Analysis and Finite Element Modelling of Water Flow in Concrete

Abstract

Due to the construction of underground structures and hazardous waste storages, understanding and modelling of seepage in concrete has become an important issue in life-span analyses. The theories and calculation methods of unsaturated soil mechanics provide an opportunity to analyze water flow in other types of porous media (e.g. concrete) as well. This study deals with the determination of the permeability for unsaturated and saturated concrete and modelling the water flow in concrete. The direct measurement of the saturated permeability, the preparation of the drying water retention curve and determination of the depth of penetration of water under pressure are involved in the series of tests. For the fitting method of the experimental water retention curves were used Fredlund and Xing (1994) and van Genuchten (1980) model. The theory of lateral shift was applied to estimate the wetting water retention curve from the drying WRC. Thus, we could calculate the unsaturated permeability functions with Fredlund et al. (1994) and van Genuchten (1980) model. The finite element modelling of the standard test for watertightness were performed with Midas GTS using the measured and calculated unsaturated property functions.

Laboratory testing of seepage in concrete

“…fibre reinforcement, admixtures) does not influence the characteristic of the pore and the capillary system significantly. This is in good agreement with earlier findings related to WRCs of concrete samples [13].…”

“…The n and m fitting parameters are kept constant for both curves. The permeability function determined are in good agreement with the function defined by Pap et al [13] but we can observe some difference in high suction range. This fact calls the attention to the importance of proper WRC definition.…”

“…[14] model. The estimated functions fit well to the function of Pap et al [13] but the results show that slightly different WRC curve may lead to significantly different permeability function. This fact also implies that that proper fitting of the WRC is essential to proper estimation of unsaturated permeability.…”

“…10 shows the normalized permeability functions for concrete. Pap et al [13] defined the drying water retention curve for concrete mixtures using Fredlund et.…”

“…3. The characteristic of a bimodal water retention curve after Satyanaga et al [13] Many types of devices and test procedures have been used for measuring the WRC. Much of the original laboratory testing equipment was developed in the agricultural discipline.…”