Study on pore development and water migration regularity in the process of strength formation of hydraulic concrete.

• Low field NMR for exploring water migration law of concrete during curing. • Industrial CT for monitoring pore development in the process of strength formation. • Investigating the relationship among strength, water migration and internal pores. Low-heat and moderate-heat cement concrete (LHCC and MHCC) are compared to study the internal pore development and water migration law in the process of strength formation. NMR and industrial CT are used for measuring. The results show that the hydration rate is the fastest within 3d, and strength increase is also the most obvious. Compared with 1d, the compressive strength of LHCC increases by 44%, accompanied by a 21% decrease of capillary water proportion. In contrast, the strength of MHCC increases by 56%, following with a 19% decrease on capillary water proportion. Although the total porosity of LHCC is significantly higher than that of MHCC during curing, the pore growth rate is lower. The pore structure of MHCC is better, in which the proportion of larger pores (>10 mm3) is obviously lower. Finally, the relationship among compressive strength, water migration and internal porosity is in good agreement with the experimental values. [ABSTRACT FROM AUTHOR]