Study of small drilling technique for evaluation of concrete strength
| Autor: | Chi-Teng Hsueh, 薛紀登 |
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| Rok vydání: | 2017 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 105 At present, the rebound hammer test is widely used to assess the in-place strength of concrete in Taiwan construction industry. However, the rebound hammer test rsults are largely affected by the suface condition of concrete being tested because only the concrete portion in contact with the plunger affects the number of rebound, for example, hard aggregates generates a high number of rebound; conversely, voids or soft aggreagate makes a low rebound. Thus, the same batch of concrete may lead to various rebound test results due to variation in surface conditions. This means that the stability of the rebound hammer test is not high. In this study, a novel test technique involving micro-drilling process of concrete was proposed. The objectives of the study were to develop a new non-destructive testing device for concrete strength evaluation. In experiment, the diameter of the drill rod, the drilling depth within a certain time period, the drill rate, and the vertical weight on the rod top were considered to be the experimental parameters. Furthermore, the compressive strengths of the drilled cores of the specimens were used to establish the relationship between the concrete strength and the drilling behavior. The experimental results show that the data obtained from tests carried out with drill rod diameter of 8 and 10 mm is very stable, and the choice of the vertical weight on the rod top has little effect. A certain trend between the concrete strength and the drilling depth as well as the drilling rate has been found. The stronger the concrete strength, the deeper the depth of drilling within a certain time period. Similarly, the stronger the concrete strength, the slower the drill rate. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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