scholarly journals Detecting the Activation of a Self-Healing Mechanism in Concrete by Acoustic Emission and Digital Image Correlation

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
E. Tsangouri ◽  
D. G. Aggelis ◽  
K. Van Tittelboom ◽  
N. De Belie ◽  
D. Van Hemelrijck
Keyword(s):  
Acoustic Emission ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Crack Formation ◽  
Healing Process ◽  
Image Correlation ◽  
Activation Process ◽  
Self Healing ◽  
Emission Analysis ◽  
Healing Agent

Autonomous crack healing in concrete is obtained when encapsulated healing agent is embedded into the material. Cracking damage in concrete elements ruptures the capsules and activates the healing process by healing agent release. Previously, the strength and stiffness recovery as well as the sealing efficiency after autonomous crack repair was well established. However, the mechanisms that trigger capsule breakage remain unknown. In parallel, the conditions under which the crack interacts with embedded capsules stay black-box. In this research, an experimental approach implementing an advanced optical and acoustic method sets up scopes to monitor and justify the crack formation and capsule breakage of concrete samples tested under three-point bending. Digital Image Correlation was used to visualize the crack opening. The optical information was the basis for an extensive and analytical study of the damage by Acoustic Emission analysis. The influence of embedding capsules on the concrete fracture process, the location of capsule damage, and the differentiation between emissions due to capsule rupture and crack formation are presented in this research. A profound observation of the capsules performance provides a clear view of the healing activation process.

Experimental study on loading rate and notch-to-depth ratio effects on flexural performance of self-compacting concrete with acoustic emission and digital image correlation technologies

2020 ◽  
pp. 030932472094900
Author(s):  
Xudong Chen ◽  
Dandan Shi ◽  
Jinhua Zhang ◽  
Xiyuan Cheng
Keyword(s):  
Acoustic Emission ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Correlation Technique ◽  
Self Compacting Concrete ◽  
Opening Displacement ◽  
Emission Analysis ◽  
Cluster Group ◽  
Depth Ratio

As no extra vibration is needed in the casting procedure of self-compacting concrete for its excellent workability under its own dead weight, the material can be applied to construction projects where vibrations are hard to perform. To better utilize self-compacting concrete in practical engineering, it is essential to conduct an in-depth study on its fracture performance. In this study, three-point bending tests on notched self-compacting concrete beams were performed considering different loading rates and notch-to-depth ratios as variables. Acoustic emission technique and digital image correlation method were utilized to collect acoustic emission signals generated in the loading procedure and monitor crack propagation in the fracture process zone, respectively. Results show that the b-value from acoustic emission analysis can be divided into three stages and the variation range increases as the notch-to-depth ratio increases. Based on clustering analysis, three cluster groups can be obtained, and it is found that the ratio of the first cluster group decreases while that of the third cluster group increases when notch-to-depth ratio increases. With the aid of digital image correlation technique, effective crack length and horizontal crack opening displacement can be recorded and it is observed that crack tip opening displacement decreases as the notch-to-depth ratio increases.

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