An initial observation one can make concerns the migration of water to the core of the material which can reach the steel reinforcements of concrete structures and oxidize them. Carbonation will degrade the concrete and will be responsible for exposing steel reinforcements. In both cases, the swelling of the steel due to rust will cause concrete splinters and weakening of the structure.
Other observations show the degradation of materials under the effect of cyclic freeze thaw actions in many regions of the world. Water in the capillaries swell and cause the material to burst, giving rise to a greater porosity. This new structure of the material will be able to absorb more water, as the porosity is greater, which in turn leads to greater damaging effects by freezing. Thus the flaking and the deterioration of stone or concrete by freezing is exponential over time.
In other cases, chlorides, associated with pollution particles, will degrade the surfaces of materials and make them brittle, friable, powdery and floury.
For more aesthetic considerations, it is advisable to provide protection in cases where, as with paving stones or slabs, the latter are likely to absorb a multitude of liquids (oil, soda, wine, coffee etc.) and dirt (grease, brake pad and tyre dust, exhaust particulates, etc.) that become embedded in the capillaries and pores. A lack of protection often makes it difficult to remove the entrenched grime.
Finally, mosses and lichens find their habitats in the damp irregularities of stones and concrete surfaces. Their proliferation also affects the aesthetics and durability of materials.
More effective than a surface film-forming coating, mineralizers penetrate material substrates by capillary action, where they crystallize lime and form silica in the capillary network and pores. Materials are thus waterproofed, consolidated and made more resistant to external attacks.