Papers by Keyword: Fibre Reinforcement

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Authors: Jun Kusui, Koichi Fujii, K. Yokoe, T. Yokota, Kozo Osamura, O. Kubota, Hiroshi Okuda
Authors: Wei Qun Cao, Li Tian, Tie Jun Zhao
Abstract: Strain-hardening cement-based composites (SHCC) resist increased tensile stress after first crack formation, over a significant range of tensile strain. This increased strength and strain capacity is achieved by effective crack bridging by fibres, across multiple cracks of widths in the micro-range. Whether the crack width limitation translates into increased durability through retardation of ingress of moisture, gas and other deleterious matter, is scrutinised in this paper. The potential of the comparatively new composite material becomes obvious, yet it is clearly outlined that further research is necessary before we fully understand the basic mechanisms underlying durability of SHCC.
Authors: Peter Paulík, Igor Hudoba, Patrik Ševčík
Abstract: Gas permeability of concrete is a property, which is recognized as one of the basic indicators of its durability. Measuring of the air permeability is mostly carried out on samples, which are not exposed (before or during the tests) to any certain external loads, which could cause microcracks in hardened cement matrix. However, in the case of real structures there is always some stress level and thus the concrete permeability is usually affected by microcracks. To know both, permeability of sound concrete and the permeability of concrete containing certain amount of microcracks, is the basic assumption for correct evaluation of its durability. Our paper deals with the permeability of loaded specimens made of high performance fibre reinforced concrete (HPFRC). This type of concrete is in Slovakia used for the construction of containers for a low and medium level radioactive waste storage and thus their properties in loaded conditions are of primary concern. Permeability was measured with Torrent Permeability Tester on cube specimens at different loading levels and after unloading. Specimens were 10 years old and varied in the amount of fibre reinforcement.
Authors: Vivek Bindiganavile, Md Toihidul Islam, Rachel Chan
Abstract: This paper describes the dynamic response of sandstone masonry units bound with fibre-reinforced mortars comparing a Portland cement-lime system with hydraulic lime. A drop-weight impact machine was used to generate stress rates up to 107 kPa/s. The dynamic impact factor and stress rate sensitivity were evaluated for the flexural strength of the sandstone and mortar, and for the bond strength of the unit, and further, the pattern of failure was noted in the units for each mortar mix and loading rate. Polypropylene microfibres were incorporated at 0%, 0.25% and 0.5% volume fraction into the mortar. Results show that the flexural bond strength was more sensitive to stress rate than the flexural strength of the mortar, at similar rates of loading. Further, the stress rate sensitivity of the bond strength decreased with an increase in the fibre content. Also, whereas the flexural toughness factors for the stone-mortar bond fell with fibre reinforcement in the stronger Portland cement-lime system, the bond improved with fibre addition when employing hydraulic lime mortar.
Authors: Gérard Bernhart, F. Nazaret, T. Cutard
Abstract: Today heat resistant cast steels are the nominal solution for Ti-SPF forming die manufacturing. Nevertheless, this materials present some drawbacks related to delivery time and cost. A fibre reinforced refractory castable (FRRC) is proposed as a new solution for prototype SPF die manufacturing. Due to the general brittleness of refractory castables, a short fibre reinforcement has been investigated in order to avoid catastrophic failure during the forming process. General macroscopic behavior of such materials is very complex and presents large evolutions with the testing temperature. The paper addresses the important benefits of the reinforcement for refractory castable in the case of loading on a complex structure. The capability of the material to support several cracks is shown in the case of a technological sample with a complex shape.
Authors: J. Bär, H.J. Gudladt, L. Fördös, Janos Lendvai
Authors: M.C.S. Ribeiro, Jordanna C. Vogt, António Torres Marques, António J.M. Ferreira
Abstract: The aim of this work is to assess the feasibility of using polymer mortars reinforced with untreated natural fibres instead of artificial ones, for applications requiring highly alkali resistant materials, such as tanks and drainage systems for wastewater treatment plants. For this purpose, several formulations of polyester polymer mortars reinforced with different contents of jute and piassava natural fibres were investigated. Flexural and compressive behaviour, before and after exposure to a strong alkaline solution was analysed and quantified. Test results highlighted the high potential of these materials as basis construction material for precast applications requiring specific resistance under alkaline environments.
Authors: Eckhard Pippel, J. Woltersdorf, A. Feldhoff, A. Hähnel
Authors: Paweł Przybyłek, Andrzej Komorek, Wojciech Kucharczyk
Abstract: The properties of a multi-layered composite can be moulded through a selection of type, shape, and the number of layers of reinforcement material as well as powder fillers. Furthermore, the type and share of the matrix as well as the kind of hardeners also exert a significant influence on mechanical properties of composites. We attempted to experimentally establish the influence of the type of hardeners on mechanical properties. The test used Charpy’s hammer, and it was performed in the configuration of impact loading parallel to the edge. We prepared specimens of the materials. The specimens contained 12 layers of different fibre reinforcement: aramid (kevlar) fibre of 230 g/m2 basis weight, glass fibre of 150 g /m2, and carbon fibre of 160 g/m2 basis weight. The base was epoxy resin – Epidian 52, which was cured at room temperature by means of the following curing agents: PAC, TFF or Z-1, manufactured by Z. Ch. Organika-Sarzyna S.A. in Nowa Sarzyna. The experiments proved the tremendous influence of the type of the hardeners on toughness KC. It can be increased even by 25% for glass fibre reinforcement, about 20% for carbon fibre reinforcement and about 10% for aramid fibre reinforcement due to the use of an appropriate type of hardener.
Authors: Eckhard Pippel, J. Woltersdorf, M. Doktor, Hans Peter Degischer
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