Monitoring of concrete segregation using AC impedance spectroscopy

Surface Bubbles Emergence as an Indicator for Optimal Concrete Compaction

“…The compaction process is essential for ensuring the strength and prolonged durability of concrete [1][2][3][4][5], a building material widely used for its robust properties. Compaction liquifies fresh concrete to fill the molds and removes unwanted entrapped air from the concrete [6,7].…”

“…To expel these entrapped bubbles, the concrete is compacted via vibration, in which the bubbles escape the fresh concrete by rising to the surface [6,7,12]. However, longer periods of vibration might cause the concrete to segregate, which results in uneven density distribution and further durability issues [1,4,6,7,13]. Gao et al [13] found a linear relationship between over-vibration-induced segregation and both compressive strength and chloride ion penetration in concrete.…”

“…The subjectivity involved in onsite decisions about when to stop compaction underlines a crucial challenge in concrete quality control. In response, many researchers attempted to develop new methods to objectively track or evaluate the compaction of fresh concrete [1,3,4,[17][18][19][20][21].…”

“…However, such methods may not accommodate the variable nature of concrete during compaction. Ojala et al [1] demonstrated this inconsistency, showing that identical vibration times applied to two comparable concrete mixes resulted in segregation in one, but not in the other, highlighting a shortfall of time-based compaction monitoring.…”

“…Ojala et al [1] investigated the use of AC impedance spectroscopy as a means of monitoring compaction. The bulk resistivity was calculated from the impedance values measured during the process of compaction.…”