| you are: Porosity of a cement stone
Porosity of a cement stone decreases, and its density increases at decrease initial VTS and increase in degree of hydration of cement. During the first moment after mixture of cement with water in the cement test there will be only capillary time and their volume is equal to water volume zatvorenija. 123456
In the course of hydration the general porosity of a cement stone decreases for the size dependent on degree of hydration.
However capillary porosity decreases faster, than the general porosity. This phenomenon is extremely important for improvement of porosity of a cement stone and speaks that a capillary time is filled with cement gel. After all the density klinkernyh grains-3,15 гсм3, and volume weight of gel (the gel taken together with a time) - nearby 1,6-1,8 гсм3, hence, cement grain after hydration occupies volume twice bolshy. 123456
Owing to filling of capillary space with new growths not only the general porosity is reduced, but instead of a large capillary time there is the small time of gel more favorable for properties of a cement stone.
Durability of the cement stone prepared from given portlandtsementa and sustained in certain conditions, depends on porosity. 123456
In half-logarithmic co-ordinates dependence porosity - durability can be presented in the form of a piece prjamojd. M.Roj and Gouda used for manufacturing of a cement stone with VTS=0,093 hot pressing (temperature 250°С, pressure 350 MPa). 123456 the cement stone Received by such way was very dense, its settlement porosity - unusually small (2,13-3,9%), therefore already through 1 sut at compression has made durability 412 MPa, and to 3 mesona has increased to 655 MPa.
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