01.11.12

Cements

But in modern sense of the term "dry blend" to such free-flowing compositions can be applied fairly conventional. Composition of dry mixes into any dry mix includes: binder (cement, plaster, lime or combination), neutral fillers to provide the optimum amount (usually sand), and special modifying additives that give the mixture cheap nfl jerseys the necessary properties. All additives for dry mixes are required – low hygroscopicity. It is necessary to ensure the safety of the mixture (ie, prevent premature hardening of binder due to adsorbed moisture). Therefore, the hygroscopic substance such as calcium chloride or potash, in the dry mixtures are used.

With the help oakley womens sunglasses of special additives which are present cheap jerseys china in any mortar, achieved excellent control of the rheological properties of compounds: they dilute solution to a mix without increasing the water content. Increased mobility of the mixture can lead to Ray Ban Outlet stratification and suctioning it out of water in case of damage to the porous substrate. To prevent these undesirable use water-retaining effects (thickening) adding: mainly water-soluble ethers, Serial polyvinyl alcohol, etc. For dry mixes, which can be used in the winter, use antifreeze additive. Often others used for this purpose complex salt additives, such as nitrite and nitrate, calcium nitrite-nitrate-calcium chloride. At the moment, many companies developed a huge number of different modifiers in the dry mixture affecting certain properties of the final product (concrete). As part of certain types of mixtures can be up to fifteen, some of which occupy a volume of a mixture of a negligible percentage.

They speed up or slow down Cure, improve workability, reduce the amount of water, increase the frost resistance and porosity. Thus, inhibitors are needed for concreting in hot weather and in some other cases, in particular for cementing wells. Air-entraining additives are essential to increase the frost resistance (due to voids concrete gets the opportunity to expand, the air is involved in conventional mixing, but in insufficient quantity). Dewatering additives, or plasticizers, can achieve a sufficient yield with less water, which leads to an increase in concrete strength. An important component of most dry mixes are polymer additives. Such a correction noticeably improves the workability of mixtures increases the strength, deformability, and water-resistant hardened solutions. But the main purpose of introducing polymer additives in the solutions – giving them high adhesive ability, ie, increasing the adhesive properties. So, just make the dry mix additives most attractive for a particular type of work. They give it special, cheap nfl jerseys the desired properties and quality.

Tags:
| Posted in General | Comments Off on Cements