Textile Reinforced Concrete – Realization in applications
Textile Reinforced Concrete (TRC) is a composite material made of open-meshed textile structures and a fine-grained concrete. Comparable to steel reinforcement the textile fabric bears the tensile forces released by the cracking of the concrete. Only a minimal concrete cover is required for the bond of the textile fabrics. Thus, the application of TRC leads to the design of filigree and lightweight concrete structures with high durability and high quality surfaces. In recent years, TRC has been successfully employed for the production of ventilated facade systems. Current investigations enlarge the application range of TRC to facade systems with large spans and load-bearing structures. In this paper, the investigations on self-supporting and structural sandwich panels regarding production methods, results of bending and shear tests, tests on sound insulation and fire resistance as well as first prototypes of slender frames and shell elements are presented.
Sustainability and Flexural Behaviour of Textile Reinforced Concrete
Concrete reinforced with conventional steel is one of the most commonly used building materials, yet it has historically shown disadvantages in terms of durability and vulnerability to corrosion attack. Various remedial methods have been applied to overcome the shortcomings of this building material, such as increasing the concrete cover, which, however, leads to an increased self-weight of the structure. Over the past decade, Textile Reinforced Concrete (TRC), encompassing a combination of fine-grained concrete and non-corrosive multi-axial textile fabrics, has emerged as a promising novel alternative offering corrosion resistance, as well as thinner and light-weight structures such as foot bridges and facade elements.

This thesis aims to preliminarily investigate the sustainability and flexural behaviour of TRC while bearing in mind its possible use for future buildings. The sustainable potential of TRC was evaluated using Life Cycle Assessment (LCA) with a cradle-to-gate perspective, such that conventional steel reinforced concrete and TRC were compared. It was revealed that TRC significantly decreased the cumulative energy demand and environmental impact of a reinforced concrete element; basalt fibre reinforcement yielded the least cumulative energy demand while carbon fibre gave the least environmental impact. Using TRC in the form of sandwich panels was also shown to yield a lower environmental impact compared to conventional reinforced concrete panels.

Moreover, experimental studies were conducted to investigate the load-carrying capacity in bending and overall structural behaviour of TRC in both one-way and two-way action. It could be concluded that one-way slabs reinforced by one layer of carbon textile mesh had superior load-carrying capacity and ductility in comparison to specimens reinforced by one layer of alkali-resistant glass or basalt. The testing of two-way slabs demonstrated that among basalt and AR-glass reinforced specimens, basalt had a slightly higher flexural capacity. Furthermore, a 2D non-linear finite element model developed based on the one-way experiments, correlated rather well with the experimental results after calibration. Lastly, analytical calculation methods developed for conventionally reinforced concrete structures were used to evaluate the experimental results. The analytical results were shown to both under and over predict the flexural capacity in one-way and two-way action.

Overall, experimental studies encompassing a greater study sample, optimized reinforcement ratios and application of fibre coatings are recommended to obtain further enhanced performance. The experimental programs, presented in this thesis, are valuable as they contribute to the expansion of fundamental knowledge related to TRC while promoting the prospective use of this novel material.
Super-resolution of overlapped waves in time and frequency domain in a directional borehole radar measurement
The Multiple Signal Classification (MUSIC) algorithm is modified in order to resolve multiple waves and to estimate reflection points in 3-D space. This algorithm is suitable for directional borehole radar with a circular dipole array antenna. Making use of the spatial frequency difference of acquired array signals, the signals are decorrelated, and the 3-D MUSIC algorithm is applied. The time domain signals of the singlehole array-type borehole radar are used in order to form a measurement vector in the MUSIC algorithm. A computer simulation confirms that the proposed algorithm may estimate the directions of arrival (DOA) for three signals. Applying the proposed algorithm to field experiment data successfully estimates the DOA of a reflected wave from a fracture in rock.