Drying characteristics of concrete under surface low air pressure

Abstract

The humidity change of C30, C50, and C80 concretes under surface low air pressure and atmospheric pressure were tested. Based on the mechanism of moisture transfer under low air pressure, a theoretical model of concrete humidity field considering the effect of pressure was established. The model was used to analyze the changes of concrete internal humidity field when the surface pressure changes. The results show that the relative humidity values of each concrete under low air pressure are lower than that of atmospheric pressure. And the effect is greater near the drying surface. The improved calculation model was used to calculate the humidity change of concrete under low air pressure. The calculated values were in good agreement with the experimental values. It can be used to study the internal humidity field of concrete under different pressure conditions.

Keywords:

• Concrete
• relative humidity
• low air pressure
• calculation model

Additional information

Funding

This work has been supported by grants from the National Science Foundation of China (No. 51908550), the National Key Research and Development Program of China (2020YFC1909900) and the project of China Academy of Railway Sciences Group Co., Ltd (2021YJ173).