Potential environmental impact of using ultra-high performance concrete in simple, two and three-span continuous prestressed concrete bridges

2021 ◽  
pp. 847-847
Author(s):  
J. Márquez ◽  
D.V. Jauregui ◽  
B.D. Weldon ◽  
C.M. Newtson
Keyword(s):  
Environmental Impact ◽  
Prestressed Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Concrete Bridges ◽  
Ultra High Performance Concrete ◽  
Prestressed Concrete Bridges ◽  
Potential Environmental Impact

scholarly journals Application of Large Prestress Strands in Precast/Prestressed Concrete Bridges

2020 ◽  
Vol 6 (1) ◽  
pp. 130-141
Author(s):  
Amin K Akhnoukh
Keyword(s):  
Prestressed Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Large Diameter ◽  
Concrete Bridges ◽  
Bridge Construction ◽  
Prestressed Concrete Bridges ◽  
Research Findings ◽  
Flexure Capacity ◽  
Precast Prestressed Concrete

The objective of this research is to investigate the advantage of using large-diameter 0.7-inch (18 mm) strands in pretention applications. Large-diameter strands are advantageous in bridge construction due to the increased girders capacity required to sustain exponential increase in vehicle numbers, sizes, and weights. In this research, flexure capacity of girders fabricated using 0.7-inch (18 mm) diameter strands will be calculated and compared to bridge capacities constructed using smaller strands. Finally, two similar bridge sections will be designed using 0.6-inch (15 mm) and 0.7-inch (18 mm) diameter strands to quantify the structural advantages of increased strand diameter. The research findings showed that a smaller number of girders is required for bridge construction when larger strands are used. Four girders are required to design the bridge panel using high performance concrete and large diameter strands, as compared to 6 girders required when regular concrete mix designs and normal size strands are used. The advantages of large strands and high-performance concrete mixes include expedited construction, reduced project dead loads, and reduced demand for labor and equipment. Thus, large strands can partially contribute to the improvement of bridge conditions, minimize construction cost, and increase construction site safety.

New Trends in Prestressed Concrete Bridges

2000 ◽  
Vol 1696 (1) ◽  
pp. 238-272
Author(s):  
Michel Virlogeux
Keyword(s):  
Prestressed Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Concrete Structures ◽  
Concrete Bridges ◽  
Prestressed Concrete Bridges ◽  
External Prestressing ◽  
Different Types ◽  
Composite Bridges ◽  
Cable Stayed Bridges

An overview of the recent evolution in the design and construction of prestressed concrete bridges worldwide is provided. Several major trends are evidenced. Certainly those trends that have had greater influences on the industry because of their wide applications are the development of external prestressing, which is now systematically used in some countries for medium-span bridges; the emergence of high-performance concrete, which extends the possibilities at the same time as it improves the durability of concrete structures; and the more frequent association of steel and concrete for composite bridges of different types and composite elements in bridges, allowing the construction of many innovative structures. For more specific applications, cable-stayed bridges, for which interesting developments have been seen in the last 10 years, and the more extensive use of heavy prefabrication in large projects, with elements up to several thousands of metric tons, are also described. Bridge architecture is also discussed in terms of the fact that good structural designs can produce elegant prestressed concrete bridges.

Flexural design of precast, prestressed ultra-high-performance concrete members

PCI Journal ◽  
2020 ◽  
Vol 65 (6) ◽  
pp. 35-61
Author(s):  
Chungwook Sim ◽  
Maher Tadros ◽  
David Gee ◽  
Micheal Asaad
Keyword(s):  
Prestressed Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Limit State ◽  
Design Guidelines ◽  
Design Tool ◽  
Supplementary Cementitious Materials ◽  
Ultra High Performance Concrete ◽  
Concrete Members ◽  
Cylinder Strength

Ultra-high-performance concrete (UHPC) is a special concrete mixture with outstanding mechanical and durability characteristics. It is a mixture of portland cement, supplementary cementitious materials, sand, and high-strength, high-aspect-ratio microfibers. In this paper, the authors propose flexural design guidelines for precast, prestressed concrete members made with concrete mixtures developed by precasters to meet minimum specific characteristics qualifying it to be called PCI-UHPC. Minimum specified cylinder strength is 10 ksi (69 MPa) at prestress release and 18 ksi (124 MPa) at the time the member is placed in service, typically 28 days. Minimum flexural cracking and tensile strengths of 1.5 and 2 ksi (10 and 14 MPa), respectively, according to ASTM C1609 testing specifications are required. In addition, strain-hardening and ductility requirements are specified. Tensile properties are shown to be more important for structural optimization than cylinder strength. Both building and bridge products are considered because the paper is focused on capacity rather than demand. Both service limit state and strength limit state are covered. When the contribution of fibers to capacity should be included and when they may be ignored is shown. It is further shown that the traditional equivalent rectangular stress block in compression can still be used to produce satisfactory results in prestressed concrete members. A spreadsheet workbook is offered online as a design tool. It is valid for multilayers of concrete of different strengths, rows of reinforcing bars of different grades, and prestressing strands. It produces moment-curvature diagrams and flexural capacity at ultimate strain. A fully worked-out example of a 250 ft (76.2 m) span decked I-beam of optimized shape is given.

scholarly journals Abrasion Resistance of Ultra-High-Performance Concrete for Railway Sleepers

2021 ◽  
Author(s):  
Ariful Hasnat ◽  
Nader Ghafoori
Keyword(s):  
Prestressed Concrete ◽  
Abrasion Resistance ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Positive Influence ◽  
Cementitious Material ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Ultra High Performance Concrete

AbstractThis study aimed to determine the abrasion resistance of ultra-high-performance concretes (UHPCs) for railway sleepers. Test samples were made with different cementitious material combinations and varying steel fiber contents and shapes, using conventional fine aggregate. A total of 25 UHPCs and two high-strength concretes (HSCs) were selected to evaluate their depth of wear and bulk properties. The results of the coefficient of variation (CV), relative gain in abrasion, and abrasion index of the studied UHPCs were also obtained and discussed. Furthermore, a comparison was made on the resistance to wear of the selected UHPCs with those of the HSCs typically used for prestressed concrete sleepers. The outcomes of this study revealed that UHPCs displayed excellent resistance against abrasion, well above that of HSCs. Amongst the utilized cementitious material combinations, UHPCs made with silica fume as a partial replacement of cement performed best against abrasion, whereas mixtures containing fly ash showed the highest depth of wear. The addition of steel fibers had a more positive influence on the abrasion resistance than it did on compressive strength of the studied UHPCs.

scholarly journals Mechanical Properties and Environmental Evaluation of Ultra-High-Performance Concrete with Aeolian Sand

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3148 ◽  
Author(s):  
Hongyan Chu ◽  
Fengjuan Wang ◽  
Liguo Wang ◽  
Taotao Feng ◽  
Danqian Wang
Keyword(s):  
Compressive Strength ◽  
Environmental Impact ◽  
Young’S Modulus ◽  
High Performance ◽  
High Performance Concrete ◽  
Young's Modulus ◽  
Ultra High Performance Concrete ◽  
Aeolian Sand ◽  
Binder Ratio ◽  
Water Binder Ratio

Ultra-high-performance concrete (UHPC) has received increasing attention in recent years due to its remarkable ductility, durability, and mechanical properties. However, the manufacture of UHPC can cause serious environmental issues. This work addresses the feasibility of using aeolian sand to produce UHPC, and the mix design, environmental impact, and mechanical characterization of UHPC are investigated. We designed the mix proportions of the UHPC according to the modified Andreasen and Andersen particle packing model. We studied the workability, microstructure, porosity, mechanical performance, and environmental impact of UHPC with three different water/binder ratios. The following findings were noted: (1) the compressive strength, flexural strength, and Young’s modulus of the designed UHPC samples were in the ranges of 163.9–207.0 MPa, 18.0–32.2 MPa, and 49.3–58.9 GPa, respectively; (2) the compressive strength, flexural strength, and Young’s modulus of the UHPC increased with a decrease in water/binder ratio and an increase in the steel fibre content; (3) the compressive strength–Young’s modulus correlation of the UHPC could be described by an exponential formula; (4) the environmental impact of UHPC can be improved by decreasing its water/binder ratio. These findings suggest that it is possible to use aeolian sand to manufacture UHPC, and this study promotes the application of aeolian sand for this purpose.

Design and preparation of ultra-high performance concrete with low environmental impact

2019 ◽  
Vol 214 ◽  
pp. 633-643 ◽  
Author(s):  
Ye Shi ◽  
Guangcheng Long ◽  
Cong Ma ◽  
Youjun Xie ◽  
Jionghuang He
Keyword(s):  
Environmental Impact ◽  
High Performance ◽  
High Performance Concrete ◽  
Ultra High Performance Concrete

Prestressed I-Beams Made of Ultra-High Performance Concrete for Construction of Railway Bridges

2014 ◽  
Vol 578-579 ◽  
pp. 776-778
Author(s):  
Petr Tej ◽  
Jiří Kolísko ◽  
Petr Bouška ◽  
Miroslav Vokáč ◽  
Jindřich Čech
Keyword(s):  
Prestressed Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Load Test ◽  
Bottom Flange ◽  
Structural Elements ◽  
Ultra High Performance Concrete ◽  
Actual Structure ◽  
Railway Bridges ◽  
Four Point Bending

This paper focuses on research into prestressed I-beams made of ultra-high-performance concrete, which are designed to be structural elements in small and medium span railway bridges. Prestressed concrete I-beams are designed with ten prestressing cables in the bottom flange. The prestressed beams are laid close together in the actual structure with panels inserted between them. The entire structure will subsequently become monolithic. At the present time, I-beams made of rolled steel are commonly used as structural elements in this type of structure. The advantage of these types of structures lies in their having a low construction height. This paper presents a computer and experimental analysis of the loading of UHPC prestressed I-beams. For the purpose of the experiments, several specimens of 7 m span were made. The specimens were subsequently tested in the laboratory in four-point bending tests. The paper presents the process and results of the experiments. Simultaneously with the experiments, computer analyses were created in which optimization of the material and geometric parameters of the beams were carried out. The paper demonstrates the correspondence of the experimental and computer-simulated load test results.

scholarly journals Innovative design approach of precast–prestressed girder bridges using ultra high performance concrete

2010 ◽  
Vol 37 (4) ◽  
pp. 511-521 ◽  
Author(s):  
H. Almansour ◽  
Z. Lounis
Keyword(s):  
Prestressed Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Concrete Slab ◽  
High Strength ◽  
Design Approach ◽  
Highway Bridge ◽  
Efficient Design ◽  
Ultra High Performance Concrete ◽  
Prestressed Concrete Girders

The construction of new bridges and the maintenance and renewal of aging highway bridge network using ultra high performance concrete can lead to the construction of long life bridges that will require minimum maintenance resulting in low life cycle costs. Ultra high performance concrete (UHPC) is a newly developed concrete material that provides very high strength and very low permeability to aggressive agents such as chlorides from de-icing salts or seawater. Ultra high performance concrete could enable major improvements over conventional high performance concrete (HPC) bridges in terms of structural efficiency, durability, and cost-effectiveness over the long term. A simplified design approach of concrete slab on UHPC girders bridge using the Canadian Highway Bridge Design code and the current recommendations for UHPC design is proposed. An illustrative example demonstrates that the use of UHPC in precast–prestressed concrete girders yields a more efficient design of the superstructure where considerable reduction in the number of girders and girder size when compared to conventional HPC girders bridge with the same span length. Hence, UHPC results in a significant reduction in concrete volume and then weight of the superstructure, which in turn leads to significant reduction in the dead load on the substructure, especially for the case of aging bridges, thus improving their performance.

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