Cement – construction material which is loose powder of dark gray color. It is the main component for concrete making and plays a major role in its evaluation indicators. Mixed in certain proportions with water, sand or crushed stone, cement allows to receive the stone monolith capable to maintain huge loadings.
Instruction
1. Concrete one of the few building materials which strength characteristics increase in humid environment. From concrete make many various designs including the bases. When choosing cement, for production of the base it is necessary to pay attention not only to the price, but also to the brand, date of production and condition of keeping.
2. There are several types of cement which are subdivided depending on structure and properties. They differ from each other by the brand and on availability of special additives (with their help the concrete skhvatyvaniye accelerates or slows down, the firmness increases, removal, etc. changes warmly). All these data are specified on bags with cement.
3. Look at cement grade, it is located after index "M" on the label. The brand indicates durability of the received concrete from this cement, the brand is higher, the ultimate strength on material compression is more. There are M100, M200, M300, M400, M500 cements, etc. Also, the more the cement grade, the quicker hardens the received concrete.
4. After digits with the brand there is additional marking showing cement.1) D0 - cement without dobavok2) D20 - additives and 20% of cement
5. After these data, characteristics of cement follow. At use of clinker, rated on structure, in cement production he receives designation H (rated). The frost resistance of cement is defined by letters of CC Square (sulfate-resistant) means that cement is used in corrosive medium. PC - portland cement.
6. Tell letters GF (hydrophobic) about the increased frost resistance and plasticity of cement. Cement with designation of BC is applied to finishing work. The B - means high-speed. Letters VRC mean water tightness of cement and also its expansion when hardening. Also it well grabs.
7. At construction of the base the use of cement of M200 brand is allowed, but on the characteristics it is better to use M500 brand cement.
8. Often on bags there is no information or the substance which is inside raises doubts. It is possible to conduct independently the analysis and to define quality of cement. At first define material fossil degree, bag corners are for this purpose checked - they petrify quicker. Then it is necessary to open and check bag contents on color: from dark gray to light gray, and fluidity: fresh cement easily is scattered, streams as sand, between fingers if there are firm lumps, cement "has already lain down".
9. Define structure. For this purpose it is necessary to dissolve cement with mineral water without gases (Borjomi or Yessentuki) and to stick together flat cake sizes 15x5, in 10 min. it has to grab and heat up noticeably if so, then cement good and without additives.