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Method of Vacuum Water Absorption to Determine the Porosity of Hardened Concrete

Yue Li, Wanguo Dong, Hong Li, and Zhanguo Li
1. Beijing University of Technology, Beijing, China

Abstract—Concrete is a porous heterogeneous system in many situation, it is necessary to estimate the strength, durability, freezing and thawing performance and corrosion resistance. However, these performances are closely related to the porosity of concrete. In this paper, Method of vacuum water absorption was used to determine the porosity of concrete. Curing for specified ages (7d, 28d, 90d),the concrete block would be cut into sheets of concrete block (100 mm * 100 mm * 10 mm ), then the hardened concrete was soaked in water under the vacuum condition, the mass difference before and after soaking in the water was measured. The ratio of mass difference divided by the concrete volume is considered as porosity. The results show that the porosity is closely related to the water to cement ratio (W/C) of concrete, especially at long curing ages. The air-entraining agent can improve the porosity of concrete, when the W/C is low, this effect is obvious.

Index Terms—hardened concrete, method of vacuum water absorption, porosity

Cite: Yue Li, Wanguo Dong, Hong Li, and Zhanguo Li, "Method of Vacuum Water Absorption to Determine the Porosity of Hardened Concrete," International Journal of Structural and Civil Engineering Research, Vol. 4, No. 3, pp. 282-286, August 2015. doi: 10.18178/ijscer.4.3.282-286