Everything about white cement

  As a plaster of yore at times

With plaster, these old relics, custom-made tens and even hundreds of years ago, modern technology has a problem. It stems not from the fact that the technology is too low, but the fact of misunderstanding place, a point from which it started many years ago, and thus what was then possessed, and what had to be modified to the parameters were better.

Such an approach also means that this problem also have a ready-made plaster - products of large companies that issue occurs among people who decide or co-decide on the choice of technology that will be used to the object regained its former glory.

Assuming that we have to facilitate the building of, say, the eighteenth century, built of stone and partly of brick, which currently has a damp plaster, of course, does not have good insulation horizontal with vertical not to mention need to renovate - a problem arises. From the contemporary point of view, it presents quite easily - what to do to dry wall, to the extent which is possible, and how to make moisture and the "crap" that can be found in the wall after applying the plaster did not go outside. Of course, the outside can not come out well The same shit, or alkalis contained in the most ordinary gray and sometimes even fly ash cements used as a base for such a plaster.

At present the bulk of typical, and perhaps all commonly used restoration plasters, based on the cement as a binding material. What not to speak of cement, it has one advantage - for our needs is a strong, even very strong despite the use of fine filler (sand dug or quartz). His strength is much larger than the old plaster or mortar.

With cement and a certain amount of roughly a dozen to twenty, twenty, sometimes little more percent, it becomes before the next challenge. How plasticise mortar to give a blur, applied to She did not issue whether the imposition of a manual or mechanical, not to involve started already in the pipe machine? Again, the answer is one and simple - a plasticizer. Formerly it was lime, but at the moment the market is a whole range of much stronger, more precise dosing, less susceptible to weather conditions etc. In a word about the head, you just need to find what will fit into the cement.

It is known that calcium is a germicide and algae killing - which translates it to be used sometimes in modern mortar, but the amount thereof is trace, 2-3% and sometimes even less. They are sometimes replaced by another chemistry. Unfortunately mortar designed in such a way usually has two disadvantages. This is the first of its strength and stamina and admittedly tightness, which is permeable to moisture. It (tightness) is significantly higher than conventional bricks. This means that efflorescence, or white-gray raids will be created, but does not come out, "fugue" but "brick", creating a bright patterns, which are a big drawback aesthetic, providing that someone with exaggerated strength. The remedy for this fact is another chemistry - this time aerators, which means creating a blank space - bubbles - in the middle of the mortar. Perfectly seen in cross-section. They allow that all this "crap" did not go out with bricks, but as it should be - a fugue.

To understand that this approach is tempered by the so-called. the spirit in which the then arose, "ancient" mortar must understand their composition, their properties and know which materials for every match.

Before rediscovered cement before re understood what even in its natural form can be used, the main and practically the only bond was lime. Used in various forms - extinguished or burned but broken finely, but the lime. That could be used as a base for the mortar had to be extinguished, or go into a lime cake. In principle, any person "sitting" in the construction industry would agree that according to current standards of the then mortars were weak, some argue that even very poor.

Position of the early nineteenth century on the building and widely understood constructing houses it says that for "normal fat" lime approximate ratio of dough limestone sand kopanego was approximately 2: 5 to 3: 5 or 1: 1.5. If the lime was very greasy - it's more sand, and if the lean is correspondingly less. What role played the lime (in the form of cakes limestone) in the mortar? It was both a binder, and as a means preserving healthy wall.

Unfortunately, however, lime is the bond to the needs of builders has several disadvantages:

  • he does not like too much moisture
  • involves relatively slow
  • not suitable for use in humid, wet with almost no mention
  • because the pace of bond - "so-so" suitable for the plaster to the inside

This meant that every eighteenth-century artist had extensive knowledge on how to modify the existing mortar, ordinary available at every village or farm means to change these imperfections. It added so desiccants plaster was added to seal the measures and accelerated the hardening of the mortar, known even such methods, which allow to create a mortar hardens within tens of minutes.

With this in mind you need to know that the mortar based on lime cake was "fluffy", ie at the turn of the mortar, even made back in the nastych the twentieth century, you can safely find these air bubbles, and next to them other additives.

The conclusion is one - can and need to replace lime (always in the sense of lime putty, slaked lime!), But only in the place in which fulfills its function as a binder. The new binder must also be resistant to moisture, or moisture can harm him. Cement pure without additives, niskoalkaliczny course fulfills this role. Replacing lime cement does not mean that they eliminate - other properties are so valuable that they should be used. Belong to them:

  • biocidal properties
  • aeration of mortar
  • workability / plasticity

Jumping a little over a hundred years forward to the 20s and 30s, one can easily see that in this manner the reasoning. In one of the books published for people who want to build your house using as we should have called economic we are very easy to find some information of interest to us.

The first of these is a proposal to produce a range of self-cement bricks, is used as described by the authors in, inter alia, Finland. Its composition is 1 part cement (then, a clean and decent) 8-10 parts of sand. It is not a strong brick, but still sufficient. It can be assumed that the approximate strength corresponds roughly brick M 7.5 - M 10. These are the construction methods, the binding of the wall and so on. At the end they did not forget to give provision for mortar: 1 part cement, approx. 1.9 parts of dough lime and approx. 8-9 parts sand. As can be seen there is a strong mortar, but sufficient. It is weaker and less tight than the bricks, the more that the then cements slightly slower bound and final strength were slightly smaller.

The most striking difference that you will notice is the replacement of lime as binder for cement, lime and leave as a plasticizer, biocide and suitable plasticity, workability and aeration of the mixture.

From that 80-year-old is currently recipe can easily take on any construction site. The prerequisite is only the use of cement with parameters similar to those to which they were accustomed to people before World War II. Cement must be niskoalkaliczny and without any additives, at the moment - white. Slaked lime due to the current technology of its production can be relatively quick and simple method (though in the eyes of the people of the '30s, with no previous mention uchodziłaby as barbaric). The most popular commercially available lime is defined as hydrated or suchogaszone. Quenched with them in such a way as not to produce an excess of water, due to technology and the needs of our preliminary. To extinguish them to the end and get the lime putty, you can simply pour into a sealed container, pour the appropriate amount of water and leave for two days minimum. Then suitable for use.

Contemporary fillers were usually dug sands containing very fine fractions, and not washed, that are clean, but these factions on our needs are a bit too little. Of course, it may be replaced eg. Quartz sands. Only so much and will allow us to create a place for the construction of mortar, whose parameters correspond to or are very close to those that were used in the twentieth century.

To replace purely mortar of lime - also we must be modeled on this principle and in accordance with it appropriately modify them. Will it be called the renovation - yes, because the idea and method of formation is consistent with contemporary, old philosophy - is an attempt to find such a variety of binder, which would be stronger, more resistant to moisture and faster binding. They found it - it's cement, which at the same time is not a reason to give up what we give slaked lime just because you can replace them with chemistry. It's a bit different starting point.

As already mentioned, the current way of extinguishing hydrated lime, for people living in the eighteenth or early nineteenth century would be barbaric. In the literature of the time, you can find three basic.

First, apparently dating from the times of "ancient" Greeks and Romans looked like this - took a lump of spent lime and crashing into tiny, throwing down the respective prepared in the right way. Therefore, it should be rather shallow and large. After the breakdown of lime into very fine particles and throwing dirt is not lent to the water, just as long gracowało, and sometimes a few long days (apparently at least several) until the lime itself become damp and begin to crumble without the addition of water. Then they przysypywano with sand (for straw had to pay attention to whether to discharge gases do not make the cover will disappear), and after a few years at least be suitable for use.

In one study, you can find the information that pitted lime may be hundreds of years old and does not lose anything from their properties. Much more can be read about waiting several years and even longer. Contemporary stories of older people is confirmed. Lime thus extinguished, and then properly pitted is the base for the mortars, which according to the author of the books in the nineteenth century. Enter into the smallest cracks.

The second method is somewhat faster and easier in the first phase. After decomposition of the calcined lime into smaller parts and lumps poured this water then hoe. At the moment when the water "disappear" the process is repeated. After its completion, the procedure is the same: that is, covered with sand and wait until lime become slaked. After at least two years, the material is ready.

The third is indirectly - to guarantee very high quality lime - its density is so high that the blade driven into it difficult to remove. Large square surrounds the stone, then the stone dusted with sand, then on such a limited square poured lime burned, przysypuje sand for a minimum of half a cubit (elbow was less than 60 cm), then flooding it all with water in an amount such that she came to lime and began the process. You have in the course of just be careful not created holes in the sand and that the amount of water was adequate.

Sometimes you can find the information that such a lime residents added the carcass of an animal, skin, hair or bones. After several years in the bottom of the "extras" disappeared, and ready to use lime had in a casein glue, which itself is a powerful, relatively quickly binds and is resistant to moisture. This meant considerable advantage bricklaying building.

Of course zwożony stone for construction or for furnaces in which lime was not able to be "out of the mine" or rather "straight from the quarry," but had to "seasoned" that turned out to be, which is fit for use. The author writes that in addition to the so-called. necrosis, which is porous, absorbs moisture, but it is light and strong, substantially stone after winter must be similarly color, grain therein must be similar and have the same or similar shape struck captures sound, cracks and fissures smoothly booty, do not crack in the fire, will not be absorbed water or in it any "shit" will not leave, and finally poured alcohol or other "sharp" liquid starts to react with it. Only then it can be used to build a house to stand the years, not a few winters. Only in this short description of the difference can be seen as it is today and how it used to be. It is also, and perhaps especially this demonstrates the knowledge and expertise of contemporary experts in the field of construction.

With the same precision and accuracy they are listed various types of mortar, and their composition, from the oldest to the contemporary author. It also clearly stated that the marble is also a limestone, but that hard, and best lime probably took the spent and then extinguished marble.

Masonry mortar in water:

  • lime still hot from the oven mix with coarse and fine stone, brick in the water will go into the mortar hard and resistant
  • lime kiln mixed together with utłuczonym raw stone and extinguish together - kit will also be hard and fit for laying in water
  • this method is described as reaching the Carthaginians, somewhere disappearing in the mists of time, or that which is "always" a popular and widely used in southern Europe ( "Tunet and edges Barbaryi") "mixed part sand, two parts of ash and three parts lime, then all carefully screened by adding a little water, three days and three nights was stirred, followed by addition of a little water and oil until a solid mass of this makes "

Other types of mortars and their properties:

  • Lime puzzola - is fit for laying in the wet, and she puzzola hardens in water. They mixed together penetrate even the flint stones and brighten them very (with black make them white)
  • strong mortar can be also done by dissolving soot ... urine in water, whereupon it is added to a lime and sand; the first part of the provision can be replaced also plaster or dust from the same stone, which is roasted lime
  • some bricks or tiles mashed, sieved, of course, added to the parts of lime mortar making moisture-resistant; tile or brick can be replaced by the crushed coal slag and iron - this type of mortars suitable for imposing and stucco
  • linseed oil, which may be substituted as peanut oil, mixed with sand and debris (i.e., again, tiles), and lime make the mortar is impermeable to water; while if there is oil, it is also good mortar can be created on the basis of a typical composition based on the thick sand and lime, but with the addition of two parts of the rubble of crushed and sieved; mortar of the composition according to the author of the excellent "for aqueducts, bridges, roads, vaults and places discovered"

Ordinary mortar for masonry depends on the fatness of lime

  • lime and sand half and half, if lime is good for 2/5 and 3/5 lime sand, lime and if it is delicious and 1: 2; wanting the plastered walls and ceiling just the same mix lime with bovine fur ...

Recipes from other countries, ancient, which so or otherwise is known for generations are also based on similar additions:

  • should be put out lime wine, add pork fat milk and fig, after adding the rare tar and linseed oil nothing better not be suitable for water supply, swimming pools and other structures having permanent contact with water...
  • similar properties had to have a kit straight from the North (written in the annals of the Swedish Academy) with the following composition: nine parts of clay small, six ash screened, five fine sand, six tar or oil, then lent the water enough to be workable, mingled long and carefully and created thereby kit is not absorbed moisture immersed in water for six months; the second version was distinguished by the fact that added no tar and oil, because they stank so much ...

All components that are at hand in the former farm or in its immediate surroundings, such as gypsum, quicklime, egg, buttermilk, cottage cheese (even slightly sullen) added to the slaked lime formed in contact with moisture or more broadly with water mortar durable and water. On the basis of this knowledge it was in the 70s the eighteenth century. Scientifically developed and tested empirically mortar, which was resistant to moisture and recommended for use. It consisted of parts of slaked lime and third parts of quicklime beaten to dust. Mortar such Once cured losing their properties even in the water./p>

In a short summary of contemporary knowledge, which apparently was wide and uses what people of that time were on hand with concrete mortar that can and should be applied in specific cases

  • mortar lining channels or places where water is in constant contact: one part brick utłuczonej and sifted, the two parts of river sand also screened, the fourth part of slaked lime, quicklime as many - beaten to dust
  • mortar or plaster water resistance: dust from coal mixed in equal parts with lime slaked
  • plaster to the inside: two parts of slaked lime, one part of broken plaster, the fourth part of quicklime
  • to the mortar for masonry (because It good mixed with lime) can include marl pounded, and all that remains after combustion in furnaces hut (pieces of stones and rubble)

All of these recipes, all modifications reaching deep roots sometimes years back, perhaps the times of late antiquity, or at least there that draw their inspiration they have one thing in common - they make changes in a particular direction of these features lime mortar, which were nuisance, namely:

  • low intake of strength
  • poor water resistance

It is difficult to expect to present finished products rather mass restoration plasters have the same or similar composition to the bag were slaked lime and quicklime, soot or ash timber, sifted and adequate cleanliness. Each of these additives served as a role - ash or charcoal essentially drying up moisture, which entered into mortar (tied it, not allowing further penetrate), brick or clay gave strength and resistance to water, quicklime in an appropriate amount mixed - hardening rate, etc

At the moment, this is the role of either cement (rate of binding and strength, also at low temperatures and adverse weather conditions) or chemical additives from the simple and popular as a water glass at a high-class plasticizers. However, bearing in mind the philosophy which was used those few hundred years ago mortar renovations should really be based on cement (as binding material), calcium, and more slaked lime (as a plasticizer, something that gives the "fat" mortar and central that it perfectly aerated) and sand or its various substitutes (as a filler).

Yes, there are mortar advertised as pure limestone, its composition based on slaked lime - but does except him their composition is the same as that used many years ago? Is contains the ashes, cheese, eggs and perhaps mashed tile, or hair pork or beef?

In the nineteenth century to the stage again enters cement. Initially, it cements are based on well-known even to the Romans puzzola, then already the roasted based on clinker and referred to as portland.

In fact, because of the fact that there were no rules or regulations that, out of which shall consist charge, while the burning process subject to further changes and modifications, this meant nothing less than that, and the effects were different for the same charge, as and various charge very similar results were obtained in the form of cement having the same or very similar properties. Although studies have already been conducted on the cement in the 50s nineteenth century (the present-Polish), it is because of the inability to buy goods with the same composition as slowly stuck on the plaster or masonry.

A study on cement issued in the 70s nineteenth century clearly recommends that the mortar adding a maximum of five parts sand to one cement. The authors emphasized that, yes tried to add more, even ten or twelve parts, but due to the fact that the cement must be strong, sand sharp and all good dry mixed, which in the conditions of contemporary construction was as they marked the basically not to meet - it is advocated that these parts do not exceed five; if the mortar is to be used in humid - further reduce the amount of sand, as there is important power. They do not talked about cramps mortar, which probably meant that the then rate bond was not as modern times sensational, but in comparison to pure lime mortar, and so was significant progress.

To fill the boxes used to build the iron bridge near Warsaw in the second half of the nineteenth century, used concrete with the following composition: five parts sand, two parts lime lasowanego and one cement, and to bulwarków on both sides of the abutments przymostowych "stronger" because one part cement It accounted for four and a half parts of sand and one and three quarters parts of lime .

For the preparation of the foundation stone recommended to use a size between one and a half to two inches thick (the thickness of approx. 40-55 mm). To tie this in principle, key aggregate use of concrete with a composition similar to that in the case of construction of a bridge in the amount per unit volume of half a stone mortar unit volume.

The authors stressed very clearly the difference in the quality of cement - one of the types of water penetration followed from the moment when the mix was the one-to-one, for another one to three (cement / sand). Interestingly the then recommendations of experts said that cement quietly tied (he had a low heat of hydration). Just how low it could be proved that the samples of concrete composed of cement or only in one part of cement and a sand immersed in water at all times able to break only after several days or even several dozens of (more than 30). Nowadays it is impossible ...

The strength of this cement (one of the best if available) after 52 days, was in a roughly around 15 MPa, what measures translated into Russian as almost 2,100 pounds per inch Russian Russian. Interestingly various attempts to bring very different results, even for cements that initial parameters and composition were very close to each other. Mortar based on cement such a resistance to at most 1 MPa, and the concrete as defined in contemporary (gravel sand cement in an amount of one part each) of about 2 MPa. Interestingly, in those days cement concrete determined what is today considered to have a relatively weak mortar

These results allow somewhat fragmented with little error stated that the then technologists or persons involved in the architecture very quickly able to appreciate the properties of cement, which did not have a lime mortar. Based, however, their knowledge of how important the role of lime and what it gives you do not throw it with contemporary recipes, even those that were anticipated where today zastosowanoby clean concrete made on the basis of strong cement, even class 42.5.

Studies indicate what was different then the binding material from the present:

  • smaller (slower) rate bonds meant that there were no current threats as well known today, which is cramping or scratches
  • the time it expected to "access" to the final strength of cement was almost twice as long now (52 days once a 28 today)
  • strength mortar was much lower, which meant that there were no problems that we encounter today (the need for strong aeration, and at the same time the need to achieve the desired strength parameters)
  • use of slaked lime all the time (as defined by long and well zlasowanego) aeration eliminated (since it assured us lime) and the use of chemicals aimed at providing plasticity, and resistance to algae (these characteristics and properties have even hydrated lime)

You should ask yourself whether was aware that opportunities have cement and that efforts should be made to standardize the parameters that must be met. The answer is definitely yes - it confirms what happened right at the beginning of the twentieth century. At that time, the Association of American cement producers seemed sort of recommendations or standards for internal rapidly growing US market. Very quickly, several thousand pieces had to be sent to the then developed world. Over the years subsequent versions and subsequent changes of these recommendations, and later regularly referred to as standards become determinants and role models for other standards - this time national.

The next question is what happened to the legacy of centuries earlier? No, it has not been forgotten. Another handbooks, recommendations and guidelines appearing quite regularly for 20 years, they consider the most natural thing in the world that the mortar or plaster use slaked lime, or forests. They recommend only shorten the fire because "only" season, and in fact about one and a half year gives a great effect in mortars. Defined as the minimum time four and six weeks, depending on the application. However, lime is no longer a binder material which has to be water resistant, it is still the other characteristics are utilized still serves to give an overrun mortar still serves to plaster does not rot and zieleniały, is still the main plasticizer cement .. .

Interestingly building in Cracow, dating back to the 20s external plaster is a kind of two parts - first, the inner part is pure or nearly pure lime plaster, charcoal in the composition. The outer layer is no longer a "regular" cement-lime plaster, dyed. This means nothing less than that still old and well-known additives were used. Drywall - a healthy plaster, not always homes or buildings have insulation of horizontal or vertical, could not always be built in such a way to go down to the prescribed 1,2 m below ground level (the thickness of the frost in winter) .../p>

What really is different plaster made on the site now, since then, having almost or a little more than a hundred years? What is the difference when a plaster "Restoration" mix the cement based low-alkali (today: white), because that then almost only existed, adding the right amount of slaked lime (normal or may be, but you may find that you need will add a plasticizer), and sand? None - except perhaps the fact that because of the fact that the current strength of cement allows for much more, with one of its units rise much more mortar. Just sand is not five or seven or maybe ten or twelve parts. In this case, any increase in the amount of sand limitation is what is called a surface area of ??cement. Approximately she says that the surface will have all the grains of cement per unit volume. And this area must be large enough to be able to tie together the lime and sand grains, which together with the island of cement into the mixer ...

Probably late 40s or early 50s began to occur disturbing changes. Changed cement - and more specifically the quality and properties. Relatively quickly it keeps increasing the strength of "normalization" and the time in which it is achieved, but at an even faster pace in the composition of the cement began to appear "undesirable" by all means add-ons - in the form of ash, sulphates, especially alkali.

Even in 1941, the Association of American companies producing cement and concrete was able to declare that if the amount of alkali in the cement exceeds 0.6%, its quality must raise very legitimate concerns.

In Europe, the war ended, the boundaries have changed and there was a period of reconstruction. Poland against this background was heavily damaged and did not belong to the group of rich countries. Even in the 40s created manuals and compendia of knowledge about the self-construction, and the more expert "for masters of masonry." And one and the other still believed that the best composition of cement-lime plaster contains, depending on the strength of cement and needs of the investor between 1: 1: 6 and 1: 3: 8 (cement / hydrated lime / sand). The only clear change in the lime was further shortening the period of its extinction. It was connected also with the fact that the widespread use began to come in hydrated lime

The above-mentioned relation of the individual components to each other is very clearly marked in an interesting book on the bricks of cement (concrete). In the second half of the 30 people associated with the broader industry to disseminate new method easier, supposedly more accessible for all, building a house. The base and the basic building blocks of brick had to be made with cement. Base ingredients were thick sand and cement. Composed as follows: Eight to ten parts of sand and one part cement.

From today's perspective and knowledge readily appreciate that there is a very strong brick, but its composition guaranteed the ease of the product. Despite the fact that the cements, let's call them the interwar, were clearly weaker than the present, the brick was perfectly suitable for the construction of houses. The idea itself is said to have come from Finland or more broadly from the North and had to be there successfully used, especially in the construction of houses.

Repeatedly mentioned principle require that the fugue was weaker and more easily permeable to moisture than the building blocks, so the manual was given its composition. Cement was converted into kilograms, slaked lime (more precisely lime putty) and sand - in liters. Assuming that the cement on the bulk density of approx. 2.4 kg / l, the composition of the mortar (described as proven in life, and research) is as follows (cement / lime putty / sand) - 1: 1,9: 8-9 . Again, as seen in mortar should not be very strong again its vital and important part of the lime putty, lime or forests suitable mortar "fluffy" or in modern language "aerating it."

Again, assessing the changes that have occurred over a hundred years (half of the nineteenth to mid-twentieth century) it is clear that they are all related to cement, its composition and strength. It is these changes affect the rest of the ingredients. The impact of this did not mean their elimination and substitution chemistry, and then another chemistry to look for what was lost.

Contractors and professionals living and working in those days knew exactly what cement properties are valuable and what he gives in the mortar. They knew which means its purity and how does it affect the mortar or plaster. They knew about it just as much appreciated lime putty, whose properties were priceless. Add to this the ability for the same techniques and technology of both plaster and masonry walls, knowledge about the advantages and disadvantages had all the used building material, which he characterized where and when you can and you have to use the stone, and in the case of brick and it which, because not everyone is suitable everywhere ...

These few sentences or comments can understand how many shares those mortars from the 30s of the last century - not to mention earlier - from what today is called the renovation mortars.

Basically erroneous assumptions used by major manufacturers in the selection of components and pre-mixes, the wrong choice of the most important material underestimation of lime lasowanego, forces such and no other methods and schemes investigation into the composition of which is presented as the best and most perfect. Forget the most important - for flexibility in the approach to the building of flexibility in the selection of the composition of the requirements of "here and now", which gives us a structure.

Using the knowledge we have left us behind our grandfathers, in conditions of normal construction can easily create a "stock" almost every mortar that Great Producers refer to as the Restoration. "Almost" refers to the type of lime mortar, the word "any" - the type of cement and lime. You only need accurate information about how to create lime forests, about what it gives us, and what effect it has on the concrete mortar or plaster, the knowledge of what is meant by these letters and digits placed on specific bags of cement and to understand why the cement was replaced by lime in the role of a binder. This is not much, after all, this is not secret knowledge, but one that had any master bricklayer even half a century ago.

This simple knowledge will save on the cost of plaster, will create exactly the plaster, which is suitable to brick or stone which is in this particular building or a historic building, with no loss of quality in the overhead or the final execution. Why then not take advantage of it if it is so close?

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