Use of Ultrasound to Evaluate Concrete Strength in the Early Ages
Leila Meneghetti, Universidade Unioeste, Cascavel, PR, Brasil
ABSTRACT The quality control of concrete structures has been done through compressive strength tests in cylinder specimens at 28 days of age, preserved separately from the structure member. With the growing use of high strength concrete in civil construction it has become extremely necessary and profitable to have performance data before the 28 days, i.e., in the early ages. Moreover, the hydration heat exerts significant influence over the strength in the early ages, making the strength in a specific structural element, usually of bigger dimensions than in a cylinder specimen, different than the others found in the ideal conditions of the laboratory tests. Knowing the concrete strength in the early ages, from twelve hours up to 3 days, has benefits such as increase in productivity and acceleration of the constructive process through the reduction of the formwork and its supporting structure removal period, increase in productivity of pre-fabricated elements and prestressing concrete members in the early ages. In these cases the strength estimate in the early ages is left to techniques and quick tests that make it possible to evaluate the structure performance. Thus the velocity of ultrasonic wave propagation was used in this research to estimate the concrete strength in the early ages. Correlation relationships were plotted for different types of normal concrete and high strength concrete taking into account the influence of the cement hydration temperature. Key words: pre-service and in-service inspection, condition monitoring, and maintenance.
Publication Source: NDTISS '99 - International Symposium on NDT Contribution to the Infrastructure Safety Systems, Nov 1999 in Tores Brazil.
Publisher: Center of Tecnology, Federal University of Santa Maria (UFSM) - [Homepage]
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