Slag and Cement
Typically, individual surface finely slag is 2500 – 3500 cm / city Fine ground slag, added to the cement, significantly affect the structure formation of cement stone. Microsilica is a waste product of silicon alloys of ferrosilicon, crystalline silicon, etc. In the process of melting the charge and recovery of quartz at temperatures above 1800oS gaseous silicon is formed, which when cooled and exposed to air oxidizes to SiO2 and condenses in the form of ultrafine particles of silica. SiO2 content in the silica fume is 85-98%. From other active mineral additives microsilica has a very small size particles (0.1-0.5 microns) and high specific surface (18-25 m / g). Located in the concrete in the pores of cement, microsilica improves the density and thus strength, impermeability and durability of concrete.
To seal the concrete require fewer mineral supplements (mixture porosity 'cement – aggregate' is relatively small) than when diluted in a wide range of cement, so the usual flow of microsilica in concrete is 5-15% of weight of cement, which is lower than other mineral supplements. In addition, in this case the interaction in concrete, Ca (OH) 2 and SiO2 is relatively limited, and it persists for a long time needed to per boards reinforcement alkaline corrosion. In the dry form because of the dispersion of ultra-high bulk density silica fume is only 0.15-0.2 t / m , making it difficult to transport. In the production of concrete is usually used pre- granular or briquetted microsilica, which greatly facilitates its transport and use. Organo-mineral supplements are combining into a single system of organic and mineral components having a specific modifying effect. Studies have shown that fine mineral supplements improve the efficiency of the plasticizers and, conversely, the latter contribute to positive action E mineral fillers on the structure of the concrete mix and concrete. NIIZhB suggested that organo-mineral complex modifier of the structure and properties of concrete MB-01 polyfunctional including superplasticizer C-3 (6-12% of weight) and microsilica and represents a powdered product bulk density of 750-800 kg / m with grain size up to 100 microns.
As a regulator of hardening (PT), injected into it organophosphorus complex. In applying this additive increases the keeping consistency of concrete mix, it is possible to obtain concrete with a strength above 100 MPa, low permeability and high durability. On the same principle established organo-mineral MB-C modifier. It includes a superplasticizer C-3, microsilica and fly ash-ash, in which 30-50% of silica fume replaced with a more affordable ash, ash, without noticeable loss performance additives. In general, organo-mineral Supplements are available in powder-shaped form, which facilitates their introduction into the concrete mix during its preparation. When designing the application in concrete additives necessary to carry out technical and economic calculations for predict the expected effect. It should be borne in mind that the use of additives in concrete technology, requires additional costs for a warehouse addition, highways, site preparation additives to additional congestion on the concrete mixing shops and factories. Some additives are relatively expensive and more scarce. It is therefore necessary to use additives in the first place where they use gives the greatest technical and economic effect. C the current situation and outlook for the Russian market additives for concrete, cement, CAS can be found in the records of the Academy of IKAR industrial markets "The market for supplements concrete, cement and dry mortar in Russia. "
