Detection of Two-Dimensional Internal Cracks in Concrete Using Point Strain Sensors
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Abstract
Tensile cracking in the concrete can destroy the structural frame since it induces water penetration in structure and foundation. For instance, in concrete pavements, cracking increases the potential for pavement distress, the probability of accidents occurring, and the damages for vehicles. Therefore, monitoring techniques to detect hidden internal cracking in concrete such as bottom-up cracks are necessary to ensure the safety of the infrastructure by distinguishing early signs of excessive damage. This study presents an approach to detect internal concrete cracks especially bottom-up cracks using point strain sensors. The stress intensity principle is used in this study to locate and estimate the growth of the cracks. Based on the stress intensity principle, theoretical derivations have been conducted to use the point strain sensors in concrete structures to detect both single and multiple bottom-up cracks. For single crack detection, laboratory experiments showed an average measurement accuracy of 85.76%. For multiple cracks, laboratory tests performed using reinforced concrete beams and the average measurement accuracy was achieved to be over 80%. With the validation in the lab, future efforts are expected to be performed in the field to provide an alternative technique to detect hidden internal cracks in concrete structures, especially pavements.