Image-based monitoring of fresh concrete compaction: quantifying the influences of compaction frequency and compaction duration on the quality of concrete components

This paper presents an innovative, image-based method of evaluating the impact of compaction frequency and compaction duration on the de-airing process of fresh concrete. By compacting the concrete in different compaction scenarios and monitoring the concrete surface with a camera, the study quantifies the temporal occurrence, spatial distribution and size of air bubbles as a function of the compaction frequency and duration. Analysis of gray values in the image also reveals indicators of segregation, such as bleed water, which indicate to under- or over-compaction. The findings suggest that particularly at frequencies of 150 Hz and 200 Hz, vibrations introduced by a poker vibrator improve de-airing efficiency enabling larger air bubbles to rise. Post-compaction analysis of hardened components confirms variations in aggregate orientation and distribution influenced by compaction frequency. This research highlights the necessity of integrating advanced monitoring methods to optimise compaction in modern concrete mix designs and move beyond traditional workability metrics to meet the evolving demands of concrete construction.