| Summary: |
The maintenance of the existing infrastructure is becoming a heavy burden for society. The funding required for the rehabilitation, strengthening or replacement of deteriorated structures is very significant and, in the Portuguese case, is expected to increase in the next decades. The energy consumption and CO2 emissions from construction sites, as well as the indirect user costs related to the service disruptions, contribute to the total costs.
In the future, sustainable structures will be those requiring just minimum preventive maintenance with no or little service disruptions. Research should focus on developing technologies to improve the existing structures and limiting the construction interventions to a strict minimum while providing long and safe service duration.
The use of thin Ultra-High Performance Fibre-Reinforced cement-based Composites (UHPFRC) layers for rehabilitation and strengthening of concrete structures has shown to be a promising technique towards this objective. Due to its outstanding properties, not only the structure can be strengthened, but also the durability can be improved due to its extremely low permeability. Moreover, its compatibility with concrete and tailored rheological properties allow for efficient and short-duration interventions.
The first objective of this proposal is the development of a second generation of UHPFRC, more eco-efficient by achieving target mechanical and transport properties with reduced cement content and incorporating spent equilibrium catalyst (ECat), a residue generated by the Portuguese oil refinery industry. Besides exploring its pozzolanic activity, Ecat is going to be used for reducing the strong autogenous shrinkage of UHPFRC, which is an important improvement when the application of this material in thin layers over hardened concrete substrates is envisaged.
The second objective of this research is a methodology for predicting the "in-structure" tensile response of UHPFRC  |
Summary
The maintenance of the existing infrastructure is becoming a heavy burden for society. The funding required for the rehabilitation, strengthening or replacement of deteriorated structures is very significant and, in the Portuguese case, is expected to increase in the next decades. The energy consumption and CO2 emissions from construction sites, as well as the indirect user costs related to the service disruptions, contribute to the total costs.
In the future, sustainable structures will be those requiring just minimum preventive maintenance with no or little service disruptions. Research should focus on developing technologies to improve the existing structures and limiting the construction interventions to a strict minimum while providing long and safe service duration.
The use of thin Ultra-High Performance Fibre-Reinforced cement-based Composites (UHPFRC) layers for rehabilitation and strengthening of concrete structures has shown to be a promising technique towards this objective. Due to its outstanding properties, not only the structure can be strengthened, but also the durability can be improved due to its extremely low permeability. Moreover, its compatibility with concrete and tailored rheological properties allow for efficient and short-duration interventions.
The first objective of this proposal is the development of a second generation of UHPFRC, more eco-efficient by achieving target mechanical and transport properties with reduced cement content and incorporating spent equilibrium catalyst (ECat), a residue generated by the Portuguese oil refinery industry. Besides exploring its pozzolanic activity, Ecat is going to be used for reducing the strong autogenous shrinkage of UHPFRC, which is an important improvement when the application of this material in thin layers over hardened concrete substrates is envisaged.
The second objective of this research is a methodology for predicting the "in-structure" tensile response of UHPFRC, which is critical for the strengthening and waterproofing efficiency and depends on the fibre content and orientation. As these may vary throughout the structure and differ from standard test specimens, the tensile response of UHPFRC cannot be intrinsically defined. A non-destructive test (NDT) based on the magnetic properties of steel fibres will be developed for in-situ characterization of the fibre content and orientation in UHPFRC layers. Using the NDT information and knowledge about fibre debonding/pull-out mechanics, the directionally dependent "in-structure" tensile response of UHPFRC will be obtained.
The outcomes of this project are expected to significantly improve the scientific knowledge about the mechanical and durability performance of UHPFRC, thus contributing to its acceptance by the technical community.
The project counts with a multidisciplinary team, with domains of expertise covering structural engineering, material science and electromagnetism. |