Información resumida sobre Mineralogia, Guías, Proyectos, Investigaciones de Geología

¡Descarga Información resumida sobre Mineralogia y más Guías, Proyectos, Investigaciones en PDF de Geología solo en Docsity! very little time to see all the topics, so that brought us a little in a hurry with this topic of minerals and suddenly in this space we can see a couple of specific applications in civil engineering so that we are not only left with the theory but rather we land ideas a little better we are going to see three specific cases in which the knowledge we have about minerals and rocks will help us to understand in a little deeper way problems that arise in the exercise of civil engineering we are going to see a case on concrete we are going to see a case on asphalt mixes and we are going to see a case on clays so and I repeat the idea is to complement the information that we already reviewed in class with applications that are a little more practical and that are more of the daily exercise of civil engineering, then we are going to start with the case of concrete and how the knowledge we have about minerals and rocks can be applied in a practical way to concrete, so before we begin, I think it is worth mentioning that concrete is one Of the materials most used by human beings, only water surpasses it in terms of the amount of material used and for us civil engineers, it is the most important and most used material in the construction of the different types of infrastructure that we manage in all the areas of civil engineering, whether it be structures, road engineering, water engineering, geotechnics, in each of these fields we have practical applications in which we use concrete, and concrete is a material that is made of cement, water, a portion of air voids and stone aggregates then we in civil engineering and from the point of view of geology do not use the term that was commonly used and that was known as stones but from the point of view of geology we have spoken of rocks rocks igneous, sedimentary rocks and metamorphic rocks and as such in the field of application of civil engineering we refer to all these materials as stony aggregates, which means rocks, so when we talk about stony aggregates or simply aggregates, we are referring to either coarse aggregates or fine aggregates such as sand, silt, clay, then the cement is composed mainly of 7 to 15% cement, 14 to 21 water, and 60 to 75% aggregates between coarse and So, let's talk first about cement and then we will talk about stone aggregates. Cement is a material that, as its name suggests, is a cementitious material that, when in contact with water and with fine aggregates, forms a mortar that joins the coarse aggregates in the framework. that we know as concrete or as concrete, but cement does not occur naturally, it is not a material that we can exploit directly, but we have to manufacture it, and to manufacture cement, what we generally do is calcinate rocks in a very large oven. limestone and clay basically the manufacture of cement is calcining limestone rocks that we exploit in nature and clayey material that we can also exploit in nature in a kiln so what we basically do is create a magma from that limestone of that clay by heating it to a temperature close to 1,500 degrees Celsius we are going to create our own magma so what we are going to do is an artificial rock if you remember when we talked about minerals we said that it had to be one of the requirements or one of the criteria was that it occur naturally in In this case, when we are going to manufacture the cement, what we are going to do is artificially create a rock that did not exist and we are going to create our own magma and from that magma we are going to create an artificial rock that is later called clinker those small round dark-colored rocks called clinker and that we produce artificially, we grind them and add plaster so that the setting is perfect, then once they are restored, confirm to me before continuing if the audio is back, please, well, as I was saying in This link can verify the manufacturing process of the cement but we continue ahead and understand from what the knowledge we already have about minerals that beyond mixing limestone with clay and suddenly adding some other material because in reality I eat what I am What I am doing is building my own magma, so in the end what I need to be able to make cement is calcium, silicon, aluminum and iron. Those four elements are what I need my magma to have in order to make cement, but for that I need raw materials that can be found in nature, so there are four main components with which cement companies can manufacture this cement. The main thing is to have limestone, so for all planting to exist, there must be a limestone quarry because it is equivalent to almost 90% of the The raw material with which the cement is made between 18 and 10% is obtained through the clay, so limestone and clay are the two main components, the two raw materials with which I make cement, but since I cannot always control the formation but texture life or very crystal formation small then minerals such as opal, cristobalite, half trevi and some types of quartz let's look at vitrified quartz, that is to say that it cooled very quickly all these all these materials and these minerals what we can see as a general concept is that due to rapid cooling they did not reach to put together a perfect three-dimensional structure like the one that a completely translucent quartz could have, but they cooled down so quickly that although putting together a three-dimensional structure did not manage to be well ordered, their arrangement does not reach to be perfect but rather it is a messy arrangement due to cooling so fast and in some cases it is a rule it is simply glass and there are other cases in which there was a quartz that was well ordered but due to the efforts that metamorphic in that quartz, a deformed quartz remains, all this does and that disorder in the structural arrangement of These minerals allow that when these rocks are exposed to aqueous solutions, that is to say, when there is an aqueous medium in which that rock is, all those things that are disordered or that are specific crystalline microcrystalline are normally reactive, a perfect three-dimensional well-formed quartz does not react because all its links are busy forming those tetrahedrons in the three-dimensional arrangement, but when it has cooled very quickly and the three-dimensional arrangement is disordered, how much is glass when it is deformed quartz, some of these silica remain available to react in the aqueous medium and that makes it possible to dissolve In water, part of that silica, then those silicas become part of that aqueous medium, so let's analyze within each of the types of rock which ones can have those minerals that cause me problems. So in igneous rocks I have to in granite when contains a high percentage of deformed quartz, it can generate reactivity problems between that silica that it will be able to release and the sodium and potassium alkalis of the certain cement in andesite, for example, we see that when you have and lime it is rich in volcanic or vitrified crystals The same thing can happen with stones such as rhyolite, la cita or latita if we remember, we said that they are exclusive igneous rocks that are generated by the rapid cooling of lava on the surface, all volcanic or higher, that are igneous rocks also when they contain minerals such as chalcedony or christo. cristobalite within the metamorphic rocks we have neisse when it contains deformed quartz in a percentage greater than 30% remember that neisse is granite that due to force and temperature has deformed but when within the country there is deformed quartz and it is in a higher percentage At 30% it begins to release enough silica in an aqueous solution so that it can react with those alkalis that the cement provides, the same with all the other metamorphic rocks that we see in this list. The idea is that you can keep these slides for later reference. and within the sedimentary rocks we see that many rocks when they contain quartz of a certain type as we said deformed room or microcrystalline quartz or cryptocrystalline in general terms when they contain quartz whose structural arrangement is disordered mainly associated as you can already deduce to very rapid cooling either due to rapid cooling on the surface or when they are igneous and intrusive rocks, because the contact zones between the hot magma and the fresh rock, because in these contacts there will also be contamination due to rapid cooling and the non- formation of crystals and have video or formation of micro crystals are crypto crystals so how can we see and understand the composition of the rocks let's say that based on experience having all these lists of possible rocks that can cause me problems is going to be that at the moment I produce a concrete I will have a warning message regarding the possible problems that concrete could present to me and these problems can be alleviated by adding certain types of additions to the concrete, such as adding ash, adding escort or blast furnace slag, there are solutions that can be taken to prevent these reactions do not happen but always starts from the fact that the engineer has knowledge about the rocks and their composition and the effects that the mineralogy of these routes may have on the processes in which he is working, then there are two tests through which which reactivity to silica cali can be prevented, which by its acronym in English will be found in the bibliography as psr. There is a chemical test, as I told you in class, although it is a bit long, it is the most accurate to measure this type of problem, but When production is going to start in the short term, there is also an accelerated bar method from which you can detect possible future problems and prevent them, take actions before preparing those concretes, so this is a true example of a practical application in which to have This prior knowledge about the rocks and the minerals that compose them will make it possible for the engineer to foresee certain end up compromising the stability of the elements with which that concrete was used, so this is a first example of how knowledge about mineralogy It will help you and it will be useful at the time of concrete production. For example, I want to see if you are following me up to this point to move on to the next one, to the next example. So now let's talk about a practical application example of how to learn about in analogy can help me prevent problems in the manufacture or production of asphalt mixes within engineering we handle what is known as concrete concrete is basically a material composed of fine and coarse aggregates that are joined by a cement when that The cementing agent is Portland cement, it is known as hydraulic concrete and in general we call it concrete, but the cementing agent can also be asphalt, certain bitumen, and in this case, it is known as asphalt concrete or more commonly as asphalt mixtures. rolling roads, highways and others, then let's talk about an application example of how knowledge about minerals can help us prevent problems in asphalt mixes before talking about the problem as such, because we must again remember how asphalt mixes are composed, mainly we have aggregates coarse and fine, we have air voids and we have asphalt, which is what these materials are used for. I have the aggregates. These conveyor belts that you see in the lower part of the image, both coarse and fine aggregates, are taken to the mixing drum, which is the one that is seen in the lower part of this drum. The stone aggregates are heated so that they can be mixed. mix better with the asphalt cement but above all in order to dry them because I do not want them to contain moisture because it can be harmful to the asphalt mix because in addition to the water that enters the fact that the aggregates remain inside their pores with moisture can generate more moisture damage issues which is the issue we're going to talk about later there is a paddle mixer in which the asphalt and aggregates are mixed and it goes up through this bucket elevator and these strands are stored under which they are they load the dump trucks with the material will be lost and we will no longer have a segmented material, we will have a material that is very similar to having aggregates. loose without any kind of cementing agent, this is an example of what happens in an asphalt mix when there is moisture damage, so in this case, as we see, acid aggregates are the aggregates that we have to take care of when we are making asphalt mixes that are true aggregates They have a high silica content, they are aggregates that, in addition to having a high silica content due to their acid nature, these surfaces of these aggregates, when they come into contact with an aqueous medium, release sodium, release potassium, and release aluminum and those free loose elements in a medium. aqueous then at once form y h lh form sodium hydroxide potassium hydroxide aluminum hydroxide and these hydroxides impair the quality of the adhesion these hydroxides are what make the aqueous medium strip the water with the asphalt that was covering the rocks so they don't It is simply that they have a high silica content, but the fact that they have this silica content also causes those surfaces of those aggregates to release sodium, potassium and aluminum and that, by forming hydroxide, damages the quality of the compatibility between the rock and the soil. asphalt and decrease adhesion and in some cases, as we see in the previous image, make it completely stripped and aggregates without any type of cement, so what can we do to prevent this type of damage, which is also known as stripping, there are some methods rapid field tests such as the boiled water method and the tray method, and there are some laboratory tests that are a little more specialized, such as the indirect tensile test called tse. The important thing is to know that this problem can be prevented even if I have aggregates that are acids and asphalts that are acids there are solutions there are additives that improve adhesion that are made up of sheets that are made up of zeolites but in order to act I have to know it before building and before manufacturing the asphalt mix I should have foreseen that possibility and having milk at the time of manufacturing the asphalt mix, having added these adhesion-improving additives to prevent that when it is in use and when I go with the water, it begins to infiltrate into the mixture, and that the adhesion between the surfaces of the asphalt is lost. the aggregates and the asphalt cement, so this is where the new one comes in. It is very positive to have knowledge about the minerals because at the moment I am going to manufacture the asphalt mix I can evaluate my aggregates I can do tests on them I can do a petrography to identify the acidity of those aggregates I can do field methods and I can do csr tests and look for additives that solve your problems if you detected them on time but again the knowledge about the minerals that make up the different types of rocks is what which will allow me, as the engineer in charge of the production of these asphalt mixes, to be able to act before their production, because if the mix is produced and installed and had this problem, there is no solution in this case, the only solution is to remove and replace that mix with new asphalt mix so this is one of the second applications where you know the different types of rocks and knowing their mineralogical composition will help me to prevent problems in the production of asphalt mixes there is a test called petrography Normally, when you are going to produce a new concrete or a new asphalt mix, you take a sample of the aggregates that you have on hand, the aggregates that you are going to use to make these concrete on these mixes, you send them to a laboratory, you will give us a photograph and still The results do not reach you telling you what types of rocks you have, what minerals and in what percentages these minerals are present in those rocks and there are geologists who even tell you within the report you may have reactivity problems please evaluate can provide can having moisture damage problems in asphalt mixes keep in mind the use of adhesion-improving additives, then it is this awareness and knowledge of the minerals that make up the rocks that will allow me to prevent and act before producing the materials to avoid Subsequent damage Finally, we are going to make a quick mention of clays, as we saw, clays are very useful for engineers because cement is made with it. Remember that cement has 10 percent clays, they are key to being able to make that magma with it. This cement is manufactured so, from the point of view of concrete, clays are a material that is very important for us as English engineers. This is one of the highlights of clays, but clays also have their shadows. Clays also cause us problems in the practice of civil engineering because as we saw we have clays such as the very morillon and it is that they have the capacity to be unstable which have the property of being unstable volumetrically speaking so if we can see here this is the ideal chemical composition of a morillon voice and it is we know that it has aluminum silicon and one has made it true normally this is the three-dimensional structure of a clay and due to that arrangement that they have, they have the capacity for many cations and a lot of water to remain trapped between those sheets of clay so that laminar structure of the of clays is perfect for trapping cations but above all for trapping a lot of water and that makes the material change a lot volumetrically due to this composition that we see here as we can see it can trap a lot of water in this part of the equation we can see it and also At the edges of these sheets, it can trap calcium ions or sodium ions, so what does that translate into? Well, this is a typical example of the damage that active expansive clays such as Morillon can cause to me, and this is the damage that can be caused to a road or a highway, but imagine that these deformations occur in a place where I have buildings made of this type of material, the damage will be even worse because, unlike roads that start lying down, the buildings They are vertical and these differential deformations can cause fractures and irreparable damage to the buildings, so to prevent this type of damage again it is very useful for me to know the mineralogy in this case of the soils, which is the same logical migra in which we have As we have been talking, we have already seen what the formula or chemical composition of Modigliani mud is, we already know it, and the solution at hand in this case is stabilization with lime. What lime is going to give me is sea h is a medium Aqueous is going to be able to allow me to have calcium cations and unions of o h so those two cations that year are not going to be able to react either with the silica present in the clay or with the alumina present in the clays and they leave to form this type of compounds that are stable and do not have volumetric instability problems, but for that to happen I need to have previously identified the clays to know that they are expansive, for which knowing about mineralogy helps me a lot to have carried out the appropriate tests and when determining I have this problem again, it also has solutions, but these solutions have to be given before the