Measuring Dynamic Young's Modulus of Low-Density Foam Concrete Using Resonant Frequency Test

Foam concrete is a cellular material mainly used in construction. Because of the low-strength feature of foam concrete, conventional concrete testing methods such as strength measurement are insufficient to characterize the key material attributes of foam concrete, especially for the low-density foam that is commonly designed for functional purposes. Inspired by the nondestructive feature of resonant frequency test, this study investigates the feasibility of using this method to evaluate the dynamic Young's modulus of foam concrete, especially at the lowdensity range. Three variables that typically alter foam concrete mechanical properties are considered for evaluating the robustness of this approach-bulk density, water-to-cementitious ratio, and fly ash replacement ratio. The fundamental transverse frequency is found to be most suitable for determining the foam modulus. The experimental results demonstrate good accuracy of using this approach for measuring the dynamic Young's modulus of different foam concrete samples. It is also confirmed that the foam modulus can be accurately designed if the bulk density of this material and solid modulus of its base cement paste are known.