scholarly journals Research on Fracture Toughness of C120 Ultra-High-Performance Concrete in Kingkey Financial Center Project

2012 ◽  
Vol 2012 ◽  
pp. 1-5
Author(s):  
Hao-Wen Ye ◽  
Nai-Qian Feng ◽  
Zhi-Wei Ran ◽  
Li-Xun Lin ◽  
Yan Ling-Hu ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Fracture Toughness ◽  
High Performance ◽  
High Performance Concrete ◽  
Polypropylene Fiber ◽  
Ultra High Performance Concrete ◽  
Fiber Fracture ◽  
Tsinghua University ◽  
Water Conservancy ◽  
Financial Center

By adding polypropylene fiber, fracture toughness of C120 ultra-high-performance concrete in Kingkey Financial Center project has been enhanced. The tests conducted by the Building Material Lab of the Civil and Water Conservancy Institute of Tsinghua University provided satisfactory results of mechanical property and fracture toughness of C120 ultra-high-performance concrete.

The Influence of the Amount of Silica Fume on the Mechanical Property of Ultra-High Performance Concrete

2008 ◽  
Vol 385-387 ◽  
pp. 701-704 ◽  
Author(s):  
Jung Jun Park ◽  
Gum Sung Ryu ◽  
Su Tae Kang ◽  
Sung Wook Kim
Keyword(s):  
Mechanical Property ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Silica Fume ◽  
High Performance ◽  
Mechanical Characteristics ◽  
High Performance Concrete ◽  
Micro Structure ◽  
Ultra High Performance Concrete

Silica fume constitutes an element of extreme importance in improving the strength and fluidity of UHPC. The adopted amount of silica fume generally is generally exceeding 25% of cement in weight but the influence of this amount on the properties of UHPC is still remaining as a domain to be investigated. Accordingly, this paper investigates the effects of the amount of silica fume on the mechanical characteristics of the fluidity, compressive strength, elastic modulus and flexural strength and on the micro structure of UHPC by means of SEM and MIP. Results revealed that adequate amount of silica fume is improving the fluidity and strength. MIP tests demonstrated that such improvement is brought by the increase of hydrates due to the pozzolan reaction and the effective densification inside concrete due to the filler. It seemed also that similar mechanical characteristics can be obtained for a volumetric ratio to cement ranging between 10 and 25%.

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.

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