Pore structure and splitting tensile strength of hybrid Basalt–Polypropylene fiber reinforced concrete subjected to carbonation

Abstract To investigate effect of carbonization on pore structure and splitting tensile strength, splitting tensile tests were subjected to normal concrete and basalt-polypropylene fiber hybrid concrete after carbonization at 0, 7, 14, 28, 56 and 80 days, respectively. The pore structure was examined using a Rapidair 457 concrete pore structure analyzer. The pore size was divided into three regimes, 0–40 µm, 40–140 µm, and 140–2000 µm. The macroscopic properties and pore structure of the concrete were analyzed, and the relations among the splitting tensile strength, fractal dimension and pore chord length frequency in three regimes of concrete were studied. Results show that hybrid basalt–polypropylene fiber reinforced concrete enhances the carbonization resistance of concrete. From the correlation analysis, it is deduced that the most sensitive pore size affecting the properties is 40–140 µm for normal concrete and 0–40 µm for hybrid basalt–polypropylene fiber reinforced concrete.