Analysing entrapped pores in concrete via x-ray computed tomography: Influence of workability and compaction time

Understanding the attributes of entrapped pores in compacted concrete is crucial for improving mechanical and durability properties of concretes. This research investigates how compaction time and workability affect entrapped pores characteristics. Using X-ray Computed Tomography, concrete specimens, with different workability classes, were analysed after being compacted for different times. Results show that increased workability and vibration time significantly reduce entrapped porosity, especially in the 2.7-4.6 mm diameter range, but this effect lessens at extended durations. Higher workability results in less spherical pores, potentially leading to stress concentrations. Additionally, concentrations of entrapped pores up to 5% were observed along specimen heights. These insights contribute to our understanding of pore properties, indicating potential adverse impacts on the performance of concrete.