They are waterproofing treatments based on various types of chemicals that may form part of the concrete structures (at the time of mixing), or be used in mortar on the surface treatments (treatments after concreting), or that may even be pulverized subsequent to the curing of mortar and/or concrete.
Its basic feature is to fill the pores and the capillaries of these areas through the creation of crystals during chemical reactions. They are suitable waterproofing treatments to be used in stable structures and in regions of little change in temperature and humidity, since the processes of movements of the structures and the mortar, usually, over time, generate surface cracks that in the short term can compromise the stagnation: note that the crystals are rigid elements.
They are used in surface treatment of concrete and/or mortar structures. They come in the form of emulsions (for molding in loco) and weldable blankets (asphalt and butyl).
Except for the specific cases of thermoplastic acrylic resins, the other require adequate protection for any kind of traffic due to the possible drillings, of fatigue (it normally uses cement and sand-based mortar for this protection), as well as the fluctuations of humidity and temperature (loss of elasticity and consequently rupture of the membranes or the welds detachment).
In principle it can be used in any weather with a better performance in the regions of little change in humidity and temperature.
New Flexible Generation (silicate-based)
It´s known that silicates react with calcium from the cement and form crystals, blocking the pores, capillaries and micro cracks of concrete. And considering that the crystals are rigid, they refer then to the rigid type of waterproofing.
In the new generation of waterproofing these silicates are modified by various processes, giving them some flexibility, sufficient to accompany the minor structural deformation.
They begin to gather the qualities of the two types mentioned above in a single technology without the need for any kind of protection (are embedded in the concrete) and without concern for the possible new micro surface cracks (excluding structural cracks), since the mass complex resulting from chemical reactions is re- hydratable, continuously occupying the new micro cracks due to structural deformation.