scholarly journals Size of the Fracture Process Zone in High-Strength Concrete at a Wide Range of Loading Rates

2010 ◽  
Vol 24-25 ◽  
pp. 155-160 ◽  
Author(s):  
R.C. Yu ◽  
X.X. Zhang ◽  
Gonzalo Ruiz ◽  
M. Tarifa ◽  
M. Cámara
Keyword(s):  
High Strength Concrete ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Loading Rate ◽  
Process Zone ◽  
High Strength ◽  
Experimental Program ◽  
Strength Concrete ◽  
Loading Rates ◽  
Wide Range

Compared with the extensive research on properties of the fracture process zone (FPZ) under quasi-static loading conditions, much less information is available on its dynamic characterization, especially for high-strength concrete (HSC). This paper presents the very recent results of an experimental program aimed at disclosing the loading rate effect on the size and velocity of the (FPZ) in HSC. Eighteen three-point bending specimens were conducted under a wide range of loading rates from from 10-4 mm/s to 103 mm/s using either a servo-hydraulic machine or a self-designed drop-weight impact device. Four strain gauges mounted along the ligament of the specimen were used to measure the FPZ size. Surprisingly, the FPZ size remains almost constant (around 20 mm) when the loading rate varies seven orders of magnitude.

Eight Types of HSC

2011 ◽  
Vol 147 ◽  
pp. 293-297
Author(s):  
Rena C. Yu ◽  
Luis Saucedo ◽  
Gonzalo Ruiz ◽  
Xiao Xin Zhang
Keyword(s):  
High Strength Concrete ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone ◽  
High Strength ◽  
Fracture Properties ◽  
Strength Concrete ◽  
Mechanical And Fracture Properties

In this paper we report the composition, mechanical and fracture properties of eight types of performance-designed high strength concrete. The influences of compositions on the material’s brittleness are explained through the calculated reference size of the Fracture Process Zone (FPZ).

scholarly journals Effect of Loading Rate on the Fracture Behaviour of High-Strength Concrete

2010 ◽  
Vol 24-25 ◽  
pp. 179-185 ◽  
Author(s):  
Gonzalo Ruiz ◽  
X.X. Zhang ◽  
R.C. Yu ◽  
E. Poveda ◽  
R. Porras ◽  
...  
Keyword(s):  
Fracture Energy ◽  
High Strength Concrete ◽  
Loading Rate ◽  
High Strength ◽  
Displacement Rate ◽  
Cohesive Law ◽  
Viscous Term ◽  
Strength Concrete ◽  
Loading Rates ◽  
Static Conditions

This research deals with the sensitivity of eight types of performance-designed high-strength concrete to the loading rate. Variations in the composition of the concrete produce the desired performance, for instance having null shrinkage or being able to be pumped at elevated heights without segregation, but they also produce variations in the fracture properties that are reported in this paper. We performed tests at five loading rates spanning six orders of magnitude in the displacement rate, from 1.74  10-5 mm/s to 17.4 mm/s. Load-displacement curves show that their peak is higher as the displacement rate increases, whereas the corresponding displacement is almost constant. Fracture energy also increases, but only for loading rates higher than 0.01 mm/s. We use a formula based on a cohesive law with a viscous term to study the results. The correlation of the formula to the experimental results is good and it allows us to obtain the theoretical value for the fracture energy under strictly static conditions. In addition, both the fracture energy and the characteristic length of the concretes used in the study diminish as the compressive strength of their aggregates increases.

Loading rate effect on fracture behavior of fiber reinforced high strength concrete using a semi-circular bending test

2020 ◽  
Vol 240 ◽  
pp. 117681
Author(s):  
Mehran Aziminezhad ◽  
Sahand Mardi ◽  
Pouria Hajikarimi ◽  
Fereidoon Moghadas Nejad ◽  
Amir H. Gandomi
Keyword(s):  
High Strength Concrete ◽  
Fracture Behavior ◽  
Loading Rate ◽  
High Strength ◽  
Rate Effect ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Strength Concrete

scholarly journals Experimental Study on the Torsional Behaviour of Prestressed HSC Hollow Beams

2020 ◽  
Vol 10 (2) ◽  
pp. 642 ◽  
Author(s):  
Luís Bernardo ◽  
Sérgio Lopes ◽  
Mafalda Teixeira
Keyword(s):  
Experimental Study ◽  
High Strength Concrete ◽  
Concrete Beams ◽  
Concrete Strength ◽  
High Strength ◽  
Experimental Program ◽  
Pure Torsion ◽  
Strength Concrete ◽  
Hollow Beams

This article describes an experimental program developed to study the influence of longitudinal prestress on the behaviour of high-strength concrete hollow beams under pure torsion. The pre-cracking, the post-cracking and the ultimate behaviour are analysed. Three tests were carried out on large hollow high-strength concrete beams with similar concrete strength. The variable studied was the level of longitudinal uniform prestress. Some important conclusions on different aspects of the beams’ behaviour are presented. These conclusions, considered important for the design of box bridges, include the influence of the level of prestress in the cracking and ultimate behaviour.

Study on Interfacial Crack Propagation and Fracture between Embedded Steel and HSHPC

2007 ◽  
Vol 348-349 ◽  
pp. 853-856
Author(s):  
Shan Suo Zheng ◽  
Lei Li ◽  
Guo Zhuan Deng ◽  
Liang Zhang
Keyword(s):  
Crack Propagation ◽  
High Performance ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
High Performance Concrete ◽  
Process Zone ◽  
Interfacial Crack ◽  
High Strength ◽  
Interfacial Fracture ◽  
Softening Process

Steel reinforced high strength and high performance concrete (SRHSHPC) specimens were experimented to study the mechanical behaviors between steel and concrete interface. In experiment, interfacial bond softening process was observed, which can be explained in terms of damage along the interface, leading to progressive reduction of shear transfer capability between steel and high strength and high performance concrete (HSHPC). In this paper, bond softening process along the interface is considered in the analysis of crack-induced debonding. Interfacial bond-slip mechanism between steel and HSHPC is studied in detail based on fracture mechanics. With the help of acoustic emissions technology, the crack propagation in the interlayer was observed, thus the interfacial crack propagation and fracture model is set up. Under the assumption that the interlayer is weak concrete compared with concrete matrix, the stress field as well as displacement field around the crack tip is deduced. The characteristics of interfacial fracture process are discussed and a model for interfacial fracture process zone is built up. With this model, the size of fracture process zone can be derived. At last, the influence of the fracture process zone on interfacial fracture toughness is determined using critical fracture toughness. All these may contribute to improvement of theory for SRHSHPC composite structure.

scholarly journals Cyclical Behavior of Concrete-Encased Composite Frame Joints with High Strength Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Lei Zeng ◽  
Zhenkun Cui ◽  
Yunfeng Xiao ◽  
Siqian Jin ◽  
Yuanyuan Wu
Keyword(s):  
Cyclic Loading ◽  
High Strength Concrete ◽  
Joint Strength ◽  
Concrete Strength ◽  
Outer Part ◽  
High Strength ◽  
Crack Pattern ◽  
Experimental Program ◽  
Strength Concrete ◽  
Composite Frame

This paper presents an application of high strength concrete to concrete-encased composite frame building based on an experimental program. The work emphasized joints behavior under reverse cyclic loading caused by earthquakes to provide information for seismic design. To investigate the internal mechanisms and seismic performance, cyclic loading tests were carried out on five half-scale interior joints. Two design variables were addressed in the research: concrete strength and axial column load. Frame joints performance including crack pattern, failure mode, deformation, ductility, strain distribution, and energy dissipation capacity was investigated. It was found that all joint specimens behaved in a manner with joint panel shear failure. Using high strength concrete increased the joint strength and had relatively little effect on the stiffness and ductility. The axial column load helped the joint strength by better mobilizing the outer part of the joint, but it had an obvious influence on the ductility and energy-dissipating capacity, which can be improved by providing enough transverse reinforcement. A typical crack pattern was also provided which can well reflect mechanical character and damage process. This research should contribute to the future engineering applications of high strength concrete to concrete-encased composite structure.

Performance of high strength concrete-filled steel columns exposed to fire

1998 ◽  
Vol 25 (6) ◽  
pp. 975-981 ◽  
Author(s):  
VKR Kodur
Keyword(s):  
Fire Resistance ◽  
High Strength Concrete ◽  
High Strength ◽  
Experimental Program ◽  
Structural Behaviour ◽  
Steel Columns ◽  
Strength Concrete ◽  
Normal Strength ◽  
Concrete Filling ◽  
Hollow Structural Section

Results from an experimental program on the behaviour of high strength concrete-filled steel hollow structural section (HSS) columns will be presented for three types of concrete filling. A comparison will be made of the fire-resistance performance of HSS columns filled with normal strength concrete, high strength concrete, and steel-fibre-reinforced high strength concrete. The various factors that influence the structural behaviour of high strength concrete-filled HSS columns under fire conditions are discussed. It is demonstrated that, in many cases, addition of steel fibres into high strength concrete improves the fire resistance and offers an economical solution for fire-safe construction.Key words: high strength concrete, steel columns, fire-resistance design, high-temperature behaviour, concrete-filled steel columns.

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