 Now this is the summary of what is happening in the cement based, the fly ash based cement in India, everybody is aware of the fly ash is no more a waste material, it has a lot of utility in the manufacturing of cement and even if you are replacing 35 to 40 percent of cement, it is a great service to the society because that much less cement is produced that much less amount of carbon dioxide is produced and application of fly ash in cement and concrete is beneficial this has already been proven by several guys. And there is IS 456 also which talks about replacement of cement by the fly ash, you might come across people who are grinding the fly ash, this becomes ultra fine fly ash and ultra fine fly ash has very niche market all over the world, this is what is known as ultra fine ultra fines in the fly ash, there is another way of finding out the or filtering out the fines from the fly ash, it could be by adopting different type of classification systems. So, they are classifiers in your 10 plus 2 chemistry you must have come across different type of classifiers is it not different particles of different densities can be classified by using either the very high jet pressure of air or by centrifuging them and another good example would be the senospheres which I will show you when I am talking about the metal characterization, these are the materials of the today contemporary materials. So, if you check on net what are the applications of senospheres ultra fine fly ash is classified fly ash and this is the need of our every power plant should be having the facilities to classify the soils fly ash and grind the fly ash and so on to make it as a value added material, lot of practical work is also going on in this context, there is something known as HVAC, this is high volume fly ash concrete which I am sure you must have come across and this is being used for infrastructure development. So, the HVAC concept is the high volumes of fly ash are used to make system more durable, alright and 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 0, what is the meaning of this? I should be using as less water as possible to make concrete, why? So, it is like Bombay, I do not have fresh water Chennai coastal areas, why? Most of the water is adulterated or this sea water, salty water, sand is not available, there is also you know contaminated sand. So, now people are trying to work on as minimum water as possible. So, when you balance W by C mathematically, when the moisture content decreases, sea also decreases. So, it is a very interesting concept where the water is less and the volume of cement which is required or the weight of the cement which is required is also less. So, you are not overdosing the concrete and hence you are trying to create systems which are going to be more durable, these are new concepts in construction technology. What are the applications? These type of materials find a lot of applications in hydrothermal and nuclear power sectors. I have been closely associated with some of these design of structures and the foundations and this is where people are using HVAC for either piles or the foundations in aggressive soils. Check it on net, what is the meaning of word aggressive soils? So, aggressive soils are the ones which might be having a lot of sulphate content in them. So, it becomes a big challenge 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 types of contamination, chloride contents could be very high, sulphate contents could be very high. So, you know the implications of these type of situations. At the same time, when you are talking about the strategic structures alright, where the nuclear power is being produced 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 inside the reactions are going on where the temperatures might go very high and normal concrete might crack 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 HVACs are being used to create highly durable systems. A 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. So, in concrete is a good example, roller compacted concrete, I do not know whether you have come across this type of thing. These type of projects have been done in India particularly in the southern part of the country and close to Bombay where the entire dam was constructed by compacting the roller compacting the concrete. So, sometimes when you type on net you will get this information and presently these situation is that people are aware of how to utilize the geomaterials for creating high value you know products. Another species of projects is marine projects, it is very difficult to do underwater grouting, cementing, construction and you have special requirements of concrete you know most of the developmental work is going on in the marine environment, pipelines of piling different types of land creations and so on. How well understood are the properties of concrete that is large amount of liage like mechanical properties? Very well, very well, it is quite in control, most of the construction is going on in this by using these materials, everything lot of research is being conducted, the material science in civil engineering has become a big subject, it is not only limited to the way you make concrete and steel and glass and wood nowadays is becoming extremely multi facet, multidisciplinary, multi component infrastructure materials. Different types of environmental engineering projects where you require you know to stop shielding against acid attacks particularly civil lines, imagine the tunnels which are being constructed for carrying water or the sewage, they are mostly sulphide attacks are very high, H2S formation is there, the entire environment because of the presence of acid formation, acid forming bacteria could be under anaerobic condition, how would you protect your structures, a big challenge. So specialized environmental engineering projects require these types of high volume fly ash concrete which are quite durable, lining of the tunnels, you read a lot on the net and you will realize where these types of concrete are being used, lining internal lining for the tunnels in which the water is flowing or the sewage is flowing. Silica fumes is another interesting man made geomaterial and this is a very high end material which is used for creating concrete, extremely fine particles and what do they do is they clog the pores of the concrete and hence the concrete becomes highly durable. So silica fume is also known as micro silica, very active form of silica, superactive silica and specific gravity would be of the order of 0.5, 0.6, 0.7, so it is a big challenge to transport this material, most of the time this material is imported in India. So when you are bringing it through you know sea liners, I think you can imagine if these specific gravities are less than water, the bulk volumes cannot be carried because you require very high volumes for very small weights and the stability of the ships is a big question, you should read all these things nowadays, become multidisciplinary subject. So it is a byproduct of the reduction of high purity quartz with coal in electric furnaces in the production of silicon and ferro silicon alloys, it is a boon for concrete but the issue is if you add more than 4 to 5 percent this becomes a deterrent for gaining 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 tendency to suck water, retain water. So when you are adding it in concrete the chances are that silica fume will absorb most of the water which is present in the concrete and the concrete would not get water to get cured, so that is why the dose has to be properly monitored. So when you produce ferrochromium, ferromagnese, ferromagnetium and calcium silicon type of things 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 oceans these type of technologies are being studied quite a lot. So Japan is a leading country where 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 have been discarded find a very special application for designing offshore structures and ground improvement is also being done by using this type of elements. So basically rubber tires are a threat to the environment because if you stack them they catch fire and even if you do not stack them you know this could be a place for mosquitoes to breed and it is very unsightly. So they collect 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 available on internet. This is where people have tried to reuse the rubber tires. I will show you one good example which was proposed by Professor Joshi from Calgary University long back and I have the animation with me. There are several applications of 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 embankments and I am sure you will realize that once the shredded tires are being used the elastic modulus and the bouncing property of the finished surface are going to be much better and damage to the automobile vehicles of tires would be extremely less as compared to the rigid pavements which are very aggressive. You can think of creating sub grids which are thermally insulated, imagine the country where the temperatures are extremely low or very high and you would require a thermal insulation layer 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 lot of case studies are available in the literature. You can lay your hands on and become state of the art. Another good example is asphalt rubber pavement. You can mix the asphalt and the crumb rubber and you can create pavements. Most of the developed countries have used this technology and hence this type of finished product gives you more riding quality and comfort. CRB you must have heard about crumb rubber bitumen. So this is another form of utilizing the scrap tires. You can shred it and you can mix it with asphalt and you can create pavements out of it. What are the pavement requirements which are fulfilled by this concept? So you will realize that durability increases when you enhance the flexibility or rigidity of the system and this can be controlled by adding the shredded tires. Deformation modulus can be controlled, this is what you are talking about. One of the examples is people have shown that the deformation and the modulus of deformation can be changed by using these type of composites. Normal resistance is the keyword. So these tires act as the thermal insulators. In our country also sometimes you know we should be proposing these type of test tracks and we should be testing them where the climatic conditions are very harsh on northern part of the country where sub zero temperatures are there and because of you know what happens freeze and thaw. The pavement gets distorted and there this seems to be a good technology. When you add the shredded tires with the asphalt then you can enhance the rutting resistance also. You must have studied about the rutting of the pavements. So because of more you know bouncing effect when you add the rubber tires chips into the asphalt the rutting resistance can be overcome, can be enhanced. Wearing can be reduced, wearing of the tires, shrinkage resistance can be reduced and so on. So in terms of applications you can think about, we can modify the skid resistance of the pavements also. The biggest problem in the temperate climates is that due to very high temperatures what happens the asphalt of the bitumen melts and particularly countries like India and because of the melting of asphalt and bitumen what happens the skid resistance decreases so this causes lot of accidents on the roads. Now I will show you one animation where you can appreciate that how rubber tires with still mesh can be utilized for creating different type of turfs or embankments particularly for the sports, valedrums, you know where the vehicles are tested, it could be a cycle valedrum, it could be a automobile testing facility where you are creating a valedrum. So this is how it looks like, these slides I have borrowed from Professor R.C. Joshi University of Calgary, this is his idea but I thought of sharing with all of you. So what is done normally is that you take the rubber tires, you splice them and after splicing you flatten them and once you 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 pavement you can stack these units one by one and you can rivet them by using anchors. The next layer would come of the another layer of anchors followed by another layer of the spliced rubber tires and keep on repeating this as long as you achieve the desired height of the system. So I am sure you must be realizing that this is a good clever idea of utilizing the industrial byproducts, automobile industry would be very happy if you can encourage the practice of this type of construction because you are saving so many millions of tons of the natural resources for creating amendments. This type of technology should be promoted and they should be practiced, yes please. Are they used in only flexible pavements or both in rigid holes? You have to do a mixed design if you remember in your transportation engineering course so you are designing as fault for your requirement, is it not? So you can use rubber tire chips as a additive and you can design the whole mixture and normally in rigid pavement you will not use but yes if you want to modulate, if you want to make a composite system where the bottom 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 good idea, you can create a composite system in the embankment itself or in the track. It reduces, it reduces the shrinkage resistance, yes but can the problem of swelling or pressure at the end? Yes, so imagine the density of this material is going to be very much because they are thick sheets. So one of the ways to negotiate with the swelling pressure of the soils would be what is that you do normally, CNC compacted natural clays. So on the swelling soils you are nullifying this effect of swelling pressure by giving a gamma into H. So I can save this gamma into H layer and what can I do? I can put this material, I can counterweight, I can apply the counterweight and I can get rid of the swelling of the clays. CNC material, compacted natural clays are normally used to balance the swelling pressure of soils in field. So imagine if swelling pressure is 2 kg per centimeter square, you require a very thick layer of compacted clay which is clay itself is not available in the market nowadays clear. So these are the situations which are forcing people to think ahead and apply new concepts. So fine, yes please. Sir, which are properties of soil get improved when rubber tides chips 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 what they do is they modulate the swelling properties and mostly very fine shredding of these tires could be fiber reinforced soils. Because if you remember that the composition of the rubber tires would be carbon and carbon could be used as a fiber also or if you can grind it and cut it and chop it in very small particles then it could be used as a amendment of the soil properties also. You can mix it with the soils. These are the idea which you can use and 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 modified and then recommend them for applications. Now these things are going to be useful now in days to come and using these concepts we are trying to help the industry. Now the previous lecture I was talking about the glass and I think I was talking about socio-economic technical issues related to the glass. Glass has become a very interesting industrial domestic byproduct in today's world particularly I have been you know professing the application of glass for artificial beach creation, beach there is something known as beach nutrition. So sea beaches can be created overnight what you have to do you have to take the unused glass crush it and that is similar to the sands and this sand can be utilized for making beaches and different other artificially created systems. You will be surprised to know that lot of applications already there in the industry now the crushed glass would look like this is similar to the sands is being used in construction aggregates as a film material, filter media, glass fault, tarmac, lot of people are making value added products out of this pure glass, art glass, terrazzo, composites, foam blocks you must have come across hydrophonics is it not. Hydrophonics are nothing but you know they grow plants without soil so this is something very interesting people have been doing this and they can also be used as a abrasive in the mineral sector and as a filler material. So depending upon this there are lot of applications this can be used in concrete also because composition wise this material is going to be same as quartz in road base, felt trenches this can be a good filter media for wastewater treatment you can replace sands and sands are not available right now as I was discussing especially you specialty uses like beach sand, sand nourishment of the beaches if you want to create a different type of landscape then there you can use this and glass fault is a new term then comes the dredging this is something which is magnonymous long back I had told you 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 the web you will find lot of case studies are available where the artificial land was created by dredging so there are different types of dredgers which are available in the market. So these are suction dredgers so what you are observing here is there are lot of pumps on the ship and they suck sands and then this is what is known as the rainbow methodology for sprinkling sand on the seashores so the whole area has been developed like this and the sand gets deposited because of the natural phenomena sediments they get deposited in the base or the ocean bodies ocean surface and 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 coming up recently internationally they are all sitting on the sediments. Japan is a beautiful example Osaka airport you can see that these are satellite airports they are not part of the land they do not have land. So what they have done is they have created a satellite airport in the sea and they have connected it with the viaduct to the mainland. There are some beautiful examples of advanced geotechnical engineering which has been done you have different type of islands palm island pearl islands in our own country lot of activities are being done in the Indian Ocean if you check on the net both for strategic as well as 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 islands are now becoming strategic lands where they can do strategic activities so it is expansion of the country imagine we never bothered about these things but see these are the activities with geotechnical engineers are involved with a lot of interesting videos are there many projects are going on bombacity where they do deep ocean blasting they cut the rock they blasted they take out the rocks they bring it close to the seashores and they create sea beds sea beaches for strategic activities and for public activities also alright now what are the beneficial applications of the dredge materials several applications of the dredge materials I have included few industrial byproducts because dredging is an industry and dredging is normally done for two purposes one is for maintenance you know if lot of sanitation 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 cannot really navigate through so you have to first maintain the channels the way you maintain channels in your you know drains in your household second is what is known as you know when you are creating infrastructure so one is the maintenance dredging another one is capital dredging so capital dredging is normally done to create infrastructure in the ocean in the oceans or the lakes or a water body so these are capital dredging but there are lot of challenges so I had been doing projects from different ports and I have been guiding them how to utilize these materials for beach nourishment shore production soil creation and enhancement land reclamation different type of habitat restoration so these things are becoming a part of geotechnical engineering I do not think that someone else is going to do all these things only you have to be an expert tomorrow to guide the industry or the ports in the country habitat restoration would be a very good example of the guys who are more interested into conservation of wildlife aquatic life so if you are creating a facility or infrastructure somewhere in the water body the aquatic life gets disturbed is it not you 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 engineering has played a very important role in this area soft clay engineering because most of these deposits after taking out from the sea you are going to you are going to place on the sea bed itself so consolidation settlement all these things you have to study strength shear strength parameters and how would you create a magnet which is two thirds submerged in water one third coming out of the water and so on 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 for a given application for a given project first thing is you have to understand what are the fundamental popular material and this is where you have to characterize the material a big series of tests which has to be done water content because most of the time these materials are having enough water in them density granulometry what is their flow ability so when we talk about the granulometry you should check his papers by Rakshi Shetty and myself we have done I think we have published three four papers on use of the sediments and then the geological 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 present in the system most of the time these heavy metals come in the sediments because of the discharges from you know vessels ships these soils could be hydrocarbon contaminated also it is a big issue most of the industries in the coastal regions they cannot withdraw water because of sedimentation for running their plants cooling towers and boiler units and so on PA edge then toxicity test has to be done because if you are utilizing a material which is a dredge material and the question would be where to dump it and after dumping it should not become toxic to the environment you have to do lot of clinical examination of sediments not many laboratories in the country and the world are fully pledged you know material characterization laboratories so this is where interdisciplinary approach has to be adopted and lot of work has to be done. So here I have listed thermal and chemical stability also you are talking about this thing so when you are creating islands by reclamation the first question would be you are using what type of material sediments from the sea or the water body and whether they are organic in nature or not organic systems cannot be utilized because they will keep on consolidating and they will decay but imagine when you create big lands how you test each sample it is not possible it is a big challenge similarly thermal stability because once you take it out and expose it to the environment UV and sunlight the chances are the sediments may decay I mean this is this is one set of the experiments which has to be done where I have not talked about the geotechnics related aspects it is that thus just the material suitability first of all and once you say that the material is suitable then you test it for its mechanical and engineering and geotechnical engineering characteristics so that becomes a big series. So this basically shows that why characterization of waste is becoming important industrial by products and from this point onwards I shaped up my research in what I call as physical, chemical, mineralogical, thermal and electrical characterization so these things we have already mastered we are quite comfortable physics of the material chemistry of the material mineralogy of the material thermal characteristics of the material electrical characteristics of the material now the bio components and all slowly and slowly I am adding to but it seems to be a Herculean task so people like you should come forward and take it up and plug them in this matrix of knowledge to make the holistic picture otherwise it is not going to be easy. So Shashank's thesis was one good example of you know what happens when bacteria interacts with the material so that was a very fundamental work which we did you must have realized we are trying to create lot of questions in my first of all and then we are trying to answer few questions which we could. So once you characterize the waste you can understand how this material is going to behave and how to recommend proper utilization schemes. As I said sometime 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 only the municipal solid waste but industrial byproducts and particular interest sediments are being you know tested and the whole mechanics is being created out of it may be 1930s and 40s and soils were tested and soil mechanics came in force no wonder in the 2, 3 years we will find that this mechanics will become a big subject. So this is how the knowledge you know keeps on spreading and bifurcating and new subjects