Development of Ultra-High Performance Concrete against Blasts: From Materials to Structures presents a detailed overview of UHPC development and its related applications in an era of rising terrorism around the world. Chapters present case studies on the novel development of the new generation of UHPC with nano additives. Field blast test results on reinforced concrete columns made with UHPC and UHPC filled double-skin tubes columns are also presented and compiled, as is the residual load-carrying capacities of blast-damaged structural members and the exceptional performance of novel UHPC materials that illustrate its potential in protective structural design. As a notable representative, ultra-high performance concrete (UHPC) has now been widely investigated by government agencies and universities. UHPC inherits many positive aspects of ultra-high strength concrete (UHSC) and is equipped with improved ductility as a result of fiber addition. These features make it an ideal construction material for bridge decks, storage halls, thin-wall shell structures, and other infrastructure because of its protective properties against seismic, impact and blast loads. Focuses on the principles behind UHPC production, properties, design and detailing aspects Presents a series of case studies and filed blast tests on columns and slabs Focuses on applications and future developments
Author: Klaus Holschemacher
Publisher: John Wiley & Sons
Release Date: 2012-03-27
Genre: Technology & Engineering
The daily work of engineers, for preliminary design and to check plausibility, would be inconceivable without them: design aids for reinforced concrete elements in the form of diagrams and tables. Now newly revised to cover Eurocode 2.
"Ultra-high performance concrete (UHPC) is an advanced cementitious composite material which has been developed in recent decades. When compared to more conventional cement-based concrete materials, UHPC tends to exhibit superior properties such as increased durability, strength, and long-term stability. This computational investigation focused on modeling the behaviors of existing UHPC structural components including a prestressed UHPC AASHTO Type II girder and a prestressed UHPC 2nd generation pi-girder. Both a concrete smeared cracking model and a concrete damaged plasticity model were tailored to model UHPC within a commercially available finite element analysis package. The concrete damaged plasticity model using three types of tension stiffening definitions can replicate both linear and nonlinear structural responses of both girders reasonably well. A set of UHPC constitutive properties were developed that facilitate the model replication of the local and global responses observed in the series of physical tests. The finite element analysis modeling techniques developed herein are intended to be applicable to other UHPC structural components"--Technical report documentation page.
Author: Gary M. Avalos
Publisher: Nova Science Pub Incorporated
Release Date: 2013-01-01
Genre: Technology & Engineering
Advances in the science of concrete materials have led to the development of a new class of cementitious composites, namely ultra-high performance concrete (UHPC). The mechanical and durability properties of UHPC make it an ideal candidate for use in developing new solutions to pressing concerns about highway infrastructure deterioration, repair, and replacement. Since 2000, when UHPC became commercially available in the United States, a series of research projects has demonstrated the capabilities of the material. Three State transportation departments have deployed UHPC components within their infrastructure, and many more are actively considering the use of UHPC. This book documents the research, development, and deployment of UHPC components and includes information about its materials and production, mechanical properties, structural design and structural testing, durability and durability testing, and actual and potential applications. The book concludes with recommendations for the future direction for UHPC applications in the United States.
Author: Mohammad N. Tahat
Release Date: 2017
Creep was investigated in this study for UHPC produced with materials local to New Mexico, USA. Creep is time-dependent strain in hardened concrete subjected to sustained stress (ACI 1997). Creep causes continuous loss of prestressing force and increases deflection in structural members. An experimental program derived from ASTM C 512 was conducted to evaluate creep of UHPC. Six UHPC mixtures with an average seven day compressive strength of 21,540 psi (149 MPa) were evaluated. The parameters varied between the mixtures include the fly ash and silica fume contents, and the sand to cementitious materials ratios. The results indicated that the locally developed UHPC experienced strain up to 405[mu epsilon] and had a creep coefficient of 0.27. The creep values of UHPC were compared to the creep values obtained from prediction models provided by AFGC/SETRA 2002, AASHTO 2012 and 2004, CEBFIP MC90, and ACI 209R-92. However, these models did not provide accurate results. Therefore, a new model was developed to predicte creep for UHPC made with local materials. The average predicted creep to measured creep ratio was equal to 0.93 with a correlation of R2=0.96.
Highlights: An approach to aid the design of UHPC bridge is proposed. Life-cycle cost and environmental impacts are assessed. Reliability and durability of novel bridges using UHPC are evaluated. UHPC bridges can reduce CO2 emissions significantly in a life-cycle. Application of UHPC is with significant benefit of sustainable perspective. Abstract: Ultra-high performance concrete (UHPC) as a novel concrete material is associated with very high strength and low permeability to aggressive environment. There have been many studies focusing on the development of UHPC materials. More studies are needed to implement the knowledge obtained from material level into the structural design and construction level. This paper emphasizes on the structural modeling and performance assessment of bridge girders made of UHPC considering the major improvements in terms of structural performance, durability, environmental impacts, and cost-effectiveness in a long-time interval. Additionally, the effect of the concrete strength increase on the life-cycle environmental impact and cost is assessed on a structural scale. An illustrative example is established to demonstrate the use of UHPC within precast-prestressed girder bridge. It is found that the use of UHPC can result in a significant reduction of concrete volume and CO2 emissions compared with conventional bridge with the same span length. Additionally, the life-cycle cost and equivalent annual cost associated with these two bridges are compared. This study aims to aid the development and adaptation of novel materials within civil engineering to make optimal use of the favorable material properties.
Ultra-High Performance Concrete (UHPC) is an evolving structural material that has attracted interest in the civil engineering industry recently. Currently, it is being used mainly for highway infrastructure in the US and also being explored for various other applications. The existing design guides on UHPC in countries like Japan, Australia and France are not as detailed as the concrete or steel guides. Most of the sections made of UHPC are slender due to its superior mechanical properties which are expected to simplify construction. Being an expensive material to use, making slender sections also helps to minimize the overall cost of the structure and makes it competitive with that of high strength steel and prestressed concrete. It has also been demonstrated to have very high compressive strength and considerable tensile strength. To begin with, an introduction on UHPC and its current applications around the world is presented, followed by a review of the existing design guides on UHPC. The importance as well as the methodology to measure fracture energy of concrete with factors to be considered for fiber reinforced concrete is discussed in detail. The main motive of this research is to introduce a creative modeling concept which served as the theoretical basis for the development of a computer program called Lattice 3D. The program is a modeling tool for engineers studying the behavior of UHPC, and in the future will be developed into a finite element protocol for analyzing complex structures made of UHPC. Parametric studies on lattice models of thin simply supported plates in compression and three-point bending of beams have been demonstrated in this research. Experimental tests conducted on briquette specimens under uniaxial tension are also discussed.