Experimental Study on the Influences of Deffctive Concrete on Chloridion Penetration Resistance

2011 ◽  
Vol 368-373 ◽  
pp. 1165-1170 ◽  
Author(s):  
Yan Liu ◽  
Cheng Yi

Micro-crack defects in concrete can affect the Chloride ion permeability of concrete in a certain extent. In the paper, the splitting experiments of concrete specimens from the four different dimensions are carried out in order to build the even damage fields. The displacements of the concrete specimens’ surface are analyzed through DSCM (Digital Speckle Correlation Method). Therefore damage parameters are determined that are damage area based on the MCOD (Micro-Crack Opening Displacement) and damage variable DE based on the weighting-damping elastic modulus. At the same time, Clˉ permeation of concrete specimens before and after the splitting test are studied by NEL method, and Clˉ diffusion coefficients D are recorded in detail. Further relationships between damage parameters and diffusion coefficients of Clˉ are discussed.

2014 ◽  
Vol 578-579 ◽  
pp. 1290-1294
Author(s):  
Zhen Qiang Wang ◽  
Yan Liu

The splitting test for concrete specimens in four different dimensions were carried out in order to build the relative even micro-crack damage fields. The real-time whole-field displacements of concrete surface were measured omni-directionally by DSCM(Digital Speckle Correlation Method). Through analyzing the obtained experimental data, two kinds of micro-crack damage parameter are established :one is damage area based on the MCOD (Micro-Crack Opening Displacement) and another is damage variable based on the weighting-damping elastic modulus, which provides a new index and method for characterization of concrete micro-crack damage.


Holzforschung ◽  
2015 ◽  
Vol 69 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Huanrong Liu ◽  
Zehui Jiang ◽  
Benhua Fei ◽  
Chungyun Hse ◽  
Zhengjun Sun

Abstract The present work is aiming at the elucidation of the tensile behaviour and fracture performance of moso bamboo (Phyllostachys pubescens Mazei ex H. de Lebaie) by means of digital speckle correlation method (DSCM) and microscopic techniques. Results indicated that fibres play a major role in longitudinal tension and impeding crack radial propagation. Hybrid I-II failure mode was observed, i.e., crack opening (in tensile stress) and shear sliding (in shear stress). According to microscopic fracture characteristics, fibres extraction and stretching, filament formation in parenchyma with fibres bridging, interface debonding and the helix fracture of fibres happened in tension, which created more interfaces and dissipated more energy. The graded composite structure of bamboo provides intrinsic and extrinsic toughening mechanisms which contribute to improved toughness and physical properties.


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