Change Rule of Porosity and Saturation of Cement Mortar under Sealed Curing Condition Based on Different Measured Methods

Abstract

Abstract: Porosity and saturation are important factors affecting the durability of concrete. To study the change rule of porosity and saturation of concrete in the state of moisture insulation, cement mortar specimens with different ages and different water-binder ratios were formed and cured under sealed condition. Then the porosity and saturation of specimens were measured by weighing method (WM), mercury intrusion porosimetry (MIP) and nuclear magnetic resonance (NMR). The results show that the change rules measured by the three methods are consistent despite of slight differences in values. For the porosity, WM has the largest value, followed by NMR, and MIP has the smallest value. And for the degree of water saturation, the test value of NMR is higher than that of WM. The porosity of cement mortar first increases and then decreases with the age of 14 d as the boundary. The porosity of the specimen with a water-binder ratio of 0.41 is the largest and the maximum porosity is 39%. The saturation degree of cement mortar first decreases and then increases with the age of 14 d as the boundary. Higher water-binder ratio leads to higher degree of water saturation and the minimum saturation degree is 32%. Due to the randomness of the detection results of MIP, the detection results of WM and NMR are closer to the real porosity of the specimen.

Key words: sealed curing, porosity, saturation, mercury intrusion porosimetry, nuclear magnetic resonance

CLC Number:

TV431

DING Qian, HUANG Yaoying, XU Xiaofeng, XIA Shifa, BAO Tengfei. Change Rule of Porosity and Saturation of Cement Mortar under Sealed Curing Condition Based on Different Measured Methods[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2021, 40(11): 3584-3592.

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