Silicates are a part of the composition of concrete, which are formed as a result of reactions that take place during the entire bonding and hardening process (crystallization). The phenomena that take place in a fresh concrete mix, and then in the concrete itself are all subjects of detailed laboratory tests.
Throughout the entire period from the first contact of cement with water, chemical reactions take place in it, the effect of which is physical phenomena. One of such phenomena is the carbonatization of concrete, which occurs as a result of contact with carbon dioxide. As a result of this reaction in the concrete, its internal structure is transformed, and thus its properties change.
Depending on the application and subsequent use of the concrete, it should be prepared accordingly. It means applying impregnation protecting against penetration of various media in concrete.
The offer of the FORMATIQ company includes a whole range of silicate impregnates with different applications.
Molecules of particular silicates have a different size, so depending on the porosity of the concrete, the way and the conditions of use, one should be able to choose the right product.
We use ForSil for porous and very absorbent concrete. This impregnant and Forsil Extra are silicas filling the pores of the surface. Applying them several times with intermittent chemical reactions creates a hard layer of silica integrated with the concrete structure. This layer protects the concrete by increasing its surface hardness, which also ensures abrasion resistance. The silica layer produced to a very high degree immunizes the concrete against the effects of moderately aggressive chemicals.
ForLit is a combination of sodium silicate and lithium silicate which excellently protects porous and partly carbonated concrete. Very small molecules of lithium silicate can penetrate the concrete deeply. Lithium silicate with its additives reacts with free calcium carbonate, which was formed as a result of carbonation. During this reaction it rises again
The pH of the concrete, and thus the carbonation process stops. Today, most concrete floors contain steel and the pH indicator plays a huge role. The gradual lowering of the concrete floor below 10.8 during the operation of the floor results in the lack of protection for steel and the corrosion process begins. This phenomenon is undesirable, and ForLit excellently prevents this.
The graph below presents a technical description of the concrete composition, which shows the dependence of silicates in the whole concrete.
Concrete impregnating agents offered by FORMATIQ are based on lithium and sodium silicates. The selection of the correct preparation depends on the place of application, the type of concrete substrate and the time in which it is to function.
The crystallization processes of aqueous solutions of silicates occur very slowly and depend on the moment of water evaporation. After the application of silicates, the phenomenon of evaporation of water from concrete occurs more and more slowly. The top layer of crystallized silicates reduces the pore diameter, and thus the further evaporation of water is slowing down. The times of these reactions depend on the molecular size of the mixture, the pore diameter and the possibility of reaction with compounds resulting from carbonation, which are found in the internal structure of the concrete. Crystallization of silicates does not cause a complete caulking – closing all pores in concrete, but it can reduce their diameter to a size so small that they will be able to transmit only molecules of water vapor. This effect gives a huge advantage over protecting concrete with sealed resin-like coatings. Resin coatings require efficient insulation against penetration or capillary water absorption. Lack of certainty as to the efficient insulation eliminates resin coatings, and this place is now perfectly complemented by the protection of concrete with silicate preparations.
Silicates combined with the process of grinding and then polishing the concrete give excellent effects not only visual. To a large extent silicate impregnation at the time of crystallization of these silicates increases the resistance of concrete to abrasion, and at the same time its surface hardness. The hardened top layer can be polished. This process closes the micropores in the concrete surface, making it resistant to the penetration of various aggressive substances. For faster closure of micropores in the concrete during the polishing step, products with polymer additives, eg ForLithium Finish, can be additionally used. This material gives a faster and higher gloss that lasts for a long time. This additional layer facilitates cleaning, increases chemical resistance, and thus stops the process of carbonation of concrete.
Once underappreciated, today’s increasingly popular silicate impregnations enjoy great popularity among conscious investors and contractors choosing these products.
The most important benefits of using them include:
The offer of the FORMATIQ company also includes preparations for cleaning and current cleaning of concrete floors, which contain additives of lithium silicates.
In this way, thanks to the usual washing procedure, the floor is enriched with lithium particles, which contribute to maintaining the proper pH of the floor, which undoubtedly has a positive effect on its durability.
The FORMATIQ company provides clients with full knowledge about the proper execution of the floor, selection of materials at the implementation stage and cares about raising the users’ awareness of the importance of proper cleaning and maintenance of the floor in terms of its durability and improvement of aesthetics.
mgr.inż Ireneusz Gmaj