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Morphological Characterization

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This is a view to show you how the most of the geomaterials which are man-made it lookslike we have been talking about blast furnace slag we have been talking about the silicafumes and so on the previous lecture and one obvious question and if you want to understandhow to use a material for it for a specific project, you have to look into is microscopicstructure. So, we were quite excited to see that silica fumes look like this. Remembersometime like I said that these are very light material, specific gravity would be .5.6.7.So, transportation is a big issue as we discussed in the class why this happens because if youlook at the surface of these particles, these are very furry structures, they have protrusionson the surface. And these protrusions or the furze they create these materials very lightand airborne. So, one of the major issues associated with silica fumes is that thismaterial becomes airborne and people may inhale it and because of high activity of silicaif it goes in your lungs, what it will do, it will suck all the water from the levelsit will produce dead cells in the lungs. It could be cancerous.So, these are very hazardous materials so, industrialization versus health of the peopleand the environmental chaos. If you are trying to understand these type of things becomeuseful. We were dealing with the blast furnace slag also in a big way because in some ofmy storm physicists, we have been talking about blast furnace slag as a man-made resource,and rather than mining for calcium from the mines, I wanted to use the calcium which ispresent in the blast furnace slag.So, we were thinking of a process by with the calcium oxide can be extracted from theslags. Now, this is a very philosophical word, I mean, I might not be able to take out calciumoxide, but what I can do is I can break calcium in the ionic form. And I can remove that iscalcium ions from the system and induce them into the marine clays on this concept Ganarajhas a patent where we have used the new material for stabilizing the marine clays. And if youfollow this, as you will realize we published a paper also on I think these are the materialswhich are non-chemical stabilizers.Nowadays, you cannot insert a chemical inside the ground, that self is hazardous. But inthe long run these chemicals will react with the wrong water and they will get transportedfrom one place to another. So, these type of teams are coming in ground modification,soil augmentation, soil rejuvenation. And remember my dream project this man made soils,so I wanted to create my man made soils. I do not want to use natural size because theseresources are quite limited.Now how to convert all these industrial byproducts and the waste material into a resource isa challenge which you are trying to address and work on. So, the blast furnace slag normallylooks very angular. Remember, this comes out of the steel making process and then onceyou grind it, pulverize it, it becomes GGBFS that is a ground granulated blast furnaceslag which is cement and very active cement and you can create PPC out of it by substitutingin 30 40% of you know PPC.Now I will discuss about the morphological characterization of geomaterials, morphologicalcharacterization is basically shape size, dimensions, regularity, irregularity. So,normally morphological characterization is done by using 2 techniques, one is 2-dimensionaltechnique and another one is 3-dimensional technique. And you will be surprised to knowthat we have shown that will be velocities and the liquefaction potential of the sandsand the shear strength depends upon the morphological features.So, these are the thoughts which take the subject of what exists. So, the standard sciencewhich you are using and which you are teaching to undergraduate students by saying that theseare standard spherical materials do never question that how spherical they are, we questionthis. And to our surprise, we realized that these standards and which you use as sphericalmaterials are truly like this, none of them is a perfect this sphere, these are as flakyas possible.So, these are the 2-dimensional sections, you take the particle and cut it and thenyou take the images. Micro-morphically the material looks like this. So, SS1 is the coarsesand SS3 is the fine sand and these are the spheres which have peculiar characteristics.In 3d, if you do the imaging, these are normal optical micro graphs. This is how the scienceand the glass bridge looks like.What we have done from this information is we went too much into the morphological characterizationof the material. Each grain has to be photographed. So, what you are seeing over here is thisis one of the grains of the sand on which you are working. And then we inscribe as manycircles as possible, it is a game of patience, you have to sit down and analyze each of theimage which you take and then one circle is subscribes the particle and once these dimensionsare known, you can define this veracity roundness and regularity of the particle.So, this is the best way to characterize the morphology of the materials at microscopiclevel. So, I mean, I would not go into the details of all these things, if you are interestedplease read the papers which are written by Anjan Patel and Prasad Bartake. We have usedthis concept also to define the crushability of the sense crushability of the particleor the crushing strength of the particles, what they call it is crushing and strength,a lot of application in different industries right now, I mean, you should appreciate onefact that industry understands that we are the experts in the minerals and soils.So, they approach you having in full faith that you are the only one who can solve theirproblems. So, where these type of issues become useful minerology? Yes, if during site investigation,the data is very erratic, so, can we use like for a certain type of area, the morphologyof the sense we can say it more or less the same. So, can we use it use this morphologiccharacterization to predict the behavior of my like given area engineering behavior. Itdepends upon whether you are having an outlook of macroscopic models or microscopic model.So, this is an interesting question that how particles of random sizes and shapes wouldcreate a metrics through which let us say this can be compacted through with the percolationof water may take place or through with shear wave velocity will travel it will travel contaminantswill travel and so on bacteria will travel. So, these are the questions which you haveto really sit down and plan the crushability you just have to focus on engineering behaviormacroscopic mechanical like can for a given area from morphologic point of view can bepredict the sphericity is very close to unity one, you know that these slides are goingto liquefy very easily because you cannot compact them.So, everything is related to the RD value, relative density e maximum And not only tothat even your friction angles internal friction angles are also function of the true frictionangle plus dilution angle plus minus depends upon how you are defining this what do youcall it as interested know, how all your defining that true friction angle would depend uponthe dilution angle and the real friction angle asperities angle of asperities. So, angleof asperities of to get added up to the friction angle or it has to be subtracted dependingupon how the shearing process taking place.These are the micro detailing of the materials, which conventional geomechanics also talksabout? This is what R and D is where you go too much into the details of the materialand try to see this, but these are very simple ideas but later finally realized that theyhave a lot of application industry. I might have done several projects from you know thecompanies which make glues, adhesives to place different types of pumps which are packedin the tubes because ultimately it is all rheology, different types which you use forsealing the cracks of, the in the corporate and so on.Becomes very interesting "Professor - student conversation starts" that this morphologydata can be used for already existing structures. I mean for like their liquefaction severalpapers if you check it on net where now people are realizing how shear wave velocities woulddepend upon the 3 parameters sphericity, roundness and regularity. So, truly speaking these 3parameters are defining the morphology of the material quantified form. "Professor - studentconversation ends" So, Vs is the function of s r and epsilon. So, rd the function ofall the see there is a shift in the concepts which you have been studying in the basicsoil mechanics.I am sure that somebody must be working on Rd as a function of all these parameters,not only e max e min. Because e max e min would have been a gross in just with the material.I hope you can realize. So, when you redefine the system. Then interesting thing is thosewho are designing chips for that you know IC circuits where you are packing the sphericalparticles. So, what you see macro level compaction, is going on at nano level and they are alsoa spherical particles.So, how would you compare the spherical particles at that level? And what type of distortionsand defects can come in the system is a very big subject where the electronics guys haveto sit with us to learn the theory of compaction theory of theory of packing up the nanoparticlesbecause see we are experts we have learned maximum below how the particles can be packedor they can be compacted. If they are round like their void ratio cannot be less than.3.34.35. So, if there is some alteration, like if, it is not perfectly around that youcan take below it I mean, once you understood the concepts.How are you going to give a solution, I do not know whether you guys realize this ornot the new concept in the market liquefaction is being tackled by purging gas bubbles, theycreate specific size of bubbles in the size, which are liquefied. So, what is bubbles aregoing to do they act as a springs between the sides. So, when earthquake comes, youknow as if you have introduced some sort of a shock absorbers and hence the particleswill not liquify a lot of papers which have been publishing this concepts.