Today we talk about the hydraulic kicks, legante used since ancient times for the creation of the most diverse architectural works. The modern era has seen them take a back seat, especially after the advent of concrete: in reality theirs features are valuable and their use is still widespread today, especially by those who seek to combine resistance with ecology. So let's start from origins of the material so as to get to the advantages of hydraulic kicks, a perfect example of ecological and environmentally friendly binder.
What are hydraulic kicks?
La hydraulic lime is a calcium hydroxide based binder which, in contact with water, sets and hardens. In particular, it is a product that derives from the calcination of marl, particular limestone stones which, within them, contain a percentage of clay greater than 6%. The main characteristic of the material is that it grips and hardens when immersed in water: the chemical process underlying the phenomenon is that ofcolloidal hydrolysis, capable of giving the final compound a very high mechanical resistance, especially when compared to that resulting from the processing of aerial limes.
If you are looking for one definition more precise than the term hydraulic lime, here it is below. Hydraulic limes are defined as products deriving from the firing of marl limestone or calcareous marl at temperatures between 1000 and 1250°.
The origins
We said it at the beginning of the article: theuse of hydraulic kicks it is very ancient. They are in fact a real milestone in the history of binders, at least until the "discovery" of Portland cement. The first to use them (albeit with different formulations) were the ancient Greeks and Romans. However, we will have to wait until end of 1700 so that the mechanism underlying the reaction of hydraulic lime, linked to the presence of clay-type impurities. It is no coincidence that the adjective hydraulic was added by the engineer Luis Vicat, who understood what the necessary proportion was between the clay and limestone component for the compound to be able to harden with the mere presence of water.
Furthermore, among the merits of Luis Vicat there is also that of having provided for the classification of hydraulic limes, which he grouped into “weakly hydraulic”, “moderately hydraulic and “eminently hydraulic”. Today this subdivision is outdated, because it has been replaced, at European level, by the EN 459-1 standard, which subdivides the Natural hydraulic kicks in NHL 2, NHL 3.5 and NHL 5.
The advantages of natural hydraulic limes: why use them
Having discovered the definition and history of these binders, we immediately move on to the many advantages of natural hydraulic limes. We list them below, so that they are easy to consult.
- They are strong and resistant: hydraulic kicks acquire strength over time, while remaining flexible and consequently making any expansion joints superfluous.
- They are eco-friendly: this binder is a greener material, especially compared to cement. Hydraulic limes, in fact, are cooked at lower temperatures and, moreover, are made of natural and recyclable raw materials.
- They are breathable, while remaining impervious to water: they avoid the formation of condensation and humidity and, for this reason, fight the generation of mould.
- They fight pollution, even indoors, because they have a very low emission of VOC, or volatile organic compounds
- They are beautiful to look at and feature highly prized natural colours. For this reason they are also used in contexts characterized by landscape restrictions and are used for restoration works in general.
Natural flooring and hydraulic limestone
Le characteristics of hydraulic kicks they make them excellent binder for natural floors which, in addition to being resistant, must also be draining. The flexibility of the material will in fact make the flooring particularly efficient, therefore capable of lasting over time and resisting the natural cycles of freezing and thawing of the ground. The naturalness of the binder, then, makes it perfect - also from the point of view of the impact on the landscape - even in eminently historical contexts or within nature itineraries.
It should therefore come as no surprise that Solid Earth, sector leader for the creation of natural floorings, make way use of hydraulic limes in its environmentally friendly binder mixes.
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