| you are: Structurally-mechanical properties of the cement test
Depending on structure of cement, an initial quantity of water and technology porosity of gel can make 28-40% of volume of gel, and nearby Xu-7z porosity (i.e. 7-12%) are necessary on a share kontraktsionnogo volume. The counteraction (stjazhenie) is the phenomenon of reduction of absolute volume of system (cement + water) in the course of hydration. найси-премиум - наполнители для кошачьих туалетов с антисептическими свойствами
The Absolute volume of reacting substances - РЎ3Рђ and waters - has made 196,97 sm3, and hydroaluminate volume - only 150,11 sm3, hence, the counteraction in the given example has made 46,86 sm3. As the counteraction almost does not reduce external volume of system, its consequence is formation in gidratirovannom cement kontraktsionnogo volume. Удобная смена директора дешево in a cement stone and concrete there is a vacuum under which influence this time is filled with water or air depending on Wednesday in which there is a material. The counteraction for usual portlandtsementov after 28-29 sut tverdenija makes 6-8 l on 100 kg of cement, i.e. In 1 Рј3 concrete with the expense knitting 300 РєРіРј3 it is formed about 18-24 l internal kontraktsionnyh a time.
The counteraction is peculiar to Each mineral of cement; it begins after mixture with water and reaches a maximum at full hydration. On fig. 50 the counteraction occurring at hydration main klinkernyh of the minerals is compared. The greatest counteraction occurs at hydration trehkaltsievogo aluminate (23,79%), it can cause internal pressure in a cement stone. two-water plaster added at a grinding klinkera, levels the counteraction as in chemical reaction of formation ettringita from SzA, plaster and water (see above) the counteraction makes only 6,14%.
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