for offshore wind turbines. In an ongoing research project, we are developing a design approach for typical offshore driven piles based on the application of injections by compaction grouting directly at the pile shaft. Compaction grouting as a ground improvement technique has been used widely as a countermeasure against liquefaction, settlement and low bearing capacity of soil under new or already existing structures. It is performed by forcing highly viscous grout into the soil to displace and compact the surrounding soil without fracturing or penetrating it. Regarding this injection method, this paper gives a brief overview about general aspects such as appropriate soil characteristics and grouting parameters, grouting equipment and fields of application particularly in the offshore sector. This indicates the ability of our optimisation concept to provide an economic alternative to larger pile dimensions and a retrofitting technique, which is available during the entire lifetime of the foundation and can be deployed only in case of necessity (e.g. excessive deformations or insufficient structural stiffness after an extreme load event). Besides the material feasibility and the constructive realisation of this improvement measure, the development of a corresponding verification concept is crucial in order to ensure the safety and durability of the retrofitted offshore piles. Here we will examine various verification concepts with their respective limitations in the framework of the limit state design. Furthermore, we will present the experimental findings from field tests in sand indicating the advantages of several local injections by compaction grouting for the enhancement of the load bearing behaviour of pile foundations. The test results were also used to validate a numerical model, developed with the finite element program PLAXIS, aiming to predict the expected bearing capacity for different injection scenarios (e.g. grout volume, location of injection points) along a pile shaft. T2 - Twenty-ninth International Ocean and Polar Engineering Conference CY - Honolulu, HI, USA DA - 16.06.2019 KW - Offshore Pile Foundation KW - Compaction Grouting KW - Grout KW - Injection Sequence KW - Tensile Capacity PY - 2019 AN - OPUS4-48504 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baeßler, Matthias A1 - Zobel, D. A1 - Cuéllar, Pablo A1 - Geißler, Peter A1 - Hüsken, Götz A1 - Grabe, J. T1 - Improvement of the Bearing Capacity of Offshore Pile Foundations N2 - The Presentation gives an overview about Background, Needs and challenges with respect to pile design and modular pile capacity increase in the Frame of Offshore-Wind Foundations. Results and ideas of the Project TOP are presented. The presentation is prepared jointly by TUHH and BAM. T2 - Offshore Wind R&D Conference 2018 CY - Bremerhaven, Germany DA - 14.11.2018 KW - Grout Injection KW - Pile Capacity KW - TOP PY - 2018 AN - OPUS4-46626 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shamsuddoha, Md A1 - Hüsken, Götz A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Baeßler, Matthias T1 - Superplasticizer and shrinkage reducing admixture dosages for microfine cement in grout systems N2 - 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. T2 - 2nd International Conference on Building Materials and Materials Engineering (ICBMM 2018) CY - University of Lisbon, Portugal DA - 26.09.2018 KW - Grout KW - Mix design KW - Shrinkage KW - Crack repair KW - Microfine cement PY - 2018 AN - OPUS4-46155 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shamsuddoha, M. A1 - Hüsken, Götz A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Baeßler, Matthias T1 - Workability and mechanical properties of ultrafine cement based grout for structural rehabilitation: A parametric study on the partial replacement with SCMs N2 - 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. T2 - International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018) CY - Cape Town, South Africa DA - 19.11.2018 KW - Analysis of variance KW - Box-Behnken KW - Grouting KW - Repair KW - Supplementary cementitious materials PY - 2018 AN - OPUS4-46712 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hüsken, Götz A1 - Shamsuddoha, M. A1 - Schmidt, Wolfram A1 - Kühne, Hans-Carsten A1 - Baeßler, Matthias T1 - Long-term mechanical and shrinkage properties of cementitious grouts for structural repair N2 - Grouts 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 23 °C 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. T2 - International Conference on Sustainable Materials, Systems and Structures (SMSS 2019) CY - Rovinj, Croatia DA - 20.03.2019 KW - Grout KW - Long-term shrinkage KW - Micro silica KW - Fly ash KW - Metakaolin PY - 2019 AN - OPUS4-47625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -