Influence of Water Content on Fundamental Frequency of Mortar Sample

2015 ◽  
Vol 1124 ◽  
pp. 273-279 ◽  
Author(s):  
Ladislav Carbol ◽  
Jan Martinek ◽  
Ivo Kusák

Ultrasonic non-destructive testing methods such as Impact-echo are often conducted under different conditions. Such results might be distorted by ambient temperature or by water content of the tested sample. Tested mortar sample displayed shift of the fundamental frequency by 3.7 %. This article confirms necessity of standardized conditions during ultrasonic testing for both laboratory and in-situ testing.

2014 ◽  
Vol 605 ◽  
pp. 139-142
Author(s):  
Seong Uk Hong ◽  
Yong Taeg Lee ◽  
Seung Hun Kim ◽  
J.H. Na

Recently, the interest in maintenance and repair of existing concrete structures have increased, and it is typical to use non-destructive testing methods such as rebound hardness test or ultrasonic pulse velocity method to execute maintenance and repair of structures efficiently. Many non-destructive testing methods are being used in practice such as at construction sites, but verification for site applications are quite inadequate. Thus, this study intends to evaluate the applicability of Impact Echo Method which is one of the non-destructive testing methods using stress wave. Total of four specimens were planned and produced. The thickness of concrete slab members was estimated using I.E(OLSENs Freedom Data PC with Win.TFS Software Version 2.5.2). The estimated materials of concrete members by IE was found to be IE-1 specimen 178mm, IE-2 specimen 197mm, IE-3 specimen 191mm, and IE-4 specimen 263mm, and the error rate was found to be 4.22%~18.67% (average 9.6%), showing that they are relatively well in agreement. In this study, the experiments were executed with the objective of estimating the thickness of concrete slab members using Impact Echo Method. Through this study, the applicability of thickness estimation in concrete slab members using impact echo method could be confirmed.


Author(s):  
S. V. Yushchube ◽  
I. I. Podshivalov ◽  
G. I. Tayukin

The paper analyzes the influence of defects detected in a monolithic base slab on the possibility of its further application in the construction of a 25-storey high-rise frame building. Non destructive testing and vertical core sampling techniques are used for the detailed analysis of the monolithic base slab. It is found that irregularities in the procedure during winter concreting of the base slab decreases the strength properties of concrete and provides the defect formation in the slab structure, namely delamination of the lower protective concrete layer and uncovering of working reinforcement. For the safe use of the 25-storey high-rise building, the base slab is proposed to be strengthened by adding in-situ reinforced concrete layer 100 cm thick.


1999 ◽  
Vol 6 (5-6) ◽  
pp. 267-272 ◽  
Author(s):  
J.N. Watson ◽  
P.S. Addison ◽  
A. Sibbald

This paper presents the results of feasibility study into the application of the wavelet transform signal processing method to sonic based non-destructive testing techniques. Finite element generated data from cast in situ foundation piles were collated and processed using both continuous and discrete wavelet transform techniques. Results were compared with conventional Fourier based methods. The discrete Daubechies wavelets and the continuous Mexican hat wavelet were used and their relative merits investigated. It was found that both the continuous Mexican hat and discrete Daubechies D8 wavelets were significantly better at locating the pile toe compared than the Fourier filtered case. The wavelet transform method was then applied to field test data and found to be successful in facilitating the detection of the pile toe.


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