MORTARS NATURAL MINERAL BASE COCCIOPESTO
infinite possibilities and structural types of masonry, often characterized by materials that conform to the morphology of the places they come from, can be treated by identifying key elements, which are the load-bearing walls such as blocks and mortars. These, composing, define the static quality of the products.
It 'important to note that the historic masonry blocks of rock, whether igneous or sedimentary origin and mortars, modular, defining the parts essential structural and building.
the malt, then, the place and time should first of all that pertains to the investigation stage that help to define the project.
This phase, according to seniority, should be treated with thorough understanding, because the mineralogical composition of the compounds, the volume ratio defined by the aggregate binder, the resulting mechanical properties of the final mixtures, through a clever pose, give satisfactory results and durable.
Regarding the volume ratio between binder and aggregates should be pointed out the importance of decreasing amounts of the latter. The mixtures that make up the rough coat, il traversato e la finitura, devono avere resistenze di compressione, flessione e modulo elastico, decrescenti secondo dati definibili anche attraverso prove fisiche.
Assoluta rilevanza riveste la conoscenza della tipologia morfologica e strutturale della roccia e della malta d’allettamento, presente, nel manufatto in esame da recuperare e conservare. Le caratteristiche intrinseche, delle murature preesistenti, rappresentano i dati di partenza per definire un mix di malte appropriate da realizzare ed adottare.
Le scelte progettuali delle malte contribuiscono, in maniera sostanziale, sia in termini strutturali, sia in resa cromatica, in particolare quando quest’ultima è ricercata solo attraverso l’uso d’aggregati naturali senza aggiunta d’additivi coloranti.
La malta per finitura non è solamente mera espressione coloristica, ma parte integrante dell’intero pacchetto che compone i diversi strati del corpo murario che devono assorbire e trasudare in modo consequenziale a garanzia di continuità e scambio.
La cromia finale, del manufatto, non è effetto percettivo affidato solo ad una pellicola superficiale ma risultato materico che assume spessore e profondità.
“Intonaci Minerali Naturali”.
CONSIDERAZIONI
L’uso in tempi passati dei materiali naturali e delle corrette tecniche di posa, hanno permesso la conservazione nel tempo dei manufatti storici ereditati.
Oggi le conoscenze acquired it possible to propose technical and philosophical content that serve to preserve and protect historical monuments and centers of social value over the centuries have resisted adding together, all up to make up the vast architectural heritage.
It requires, therefore, contribute to the conservation of the assets inherited.
time no longer the protagonist of way and corrosion, but the material that makes up the artifacts, such as basic essence that survives over time and to remain solid and eternal.
Through the manipulation of matter, seen as strong and durable substance, the Man in its ongoing research and processing has demonstrated the ability to balance power with wisdom l’ambiente che lo circonda.
Un elemento naturale e fondamentale, usato consapevolmente fin dall’era Mesopotamica, è stato ed è ancora oggi il CARBONATO DI CALCIO, tale materia naturale da sempre è stata trasformata ed adoperata, anche, come legante.
La ricerca, deve mirare, alla possibilità di proporre elementi costruttivi naturali, come la storia insegna, che meglio si sono conservati nel tempo.
Nel periodo contemporaneo, momento in cui è forte la necessità di recuperare i Manufatti storici ereditati, necessita fare chiarezza sulla possibilità di riproporre materiali naturali che nel corso dei tempi forse si sono confusi con interpretazioni che spesso sono lontane dalla vera essenza della materia to be rediscovered.
If we are to successfully intervene in the recovery of historic buildings and monuments in order to pass on to our children what we have inherited from our parents, culture and sensitivity requires technical expertise.
To better understand the intrinsic meaning of the lime used as binder is to be noted that the need to tie and then cement, brick elements such as the archaic object identified as the first prefabricated module built and used by man since the last Ice Age (7000 c) in order to obtain compounds that would provide structural stability and durability to the products, what is the applicant in time.
note: It defines concrete, the result obtained by mixing components that react chemically and mechanically solidified.
2) calcium carbonate, used as an alloying element, pure lime
The mineralogical nature of the calcium carbonate also determined on the basis of the possibility of change of temperature of firing, in the specified way to the marl, the end result of product.
Formula Limestone CaCo3 also commonly called, is the stone in its percentage of purity up to 98% identified the pure lime or calcium lime. This carved stone and fired up to 1000 degrees which causes that matter to excellence, free from impurities, is searched. The hydrated lime
pure. Processing.
LIME FOOTBALL can be processed in putty, in lumps or powder, milk. I see
processes: cooking that turns the limestone into quicklime, the lime off properly, can give:
hydrates in the pit, putty putty or milk;
quicklime properly extinguished through a controlled hydration can be machined lumps of lime and then ground into powder.
The use of such kicks mixed with mineral aggregates, which do not contain glassy are not recommended in wet areas.
remains to be noted that this pure limestone, slaked worked, it is strongly recommended for the recovery of plaster interior decorations, never subjected to moisture. NHL
natural hydraulic lime.
If the calcium carbonate CaCO3, in its mineral composition, clay content present in varying amounts (for residual free lime supeioroe 15%, after firing up to 1250 ° marl, we shall have a NHL 3.5, see regulations EN459-1) able to get a lime harden in the presence of water, this is defined as Natural Hydraulic Lime "NHL" available only from marly limestone workable in lumps or in powder form and never slaked otherwise reacting with water , harden off the stage directly. Hydration must occur, spraying, in maniera controllata durante la fase di spegnimento della calce viva mantenuta a circa 120°.
L’idraulicità è data da componenti mineralogici specifici, in particolar modo dagli elementi vetrosi AS presenti nella marna, trasformati ed usati come i silicati e gli alluminati.
Questi, composti chimici, si ottengono in una NHL dal legame che avviene in fase di cottura tra l’0ssido di calcio presente nel calcare marnoso e la presenza nello stesso di Ossido di allumina e Ossido di silice data dalla componente argillosa, il tutto si trasforma DURANTE LA COTTURA:
- ossido di calcio + ossido di silice = SILICATI
- ossido di calcio + ossido di allumina = ALLUMINATI
La calce libera che influisce anche sull’indice: NHL 2, NHL3, 5, NHL 5, representing the amount of calcium oxide + H2O (also known as Portland) in excess and not combined in the cooking phase as seen previously. The higher the presence of free lime, the lower the resistance and the level of water availability
4) Mortars: AERE
MORTARS;
MORTARS WITH AIR HYDRAULIC BEHAVIOR, NATURAL
hydraulic mortar.
The lime derived from pure limestone to 98%, mixed with aggregates of different nature can give according to the mineralogical content of the latter, mortars of different types: first type
air mortars obtained with mineral aggregates: Taking el ' depend on the hardening total evaporation of water (moisture fear);
A second type
mortars air with hydraulic behavior HL: they hold even in the presence of water and then have hydraulic behavior. The legislation is not binding on the construction of a mortar HL then this can be added to Portland cement, masonry recommended in history (presence of gypsum, problems for the possible formation of ettringite).
second type B
CAUTION: MAY BE MADE ONLY hydraulic mortar HL USING APPROPRIATE MATERIALS AND AGGREGATES as silica sand, earthenware, pumice.
third type
natural hydraulic mortars hydraulic lime derived from natural limestone Marl, mixed with any type of aggregate will always natural hydraulic mortars.
It 'important to stress that a lime produced by a pure calcium carbonate (up to 98%) mixed with inert substances (first type) loses strength when subjected to rain or rising damp weather, etc. .. This leads, preferably, the exclusion of the use of mortars made with Air inert of which you can be assured in the mineralogical sense.
In humid environments, the mixture of plaster must be made with active hydraulic units (according to type b) having so mineralogical content with compounds such as vitreous silica oxide and aluminum oxide. This may ensure the exclusion of addition of Portland cement, and water resources to obtain the guarantee of durability. As stated
requires the need to know the aggregate, which is mixed with lime, it must contain enough in its chemical component glass, intended as AS (alumina and silica).
The reading is difficult in the case of aggregates by their nature can have or not have certain characteristics (such as volcanic aggregate, only referring to content glassy AS in terms of solubility, can not have them or have them inside the its mineral component, this possibility is mainly due the cooling time and the last layer which was extracted from the aggregate quarry from lava (basalt or rhyolite).
The reliable choice, which sees the use of a cluster than inside it contains the soluble components glassy AS needed to obtain an active hydraulic lime is to be sent to the cooked green clay mineralogical whose components necessary to us with substantive .
Clay is composed mainly = "SiO2 + Al2O3 + Fe2O3.
A lime mixed with pozzolana COCCIOPESTO E (the latter obtained by baking the clay at temperatures not exceeding 950 ° and then properly seasoned ground) results in a hydraulic mortar that is not afraid of natural wetlands, which will ensure over time, mechanical strength.
It is noted that a layer of lime-free AS is recommended only in very dry environments, as well as previously said the only use of inert materials mixed with "well seasoned hydrated lime" affected by the moisture, even with the addition of cement Portland.
greetings.
arch.giuseppe antonio Longhitano Tiepolo.
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