scholarly journals Experimental Investigations of the Dimensional Stability and Durability of Ultra-High-Performance Concrete

2017 ◽  
Vol 6 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Yang Chen ◽  
Faris Matalkah ◽  
Yening Yu ◽  
Weerirsiri Rankothge ◽  
Anagi Balachandra ◽  
...  
Keyword(s):  
Dimensional Stability ◽  
High Performance ◽  
High Performance Concrete ◽  
Experimental Investigations ◽  
Ultra High Performance Concrete

Experimental investigations of aerogel-incorporated ultra-high performance concrete

2015 ◽  
Vol 77 ◽  
pp. 307-316 ◽  
Author(s):  
Serina Ng ◽  
Bjørn Petter Jelle ◽  
Linn Ingunn Christie Sandberg ◽  
Tao Gao ◽  
Ólafur Haralds Wallevik
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Experimental Investigations ◽  
Ultra High Performance Concrete

Push-Out Test on Shear Connectors Embedded in UHPC

2013 ◽  
Vol 351-352 ◽  
pp. 50-54 ◽  
Author(s):  
Jee Sang Kim ◽  
Sang Hyeok Park ◽  
Chang Bin Joh ◽  
Jong D.K. Kwark ◽  
Eun Suk Choi
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Experimental Investigations ◽  
Load Carrying Capacity ◽  
Ultra High Performance Concrete ◽  
Shear Connectors ◽  
Aspect Ratios ◽  
High Durability ◽  
Load Carrying ◽  
Push Out

The various push-out tests have been performed to investigate the load carrying capacity and ultimate behavior of headed studs in UHPC (Ultra High Performance Concrete), which has high compressive and tensile strength as well as high durability compared to ordinary concrete. The test program included the studs with a diameter of 16mm and 22mm for various aspect ratios (height to depth ratio of a stud) and cover depths. This paper presents the main results of the experimental investigations.

scholarly journals Experimental Investigations on Temperature Generation and Release of Ultra-High Performance Concrete during Fatigue Tests

2020 ◽  
Vol 10 (17) ◽  
pp. 5845
Author(s):  
Melchior Deutscher ◽  
Ngoc Linh Tran ◽  
Silke Scheerer
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Construction Material ◽  
Maximum Temperature ◽  
Experimental Investigations ◽  
Heating Process ◽  
Parameter Study ◽  
Ultra High Performance Concrete ◽  
Resource Saving ◽  
Premature Failure

Smarter, more filigree, and resource-saving buildings are the aim of developments in the construction industry. In reinforced concrete construction, ultra-high strength concretes have been developed to achieve these goals. Due to their use and requirements, these highly pressure-resistant materials are increasingly exposed to cyclically occurring and high-frequency loads. Examples of this are applications in long-span bridges or wind turbines. Research into the fatigue behaviour of the new construction material is therefore very important for the standardization and practical introduction of the high performance material. In this article, we want to investigate the heating process of ultra-high performance concrete (UHPC) under fatigue stress in more detail. In previous investigations in this project, an influence of the heating on the fatigue strength could be determined. A systematic parameter study has defined decisive load configurations for a maximum heating process. The aim is now to better understand the heating process. For this purpose, the temperature generation rate and the temperature release, which probably influences the overall temperature development, are investigated. A test program with eight experiments gives information about the temperature release during the experiment and the heating rate with and without pre-damage in the sample. In addition, the causes of failure caused by temperature are investigated with additional insulated tests. The results are presented, discussed, and conclusions are drawn in the article. For instance, fatigue damage affects the rate of temperature increase, but not the thermal conductivity of the material. In the different configurations, the test specimens essentially overlap at the maximum temperature reached in the inner test specimen. In addition to the assumed influence of the temperature gradients in the cross section as a cause of premature failure due to additional constraint stresses, the maximum temperature in particular turns out to be decisive, independent of the gradient.

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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