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We are measuring the contact angle of cement mastic
Asphalt is PG 64-22
The larger the contact angle, the more hydrophilic, the smaller the more hydrophobic
However, the measured value of the contact angle of cement mastic is small. Isn't the cement resistant to water damage? Isn't more hydrophobic.
small is how much give the value is less than 90 or more than 90degre
Hi, everything is right, you just confuse a little bit. The contact angle is the angle between the cement matrix surface and water/air border (see https://en.wikipedia.org/wiki/Contact_angle#/media/File:Contact_angle.svg). That is why, the larger the contact angle is - the more hydrophobic material is and vice versa. In your case, if the angle is small it means that the material is hydrophilic. The contact angle depends on different parameters like the composition of the cement mastic or roughness (it can be because of the surface irregularities). In general, cement-based materials are porous (7% in the case of ordinary concretes) so, even if they are not hygroscopic, they absorb some quantity of water.
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