Early Stage Researcher
University College Dublin (UCD)

Project 1: Reliability of concrete structures reinforced with braided FRP

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Research Interests:

Materials science & engineering; Environmental & earth science; Geophysics & engineering geology; GeoMaterials technology; Building materials

Biography:

She holds a BSc in Geology & Geo-Environment from National & Kapodistrian University of Athens and she obtained her MSc degree in Materials Science & Engineering from National Technical University of Athens.

During her studies, she successfully completed her thesis in the field of Materials Technology and she joined in university’s internship program.

Then, she worked as geotechnical engineer in private sector and she participated as research associate in three scientific projects and international conferences before joining TRUSS ITN in September 2015.

Research Outputs:

  • Stamatakis, M., Antonopoulou, S., Kavouri, S., Stamatakis, G., Papavlasopoulou, N. and Anastasatou, M. (2014), “Biogenic Micro – Silica: A multifunctional raw material in environmentally friendly applications”, in Proceedings of 22nd International Conference on Materials and Technology, Portorose, Slovenia.
  • Antonopoulou, S., Badogiannis, E. and Tsivilis, S. (2013), “Comparison of geopolymers and cement mortars as concrete repairing materials”, in Proceedings of 9th National Scientific Conference on Chemical Engineering, Athens, Greece.
  • Stamatakis, M., Fragoulis, D., Stamatakis, G. and Antonopoulou, S. (2010), “The opaline silica-rich sedimentary rocks of Milos Island, Greece and their behavior as pozzolanas in the manufacture of cement”, Advances in Cement Research, 22 (3): 171 – 183. DOI: http://dx.doi.org/10.1680/adcr.2010.22.3.171%20
Publications in TRUSS

In recent years, degradation of reinforced concrete (RC) structures due to corrosion of reinforcing steel has become a major concern worldwide. This affects long-term durability, total service life and structural safety of RC elements. Advanced composite materials, such as Basalt Fibre Reinforced Polymer (BFRP), are currently being developed and are showing promising results as a viable alternative to steel in infrastructure applications. More specifically, these materials can offer significant advantages related to both their non-corrodible nature and their enhanced physical and mechanical properties. However, their brittle nature is considered as the main limitation preventing their use on a larger scale. A detailed investigation of manufacturing technologies and design methodologies for the optimum development of BFRP composites, indicates that braiding methods could provide the required performance benefits through increased ductility and flexibility; it can also enhance the bond between FRP and concrete.

This study focuses on exploring the potential of braided Basalt Fibre Reinforced Polymer reinforcement through design optimisation and evaluation of their structural performance. Braided BFRP preforms with different configurations were produced changing key braiding parameters in order to achieve the desired structural geometry and meet the performance characteristics of existing rebar reinforcement. Following from that, successful epoxy resin impregnation trials in regular and spiral configurations confirmed the possibility of manufacturing braided BFRP composites in complex shapes. Moreover, a theoretical numerical approach based on Classical Laminate Theory (CLT) has been developed to determine the stiffness properties of manufactured braided composites, calculating the effective longitudinal in-plane modulus of each braided sample. The relation between geometrical factors and processing conditions on the physical and mechanical properties of the braided rebars was clearly observed. Future plans include assessment of the manufacturing process for improved rebar design, advanced material analysis and characterization tests combined with experimental validation of the developed numerical approach. In addition, finite element analysis (FEA) models will be developed for braided BFRP composites in order to assess the relation between braiding parameters and rebar performance.

In recent years, the development and use of Fibre Reinforced Polymer composite materials in infrastructure have gained increasing attention worldwide. More specifically, natural mineral fibres such as basalt are currently being developed and are showing promising properties. Within an appropriate polymer matrix, their use as reinforcement in concrete structures offers performance benefits related to their environmentally friendly and non-corrodible nature. In particular, BFRPs have the potential to replace conventional internal steel rebar and thus, to be the next generation material in concrete reinforcement applications. A detailed literature review indicates that a careful selection of the appropriate manufacture technique and design methodology are required in order to prevent brittle failure on a concrete structure reinforced with FRP composite material. This paper reports on how to use the additional helical reinforcement and the braid configuration in order to increase strength, structural ductility and long term durability. Moreover, this study outlines the development of an analytical numerical model to predict the longitudinal elastic modulus of braided composites, as well as its validation by comparison of the results with available data from the literature.

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In recent years, significant research has been conducted, by both industry and academia, into the optimum development and use of Fiber Reinforced Polymer composite materials in infrastructure. In particular, it is widely recognised that FRPs have the potential to replace conventional internal steel rebars in concrete reinforcement and offer performance benefits related to their advanced properties, such as corrosion resistance, high tensile strength etc. A review of the available literature indicates that brittle behaviour of FRP can significantly decrease the expected ultimate load capacity and, thus have a negative effect on structure’s long term durability. However, selecting braiding as manufacture technique and enhancing flexural capacity and shear strength through additional helical reinforcement, could provide structure with the additional ductility needed to prevent a brittle failure. Furthermore, the impact of deterioration mechanisms, focusing on the interaction between FRP and concrete in a structure, is an aspect for further investigation via laboratory testing and advanced analysis. This study summarises the results of research on structural design and manufacture methods of FRP composite materials by presenting new configuration and types of FRP reinforcement in order to encourage the use of these promising materials in construction industry.

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