Mechanical and radiation shielding properties of concrete reinforced with boron-basalt fibers using Digital Image Correlation and X-ray micro-computed tomography

The paper presents experimental investigations of the radiation shielding, mechanical and fracture properties of concrete reinforced with 5 kg/m(3) of novel basalt fibers infused with boron oxide (BBF). However, further studies concerning other dosages i.e. 1 kg/m(3), 10 kg/m(3), 15 kg/m(3) and 20 kg/m(3) are currently carried out. Experiments with neutron source revealed that addition of BBF as a dispersed concrete reinforcement could improve the neutron radiation shielding of plain concrete by up to 25%. On the basis of mechanical tests, it turned out that compressive strength, tensile splitting strength and flexural of concrete reinforced with BBF were lower by up to 15% than analogous values for plain concrete. Simultaneously, shrinkage strain of BBF concrete was lower by about 10% than of plain concrete. Fracture process zone development on the surface of samples was investigated by Digital Image Correlation (DIC) using camera with the 36 megapixel matrix that allowed to obtain pixel size of 18 mu m resulting in the length resolution equal approximately 60 pixel/mm whereas analyses of 3D material micro-structure, air voids, width and curvature of crack were carried out by X-ray micro-computed tomography (micro-CT) with 0.2 mm brass filter, voltage and the current equal 130 keV and 61 mu A, respectively. The voxel size of the X-ray micro-CT was 39.68 mu m. Experiments revealed that basalt fibers infused with boron oxide as a concrete dispersed reinforcement improved the ability of limiting micro-cracking area and bridging macro-cracking by up to 28%. (C) 2020 Elsevier Ltd. All rights reserved.