Application Of Ultra-high Performance Concrete Research Articles

New Composite Construction Method with STEEL/UHPFRC Constructing Railway Bridges

In Austria last years sequenced according modern technology successfully bridges were made from UHPC or UHPFRC [1], [2], [3]. A couple of well-done examples of these bridges I presented on the occasion of Prof. Sparowitz birthday publication in 2017 [2]. Recently in Austria another example of a railway bridge consisting innovative material UHPFRC - created as a composite construction - was projected by ZKP ZT GmbH by order of Austrian Railway Company ÖBB. Innovative and new is the application of Ultra-High Performance Concrete in combination with Steel S355J2+N creating a composite action in highest utilization of both material strengths and auxiliary connected with a steel panel. Construction work was done from March to September 2017, the bridge was finished in October 2017 in single railway track Lavanttalbahn near city Wolfsberg in Carinthia.

A comparative study for the impact performance of shaped charge JET on UHPC targets

Abstract With the development of two-stage munitions (a precursor shaped charge (SC) and a following kinetic energy projectile) to attack the hard concrete targets, as well as the increasing applications of ultra-high performance concrete (UHPC) in both civil and military protective structures, a comparative study on the impact performance of SC formed jet on UHPC target is performed experimentally and numerically at present. Firstly, a series of jet penetration/perforation test on the UHPC, 45# steel and UHPC/45# steel composite targets are conducted. By assessing the penetration depth and borehole (crater and tunnel) diameter, the influences of target material and configuration as well as the standoff distance of SC on the impact performance of jet are experimentally discussed. Then, by adopting the 2D multi-material Arbitrary Lagrange-Euler (ALE) algorithm, Fluid-Structure Interaction (FSI) method and erosion algorithm implemented in the finite element code LS-DYNA, the formation and impact performance of jet in the present test are well reproduced. Finally, based on the validated numerical algorithms, constitutive models and the corresponding parameters, the influences of target material (UHPC, NSC and 45# steel), standoff distance, target configuration (stacked and spaced) and weight efficiency on the impact performance of jet are further discussed. The derived conclusions could provide helpful references for evaluating the ballistic performance of jet and designing the protective structures.

Development and Applications of Ultra-high Performance Concrete in Bridge Engineering

Ultra-high Performance Concrete (UHPC) is a new type of cement composites, which attracts extensive attention and is applied to bridge engineering area, on account of its superior mechanical performance and durability. With regard to the development and application of ultra-high performance concrete in bridge engineering, the thesis analyzes its application examples, discusses its limited factors and predicts its application future, based on the preparation methods of UHPC and conclusion on the basic performance of materials. UHPC has gradually applied to bridge engineering at home now, which should become application guidance or technical standard in the future, combined with practical projects to promote the research on the application techniques.

Ultra-high performance concrete: From fundamental to applications

Over the last twenty years, remarkable advances have taken place in the research and application of ultra-high performance concrete (UHPC), which exhibits excellent rheological behaviors that include workability, self-placing and self-densifying properties, improved in mechanical and durability performance with very high compressive strength, and non-brittleness behavior. It is the ‘future’ material with the potential to be a viable solution for improving the sustainability of buildings and other infrastructure components. This paper will give an overview of UHPC focusing on its fundamental introduction, design, applications and challenges. After several decades of development, a wide range of commercial UHPC formulations have been developed worldwide to cover an increasing number of applications and the rising demand of quality construction materials. UHPC has several advantages over conventional concrete but the use of it is limited due to the high cost and limited design codes. This paper also aims to help designers, engineers, architects, and infrastructure owners to expand the awareness of UHPC for better acceptance.

Shear behavior of ultra-high performance concrete

The application of ultra-high performance concrete (UHPC) as an alternative to conventional/normal concrete (NC) has grown rapidly in recent years. However, there is limited knowledge on its shear behavior, which is essential for developing design guidelines for structural applications. A detailed parametric study was conducted on 38 beam specimens, half of which were made of UHPC and the other half made of NC. To ensure applicability of findings, two types of UHPC mixes were used, a proprietary and a generic mix. Eighteen of the beams were prepared and tested in Tabriz, Iran, while the other 20 were made and tested in Miami, FL. Test parameters included type of concrete (UHPC and NC), shear span-to-depth ratio (0.8, 1.2, and 2.8), reinforcement ratio (2.2% to 7.8%) and reinforcement anchorage. All specimens had the same length but different cross sections. Test results proved UHPC specimens to have much higher shear strength and ductility than NC beams. Normalized shear and shear strength both increased for shorter shear spans and higher reinforcement ratios. The anchorage did not affect UHPC beams, while it improved ductility of NC beams. Theoretical shear strengths, as determined by RILEM equations for UHPC beams, proved very conservative, confirming the need for more accurate assessment of shear strength of UHPC.

A review and analysis of circular UHPC filled steel tube columns under axial loading

Ultra high performance concrete (UHPC) has aroused interest around the world owing to superior mechanical and durability properties over conventional concrete. However, the application of UHPC in practice poses difficulties due to its inherent brittleness. UHPC filled in steel tube columns (UHPC-FSTCs) are capable of restricting the brittle failure of non-reinforced UHPC columns and forming a high performance member with enhancement of strength and ductility. Currently, research on UHPC-FSTCs remains very limited and there is relatively little information about the mechanical behavior of these columns. Therefore, this study presents a review of past experimental studies to have a deeper insight into the compressive behavior of UHPC-FSTCs under axial loading on entire section and on concrete core. Based on the test results obtained from Schneider (2006) and Xiong (2012), an analysis was conducted to investigate the influence of the confinement index (<TEX>${\xi}$</TEX>) and diameter to steel tube thickness ratio (D/t) on the strength and the ductility in short circular UHPC-FSTCs. Furthermore, the appropriateness of current design codes including EC4, AISC, AIJ and previous analytical models for estimating the ultimate loads of composite columns was also examined by the comparison between the predictions and the test results. Finally, simplified formulae for predicting the ultimate loads in two types of loading pattern were proposed and verified.

Application of Ultra-high Performance Concrete in Lifeline Engineering

Ultra high performance concrete (UHPC) is a new type of cement based composites with high strength and excellent durability. Firstly, this paper introduces the development history and technical performance of UHPC, then application of UHPC in lifeline engineering is summarized: the UHPC application examples of 18 bridges abroad; the application of UHPC in bridge joints and bridge deck pavement; advantages of its anti-permeability and frost resistance in combination with the durability of UHPC in pipeline transportation. Based on this, the paper makes an improvement on the UHPC concrete formula, which makes it easier to be popularized in China, and 2 sets of UHPC-ECC composite pipe specimens were designed and tested for the first time. Experiments showed that the composite pipe has advantage of high strength, corrosion resistance, no leakage, and it can be widely used in the field of petroleum and hazardous chemicals transportation and so on.

An Experiment on the Bond-Slip Behaviors of Pre-Tensioned Prestressed UHPC Members

An Ultra High Performance Concrete (UHPC) exhibits very high compressive and tensile strength and excellent durability comparing to those of the conventional concrete. The applications of UHPC to precast and/or prestressed concrete result the optimum utilization of high strength characteristics. This paper experimentally investigates the bond-slip behaviors between prestressing strands and UHPC in pretnesioned members. The diameters of strands, 12.7mm and 15.2mm, the cover depths and tensioning forces are chosen as variables, which are known to affect the bond behaviors. The bond-slip curves for various specimens are obtained and the equations for bond strengths of UHPC are derived based on experiments.

Ultra-High Performance Concrete: Mechanical Performance, Durability, Sustainability and Implementation Challenges

In this study, an extensive literature review has been conducted on the material characterization of UHPC and its potential for large-scale field applicability. The successful production of ultra-high performance concrete (UHPC) depends on its material ingredients and mixture proportioning, which leads to denser and relatively more homogenous particle packing. A database was compiled from various research and field studies around the world on the mechanical and durability performance of UHPC. It is shown that UHPC provides a viable and long-term solution for improved sustainable construction owing to its ultra-high strength properties, improved fatigue behavior and very low porosity, leading to excellent resistance against aggressive environments. The literature review revealed that the curing regimes and fiber dosage are the main factors that control the mechanical and durability properties of UHPC. Currently, the applications of UHPC in construction are very limited due to its higher initial cost, lack of contractor experience and the absence of widely accepted design provisions. However, sustained research progress in producing UHPC using locally available materials under normal curing conditions should reduce its material cost. Current challenges regarding the implementation of UHPC in full-scale structures are highlighted. This study strives to assist engineers, consultants, contractors and other construction industry stakeholders to better understand the unique characteristics and capabilities of UHPC, which should demystify this resilient and sustainable construction material.

Manufacturing ultra-high performance concrete utilising conventional materials and production methods

Ultra-high performance concrete (UHPC) which is characterised by high strength and, when reinforced with steel fibres, high ductility, has the potential to revolutionise the construction industry. The application of UHPC is currently mainly limited to landmark projects due to the high cost of manufacture, which often involve specialist materials such as specially graded sands and the need for complex mixing and curing regimes. Moreover, mix designs are commonly proprietary information or incompletely reported. As a result of the complexity of material requirements and the restricted nature of complete mix design details it can be difficult to reproduce reported results. This paper aims to address these issues by investigating the potential for producing UHPC using widely available fine and coarse aggregates. It is shown that UHPC of compressive strengths in the range of 130–160MPa can be produced using commonly graded aggregates without the requirement for complex mixing or curing regimes. It has been shown that the fineness modulus of aggregates as well as the superplasticiser content strongly influences the compressive strength. An investigation of the axial and lateral stress–strain relationship of the mixes investigated show they possess a substantial residual stress plateau post softening.

UHPC From Research to Standardization: European Approaches

Abstract In Europe, different approaches to standardize ultra-high-performance concrete (UHPC) materials, and the design of structures made from it, are pursued based on different philosophies and market situations. The first standard available was published in France. It primarily deals with material models and design procedures for steel-fiber-reinforced UHPC. Material-related aspects are not considered. This is because, as a rule, industrially prefabricated dry premixed concretes with consistent material properties are used. Thus, the European Standard for concrete materials, EN 206 [EN 206, 2012-03, 2012, “Concrete—Specification, Performance, Production and Conformity,” German Version, German Standardization Body, Beuth Verlag, Berlin], is of minor relevance. The philosophy in other countries, like in Germany, is to make UHPC a commonly available material based on individual, application-oriented compositions, as far as possible being manufactured in precast or ready-mix plants from appropriate regionally available raw materials. Thus, the application of UHPC will be favorably supported by considering UHPC to be part of the harmonized European concrete materials and design standards, EN 206, covering the material aspects, and EN 1992-1-1 [EN 1992-1-1: 2011-01, 2011, “Eurocode 2:2 Design of Concrete Structures. Part 1-1: General Rules and Rules for Buildings,” German Version, German Standardization Body, Beuth Verlag, Berlin] (Eurocode 2) covering the design. This approach requires advice on how to evaluate the appropriate raw materials, to prepare adequate mixtures, and to define technically based rules and requirements covering both mechanical, as well as durability aspects, e.g., by defining strength- and durability-related classes, as for ordinary and high-performance concrete. The requirements have to be related to reliable testing procedures. It has been proven by several research projects in Germany that European standard testing procedures may principally be adopted but have to be modified in some points, e.g., with respect to the specific fresh concrete properties, the specimen preparation, tests to evaluate the fiber efficiency, etc. These topics are under discussion in a UHPC-related committee of the German Standardization Body (DIN) drafting a standard-like technical guideline covering all three aspects, namely, materials, design, and testing. Another technical guideline on UHPC is elaborated by Fédération Internationale du Béton (FIB). The approach is “in between,” meaning that some material aspects are covered as far as their relevance for the structural design. The focus lies on the design covering different design procedures for fiber, as well as for conventionally reinforced structural elements.

Ultrahigh performance concrete-properties, applications and perspectives

Over the last twenty years, remarkable advances have taken place in the research and application of ultra-high performance concrete (UHPC), which exhibits outstanding mechanical properties and excellent durability. It has shown great potential for the next generation infrastructure construction from the sustainability point of view. This paper will give an overview on UHPC, with particular focus on the properties, applications and perspectives. After several decades of development, several types of commercial UHPC materials are available in the market, and the properties of UHPC have been characterized by numerous experimental and field tests. Generally speaking, the performance (e.g. mechanical properties and durability) of UHPC is much better than normal concrete (NC) and high performance concrete (HPC). Therefore, the uses of UHPC are growing all over the world, in both fields of new construction and retrofitting. Nevertheless, it is still a special material and technology, which is not worldwide accepted. So some application prospects of UHPC are briefly introduced in the paper, and the efforts, which have to be made to turn UHPC into a widespread ‘regular’ technology, are discussed. This paper aims to help designers, engineers, architects and infrastructure owners to know the capacities of UHPC and thus to increase the applications of this material.

Development of ultra-high-performance geopolymer concrete

This paper presents the development of ambient temperature cured ultra-high-performance geopolymer concrete (UHPGPC). Ultra-high-performance concrete (UHPC) mixtures were developed by completely eliminating Portland cement and activating industrial by-product materials such as ground granulated blastfurnace slag and silica fume. Local standard sand (maximum size 2 mm), quartz sand (600 μm) and 0·16 mm diameter steel fibres of 13 and 6 mm length were used. Fresh properties (density and flowability) and mechanical properties (compressive strength) of the UHPGPC produced under ambient temperature curing conditions were evaluated. Four mixtures with fibres and one mix without fibre addition were studied as the UHPGPC mixtures. The highest average compressive strengths obtained were 175 MPa for UHPGPC with steel fibres (1% 6 mm and 2% 13 mm) and 124 MPa for UHPGPC without fibres. Prismatic specimens (100 × 100 × 500 mm) were cast to determine the flexural strength, which was found to be 10·3–13·5 MPa and 9·1 MPa for mixes with and without steel fibres respectively. The compressive and flexural strengths obtained in this work are comparable to UHPC strengths presented in the literature. Production of this innovative material with industrial by-products and without the conventional curing regimes used for UHPC will improve sustainability and lead to cast-in-situ applications of UHPC.

Stress-Strain Model of Ultrahigh Performance Concrete Confined by Fiber-Reinforced Polymers

The application of ultrahigh performance concrete (UHPC) as an alternative to conventional concrete has grown rapidly in recent years. However, to date, little is known about the confinement behavior of UHPC, knowledge that is necessary to develop design guidelines for UHPC columns. In a previous study, the authors investigated the stress-strain behavior of a series of UHPC-filled fiber-reinforced polymer (FRP) tubes with different fiber types and thicknesses under uniaxial compression. The FRP confinement was shown to significantly enhance both the ultimate strength and strain of UHPC. It was also shown that the existing confinement models are incapable of predicting the behavior of FRP-confined UHPC. Therefore, in this study, two commonly used FRP confinement models are recalibrated based on test results of FRP-confined UHPC. A model was further modified based on the stress-strain model of unconfined UHPC to better capture the linear response of UHPC before the activation of FRP confinement. A comparison of the three models showed that a recalibrated model provides the most accurate prediction of the stress-strain behavior of FRP-confined UHPC in terms of the stress-strain curve and ultimate strength and strain.

Effect of casting method and shear span-to-depth ratio on the behaviour of Ultra-High Performance Concrete cross arms for high voltage transmission lines

This paper reports on a project that is in an area of high economic and technological importance to the hydro-power utilities. Currently, most high voltage transmission line poles and their cross arms are made either from wood or steel. As an emerging technology, the project addresses an important topic on the application of Ultra-High Performance Concrete (UHPC) cross arms, in high voltage transmission poles, as a competitive alternative in today’s market to replace the existing deteriorated wood and steel cross arms. The characteristic properties of UHPC cross arms make them the ultimate materials for the construction of thin members. Given all the advantages of UHPC concrete, and the market demand for a reliable and durable solution, it is expected that these UHPC cross arms are a repetitive application. Experimental test results of an investigation on the structural evaluation of prestressed UHPC C-channel cross arms are reported in this paper. The testing program was designed to corroborate the structural capacity of the UHPC cross arms under given loading scenarios according to specifications used by the hydro-power industries. Several tests were performed to examine the effect of steel-fibre orientation around the internal ordinary steel rebars on the flexural strength of UHPC cross arms using different casting types; and to evaluate the effect of varying the shear span-to-depth (or height) ratio on the flexural and shear capacity of the prestressed UHPC cross arms.