Usability of Textile Reinforced Concrete: Structural Performance, Durability and Sustainability

Doktorsavhandling, 2015

Textile reinforced concrete (TRC) is an innovative high performance composite material consisting of open multi-axial textiles embedded in a fine-grained concrete matrix. Despite the fact that TRC-based research has revealed many promising attributes, it has yet to reach its recognition due to a lack of available design tools, standards and long-term behaviour. To be able to reach this next stage, consistent test methods and reliable models need to be established to reduce uncertainty and the need for individual and extensive experimental studies. This thesis aims to investigate structural performance, durability and sustainability aspects of TRC for its usability in the built environment. The structural performance was experimentally and analytically evaluated for the individual material constituents, material interaction, as well as global TRC components. The linking of the structural performance of these various levels was investigated by means of non-linear finite element analysis (FEA). The durability of TRC was characterized according to the influence of accelerated ageing based on alkali resistance on the structural performance of textile reinforcement. Furthermore, the environmental sustainability of TRC was evaluated in comparison to conventional RC using a Life Cycle Assessment (LCA). The experimental quantification of the structural performance on the material and interaction levels was found to be decisive to understand the composite behaviour. In general, the bond behaviour in TRC has been identified as a critical feature affecting the global behaviour. Particularly for carbon textiles, the bond behaviour needs to be improved; an enhancement of the load bearing behaviour was successfully observed using surface coatings, short fibres, and high performance concrete. Linking the experimental data from the material and interaction levels to the global level in FEA led to promising results such that further insight on the actual failure behaviour could be gained. The accelerated testing was generally too aggressive for textiles made of basalt and AR-glass leading to extensive degradation; however, carbon textiles were found to be a promising alternative as they have superior durability properties in an alkaline environment without undergoing any strength loss. Through accelerated testing, it was found that the exposure time, temperature and test solution need to be material specific. The applied sizing or coating on the textiles also had a considerable influence on the extent of degradation. Based on the conducted LCA, the reduction of the concrete cover in a TRC panel significantly decreased its environmental impact compared to traditionally reinforced solutions. Ultimately, the experimental and modelling approaches developed in this work can be applied to further characterize the short- and long-term behaviour of TRC for the built environment.