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Water content diagnostics of concrete using nonlinear acoustics means
It is known that water or moisture affects the concrete strength seriously. In this paper, the concrete strength is evaluated from the relationship between water content and the acoustic nonlinearity parameter. To measure the influence of water content, a test piece was put in an oven to change the amount of water. Acoustical parameters were measured while one kilogram of water was vaporized until the weight of the concrete was no longer changed. All results were measured at the first natural frequencies of the concrete rod with one acoustically rigid boundary and one acoustically compliant boundary. The results of measurements were made on nonlinear parameters gamma1 and gamma2 as a function of the water content in concrete. The result of gamma1 not equal gamma2 reflects the asymmetry of the compressive and expansion processes, and the phenomena of gamma1 and gamma2 changing reversely with water content also proved the difference of these two processes. Moreover, nonlinear parameter and frequency shift are more sensitive to the damage of the concrete than the linear parameters obtained by the traditional acoustics methods. So, this method based on nonlinear acoustics maybe provides a better means of the Non Destructive Testing (NDT) of concrete.
Water content diagnostics of concrete using nonlinear acoustics means
It is known that water or moisture affects the concrete strength seriously. In this paper, the concrete strength is evaluated from the relationship between water content and the acoustic nonlinearity parameter. To measure the influence of water content, a test piece was put in an oven to change the amount of water. Acoustical parameters were measured while one kilogram of water was vaporized until the weight of the concrete was no longer changed. All results were measured at the first natural frequencies of the concrete rod with one acoustically rigid boundary and one acoustically compliant boundary. The results of measurements were made on nonlinear parameters gamma1 and gamma2 as a function of the water content in concrete. The result of gamma1 not equal gamma2 reflects the asymmetry of the compressive and expansion processes, and the phenomena of gamma1 and gamma2 changing reversely with water content also proved the difference of these two processes. Moreover, nonlinear parameter and frequency shift are more sensitive to the damage of the concrete than the linear parameters obtained by the traditional acoustics methods. So, this method based on nonlinear acoustics maybe provides a better means of the Non Destructive Testing (NDT) of concrete.
Water content diagnostics of concrete using nonlinear acoustics means
Diagnose des Wassergehalts von Beton mittels nichtlinearer akustischer Mittel
Zhou, Dao (author) / Liu, Xiaozhou (author) / Gong, Xiufen (author) / Li Ma (author)
2008
6 Seiten, 4 Bilder, 1 Tabelle, 8 Quellen
Conference paper
Storage medium
English
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