This paper reports on the results of X-ray imaging of steel fibre reinforced concrete in tension. The observations on fundamental behaviour and influences in the development of models for structural design are discussed. It is observed that crack paths find ways of least resistance through a section and divert around fibre ends, where possible. In
In this paper, a material design concept based on Hybrid Fiber Reinforced Cement-based Composites (HFRCC) is applied to Ultra High Performance Concrete (UHPC) so that a multi-level- reinforcement system for cracking will enhance the peak stress after crack initiation (i.e. tensile strength) and tensile strain capacity (i.e. strain at the peak stress, or ductility). UHP-HFRCC
With the aim of investigating fiber orientation in ultra high performance fiber reinforced concrete (UHPFRC), a transparent model concrete containing fibers was placed in beam molds to visualize fiber orientation during placing. As a result, fibers were found to be obliquely oriented upward when the pouring position of concrete was fixed near one end of
High Performance Concrete Sandwich Elements (HPCSE) are an interesting option for future low or plus energy building construction. Recent research and development work, however, indicate that such elements are prone to structural cracking due to the combined effect of shrinkage and high temperature load. Due to structural restraints, autogenous shrinkage may lead to high self-induced
The use of fiber-reinforced high-performance concrete (FRHPC) is becoming more extended; therefore it is necessary to develop tools to simulate and better understand its behavior. In this work, a discrete model for the analysis of fracture mechanics in FRHPC is presented. The plain concrete matrix, made of mortar and coarse aggregates, is modeled by means
Effects of aggregate type on the mechanical behavior of both normal- and high-strength concretes were investigated under bending and mechanical properties under compression. Basalt, sandstone, Eocene and Devonian crushed limestone coarse aggregates were used in the concrete mixtures. For each coarse aggregate type, normal and high strength concretes were made with the same Portland cement
Hydrogen embrittlement is believed to be one of the main reasons for cracking of steel structures under stress and stress corrosion cracking process. To control and prevent the cracking of steel it is necessary to understand the chemical and physical properties of hydrogen inside iron. Usually, pre-stressed steels are high strength steels that include a
The tensile stress-strain response of Ultra-High Performance Fibre Reinforced Concrete (UHPFRC) is a basic constitutive property, and reliable knowledge of this response is necessary for appropriate application of the tensile-carrying capacity of such advanced cement materials. Reference tests methods like direct tensile tests which aim at assessing this property, have found limited application due to
This paper is a contribution to the material description of Ultra High Performance Concrete (UHPC) at high-speed dynamic loading conditions. Based on a series of Hopkinson-Bar experiments, dynamical material parameters such as the Tensile Strength, Young’s Modulus and Fracture Energy are 2 –1 determined at high strain rates of 10 s . A comparison with
This work reports on an experimental investigation dealing with the effects of transverse reinforcement, in the form of stirrups, on the behaviour under load of high performances concrete (HPC) beams. The crack patterns and crack widths, the failure modes, the shear strengths and the ductility of HPC beams containing transverse stirrups were assessed and compared