Estimation of porosity and pore distribution in Hydrated Portland cement at elevated temperatures using synchrotron micro tomography

Abstract

The porosity of concrete affects the mechanical properties and durability, during its exposure to extreme temperatures where the chemical and physical changes in PC affect the integrity of concrete as a whole because of its binding properties. An attempt is made to analyze the porosity in hydrated PC using synchrotron micro-tomography at temperatures of 27°C, 100°C, 400°C, 500°C, and 800°C. These temperatures are significant in the context of the mass loss and phase changes taking place during the thermal analysis. Image analysis is carried out to estimate porosity, radius, and circularity of pores for all the individual 2D slices. 3D analysis is carried out to estimate the diameter, area, and volume of pores present in the sample. The number of pores in the 2D slices has increased from 5974 to 11564 at 27°C and 800°C; while the total number of pores present in the sample at 27°C is 317 and at 800°C it is 3361. With the increase in temperatures, the area of pores 947 µm 2 contributed to 44.16 volume percent at 27°C, whereas at the temperatures of 800°C the area of 136 µm 2 pores volume percent is 41.