Pore characteristics (>0.1 mm) of non-air entrained concrete destroyed by freeze-thaw cycles based on CT scanning and 3D printing

In this study, the deterioration mechanism of concrete subjected to freezing-thawing (F-T) actions was analyzed. The evolution and spatial distribution of internal pore structure were key factors in the damage mechanism and mechanical properties of concrete in the F-T environment. X-ray computed tomography (CT) was used to examine the evolution of concrete internal damage under F-T cycles. CT-identified pore structures were reconstructed as digital virtual-models and the porosity and pore distribution of these pore structures were characterized by image analysis. Three-dimensional printing (3DP) specimens containing CT-identified pore structures were prepared and replicated based on these digital virtual-models. Uniaxial compression tests were conducted on both concrete specimens and 3DP specimens, which have a similar loss percentage of uniaxial compressive strength (UCS). These results show that 3DP technology can provide a new strategy for experimental study of concrete material.