Experimental Analysis of Fracture in High Strength Cementitious Composites

1984 ◽  
Vol 42 ◽  
Author(s):  
Farhad Ansari
Keyword(s):  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone ◽  
High Strength ◽  
Plain Concrete ◽  
Laser Speckle ◽  
Cementitious Composites ◽  
Special Technique ◽  
Technical Literature ◽  
Speckle Metrology

AbstractCharacterization of cementitious composites by their fracture properties has been difficult due to controversial results reported in the technical literature. Existing studies on the fracture behavior of plain concrete reveal some fracture characteristics that differ from those normally observed in metallic materials. Among these characteristics is the existence of a micro-cracking zone or process zone at the tip of an advancing crack. The determination of the fracture process zone in concrete is a difficult experimental problem, because the resulting deformation is strongly localized.In the present study, in-plane displacements in front of notched high strength concrete have been monitored. Laser speckle metrology, which is a special technique utilizing the speckle patterns of laser light for measurement of in-plane displacements, is employed. Experimental results indicate that a precise description of the fracture process zone is possible by speckle metrology.

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 CHARACTERIZATIONS ON FRACTURE PROCESS ZONE OF PLAIN CONCRETE

2019 ◽  
Vol 25 (8) ◽  
pp. 819-830
Author(s):  
Yuxiang Tang ◽  
Hongniao Chen
Keyword(s):  
Fracture Process ◽  
Fracture Process Zone ◽  
Process Zone ◽  
Speckle Pattern ◽  
Plain Concrete ◽  
Cohesive Crack ◽  
Electronic Speckle Pattern Interferometry ◽  
Crack Model ◽  
Fe Model ◽  
Durability Analysis

The fracture property of concrete is essential for the safety and durability analysis of concrete structures. Investigating the characteristics of the fracture process zone (FPZ) is of great significance to clarify the nonlinear fracture behaviour of concrete. Experimental and numerical investigations on the FPZ of plain concrete in pre-notched beams subjected to three-point bending were carried out. Electronic speckle pattern interferometry (ESPI) technique was used to observe crack evolution and measure the full-field deformation of the beams. The development of the FPZ were evaluated qualitatively and quantitatively based on the in-plane strain contours and displacement field measured by ESPI, respectively. By integrating the cohesive crack model and finite element (FE) model, various tension softening curves (TSCs) were employed to simulate the fracture response of concrete beams. By comparing the deformation obtained by FE simulation and experiments, the TSCs of plain concrete were evaluated and most suitable TSCs of concrete were recommended.

Applications of Acoustic Emission Technique Associated with the Fracture Process Zone in Concrete Beam – A Review

2012 ◽  
Vol 626 ◽  
pp. 147-151 ◽  
Author(s):  
Siti Ramziah Basri ◽  
Norazura Muhamad Bunnori ◽  
Sakhiah Abdul Kudus ◽  
Shahidan Shahiron ◽  
Mohd Nazli Md. Jamil ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
Concrete Beam ◽  
Process Zone ◽  
Failure Mechanisms ◽  
Aggregate Size ◽  
Plain Concrete ◽  
Bending Test ◽  
Acoustic Emission Technique

This paper summarized the recent development within the application of acoustic emission technique in the formation of fracture process zone and the AE energy released during the fracture process in concrete beam specimens. AE technique is a non destructive technique which is a useful tool to study the energy released during the different failure mechanisms in different types of materials and fracture process is one of the failure mechanisms in concrete. Most of the researchers were applied three point bending test on plain concrete in order to determine the facture process zone of the concrete and some of them were used numerical modeling to verify their results. The results between AE data and experimental in different parameters such as specimens size and aggregate size are normally compared. As a conclusion, AE technique is a very useful tool to determine the fracture process zone in concrete.

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.

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