Analytical Methods for Prediction of Water Absorption in Cement-Based Material--
Analytical Methods for Prediction of Water Absorption in Cement-Based Material
王立成
【摘要】：The capillary absorption of water by unsaturated cement-based material is the main reason of degradation of the structures subjected to an aggressive environment since water often acts as the transporting medium for damaging contaminants.It is well known that the capillarity coefficient and sorptivity are two important parameters to characterize the water absorption of porous materials.Generally,the former is used to describe the penetration depth or height of water transport,which must be measured by special and advanced equipment.In contrast,the sorptivity represents the relationship between cumulative volume of water uptake and the square root of the elapsed time,which can be easily measured by the gravimetric method in a normal laboratory condition.In the present study,an analytical method is developed to build up a bridge between these two parameters,with the purpose that the sorptivity or the gravimetric method can be used to predict the penetration depth of water absorption.Additionally,a new model to explain the dependence of sorptivity on initial water content of the material is developed in order to fit the in situ condition.The comparison of predicted results by the analytical method with experimental data or numerical calculation results,as well as some previous models,validates the feasibility of the methods presented in this paper.
【作者单位】：
State
【关键词】：
water absorption;capillarity coefficient;sorptivity;cement-based material;initial water content
【基金】：supported by the Key Programs of Ministry of Education of China(Grant No.109046)
the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Eduation Ministry
the Program of Innovative Research Team of Education of China(Grant No.IRT0518)
【分类号】：P751
【正文快照】：
1 .IntroductionThe cement-based materials ,suchasthe mortar and concrete ,are oftensubjectedto deteriorationprocesses in which water usuallyacts asthe principal mediumtotransmit aggressive agents (e .g.chlo-ride or sulfateions) (Yanget al.,2006) .Itistyp
