Papers by Keyword: Steel Fiber Reinforced Concrete

Abstract: Not only in the construction industry, but also in other technical areas, efforts are being made to reduce the costs or difficulty of producing a certain product and at the same time to improve some of its properties. With the development of modern technologies come new possibilities in the development and production of such products. Fiber reinforced concrete is one of them. Fiber reinforced concrete does not fully replace reinforced concrete, but even with a reduction in price and production time, it has a certain part of the properties of reinforced concrete, which can be used for structural elements with specifically required properties. The subject of the presented paper is the testing and comparison of compressive and split tensile strength of steel fiber reinforced concrete (SFRC) with steel fibers MasterFiber 482 with dosage 60 kg/m³ and 90 kg/m³ and SFRC with 5 different types of steel fibers with dosage 50 kg/m³, where dosage 0 kg/m³ represents ordinary portland concrete (OPC). Submitted paper is also focused on specific test methods of concrete, such as measurement of resistance to frost and defrosting chemicals and pressure water seepage.

Abstract: The number of researches on steel fiber reinforced concrete (SFRC) fire resistance is insignificant. For the calculation of building structures for fire resistance, it is necessary to use the thermophysical characteristics of concrete: thermal conductivity, heat capacity and thermal diffusivity. The physicomechanical characteristics of SFRC depend on the volumetric content of the fiber in it. This paper presents the results of studies of thermophysical properties of SFRC. The studied SFRC had a high-strength self-compacting cement-sand matrix and a different percentage of fiber content (from 0 to 6%). The experiments were carried out for SFRC with steel wavy fiber 15 mm long and 0.3 mm in diameter. As a result of experimental studies, it was discovered that with an increase in the volumetric content of the fiber, a decrease in the values of heat flow, thermal conductivity and thermal diffusivity coefficients, specific heat capacity is observed and the thermal resistance of SFRC increases.

Abstract: In order to study the flexural behavior of steel fiber reinforced concrete (SFRC) shield tunnel segment, two full scale shield tunnel segments and twelve reduced scale shield tunnel segments were made and tested. Based on the experiment study, the effectiveness of reduced scale segment was analyzed. Meanwhile, based on the fail mode, load-deflection curves and crack width, the part substitution of steel reinforcement by steel fibers was studied. Test results showed that the reduced scale model can reflect the flexural behavior of full scales tunnel segment and 45kg/m³ steel fibers of 3D type can replace 17% longitudinal reinforcement and 70% stirrups.

Abstract: The article deals with steel fiber reinforced concrete (SFRC), specifically with its physical mechanical parameters which influence both design and reliable behavior of the building material in structures. The resulting physical mechanical properties of the SFRC depend on the properties of the individual components and also on their quantity. In the building practice, a common dosing of steel fibers that are added into fresh concrete mixture is ranging between 0.5% and 2%. The paper also describes the methodology of certain laboratory tests suitable for SFRC and the ways of data evaluation. The experiments proved a substantial influence of the quantity of steel fibers in the individual mixtures to the resulting mechanical properties.

Abstract: Non-destructive testing (NDT) is seeing increasingly frequent use in civil engineering thanks to the fact that the tests are repeatable and do not cause serious damage to the material. The requirements for the development and modernization of available testing devices and methodologies are ever increasing and the testing of existing structures often requires the use of NDT. Unfortunately, every measurement and methodology has its limits and the measurement devices for the evaluation of steel fiber reinforced concrete (SFRC) are no exception. In recent decades there has been an effort to modernize and develop existing measurement devices for SFRC testing. This building material is commonly used especially in large-scale structures. Nevertheless, the technology of SFRC could seem complicated when compared with ordinary concrete and the very nature of this composite material could lead to SFRC inhomogeneity during construction. This paper describes the assessment of SFRC by more or less available methodologies and measurements utilizing non-destructive principles.

Abstract: This study presents the analysis of the constitutive behavior of fiber-reinforced polymer (FRP)-confined steel fiber reinforced concrete (SFRC) using a newly developed concrete damage-plasticity approach. Finite element (FE) analysis is conducted based on Lubliner’s model. The new concrete damage-plasticity approach accurately incorporates the effects of the steel fiber volume fraction and aspect ratio, confinement level, concrete strength, and nonlinear dilation behavior of confined concrete. New failure surface and flow rule were established using the experimental database. In order to validate the damage-plasticity model, the predictions from the FE analysis are compared with both experimental results and predictions of an accurate existing model for FRP-confined plain concrete. The analysis results indicate that the proposed approach accurately predicts the compressive behavior of FRP-confined SFRC.

Abstract: The steel fibre reinforced concrete is expensive compared with the ordinary concrete. The costs for the production, the transport and the setting of steel fibre reinforced concrete should be directly proportional to its quality. The quality of material can be quantified in a broad spectrum of properties (the workability, the mechanical and physical properties, the durability, etc.). This article is focused on the influence of mechanical and physical properties (the tensile strength and the residual tensile strength) on ULS and SLS. The paper is limited only to the bending load bearing capacity from ULS point of view and limited only to vertical deformation from SLS point of view. The example is a part of paper – the calculation of two bending structures. Firstly, it is calculated as the structure of ordinary reinforced concrete and secondly it is calculated as the structure of reinforced steel fibre reinforced concrete. The geometric arrangement, the type and the quantity of reinforcement are identical for both calculated structures. The calculated structures are different only in the tensile strength and the residual tensile strength. All other input parameters (including modulus of elasticity) are identical for both calculated structures, in order the influence of tensile strength on ULS and SLS excels. The presented results should be the basic concept for the effectiveness assessment of steel fibre reinforced concrete application.

Abstract: The paper deals with field tests of cementitious composites suitable for protective structures and critical infrastructure. The tests of ballistic resistance against contact and distant explosions are performed according to the NATO standards. The results of tests of plain concrete, steel fibre reinforced concrete and high performance fibre reinforced concrete are analysed.

Abstract: This paper deals with the experimental testing and theoretical analysis of the flexural load-bearing capacity of I-shaped pillars in noise barriers made of reinforced concrete, prestressed concrete and prestressed steel fiber reinforced concrete. The pillars were loaded as a cantilever under a flexural load, which corresponds to their actual loading when the effect of wind on the panels of the noise barrier is taken into account. For the purpose of the present research, three specimens of I-pillars were tested. The results of the experimental loading tests, as well as the calculated results and the comparison between them, are herein presented.

Abstract: Efficiency of crack repair in Steel Fiber Reinforced Concrete (SFRC) was estimated on the base of the results obtained by wedge split test (WST) method. The main part of the paper pointed at the discussion of laboratory investigations into the thermal compatibility of the selected repair system, where cracks in the SFRC were sealed with low-viscosity epoxy adhesive. The obtained results show that ultimate split strength decreases with increasing into the number of freeze-thaw cycles, similar as adhesion between used epoxy adhesive and concrete surface. Because of bridged fibers of cracks have been reactivated by sealing those cracks with epoxy adhesive, toughness or energy absorption are achieved. Therefore, resistance of repaired SFRC in this way should be expected during the application where it is.subjected to thermal cyclizing (freeze-thaw cyclizing), including wetting and drying.