Loading
Notes
Study Reminders
Support
Text Version

Application of Industrial By-Products

Set your study reminders

We will email you at these times to remind you to study.
  • Monday

    -

    7am

    +

    Tuesday

    -

    7am

    +

    Wednesday

    -

    7am

    +

    Thursday

    -

    7am

    +

    Friday

    -

    7am

    +

    Saturday

    -

    7am

    +

    Sunday

    -

    7am

    +

Video 1: High Volume Fly Ash Concrete
Now, this is the summary of what is happening in the cement based, the flyash based cementin India. Everybody is aware of the flyash is no more a waste material. It has a lotof utility in the manufacturing of cement and even if you are replacing 35-40% of cement,it is a great service to the society, because that much less cement is produced, that muchless amount of carbon dioxide is produced.And application of flyash in cement and concrete is beneficial. This has already been provenby several guys and there IS 456 also which talks about replacement of cement by the flyash.You might come across people who are grinding the flyash. This becomes ultra fine flyashand ultrafine flyash has very niche market all over the world. This is what is knownas ultrafines in the flyash. There is another way of filtering out the fines from the flyash.It could be by adopting different type of classification systems. So they are classifiers.In your 10+2 chemistry, you must have come across different type of classifiers, is itnot? Different particles of different densities can be classified by using either the veryhigh jet pressure of air or by centrifuging them and another good example would be thecenosphere, which I will show you, when I am talking about the material characterization.These are the materials of today, contemporary materials. So, if you check on net, what arethe applications of cenosphere, ultrafine flyashes, classified flyash and this is theneed of the hour. Every power plant should be having the facilities to classify the soilsflyash and grind the flyash and so on to make it as a value added material. Lot of practicalwork is also going on in this context.There is something known as HVAC. This is high volume flyash concrete which I am sureyou must have come across and this is being used for infrastructure development. So theHVAC concept is the high volumes of flyash are used to make system more durable alrightand these type of systems need very low water content. So if you remember W by C ratio,the present day research is on the concept that W by C should be tending to zero. Whatis the meaning of this?I should be using as less water as possible to make concrete. Why? So in city like Bombay,do not have fresh water, Chennai, coastal areas. Why? Most of the water is adulteratedor the sea water salty water. Sand is not available, you know, contaminated sand. Nowpeople are trying to work on as minimum water as possible. So when you balance W by C mathematically.When the moisture content decreases, C also decreases.So this is a very interesting concept, where the water is less and the volume of cementwhich is required of the weight of the cement, which is required is also less. So you arenot overdosing the concrete and hence you are trying to create systems, which are goingto be more durable. These are new concepts in construction technology. What are the applications,these type of materials find lot of applications in hydrothermal and nuclear power sectors.I have been closely associated with some of these design of structures and the foundationsand this is where people are using HVAC for either piles or the foundations in aggressivesoils. Check it on net, what is the meaning of word aggressive soils. So aggressive soilsare the ones which might be having lot of sulfate content in them. So it becomes a bigchallenge to lay the foundations, when the soils are aggressive in nature.They could be highly contaminated soils, alright, very low pH, very high pH, different typesof contamination. Chloride contents could be very high. Sulfate contents could be veryhigh. So you know the implications of these type of situations. At the same time whenyou are talking about the strategic structures, alright, where the nuclear power is beingproduced, domes, shells of the atomic power plants where you want extremely durable systems.And they should be thermally insulated, is this correct or not? Because imagine insidethe reactions are going on where the temperatures might go very high and normal concrete mightcrack and if normal concrete cracks, the chances are the radiations may come out into the atmosphere.So these are very niche areas, in which you know HVAC are being used to create highlydurable systems.Lot of research is being done in the realm of materials in civil engineering. Similarly,for dams, barrages, irrigation projects, these type of materials are being used. Lean concreteis a good example. Roller compacted concrete, I do not know whether you have come acrossthis type. These type of projects have been done in India, particularly in the southernpart of the country and close to Bombay, where the entire dam was constructed by compactingthe roller compacting the concrete.So sometimes when you type on net, you will get this information and presently these situationis that people are aware of how to utilize the geomaterials for creating high value products.Another species of projects is marine projects, where it is very difficult to do underwatergrouting, cementing, construction and you have special requirements of concrete. Mostof the developmental work is going on in the marine environment pipelines of piling differenttypes of land creations and so on.“Professor - student conversation starts” How well understood are the properties ofconcrete that has large amount of flyash, like mechanical properties. Very well, verywell. It is quite in control. Most of the construction is going on in this by usingthese materials. Everything, a lot of research is being conducted. The material science incivil engineering has become a big subject. It is not only limited to the way you madeconcrete and steel and glass and wood.Nowadays, it is becoming extremely multifacet, multidisciplinary, multi-component infrastructurematerials. “Professor - student conversation ends” Different types of environmental nearingprojects where you require you know to stop shielding against acid attacks, particularlysewage lines. Imagine the tunnels which are being constructed for carrying water or thesewage, they are mostly sulfate attacks are very high, H2S formation is there.The entire environment because of the presence of acid formation, acid forming bacteria couldbe alright, under anaerobic condition, how would you protect your structures, a big challenge.So specialized environmental engineering projects require these type of high volume flyash concrete,which are quite durable. Lining of the tunnels, you read a lot on the net and you will realizewhere these type of concretes are being used. Lining, internal lining for the tunnels inwhich the water is flowing or the sewage is flowing.

Video 2: Silica Fumes and Rubber Tires
Silica fumes is another interesting manmade geomaterial and this is a very high end material,which is used for creating concrete, extremely fine particles and what do they do is, theyclog the pores of the concrete and hence the concrete becomes highly durable. So silicafume is also known as microsilica, very active form of silica, super active silica and specificgravity would be of the order of 0.5, 0.6, 0.7. So it is a big challenge to transportthis material.Most of the time, this material is imported in India. So when you are bringing it throughsea liners, I think you can imagine if though these specific gravities are less than waterthe bulk volumes cannot be carried because you require very high volumes for very smallweights and the stability of ships is a big question. You should read all these things.It becomes multidisciplinary subject. So it is a byproduct of the reduction of high purityquartz with coal in electric furnaces, in the production of silicon and ferrosiliconalloys.It is a boon for concrete, but the issue is if you add more than 4-5%, this becomes adeterrent for gain in strength of the concrete, because silica fumes are highly corrosive.Finer the particle surface area is going to be extremely high and then it has a tendencyto suck water, retain water. So when you are adding it in concrete, the chances are thatsilica fume will adsorb most of the water which is present the concrete and the concretewould not get water to get cured. So that is why the dose has to be properly monitored.So when you produce ferrochromium, ferromanganese, ferromagnesium and calcium silicon type ofthings, then this type of material is becoming you know industrial byproduct.Another interesting thing which I was discussing in the previous lecture, is the reuse of tires.So in a small area nations, which are you know surrounded by water, particularly oceansthese types of technologies are being studied quite a lot. So Japan is a leading countrywhere lot of reuse of tires is being practiced. So if you type on net whenever you get time,you will realize that tires which are coming out of the automobile industry, which havebeen discarded.Find a very special application for designing offshore structures and ground improvementis also being done by using this type of elements. So basically, rubber tires are a threat tothe environment, because if you stack them, they catch fire and even if you do not stackthem, this could be a place for mosquitoes to breed and it is very unsightly. So theycollect water also and they become the breeding space for mosquitoes.The question is, can something be done with this or not. Read the papers which are availableon internet. This is where people have tried to reuse the rubber tires. I will show youone a good example, which was proposed by Professor Joshi from Calgary University longback and I have the animation with me.There are several applications on the scrap tires and some of them are road embankment.You can shred the tires, you can use them as aggregate for making the road embankmentsand I am sure you will realize that once the shredded tires are being used the elasticmodulus and the bouncing property of the finished surface are going to be much better and damageto the automobile vehicles tires would be extremely less as compared to the rigid pavements,which are fairly aggressive.You can think of creating sub-grades, which are thermally insulated. Imagine the countrieswhere the temperatures are extremely low or very high and you would require a thermalinsulation there between the formation and the embankment or the crust of the pavement.So this is where very judiciously these type of materials have been inserted and a lotof case studies are available in the literature. You can lay your hands on and become stateof the art.Art another good example is you know asphalt rubber pavement. So, you can mix the asphaltand the crumb rubber, and you can create pavements most of the developed countries have usedthis technology and hence this type of finished product will give more riding quality andcomfort. CRB, you must have heard about, crumb rubber bitumen. So, this is another form ofutilizing the scrap tires. You can shred it and you can mix it with asphalt and you cancreate pavements out of it.What are the pavement requirements, which are fulfilled by this concept? So you willrealize that durability increases, when you enhance the flexibility or rigidity of thesystem and this can be controlled by adding the shredded tires. Deformation modulus canbe controlled. This is what you are talking about. One of the examples is people haveshown that the deformation and the modulus of deformation can be changed by using thistype of composites.Thermal resistance is the keyword. So these tyres act as the thermal insulators. In ourcountry also, sometimes we should be proposing this type of test tracks and we should betesting them where the climatic conditions are very harsh or northern part of the country,where sub-zero temperatures are there and because of you know what happens freeze andthaw. The pavement gets distorted. There this seems to be a good technology.When you add the shredded tires with the asphalt, you can enhance the rutting resistance also.You must have studied about the rutting of the pavements. So because of more you knowbouncing effect when you add the rubber tires. chips into the asphalt. The rutting resistancecan be overcome, can be enhanced. Wearing can be reduced wearing of the tires. Shrinkageresistance can be reduced and so on. So there are lot of applications, you can think about.We can modify the skid resistance of the pavements also. The biggest problem in the temperateclimates is that due to very high temperatures, what happens, the asphalt or the bitumen meltsand particularly in countries like India and because of the melting of asphalt and bitumen,what happens, the skid resistance decreases. So this causes a lot of accidents on the roads.Now I will show you one animation, where you can appreciate that how rubber tires withsteel mesh can be utilized for creating different type of turfs or embankments, particularlyfor the sports.Velodromes you know where the vehicles are tested. It could be a cycle velodrome, itcould be a automobile testing facility, where you are creating a velodrome. So, this ishow it looks like.These slides, I have borrowed from Professor R. C. Joshi, University of Calgary. This ishis idea, but I thought of sharing with all of you. So, what is done normally is, thatyou take the rubber tires, you slice them and after slicing, you flatten them and onceyou have flattened, this becomes one of the units, which can be used for creating.So, if you talk about the width of the pavement and the longitudinal direction of the pavement,you can stack these units one by one and you can rivet them by using anchors. The nextlayer would come of the another layer of anchors followed by another layer of the sliced rubbertires and keep on repeating this as long as you achieve the desired height of the system.So, I am sure you must be realizing. This is a good clever idea of utilizing the industrialbyproducts.Automobile industry would be very happy, if you can correct the practice of this typeof construction, because you are saving so many millions of tons of the natural resourcesfor creating embankments. This type of technology should be promoted, and they should be practiced.Yes please. “Professor - student conversation starts” Are they used in only (()) (17:23)pavements or both rigid also.You have to do a mix design and if you remember in your transportation engineering course,so you are designing asphalt for your requirement, is it not? So you can use a rubber tyre chipsas the additive and you can design the whole mixture and normally in rigid pavement, wewill not use but yes if you want to modulate, if you want to make a composite system, thebottom portion of the pavement is rigid and top you want to give cushioning effect.Particularly the places close to the signals, where most of the braking action takes place,where you apply brakes, where the rutting is maximum. So there this seems to be a goodidea. You can create a composite system in the embankment itself or on the track. ITcan reduce the shrinkage resistance but can the problem swelling occurs during the bouncing.So imagine the density of this material is going to be very much, because they are thicksheets. So one of the ways to negotiate with the swelling pressure of the size would be,what is that you do normally CNC, compacted natural clays.So on the swelling soils you will nullifying the effect of swelling pressure by givinga gamma into H. So I can save this gamma into H layer and what can I do? I can put thismaterial. I can apply the counterweight and I can get rid of the swelling of the claysCNC, material compacted natural clays are normally used to balance the swelling pressureor soils in field. So imagine if swelling pressure is 2 kg per centimeter square, yourequire a very thick layer of compacted clay, which is clay itself is not available in themarket nowadays clear.So these are the situations, which are forcing people to think ahead and apply new concepts.Sir, which all properties of soil get improved when rubber tire chip is used for soil stabilization.See people you will find in literature, actually I have not done much research in this area.So I am just talking about, whatever I have learned from the literature. Basically, whatthey do is, they modulate these swelling properties and mostly very fine shredding of these tirescould be fiber reinforced soils.Because if you remember that the composition of the rubber tires would be carbon and carboncould be used as a fiber also or if you can grind it and cut it and chop it in very smallparticles then it could be used as an amendment of the soil properties also. You can mix itwith the soils. “Professor - student conversation ends” These are the idea which you can useand you can create your own recipe and then what you have to do after creating a recipe.You have to test it in the laboratory and prove how the properties have been modifiedand then recommended for applications. Now these things are going to be useful in daysto come and using these concepts you are trying to help the industry. Now the previous lecture,I was talking about the glass and I think I was talking about social, economic, technicalissues related with this. Glass has become a very interesting industrial domestic by-productin today's world.

Video 3: Glass Aggregates and Dredged Materials
Particularly I have been you know professing the application of glass for artificial beachcreation. There is something known as beach nutrition. So sea beaches can be created overnight.What you to do? You have to take the unused glass, crush it and that is similar to thesands and this hand can be utilized for making beaches and different other artificially createdsystems. You will be surprised to know that a lot of application is already there in theindustry.So the crushed glass would look like this. It is similar to the sands. It is being usedin construction aggregates as a fill material, filter media, glassphalt, tarmac. There arepeople are making value-added products out of this. Fused glass, art glass, terrazzocomposites, foam blocks, you must have come across hydroponics, is it not? Hydroponicsare nothing but you know they grow plants without soil.So this is something very interesting people have been doing this and they can also beused as a abrasive in the mineral sector and as a filler material. So depending upon this,there are a lot of applications. This can be used in concrete also, because compositionwise this metal is going to be same as quartz, go in road base, fill trenches. This can bea good filter media for wastewater treatment. You can replace sands and sands are not availableright now.As I was discussing specialty uses like beach sand, sand nourishment of the beaches. Ifyou want to create a different type of landscape, then there you can use this and glassphaltis a new term.Then comes the dredging. This is something which is magnanimous. Long back I had toldyou in the class that nowadays geographical boundaries of the country keep on changing,particularly in the coastal areas. So in coastal areas, if you see through the net and theweb you will find lot of case studies are available, where the artificial land was createdby dredging. So there are different types of dredgers, which are able in the market.So these are suction dredgers.So what you are observing here is a lot of pumps on the ship and they suck sands andthen this is what is known as a rainbow methodology for sprinkling sand on the sea shores. So,the whole area has been developed like this and the sand gets deposited because of thenatural phenomena. Sediments they get deposited in the base or the ocean bodies, ocean surfaceand then you can create land out of it.Do a bit of internet checking and you will find that most of the airports which are comingup recently internationally, they are all sitting on the dredged sediments. Japan isa beautiful example. Osaka Airport, you can see that these are satellite airports. Theyare not part of the land. They do not have land. So, what they have done is, they havecreated a satellite airport in the sea and they have connected it with a viaduct to themainland.These are some beautiful examples of advanced geotechnical engineering, which is being doneby different type of islands, palm island, pearl islands. In our own country lot of activitiesare being done in the Indian Ocean. If we check on the net, both for strategic as wellas for civilian application and Chinese example you must be reading in everyday newspaper.So, they have created thousands of islands and what they are doing now?In the South China sea, they are not allowing traffic. They charge toll and then these landsare now becoming strategic lands, where they can do strategic activities. So, it is expansionof the country. Imagine we never bothered about these things, but these are activitieswith geotechnical engineers involved. A lot of interesting videos are there. Many projectsare going on Bombay city. They do deep ocean blasting. They cut the rock, they blast it,they take out the rocks.They bring it close to the seashores and they create sea beds, sea beaches for strategicactivities and for public activities also, alright.Now what are the beneficial applications of the dredged materials? There are several applicationsof the dredged materials. I have included few industrial by-products because dredgingis an industry and dredging is normally done for two purposes. One is for maintenance,you know if lot of siltation occurs in the channels, which are bringing ships to the,what you call it, to the let us say port, seaport. So, ships which have big hulls cannotreally navigate through. So, you have to first maintain the channels.The way you maintain channels in your drains in your household. Second is what is knownas when you are creating infrastructure. So, one is the maintenance dredging, another oneis capital dredging. So capital dredging is normally done to create infrastructure inthe ocean or the lakes or a water body. So, these are capital dredging, but there arelot of challenges. So, I had been doing projects from different ports and I have been guidingthem.How to utilize these materials for beach nourishment, shore production, soil creation and enhancement,land reclamation, the different type of habitat restoration. So, these things are becominga part of geotechnical engineering. Do not think that someone else is going to do allthese things. Only you have to be an expert tomorrow to guide the industry or the portsin the country.Habitat restoration would be a very good example of the guys who are more interested into conservationof wildlife, aquatic life. So, if you are creating a facility or infrastructure somewherein the water body, the aquatic life gets disturbed, is it not? We have disturbed the marine environment.So now people have started pitching in this concept of how to restore this habitat. So,they create islands for flora and fauna to flourish and these are dedicated places.And I am sure that you can realize that geotechnical engineers play a very important role in thisarea. Soft clay engineering, because most of these deposits after taking out from thesea, you are going to place on the seabed itself. So consolidation, settlement all thesethings you have to study, strength shear strength parameters and how to create a embankmentwhich is two-thirds submerged in water, one-third coming out of the water and so on.

Video 4: Characterization of Waste
Now when it comes to the characterization of the waste, this is a very big subject.So as I said in the beginning of lecture today, that before you start using the material fora given application for a given project, first thing you have to understand what are thefundamental properties of a material and this is where you have to characterize the material.There a big series of tests, which has to be done, water content, because most of thetime these materials are having enough water in them, density, granulometry, what is theirflowability. So, when we talk about the granulometry, you should check these papers by Rakshit Shettyand myself. We have done I think, we have published 3, 4 papers on use of sedimentsand then the illogical characteristics of sediments.And you have to test these sediments for following constituents, organic content, carbonate content,different type of heavy metals which are present in the system, organochlorines which are presentin the system. Most of time, these heavy metals come in the sediments because of the dischargesfrom vessels, ships. These soils could be hydrocarbons contaminated also. This is abig issue most of industries in the coastal regions, they cannot withdraw water becauseof sedimentation for running their plants, cooling towers and boiler units and so on.PAH then toxicity test has to be done, because if you are utilizing a material, which isa dread material and the question would be where to dump it and after dumping, it shouldnot become toxic to the environment. You have to do a lot of clinical examination of sediments.Not many laboratories in the country and the world are full-fledged, you know materialcharacterization laboratories. So this is where interdisciplinary approach has to beadopted and lot of work has to be done.So here I have listed thermal and chemical stability also. You were talking about thisthing. So, when you are creating islands by reclamation the first question would be youare using what type of material, sediments from the sea or the water body and whetherthey are organic in nature or not. Organic systems cannot be utilized because they willkeep on consolidating and they will decay, but imagine when you create big lands howwill you test each sample?It is not possible. It is a big challenge. Similarly, thermal stability because onceyou take it out and expose it to the environment, UV and sunlight the chances are the sedimentsmay decay. I mean this is one set of the experiments, which has to be done where I have not talkedabout the geotechnics related aspects. That is just the material suitability first ofall and once you say that the material is suitable, then you test it for its mechanicaland engineering and geotechnical engineering characteristics. So that becomes a big series.So, this basically shows that why characterization of waste is becoming important industrialbyproducts. From this point onwards, I shaped up my research in what I call as physico-chemico-mineralogicalthermal and electrical characterization. So, these things we have already mastered. Weare quite comfortable, physics of the material, chemistry of the material, mineralogy of thematerial, thermal characteristics of the material, electrical characteristics of the material.Now the biocomponents and all slowly and slowly I am adding too, but it seems to be a Herculeantask. So, people like you should come forward and take it up and plug them in this matrixof knowledge to make the holistic picture, otherwise not going to be easy. So, Shashankthesis was one good example of, what happens when bacteria interacts with the geomaterials.So that was a very fundamental work, which we did. You must have realized.We were trying to create a lot of questions in mind first of all and then you are tryingto answer few questions, which we could. So, once you characterize the waste, you can understandhow this material is going to behave and how to recommend proper utilization schemes. AsI said some time back, there are guys who are talking about the waste mechanics.It is a new concept, which is becoming a part of environmental geomechanics where not onlythe municipal solid waste, but industrial byproducts and particularly dredged sedimentsare being tested and the whole mechanics is being created out of it, maybe 1930s and 40sand soils are tested and soil mechanics came in force. No wonder in another 2, 3 years,you will find that these mechanics will become a big subject. So, this is how the knowledgekeeps on spreading and bifurcating new subjects get created.