A multi-frequency ultrasonic method for nondestructive detection of setting times and internal structure transition of building materials

Abstract

Setting times of building materials are crucial factors in the construction industry, as they directly affect the construction process. Accurate determination of setting times is essential to ensure that construction materials meet design requirements before demolding. This study introduces a new method using longitudinal waves with multi-frequencies to nondestructively determine the setting times of building materials. The measurement performance was examined by comparing the wave velocity with the results obtained using Vicat and calorimetry methods. A broad range of frequencies was applied to capture the transition of particle size and phase densification during the hardening process. The results showed that the collected data, including SEM images, and formation/transformation of chemical structures, supported the high accuracy in measuring the setting times via velocity regardless of sample type and hardness condition. Furthermore, by utilizing multi-frequencies, the proposed setup improved the detection sensitivity, capable of quantitatively monitoring the modification of internal structures during the monitoring period.