• Structural Engineering and Mechanics
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• v.74 no.3
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• pp.313-323
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• 2020

Non-destructive tests are commonly used in construction industry to access the quality and strength of concrete. However, till date there is no non-destructive testing method that can be adopted to evaluate the bond condition of reinforced concrete beams. In this regard, the presented research work details the use of ultra-sonic pulse velocity test method to evaluate the bond condition of reinforced concrete beam. A detailed experimental research was conducted by testing four identical reinforced concrete beam samples. The samples were loaded in equal increments till failure and ultra-sonic pulse velocity readings were recorded along the length of the beam element. It was observed from experimentation that as the cracks developed in the sample, the ultra-sonic wave velocity reduced for the same path length. This reduction in wave velocity was used to identify the initiation, development and propagation of internal micro-cracks along the length of reinforcement. Using the developed experimental methodology, researchers were able to identify weak spots in bond along the length of the specimen. The proposed method can be adopted by engineers to access the quality of bond for steel reinforcement in beam members. This allows engineers to carryout localized repairs thereby resulting in reduction of time, cost and labor needed for strengthening. Furthermore, the methodology to apply the proposed technique in real-world along with various challenges associated with its application have also been highlighted.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.1
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• pp.129-136
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• 1999

In this paper, the new non-destructive equation will be proposed and evaluated in comparison to the other foreign's non-destructive equation. Through the comparisons cores strength of mock structure with compressive strength obtained from new non-destructive equation ; rebound hammer, ultra-sonic pulse velocity and combined method, it will be analyzed about application of non-destructive equation. The results are following. The new non-destructive equations follow ; (1) $F_c=9.5R{\cdot}N+62.5$ (2) $F_c=243Vp-739$ (3) $F_c=8.1R_o+205.3V_p-802$ where, $F_c$ : Compressive Strength, $R_o$ : Rebound Number. $V_p$ : Ultra-Sonic Pulse Velocity Trough the result of mock structure test, the combined method is superior to rebound method and ultra-sonic pulse velocity method in the estimation of concrete strength. In order to apply the non-destructive equation of concrete strength to the structures, it is necessary that we should be made process study on the non-destructive equation for estimation of concrete strength in the range, time and strength of application under long-term.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.10a
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• pp.435-440
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• 1994

It is considered to pressing problem that the develpment of the rapid and simple method and measuring instrument, can evaluate for quality of concrete at early period. Accordingly in this paper proposed to earlier evaluation method on quality of concrete using resistance method and ultra-sonic pulse velocity test. It was found to the possibility of development on test method and instrument through a series of fundmental investigation.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.04a
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• pp.117-120
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• 1991

Cracks of concrete structure must be analyzed and estimated synthetically in order to have a maintenance and to insure the safety and the durability of structure. Concrete cracks have to be surveyed with respect to depth, width, shape and direction etc, but crack depth among these items is not measured easily. Occasionally, it needs to measure the crack depth of concrete structure for the purpose of evaulating the safe capacity and the necessity of repair. Therefore, this research is performed to verify the applicability and the accuracy of Ultra-sonic Pulse Velocity Technique(Tester), in non-destructive testing methods of concrete crack depth.