ASeminar ReportOn

Green ConcreteSubmittedInPartial FulfillmentOfAwardOf

BACHELOR OF TECHNOLOGY

DegreeInCIVIL ENGINEERINGByPankaj Kumar20123rd Year/ VIth Sem

SHRI RAMSWAROOP MEMORIAL UNIVERSITYDEWA ROAD, BARABANKI, INDIAAPRIL, 2014

CERTIFICATE

FACULTY OF CIVIL ENGINEERINGSHRI RAMSWAROOP MEMORIAL UNIVERSITYLUCKNOW

Certified that Pankaj Kumar, student of B.Tech. third year, had carried out the Seminar work represented in this report entitled Green Concrete for the awardof Bachelor of Technology in Civil Engineering from Shri Ramswaroop Memorial University, Lucknow.

Faculty Incharge

Ms. Deepti VermaAsst. Prof.Faculty of Civil Engg.SRMU Lucknow.

Dean of Civil Department

Prof. (Dr.) Abhishek SaxenaDeanFaculty of Civil Engg.SRMU Lucknow.

ACKNOWLEDGEMENT

With feeling of joy and thank, I place in your hand my Seminar report. It my pleasant privileges to thank all those who help me in moulding and shaping my report. Without their guidance, cooperation and best wishes it would have been impossible for me to complete my seminar report. A big thanks to all those who helped me by sparing time amidst their busy schedule and for being kind enough to help me whenever I needed them. I feel grateful and wish to express my gratitude to Dr. Abhishek Saxena, Dean of Civil Department of SRMU for providing me an opportunity for making seminar report on Green Concrete. I would like to acknowledge special thank to Asst. Prof. Deepti Verma for his continual guidance and support for Seminar.Finally, I am thankful to all who providing me the necessary information, cooperation in Seminar. I thank god almighty for his abundant blessing because without it this Seminar report was only a dream.

INDEX

1.0. Introduction ............................................................................................................ 42.0. Source of Carbone.................................................................................................. 43.0. Features of Green Concrete..................................................................................... 53.1. Cement..................................................................................................................... 53.2. Aggregate................................................................................................................. 53.3. Resources................................................................................................................. 54.0. Characteristic of Green Concrete............................................................................. 55.0. Materials for Green Concrete................................................................................... 66.0. Coarse Aggregate..................................................................................................... 76.1. Fresh Local Aggregate............................................................................................ 76.2. Recycled Demolition Waste Aggregate.................................................................. 86.3. Recycled Concrete Material (RCM)........................................................................96.4. Blast Furnace Slag (BFS)........................................................................................ 97.0. Fine Aggregate (Sand)............................................................................................. 107.1. Manufactured Sand for Concrete.............................................................................107.1.1. Optimum Shape........................................................................................................117.1.2. Natural Sand Vs Manufactured Sand......................................................................117.2. Recycled Glass Aggregate.......................................................................................127.3. Blast Furnace Slag (BFS).........................................................................................128.0. Cementitious materials - Fly Ash.............................................................................138.1. Use of Fly ash & Economic Impact..........................................................................138.2. Advantages of Using Fly Ash in Concrete................................................................149.0. Green Concrete Mix Design......................................................................................149.1. Green Concrete Mix Design Objectives................................................................... 159.2. Advantage of Green Concrete................................................................................. .159.3. Improved engineering properties............................................................................ .1610.0. Green Concrete Durability Technology.....................................................................1610.1. Lower Heat of Hydration..........................................................................................1710.2. Corrosion Inhibition....... ..........................................................................................1710.3. Enhanced Hydrocarbon & Chloride Resistance....... ............................................... 1710.4. Resistance to Microbial Induced Corrosion (MIC)...................................................1711.0. Conclusions...............................................................................................................1812.0. Reference ..................................................................................................................18

1.0. IntroductionMost people associate GREEN concrete with concrete that is coloured with pigment. However, it is also referred which has not yet hardened. But in the context of this topic, green concrete is taken to mean environmentally friendly concrete. This means concrete that uses less energy in its production & produces less carbon dioxide than normal concrete is green concrete. Engineers and architects have choices of the material and products they use to design projects when it comes to a building frame the choice is typically between concrete, steel and wood. Material choice depends on several factors including first cost, life cycle cost and performance for a specific application. Due to growing interest in sustainable development, engineers and architects are motivated more than ever before to choose materials that are more sustainable. However, such choice is not as straight forward as selecting an energy star rated appliance or a vehicle providing high fuel mileage. Engineers and architects can compare materials and choose one that is more sustainable or specify a construction material in such a way as to minimize environmental impact? Recent focus on climate change and the impact of greenhouse gas emissions on our environment has caused many to focus on CO2 emissions as the most critical environmental impact indicator. Life Cycle Assessment (LCA) is the parameter; the construction industry should look into. LCA considers materials over the course of their entire life cycle including material extraction,Manufacturing, construction, operations, and finally reuse/recycling. Concrete is one of the world's most widely used structural construction material. High quality concrete that meets specification requires a new standard of process control and materials optimization. Increasingly, concrete is being recognized for its strong environmental benefits in support of creative and effective sustainable development. Concrete has substantial sustainability benefits. The main ingredient in concrete is cement and it consists of Limestone (Calcium Carbonate CaCO3). During manufacture of cement, its ingredients are heated to about 800 - 10000C. During this process the Carbon Dioxide is driven off. Approximately 1kg of cement releases about 900gms of Carbon Dioxide into the atmosphere.

2.0. Source of CarboneCement production accounts for more than 6% of all CO2 emission which is a major factor in the world global warming (Greenhouse gas). India is the third largest cement producer in the World and one of the largest consumers of cement per capita in the world. Rough figures are that India consumes about 1.2 Ton/year/capita, while as World average is 0.6 Ton/year/capita. There have been a number of efforts about reducing the CO2 emissions from concrete primarily through the use of lower amounts of cement and higher amounts of supplementary cementitious material (SCM) such as fly ash, blast furnace slag etc. CO2 emissions from 1 ton of concrete produced vary between 0.05 to 0.13 tons. 95% of all CO2 emissions from a cubic meter of concrete is from cement manufacturing. It is important to reduce CO2 emissions through the greater use of SCM.

3.0. Features of Green Concrete 3.1. CementMost of CO2 in concrete is from the cement manufacturing process. A typical cubic meter of concrete contains about 10% cement by weight. Out of all ingredients, cement gives out most carbon dioxide. The reaction in the process of Cement manufacture is: CaCO3 = CaO + CO23.2. AggregateUse of virgin aggregates contributes about 1% of all CO2 emissions from a typical cubic meter of concrete. Therefore, the use of alternate aggregate is desirable. The use of local and recycled aggregates is desirable as it can reduce transportation and fuel cost and supportSustainable development.

3.3. ResourcesThe growing shortage of natural aggregate and sand is another aspect the construction industry must consider. While this may not appear to be a priority topic, pressure from environmentalist and conservationists worldwide will continue to encourage both legislators and construction engineers to look for viable alternatives to natural resources. Use of recycled materials like aggregate, water is some ingredient which should be encouraged since fresh resources are becoming increasingly scarce.

4.0.Characteristic of Green Concrete a. Optimizes use of available materialsb. Better Performancec. Enhanced cohesion workability / consistencyd. Reduced shrinkage / creep.e. Durability - Better service life of concretef. Reduced carbon footprintg. No increase in costh. LEED India Certification

5.0. Materials for Green ConcreteGreen construction materials are composed of renewable, rather than non-renewable resources. Green materials are environmentally responsible because impacts are considered over the life of the product. Depending upon project-specific goals, green materials may involve an evaluation of one or more of the following criteria. a. Locally available: Construction materials, components, and systems found locally or regionally, saving energy and resources in transportation to the project site.b. Salvaged, re-furnished, or re-manufactured: Includes saving a material from disposal and renovating, repairing, restoring, or generally improving the appearance, performance, quality, functionality, or value of a product.c. Reusable or recyclable: Select materials that can be easily dismantled and reused or recycled at the end of their useful life.Recycled materials that the Industry has found to perform favourably as substitutes for conventional materials include: fly ash, granulated blast furnace slag, recycled concrete, demolition waste, micro silica, etc. Generation and use of recycled materials varies from place to place and from time to time depending on the location and construction activity as well as type of construction projects at a given site. Following materials can be considered in this category and are discussed here.a. Recycled Demolition Waste Aggregateb. Recycled Concrete Aggregatec. Blast furnace Slagd. Manufactured Sande. Glass Aggregatef. Fly ash

6.0. Coarse AggregateAggregate contents have direct and far-reaching effect on both the quality and cost of concrete. Unlike water and cement, which do not alter in any particular characteristic except in the quantity in which they are used, the aggregate component is infinitely variable in terms of shape, size and grading etc. With coarse aggregates graded infractions between 5mm and 40mm, differences in particle shape and surface texture affect the bulk void content and frictional properties of concrete. Generally the requirement of course aggregate in concrete is more than 50% as shown in figure 6.1. Similarly sand required is about 30%. They contribute in large quantity so its availability and effect on environment must beCarefully examined. Following source of coarse aggregate are discussed.6.1. Fresh Local Aggregate6.2. Recycled Demolition Waste Aggregate6.3. Recycled Concrete Material (RCM)6.4. Blast Furnace Slag (BFS)

Fig. 6.1 Distribution of Ingredients in a typical Concrete Mix6.1. Fresh Local AggregateMany places there are stone quarry available. Though these may not be of high quality stone like granite, basalt, Dolomite etc. but they may be of little lower quality. These can be used in making concrete with the help of appropriate mix design - may be for lower characteristic strength. A typical local aggregate in sand stone is shown in figure 6.2.

Fig. 6.2. Typical shape of local sand Stone aggregate6.2. Recycled Demolition Waste AggregateConstruction industry produces huge waste called demolition waste or MALWA. It is estimated that per capita waste generation (including Municipal waste) generally range from 0.4 to 0.8 Kg per day per person. A typical waste dump is shown in figure 6.3. The waste contributes to greenhouse gas emissions and thus waste prevention and/or its recycling will reduce greenhouse gases and methane gas emissions etc. Therefore, for sustainability of resources, it is necessary that all waste must be scientifically managed. Waste Management is Collection, Transport, Processing, Recycling or disposal of waste materials. When analyzed, a typical waste product distribution in any solid waste dump is shown in figure 6.5. This waste distribution shows that there is about 50% demolition waste in the dump. In order to have sustainability of resources this demolition waste must be recycled and used.Recycled Aggregate is produced from Broken Building Part called MALWA. Such demolition waste - MALWA, can be converted to Course aggregate. The Demolition waste can be broken into the pieces of approximately 20 & 10 mm size with the help of light crusher. Typical shape & colour of recycled aggregate is shown in figure 6.4. This type of processing the waste will make the system Sustainable. The properties of recycled aggregates will vary from place to place and from time to time. For example, the specific gravity of recycled aggregate may be less than fresh conventional aggregate because it may have mixture of materials. Fig. 6.3. A typical waste dump Fig. 6.4. Shape and colour of Recycled aggregate

Fig. 6.5. Distribution of material in waste Dumplying on road side

6.3. Recycled Concrete Material (RCM)Recycled Concrete Material (RCM), also known as crushed concrete is similar to demolition waste. It is a reclaimed Concrete material. Primary sources of RCM are demolition of existing concrete pavement, building slabs & foundations, bridge structures, curb and gutter and from commercial/private facilities. This material is crushed by mechanical means into manageable fragments. The resulting material is in the form of Coarse Aggregate. Comprised of highly angular conglomerates of crushed quality aggregate and hardened cement, RCM is rougher and more absorbent than its virgin constituents.Crushed concrete's physical characteristics make it a viable substitute for coarse aggregateHowever, its physical and chemical properties must be determined before use. The properties of recycled aggregates will vary from place to place and from time to time. SuchAggregate can be used in concrete mix or in Highways concrete construction similar to demolition waste aggregate concrete.

Fig. 6.6. Failure Pattern of Crushed Bricks made with Recycled Aggregate

6.4. Blast Furnace Slag (BFS) In India more than 10 million tonnes of Blast Furnace Slag is produced every year and it is increasing with the increase in steel production. Blast furnace slag is a waste product from the manufacture of pig iron and obtained through rapid cooling by water or quenching molten slag. Iron ore, as well as scrap iron, is reduced to a molten state by burning coke fuel with fluxing agents of limestone and/or dolomite. Blast furnace slag is a non-metallic co-product produced in the process of steel production. BFS forms when slugging agents (e.g., iron ore, coke ash, and limestone) are added to the iron ore to remove impurities. In the process of reducing iron ore to iron, a molten slag forms as a non-metallic liquid (consisting primarily of silicates and alumino silicates of calcium and other bases) that floats on top of the molten iron. The molten slag is then separated from the liquid metal and cooled. Different forms of slag product are obtained depending on the method used to cool themolten slag and subsequent processing: BFS consists primarily of silicates, aluminates, silicates, and calcium-alumina-silicates. Air-Cooled Blast Furnace Slag (ACBFS), one of various slag products, is available when the liquid slag is allowed to cool under atmospheric conditions. Crushed Air-Cooled Blast Furnace Slag may be broken down as typical aggregate with the help of processing equipment to meet gradation specifications. Thus, blast furnace slag can be available as an aggregate as construction materials and acceptable as coarse or fine aggregate for use in green Concrete. A typical shape of ACBFS coarse aggregate is shown in figure 6.7.

Fig. 6.7. A typical shape of ACBFS Coarse aggregate

7.0. Fine Aggregate (Sand)Following source of Fine aggregate are normally used. Some are discussed here:7.1. Manufactured Sand7.2. Recycled Glass aggregate.7.3. Blast Furnace Slag (BFS)7.1. Manufactured Sand for ConcreteSand is generally obtained from river bed. However, sand can also be manufactured / produced after crushing stone from rocks. This process is similar to getting crushed coarse aggregate. Infect after crushing rock stone for coarse aggregate and sieving it on set of sieves between 40 - 6 mm size, the remaining portion passing through 6 mm is called stone dust. This can also be said to be a bi-product of manufacturing coarse aggregate. Such product / stone dust is generally in cubical form and depend on the type of rock being crushed and can be called manufactured sand. Cubical sand manufactured from crushed rock is the most desirable fine material for concrete production. It is generally accepted that particle shape depends on the rock type, breakage energy and the type of crusher used. It is also generally accepted that the crushers most successful at producing non-flaky aggregates are autogenous (rock on rock) and vertical-shaft impactor. If it is produced simultaneously, it saves energy and cost, providing further economies in the overall production cost. Here, fracture in rock generally takes place along the rock's natural grain, producing the characteristic cubical shape and surface texture.

7.1.1. Optimum ShapeThe optimum shape of sand is cubical as shown in figure 8. Similarly, an even gradation of the total coarse aggregate fraction is desirable so that the smaller particles of sand can fit between the larger particles, thereby minimizing the voids. Well shaped aggregates also minimize the incidence and degree of segregation.

Fig. 7.1. Shape of Manufactured Sand (Enlarged view through Microscope)

7.1.2. Natural Sand Vs Manufactured SandNatural sand often contains undesirable minerals and clays, and the effect of these materials on both the fresh and the hardened concrete can be extremely harmful. For example, the effect of clay particles in fresh concrete is obvious, as the particles absorb disproportionate volume of water and hence swell to many times their original size. This swelling occupies a volume in the cement paste in its fresh state. When it hardens, the clay particles contract and leave minute voids which in turn increase the shrinkage and permeability. This in turn reduces the concrete's chemical resistance and compressive strength. Other undesirable materials, ranging from basic chlorides to harmful chemicals, can exist in such fine material fraction. The use of manufactured sand, however, reduces the risk of impurities. It has been proven that about 20kg of cement can be saved for every cubic meter of concrete that is made by replacing a poorly shaped aggregate with a cubical aggregate. In addition, both compressive strength and flexural strength are improved by using cubical aggregates, which also increases workability and reduces bleeding and shrinkage. The impact of the physical characteristics of the sand used in the concrete mix is even greater than that of the coarse aggregate fractions, both in the concrete's plastic and hardened states.

7.2. Recycled Glass AggregateGlass is formed by super cooling a molten mixture of sand (silicon dioxide), soda ash (sodium carbonate), and/or limestone to form a rigid physical state. Glass aggregate is a waste product of recycled mixed glass from manufacturing and post consumer waste. Glass aggregate, also known as glass cullet, is 100 percent crushed material that is generally angular, flat and elongated in shape. This fragmented material comes in variety of colours or colourless. The size varies depending on the chemical composition and method of production / crushing.When glass is properly crushed, this material exhibits fineness modulus & coefficient of permeability similar to sand. It has very low water absorption. High angularity of this material, compared to rounded sand, enhances the stability of concrete mixes. Such material can be easily used in concrete construction as fine aggregate and give a better cohesive mix which will save on the consumption of cement.

7.3. Blast Furnace Slag (BFS)Blast furnace slag is described above under coarse aggregate. Here if blast furnace slag may be broken down as typical fine aggregate also with the help of processing equipment to meet gradation specifications. Thus it can be available as fine aggregate also as construction materials and acceptable for use in green Concrete. A typical shape of ACBFS fine aggregate is shown in figure 7.2.

Fig. 7.2. A typical shape of ACBFS fine aggregate

8.0. Cementitious materials - Fly AshFly ash is a by-product produced during the operation of coal-fired power plants. The finely divided particles from the exhaust gases are collected in electrostatic precipitators. These particles are called Fly ash. Gray to black represents increasing percentages of carbon, while tan colour is indicative of lime and/or calcium content. Fly ash particles are very smooth and quite spherical in shape. These particles range from 1 to 150 m in diameter. A typical shape of fly ash particles is seen in figure 8.1. Based on its composition, fly ash is classified into two groups: ASTM Class C or high calcium fly ash and ASTM Class F or low calcium fly ash are the two categories of fly ash.

Fig. 8.1.Flyashparticlesat2,000 x magnification(seen through Electron Microscope)

8.1. Use of Fly ash & Economic ImpactFly ash can be used as part replacement of Cement in Concrete. Finer the fly ash, better is its reactivity and lesser is its water requirement. Fly ash particles finer than 10 microns get adsorbed on cement particles giving a negative charge causing dispersion of cement particle flocks, thereby releasing the water trapped within the cement particle flocks and improves workability.

8.2. Advantages of Using Fly Ash in ConcreteUtilization of fly ash as a part replacement of cement or as a mineral admixture in concrete saves on cement and hence the emission of CO2. Use of good quality fly ash in concrete has shown remarkable improvement in durability of concrete, especially in aggressive environment.Some of the technical benefits of the use of fly ash in Green Concrete are:a. Higher ultimate strengthb. Increased durabilityc. Improved workabilityd. Reduced bleedinge. Increased resistance to alkali-silica reactivity.f. Reduced shrinkage.

9.0. Green Concrete Mix DesignThe concrete mix design method for such concrete is the same as for conventional concrete.However, the constituent materials shown in figure 9.1 must pack themselves in such a manner that they occupy minimum volume or give minimum voids in concrete. In figure 11 all individual material has large voids. For getting a dense or impervious green concrete, all such voids must be packed with smaller particles of next type of material. This can be done by seeing the slump test of dry all in aggregates and other materials. They must stand in natural angle of repose as seen in figure 12.

Fig.9.1. Shape of packing of material for making concrete in isolated configuration

9.1. Green Concrete Mix Design ObjectivesOptimizes void space between aggregates by optimizing particle proportions and packing of materials. This makes more effective use of the cement binder. a. Aggregates replace excess cement paste to give improved stability, less shrinkage and increase in strength & durability.b. Less cement also generates less heat of hydration.c. The slump of the concrete and its flow are a function of the shape & the quantity of the predominant size of the aggregate in the mix.d. Use of more fine aggregate gives higher slump & flow. So the optimum proportions of coarse & fine aggregate must be critically found to have the best and dense concrete in both fresh & hardened stage of concrete.

Fig.9.2. Slump test of all in combined aggregate

9.2. Advantage of Green ConcreteIt will give enhanced cohesion so user friendly - easier to place, compact & finish concrete. It can be seen in concrete slump given in figure 9.2. Some other advantages of such mix are:

a. Optimized mix designs mean easier handling, better consistency and easier finishing.b. Reduction in shrinkage & creep.c. Green Concrete uses local and recycled materials in concrete.d. The heat of hydration of green concrete is significantly lower than traditional concrete.e. This result in a lower temperature rise in large concrete pours which is a distinct advantage for green concrete.

9.3. Improved engineering propertiesa. Mix can result in a reduced paste volume within the concrete structure resulting in a higher.b. Level of protection against concrete deterioration.c. Higher strength per kilogram of cement.d. Increased durability & lower permeability.e. More aggregates typically mean higher Modulus of elasticity.

Fig. 9.3. Typical spread of mix-note the aggregate distribution & that it does not bleed

10.0. Green Concrete Durability TechnologyGreen cement concrete technology produces concrete with the following enhanced durability characteristics:

10.1 Lower Heat of Hydration Green low carbon concrete produces substantially less heat than traditional cements minimizing the potential for cracking due to thermal stresses. In most cases secondary methods used for mitigating heat during curing can be eliminated, making green concrete ideal for placements of mass concrete.10.2. Corrosion Inhibition Green concrete features very low to low permeability per ASTM C1202 (without any additional mix design modifications or addition of additives.) Green cement inherently inhibits chlorides from travelling through its dense, crystalline matrix where it can initiate a corrosion cell on reinforcing steel, leading to costly deterioration and loss of structural integrity.10.3. Enhanced Hydrocarbon & Chloride ResistanceGreen concrete's very dense, discontinuous capillary system resists chloride and hydrocarbon penetration making an ideal sustainable construction material choice for concrete exposed to vehicles and de-icing solutions.10.4. Resistance to Microbial Induced Corrosion (MIC)Microbial Induced Corrosion creates severe deterioration of Portland cement concrete in the wastewater environment. Green cement concrete technology is inherently resistant to the corrosive effects of MIC because its base chemistry has greatly reduced quantities of calcium hydroxide and calcium silicate hydrates. These two minerals cause Portland cement based concrete to fail when exposed to corrosive acids.10.5. Long LifeConcrete PavementsGreen cement concrete provides low permeability, exceptional freeze thaw, scaling and sulphate resistance coupled withan inherent immunity to an alkali silica reaction (ASR).This unique performance set combined with exceptionally low shrinkage and significantly less micro-cracking than traditional concretes makesa durable and environmentally friendly cement choice for highway and airport concrete pavements.

11.0. ConclusionsThe economic feasibility of recycling depends largely on the application. In general, virginMaterials have a quality control advantage over recycled materials. But the economic feasibility of recycling will increase in time, as virgin materials become increasingly scarce and the disposal costs of construction debris and other waste materials keep increasing. More important, we will see a proliferation of Green Building and sustainability development principles, which will modify economic picture in favour of the environment. We all agree that we cannot keep wasting our natural resources. Eventually they all will run out. It is basically up to governmental authorities to level the playing field by holding producers responsible for the costs associated with disposal of their products, whether these are associated with reuse, recycling, or land filling. In many European countries, this is already the law and forces manufacturers to design their products with those disposal costs in mind. In other words: let him who pollutes pay for the cleanup.

12.0. Reference 1. Yash Krishi Takniki Evam Vigyan Kendra (2014) Available at: http://www.yashkrishi.com/GreenConcrete.asp (Accessed: 15April 2014)2. CeraTech, Inc. (2014) Available at: http://www.ceratechinc.com/Products/ekkomaxx/Durability (Accessed: 15April 2014)3. Meyer .C ,Concrete as a Green Building Material Columbia University, New York, NY 10027, USA8