concrete sorptivity

[mizz]

Hi all....

Im new here. Hoping to get some view or explaination on concrete sorptivity. what mechanism drawn the water into concrete pore. My thinking is,

1. due to suface tension force which occur when water is introduce to the concrete where its pull the water into the pore.

2. is due to capillary force which refer to the different in pressure between 2 sides of the menisci formed by water in the pores of the concrete. (which appear afterfirst stage).

however, my confuse is on 1)is capillary force similar to capillary action and 2)is the surface tension force (totally) is the acctual mechanism for the suction to occur.

hope somebody can help me with this. very fundamental but what to do, its make me confuse. thanks all..........

 

[davefitz]

Not my area of expertise, but we needed to understand this when building concrete structures that are exposed to salt water or high chloride water.See attached for a typical analysis of this phenomena. They refer to the "newton-einstein" equation.

<

http://www.niss.org/technicalreports/tr87.pdf>

 

[Ron]

Sorptivity cannot be separated from diffusion and the states of water contained in the pores; whether liquid, vapor or transition. Each affects the sorptivity or absorption in a different manner. For instance, the presence of the vapor phase in the pores allows lower surface tension which allows better interstitial absorption.

Likewise, capillarity is dependent on surface tension.