Consideraciones relativas al diseño y a la alta durabilidad de dovelas de hormigón reforzado con fibras no metálicas (hrfnm)
- Autores: Janill De la Cruz
- Directores de la Tesis: Ignacio Segura Pérez (dir. tes.), Pablo Pujadas Alvarez (codir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2020
- Idioma: español
- Materias:
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- Resumen
The use of the fibre reinforced concrete (FRC) as a construction material has expanded beyond the traditional applications since the publication of design codes and structural guidelines. Fibre reinforced concrete for tunnel lining segments rings is already a standard practice worldwide, where the technical advantages that its use leads are known. Despite of numerous advantages of the FRC, incertitude still exists regarding the design, characterization and performance of these materials.
There are several references in the literature on experimental campaigns reinforced with conventional rebars as reinforced with the partial or total replacement of conventional rebars by structural steel fibres. However, studies on the concept of a sustainable precast tunnel segment, reinforced only with macro-synthetic structural fibres is for the moment very minority, in a few cases barely existing, due to the lack of experience with this type of fibres and the lack of knowledge of the benefits they can offer in a long term. In this context, further research is required to improve current tools to characterize and design nonmetallic FRC structures.
The main topics addressed in this thesis are oriented to: 1. analyse the structural viability of non-metallic structural macrofibres for tunnel lining segments. 2. Study the durability of plastic fibres against external agents. 3. Establish a design proposal for non-metallic structural fibre-reinforced segments on a real scale.
In order to achieve the objectives of the present doctoral thesis, the first part is focused on the study of the structural viability of non-metallic macro-fibres with a structural purpose. For this purpose, several experimental campaigns are carried out in order to evaluate the characterization of the material, observing the influence on the physical and mechanical properties from the type and content of fibers used in the concrete. Subsequently, the study focuses on quality control at early ages. Finally, this first part is concluded with the development of a new technique capable of determining the fibre content in the nMFRC.
As important as the resistant capacity of the structures, is their ability to resist during their lifetime period of aggressions that the segments are exposed to. Therefore, it has been considered to study the durability of plastic fibres against external agents. As such, an experimental campaign is carried out in which the filament of the non-metallic fibres is subjected to various aggressive environments and exposures in order to characterise the physical and mechanical properties.
Finally, once the structural and durable viability of non-metallic fibres with a structural purpose has been studied, the need to carry out a study of the element on a real scale arises. In this sense, a full-scale study of the segment is carried out, based on the experimental results of the bending test on segments reinforced with polypropylene fibres (10 kg/m3) and metallic fibres (40 kg/m3).
