SIZE EFFECT ON FRACTURE ENERGY OF CONCRETE DETERMINED BY THREE-POINT BENDING

1997 ◽  
Vol 27 (7) ◽  
pp. 1031-1036 ◽  
Author(s):  
Qian Jueshi ◽  
Luo Hui
2011 ◽  
Vol 346 ◽  
pp. 40-46 ◽  
Author(s):  
Wai Ching Tang ◽  
Yiu Lo ◽  
Hong Zhi Cui

In this research, the mechanical and fracture behaviours of concrete containing waste CD shreds were investigated using the three-point bending notched beam test, according to RILEM recommendations. The size effect of waste CD shred on concrete properties was the focus of this research. The study indicates that the fracture energy and modified characteristic length were found to increase significantly with increasing the size and volume fraction of CD shreds due to anchoring and bridging effects. In other words, concrete with higher amounts and larger sizes of CD shreds exhibit higher cracking resistance and the brittleness decreases accordingly. However, the strength properties were found to decrease when concrete with larger portion and size of CD shreds.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3795
Author(s):  
Fernando Suárez ◽  
Jaime C. Gálvez ◽  
Marcos G. Alberti ◽  
Alejandro Enfedaque

The size effect on plain concrete specimens is well known and can be correctly captured when performing numerical simulations by using a well characterised softening function. Nevertheless, in the case of polyolefin-fibre-reinforced concrete (PFRC), this is not directly applicable, since using only diagram cannot capture the material behaviour on elements with different sizes due to dependence of the orientation factor of the fibres with the size of the specimen. In previous works, the use of a trilinear softening diagram proved to be very convenient for reproducing fracture of polyolefin-fibre-reinforced concrete elements, but only if it is previously adapted for each specimen size. In this work, a predictive methodology is used to reproduce fracture of polyolefin-fibre-reinforced concrete specimens of different sizes under three-point bending. Fracture is reproduced by means of a well-known embedded cohesive model, with a trilinear softening function that is defined specifically for each specimen size. The fundamental points of these softening functions are defined a priori by using empirical expressions proposed in past works, based on an extensive experimental background. Therefore, the numerical results are obtained in a predictive manner and then compared with a previous experimental campaign in which PFRC notched specimens of different sizes were tested with a three-point bending test setup, showing that this approach properly captures the size effect, although some values of the fundamental points in the trilinear diagram could be defined more accurately.


1990 ◽  
Vol 35 (1-3) ◽  
pp. 107-115 ◽  
Author(s):  
F.H. Wittmann ◽  
H. Mihashi ◽  
N. Nomura
Keyword(s):  

2014 ◽  
Vol 513-517 ◽  
pp. 20-23
Author(s):  
Hai Chao Wang ◽  
Xue Hua Wang ◽  
Xue Hui An

The different fracture characteristics of self-compacting rock-filled concrete with large-size natural and recycled aggregate are analyzed by three-point bending experiment. According to the analysis of the crack propagation process, the fracture mechanism differences of self-compacting rock-filled concrete with large-size natural and recycled aggregate are discussed. The further analysis of the differences of fracture toughness, fracture energy, and are gain


2015 ◽  
Vol 8 (3) ◽  
pp. 323-340 ◽  
Author(s):  
A. H. A. SANTOS ◽  
R. L. S. PITANGUEIRA ◽  
G. O. RIBEIRO ◽  
R. B. CALDAS

Size effect is an important issue in concrete structures bearing in mind that it can influence many aspects of analysis such as strength, brittleness and structural ductility, fracture toughness and fracture energy, among others. Further this, ever more new methods are being developed to evaluate displacement fields in structures. In this paper an experimental evaluation of the size effect is performed applying Digital Image Correlation (DIC) technique to measure displacements on the surface of beams. Three point bending tests were performed on three different size concrete beams with a notch at the midspan. The results allow a better understanding of the size effect and demonstrate the efficiency of Digital Image Correlation to obtain measures of displacements.


2017 ◽  
Vol 3 (1) ◽  
pp. 47 ◽  
Author(s):  
Sıddık Şener ◽  
Kadir Can Şener

The universal size effect law of concrete is a law that describes the dependence of nominal strength of specimens or structure on both its size and the crack (or notch) length, over the entire of interest, and exhibits the correct small and large size asymptotic properties as required. The main difficulty has been the transition of crack length from 0, in which case the size effect mode is Type 1, to deep cracks (or notches), in which case the size effect mode is Type 2 and fundamentally different from Type 1. The current study is based on recently obtained comprehensive fracture test data from three-point bending beams tested under identical conditions. In this test, the experimental program consisted of 80 three-point bend beams with 4 different depths 40, 93, 215 and 500mm, corresponding to a size range of 1:12.5. Five different relative notch lengths, a/D = 0, 0.02, 0.075, 0.15, 0.30 were cut into the beams. A total of 20 different geometries (family of beams) were tested. The present paper will use these data to analyze the effects of size, crack length. This paper presents a studying to improve the existing universal size effect law, named by Bazant, using the experimentally obtained beam strengths for various different specimen sizes and all notch depths. The updated universal size effect law is shown to fit the comprehensive data quite well.


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