Browsing by Subject "integrity testing"

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Access status: Open Access ,
Badania prędkości fali akustycznej w betonie pali CFA
(Wydawnictwa AGH, 2011) Gorska, Karolina; Rybak, Jarosław
Regarding the issue of the pile quality (continuity and length) tests by means of non-destructive methods, it seems essential to estimate the velocity of the elastic wave in the concrete. For example, considerable differences are observed in the measurement of the wave velocity before and after the pre-cast concrete piles are driven. For reinforced concrete piles made of the C50 concrete, the elastic wave velocity measured before driving reaches 4500 m/s, and after the driving - it oscillates around 4000 m/s. That is probably connected with the micro-cracking caused when driving the pile. The errors in velocity estimation may lead straight to proportional faults in the estimation of the pile's length (10%). It is even more complicated to determine the wave velocity in the process of the young concrete setting (before the 15th day of concrete embedding). Very few publications on that subject show large changeability of the estimated velocity and suggest that each time at the construction site calibration should take place. Calibration, however, is possible only when the person who runs the tests is in possession of fully credible information about the length of the examined (controlled) piles. The research conducted at Wroclaw University of Technology show that in the case of the concrete piles made of the C25 concrete, examined between the 5th and 15th day after the concrete embedding, the measured elastic wave velocities ranged from 3000-4000 m/s.