Abstract:The use of non-metallic, textile reinforcement structures in place of steel reinforcement is a key component in making concrete constructions more sustainable and durable than they currently are. The reason for this is the corrosion resistance of textile reinforcements, which makes it possible to reduce the thickness of the concrete cover and at the same time extend the service life of concrete structures. This reduces the amount of cement required and thus also the emission of the greenhouse gas carbon dioxid… Show more
“…Due to corrosion resistance and a high load-bearing capacity compared to conventional steel bars, CRC allows up to 80% reduced concrete overlay and a lifespan of more than 200 years, making it a perfect material for a sustainable building of the future [ 3 ]. It is especially suitable in the use of thin-walled and lightweight concrete components with high load-bearing capacities as well as for reinforcing existing constructions [ 4 ].…”
Textile reinforcements have established themselves as a convincing alternative to conventional steel reinforcements in the building industry. In contrast to ribbed steel bars that ensure a stable mechanical interlock with concrete (form fit), the bonding force of smooth carbon rovings has so far been transmitted primarily by an adhesive bonding with the concrete matrix (material fit). However, this material fit does not enable the efficient use of the mechanical load capacity of the textile reinforcement. Solutions involving surface-profiled rods promise significant improvements in the bonding behavior by creating an additional mechanical interlock with the concrete matrix. An initial analysis was carried out to determine the effect of a braided rod geometry on the bonding behavior. For this purpose, novel braided rods with defined surface profiling consisting of several carbon filament yarns were developed and characterized in their tensile and bond properties. Further fundamental examinations to determine the influence of the impregnation as well as the application of a pre-tension during its consolidation in order to minimize the rod elongation under load were carried out. The investigations showed a high potential of the impregnated surface-profiled braided rods for a highly efficient application in concrete reinforcements. Hereby, a complete impregnation of the rod with a stiff polymer improved the tensile and bonding properties significantly. Compared to unprofiled reinforcement structures, the specific bonding stress could be increased up to 500% due to the strong form-fit effect of the braided rods while maintaining the high tensile properties.
“…Due to corrosion resistance and a high load-bearing capacity compared to conventional steel bars, CRC allows up to 80% reduced concrete overlay and a lifespan of more than 200 years, making it a perfect material for a sustainable building of the future [ 3 ]. It is especially suitable in the use of thin-walled and lightweight concrete components with high load-bearing capacities as well as for reinforcing existing constructions [ 4 ].…”
Textile reinforcements have established themselves as a convincing alternative to conventional steel reinforcements in the building industry. In contrast to ribbed steel bars that ensure a stable mechanical interlock with concrete (form fit), the bonding force of smooth carbon rovings has so far been transmitted primarily by an adhesive bonding with the concrete matrix (material fit). However, this material fit does not enable the efficient use of the mechanical load capacity of the textile reinforcement. Solutions involving surface-profiled rods promise significant improvements in the bonding behavior by creating an additional mechanical interlock with the concrete matrix. An initial analysis was carried out to determine the effect of a braided rod geometry on the bonding behavior. For this purpose, novel braided rods with defined surface profiling consisting of several carbon filament yarns were developed and characterized in their tensile and bond properties. Further fundamental examinations to determine the influence of the impregnation as well as the application of a pre-tension during its consolidation in order to minimize the rod elongation under load were carried out. The investigations showed a high potential of the impregnated surface-profiled braided rods for a highly efficient application in concrete reinforcements. Hereby, a complete impregnation of the rod with a stiff polymer improved the tensile and bonding properties significantly. Compared to unprofiled reinforcement structures, the specific bonding stress could be increased up to 500% due to the strong form-fit effect of the braided rods while maintaining the high tensile properties.
“…5,6 Hereby the carbon concrete is particular convincing with its high load-bearing capacity of the textile reinforcement in addition to a required smaller concrete cross-section. These textile reinforcement structures, produced with the highly efficient multiaxial warp knitting technology, 7,8 focus mainly on closed 2D non-crimp-fabrics (NCF) and grid-like NCF structures with regular grid spacing (Figure 1). Figure 1.Closed 2D NCF (a) and grid-like NCF structure with regular grid spacing (b).…”
Section: Introductionmentioning
confidence: 99%
“…For use in composites the water-soluble base fabric is removed and the remaining reinforcement structure consolidated using epoxy resin or thermoplastic matrices. 17 Robot supported yarn placement can be used for planar and three dimensional reinforcement structure by placing impregnated yarns on a support structure 8,18 (Figure 2(b)). Figure 2.Basic principle of TFP process 17 (a) and robot-supported yarn placement 8 (b).…”
Section: Introductionmentioning
confidence: 99%
“…17 Robot supported yarn placement can be used for planar and three dimensional reinforcement structure by placing impregnated yarns on a support structure 8,18 (Figure 2(b)). Figure 2.Basic principle of TFP process 17 (a) and robot-supported yarn placement 8 (b).…”
Textile reinforcements have revolutionized many industries, most of all aerospace, automotive and building. Due to its high performance and the significant increased lightweight potential, they have established themselves as an efficient and sustainable alternative to conventional materials. However, in view of the increasing demand of an ever growing population in contrast to a scarcity of resources and urge of material efficiency in the face of climate change, novel technologies for highly material efficient products in large-scale productions are required. In this regard, a major research field involves the multiaxial warp-knitting technique for the production of high performance textile preforms. In several steps, this technology has been further developed to enable the production of application-specific and bionic-inspired textile preforms, which are characterized by a force compliant and multi-material design. Yet the structural possibilities are still limited. This article presents a novel developed warp yarn manipulation system for multiaxial warp-knitting machines. The system enables the fabrication of 2D net-shape non-crimp-fabrics (NCF) made of up to 16 single warp yarns that specify by an alternating diagonally offset and overlapping edge-strand. This structure is suitable for the use as textile lattice girder for reinforcing concrete slab structures Hereby the developed warp yarn manipulation system allows highly various structural parameters of the 2D net-shape NCF for highest material efficiency and product variety. The technological development is discussed in means of the constructive and electronic control design as well as a specific application example for new net-shape reinforcement structures.
“…AR-glass and carbon rovings are the most commonly used reinforcing materials for construction purposes. Unlike conventional steel-bar reinforcement, textile reinforcements can be easily integrated into complex structures; possess high resistance to corrosion, which eliminates the need for high wall thicknesses; and enable us to build thin-walled concrete structures [ 10 , 11 , 12 , 13 , 14 ]. For example, the non-corrosive nature of TRC in bridges enables the reduction of the entire structural weight by approximately 40% through decreased cement use, reduces transport costs for the precast concrete elements and provides a more consistent structure when compared to traditionally reinforced bridges [ 15 , 16 ].…”
This study investigated the ability of electrically conductive carbon rovings to detect cracks in textile-reinforced concrete (TRC) structures. The key innovation lies in the integration of carbon rovings into the reinforcing textile, which not only contributes to the mechanical properties of the concrete structure but also eliminates the need for an additional sensory system, such as strain gauges, to monitor the structural health. Carbon rovings are integrated into a grid-like textile reinforcement that differs in binding type and dispersion concentration of the styrene butadiene rubber (SBR) coating. Ninety final samples were subjected to a four-point bending test in which the electrical changes of the carbon rovings were measured simultaneously to capture the strain. The mechanical results show that the SBR50-coated TRC samples with circular and elliptical cross-sectional shape achieved, with 1.55 kN, the highest bending tensile strength, which is also captured with a value of 0.65 Ω by the electrical impedance monitoring. The elongation and fracture of the rovings have a significant effect on the impedance mainly due to electrical resistance change. A correlation was found between the impedance change, binding type and coating. This suggests that the elongation and fracture mechanisms are affected by the number of outer and inner filaments, as well as the coating.
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