Effects of loading rate and notch-to-depth ratio of notched beams on flexural performance of ultra-high-performance concrete

2017 ◽  
Vol 83 ◽  
pp. 349-359 ◽  
Author(s):  
Weina Meng ◽  
Yiming Yao ◽  
Barzin Mobasher ◽  
Kamal Henri Khayat
Keyword(s):  
High Performance ◽  
Loading Rate ◽  
High Performance Concrete ◽  
Ultra High Performance Concrete ◽  
Flexural Performance ◽  
Depth Ratio

Evaluation of Flexural Performance in UHPC(Ultra High Performance Concrete) According to Placement Methods

2009 ◽  
Vol 417-418 ◽  
pp. 581-584 ◽  
Author(s):  
Gum Sung Ryu ◽  
Su Tae Kang ◽  
Jung Jun Park ◽  
Gyung Taek Koh
Keyword(s):  
Flexural Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Initial Crack ◽  
Ultra High Performance Concrete ◽  
Remarkable Feature ◽  
Flexural Performance ◽  
Placement Method ◽  
Compaction Properties ◽  
And Diffusion

Apart from its high compressive, tensile and flexural strengths reaching approximately 200MPa, 15MPa and 35MPa, respectively, Ultra High Performance Concrete (UHPC) is characterized by its high resistance against degrading factors that can delay their penetration and diffusion speeds down to 1/20 to maximum 1/10,000 compared to ordinary concrete. UHPC also exhibits self-compaction properties with a slump flow of about 220mm. Furthermore, the most remarkable feature of UHPC is the improvement of its flexural strength and toughness through the admixing of steel fiber. Accordingly, this study evaluates the effects of the placement method on the flexural performance of UHPC. As a result, the flexural strength of UHPC appears to be extremely dependent on the placement method with variation of the maximum flexural strength up to 2 to 3 times while poor influence is observed on the initial crack strength.

Flexural Performance of Ultra-High Performance Concrete Ballastless Track Slabs

2016 ◽  
Author(s):  
Weina Meng ◽  
Kamal Henri Khayat
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Superior Performance ◽  
Concrete Slabs ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
Cracking Behavior ◽  
Flexural Performance ◽  
Ballastless Track ◽  
Track Slab

Ballastless track slab offers excellent stability and durability and has been well accepted in high-speed railways worldwide. Rails are typically laid on precast concrete slabs that are subjected to dynamic load transferred from the rails. Cracks can be induced by shrinkage and mechanical loading in concrete, which accelerates the degradation and affects the performance of the track slab. As tens of thousands of miles of ballastless track are constructed, effective and efficient maintenance for the concrete slabs has become an issue. In this paper, ultra-high performance concrete (UHPC) is proposed to fabricate ballastless track slab. UHPC is a superior fiber-reinforced, cementitioius mortar, which has greatly-improved mechanical strengths and durability. A recently-developed UHPC is evaluated in terms of the flowability, durability, shrinkage, and mechanical properties. A functionally-graded slab design is proposed with the consideration of initial material cost. The slab is cast with two layers: a layer of conventional concrete at the bottom, and a layer of UHPC on the top. A three-dimensional finite element model is developed for ballastless track slab whose flexural performance is investigated and compared with that of slab made with conventional concrete. Concrete damage plasticity model is incorporated to consider the post-cracking behavior. The results indicate that the proposed UHPC is promising for fabricating ballastless track slab with superior performance.

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