CAPILLARY ABSORPTION FOR CEMENTITIOUS MATERIAL CONSIDERING WATER EVAPORATION AND TORTUOSITY OF CAPILLARY PORES

Author(s): Jinbo Yang, Yue Li, Peng Zhang and Wanguo Dong
Book Title: RILEM International Symposium on Concrete Modelling - CONMOD 2014
Editor: Kefei Li, Peiyu Yan and Rongwei Yang
ISBN: 978-2-35158-139-1
e-ISBN: 978-2-35158-140-7
Publisher: RILEM Publications SARL
Publication year: 2015
Pages: 328-334
Total Pages: 7
Language: English

Abstract: This paper presents the theoretical analysis of capillary absorption dynamics for cemementitious material. Fractal theory is applied to analyse tortuosity of capillary pores in cementitious material and a definition of tortuosity is given. The dynamic equation of capillary absorption considering water evaporation and tortuosity of capillary pores is derived. Based on the dynamic model, the capillary coefficient and sorptivity of concrete are explained theoretically. In absorption test, water evaporation is one of the main reasons caused variations from linearity between water absorption height and the square root of time, or between water amount absorbed and the square root of time. In cementitious material, the evaporation rate is very small compare to capillary flow velocity at the initial time of absorption test. For simplification of testing procedure, there is no meaning to modify absorption test. Some absorption experimental results are used to analyse tortuosity parameter. The calculation results show that tortuosity parameter should be a property of capillary pores. It can be used to calculate the absorption height of cementitious material which is important for service life predicting of real structure.

Online publication: 2015
Publication Type: full_text
Public price (Euros): 0.00