Practical considerations of porosity, strength, and acoustic absorption of structural pervious concrete

This study was conducted to address practical problems in producing structural pervious concrete, such as issues with mix proportioning, paste sagging, porosity, strength, and acoustic absorption. Concrete mixtures with varying aggregate types, target void ratios, and fiber contents were cast in cylindrical and panel-type specimens to determine the compressive strength, porosity, and acoustic absorption coefficient. Porosities of the concrete measured by two methods, i.e., using the volumetric method and computed tomography scanning, were compared to confirm the pore network distribution. A surface impedance method was used to measure the acoustic absorption of the panel samples. Paste with a flow of 170 +/- 10 mm containing synthetic fibers prevented sagging successfully even after mechanical vibration. The concrete produced with this paste and having target void ratios of 10-15% possessed adequate connected open pores for acoustic absorption coefficient over 0.5 and structural strength exceeding 20 MPa.