An experimental investigation on properties of ggbs based geopolymer concrete for high volume traffic

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IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.

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An experimental investigation on properties of ggbs based geopolymer concrete for high volume traffic

  1. 1. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308 __________________________________________________________________________________________ Volume: 03 Special Issue: 06 | May-2014 | RRDCE - 2014, Available @ http://www.ijret.org 313 AN EXPERIMENTAL INVESTIGATION ON PROPERTIES OF GGBS BASED GEOPOLYMER CONCRETE FOR HIGH VOLUME TRAFFIC Ravi Kumar R1 , Sridhar R2 1 Assistant Professor, Department of civil Engineering, Shri Madhwa Vadiraja Institute of Technology and Management, Udupi 2 Research Scholar, Ghousia college of Engg &Assoc. professor, Department of civil Engg, Alva’s Institute of Engg & Technology, Moodbidri, Karnataka, India Abstract The Civil Engineering construction is progressing massively day by day with the increase in demand for the cement production. One ton production of cement emits about one ton of Carbon di Oxide into the atmosphere, including for burning of the fuel fossils and for process of production using raw materials. This enormous liberation of Carbon di Oxide from the cement industries is one of the major issues for the cause of ecological imbalance, resulting in green house effect. This emission of carbon di oxide into the atmosphere is minimized by using the industrial by products or industrial wastes (binders) generated from the Steel Plants, called as Ground Granulated Blast Furnace Slag (GGBS) and adding GGBS with the Sodium Hydroxide Solution and Sodium Silicate Solutions, (together called as alkaline activators), which forms a good bond between the GGBS and other body forming inert aggregates (Coarse and Fine Aggregates), without using the Ordinary Portland Cement. This new product branded as Geo-Polymer Concrete, which addresses the solution to ecological issues and forms alternate construction material in the Civil Engineering industry. In the present work, an attempt has been made to establish the mix proportion to Geopolymer Concrete, to study the Engineering Properties of Geopolymer Concrete and to prove that the new alternate material is ecofriendly. The mix combinations of alkaline solutions are achieved by adding NaOH solution of varied molarity 12M, 14M and 16M, with the Sodium Silicate Solution maintaining a ratio (Sodium Silicate to NaOH) of 2.5, 5.0 & 7.5 with the alkaline liquid to binder ratio as 0.3, 0.4 and 0.5. The alkaline activator solutions are prepared 24 to 30 hrs in advance to mixing with the dry materials. The conventional method of mixing, compacting and moulding is followed for the production of the Geopolymer concrete. The Cubes, Cylinders and Beams are cast using the mould conforming to BIS Codal provisions. The appropriate measurement of alkaline solutions is mixed with the calculated ingredients like GGBS and other inert materials, with proper compaction, the specimens are prepared. The specimens thus made are cured for 24 hrs. in the ambient temperature, covering the entire specimens with High Density Polyethylene Sheet in order to avoid the escape of the water from the green mix. Later the specimens in the mould are kept at elevated temperature of 120° C for another 24 hrs in the dry oven for further curing. The engineering properties namely, Compressive Strength, Flexural Strength and Splitting Tensile Strength on Geopolymer Concrete specimens are studied and compared the properties with the Ordinary Portland Cement Concrete. The results showed that geopolymer concrete exhibited encouraging results compared to Ordinary Portland Cement Concrete (Compressive Strength= 50 MPa, Flexural Strength= 4.5 MPa & Splitting Tensile Strength= 3.5 MPa) and Cost analysis indicated that Geopolymer concrete Costs 18% more than the Ordinary Portland Cement Concrete satisfying all the engineering properties. Thus, Geopolymer Concrete, contains no Ordinary Portland Cement, is an ecofriendly construction material, to make use in the various construction activities including the structural elements required for pavements. Keywords: Geopolymer Concrete, Ground Granulated Blast Furnace Slag (GGBS), alkaline liquid, Sodium Silicate Solution. -----------------------------------------------------------------------***----------------------------------------------------------------------- 1. INTRODUCTION In the present scenario, environmental pollution is the biggest menace to the human race on this planet causing ecological imbalance. There are many reasons which cause pollution. In the construction industry, cement is the main ingredient/ material for the concrete production. The production of cement involves the emission of carbon di oxide during its production. There are two different sources of carbon di oxide emission during cement production. Combustion of fossil fuels to operate the rotary kiln is the largest source and other
  2. 2. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308 __________________________________________________________________________________________ Volume: 03 Special Issue: 06 | May-2014 | RRDCE - 2014, Available @ http://www.ijret.org 314 one is the chemical process of calcining limestone into lime in the cement kiln also produces carbon di oxide. In India about 2,069,738 thousands of metric tons of carbon di oxide is emitted in the year of 2010. The cement industry contributes about 5% of total global carbon dioxide emissions. The cement is manufactured by using the raw materials such as lime stone, clay and other minerals by procuring them by quarrying process which also causes environmental degradation. To produce 1 ton of cement, about 1.6 tons of raw materials are required and the time taken to form the lime stone is much longer than the rate at which humans use it. On the other side, the demand of concrete is increasing day by day for its ease of preparing and fabricating in all sorts of convenient shapes. So to overcome this problem, the concrete to be used should be environmental friendly. To produce environmental friendly concrete, it is necessary to replace the cement with the industrial by products such as fly-ash, GGBS (Ground granulated blast furnace slag) etc. with new binding activator to form a new product called “Geo Polymer Concrete”. The term geopolymer was first coined by Davidovits in 1978 to represent a broad range of materials characterized by chains or networks of inorganic molecules. Geopolymers are chains or networks of mineral molecules linked with co-valent bonds. Geopolymer is produced by a polymeric reaction of alkaline liquid with source material of geological origin or by product material such as GGBS. Geo-polymers have the chemical composition similar to Zeolites but they can be formed an amorphous structure. For binding of materials the silica and the alumina present in the source material are induced by alkaline activators. The most common alkaline liquid used in the geo-polymerization is the combination of Sodium hydroxide and Sodium silicate. This combination increases the rate of reaction. Among fifteen Alumino-silicate minerals, all the Al-Si minerals are more soluble in sodium hydroxide solution than in potassium hydroxide solution. Ground granulated blast furnace slag (GGBS) is a by-product from the blast-furnaces used to make iron. During the process, slag was formed and it is then dried and ground to a fine powder. 2. LITERATURE REVIEW 2.1 History of Geopolymers Davidovits coined the term geopolymer in 1978 to represent a broad range of materials characterised by chains or networks of inorganic molecules [Davidovits, 1979, 1993, 2008][5] , and explained in many of his publications about the possibility of GPs being used by Egyptians construction of pyramids, based on microscopy, IR and NMR spectroscopy of sparse specimens from ancient Egyptian constructions [Davidovits and Morris, 1988; Davidovits, 1999][7] .Demortier observed the noticeable differences in porosities in the top and bottom sections of pyramid blocks which were also subjected to X-ray and NMR analyses to conclude that pyramids could be made from „concreting‟ operations [Demortier, 2004]. Use of slurry to form bearing courses of horizontal joints and vertical joints between the blocks including presence of hair in the joints of pyramids did indicate the possibility of „concrete‟ like technology for pyramid constructions . 2.2 Fresh Geopolymer Concrete Mixes Hardjito et al, (2002)[17] observed that fresh geopolymer concrete is highly viscous and cohesive with low workability when the calcined kaolin was the source material. 2.3 Structural Usages Davidovits and Sawyer (1985)[6] used ground blast furnace slag to produce geopolymer binders. This type of binders patented in the USA under the title „Early High-Strength Mineral Polymer‟, was used as a supplementary cementing material in the production of precast concrete products. 2.4 Activating Medium A combination of sodium or potassium silicate and sodium or potassium hydroxide has been widely used as the alkaline activator (Palomo et al, 1999; van Jaarsveld, van Deventer & Lukey 2002; Xu & van Deventer, 2000; Swanepoel & Strydom, 2002)[23,32] , with the activator liquid-to-source material ratio by mass in the range of 0.25-0.30 (Palomo, Grutzeck & Blanco 1999; Swanepoel & Strydom 2002)[31] . Anurag Mishra (2008, 2009) conducted experiments on FA based GPC by varying the concentration of NaOH and curing time. Total nine mixes were prepared with NaOH concentration as 8M, 12M, 16M and curing time as 24hrs, 48hrs, and 72hrs. The investigation indicated: an increase in compressive strength with increase in NaOH concentration and curing time, increase in compressive strength after 48hrs curing time not significant. Compressive strength up to 46 MPa was obtained with curing at 60ºC. Water absorption decreased with increase in NaOH concentration and curing time. 3. SCOPE AND OBJECTIVES PRESENT WORK 3.1 Need for the Present Study It is evident from the present facts that the production of Ordinary Portland Cement is causing much of the environmental hazards such as-  Emission of green house gases.  Enormous consumption of power for the manufacture of cement.  Minimize the waste of potable water in construction industries. As such, a new alternate binding material is necessary in order to address the problems, resulting in development of geopolymer concrete.
  3. 3. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308 __________________________________________________________________________________________ Volume: 03 Special Issue: 06 | May-2014 | RRDCE - 2014, Available @ http://www.ijret.org 315 3.2 Scope and Objectives of Present Study The aim of this research is to evaluate the performance and suitability of GGBS based geopolymer concrete as an alternative to the use of Ordinary Portland Cement (OPC) in the production of concrete. The individual objectives will include:  To evaluate the different strength properties of geopolymer concrete mixture with GGBS.  To make workable, high strength geopolymer concrete containing GGBS without usage of Ordinary Portland Cement.  To find out effective utilisation of industrial by product like GGBS.  To develop an eco-friendly alternative binding material. 4. MATERIALS 4.1 Materials Used for Conventional Concrete  Cement  Aggregates  Water 4.2 Materials Used For GPC The materials used for preparing GGBS based geopolymer concrete specimens are,  Ground Granulated Blast Furnace Slag (GGBS)  Sodium hydroxide flakes  Sodium silicate solution  Fine aggregate  Coarse aggregate Fig: 4.1 Ground Granulated Blast Furnace Slag The physical properties and chemical compositions of GGBS are given in the table 4.1 and 4.2 Table 4.1: Physical Properties of GGBS Sl.no Properties Values 1 Specific gravity 2.78 2 Fineness by 90µ sieve 6% Table 4.2: Chemical Composition of GGBS Sl no. Chemical composition Mass % 1 C 16.82 2 O 37.06 3 Mg 2.56 4 Al 3.56 5 Si 4.95 6 Ca 26.75 7 Mn 2.25 8 Cu 6.05 4.3 Sodium Hydroxide Generally the sodium hydroxides with purity of 98% available in solid from by means of flakes were used for the present investigation. The mass of water is the major component in both the alkaline solutions. In order to improve the workability extra water has been added to the mixture. In the present investigation sodium hydroxide flakes were obtained from the Travancore – Cochin Chemicals Limited through a local dealer. Fig: 4.2 Sodium Hydroxide Flakes
  4. 4. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308 __________________________________________________________________________________________ Volume: 03 Special Issue: 06 | May-2014 | RRDCE - 2014, Available @ http://www.ijret.org 316 4.4 Sodium Silicate Solution Sodium silicate is also known as water glass or liquid glass, available in liquid (gel) form. The sodium silicate solution is commercially available in different grades. The sodium silicate solution with SiO2 = 32.68%, Na2O = 15.63%, and water = 51.69% by mass, has been used for the present study. As per the manufacture, silicates were supplied to the detergent company and textile industry as bonding agent. Same sodium silicate is used for the making of geopolymer concrete. In the present investigation sodium silicate solution was purchased from local market. Fig: 4.3 Sodium Silicate Solutions 5. MOLARITY CALCULATION For 12 M NaOH calculation NaOH solution with a concentration of 12 Molar consists of 12 x 40 = 480 grams of NaOH solids per litre of the water, were 40 is the molecular weight of NaOH Therefore, 0.480 kg of NaOH flakes in 1 kg of water 1.48 kg of mass of NaOH solution contains 0.480 kg of flakes 1.0 kg of mass of NaOH solution contains=1*0.48/1.48= 0.3243 kg flakes 1 kg of mass of NaOH solution contains 0.3243 kg NaOH flakes Table 5.1: Molarity Calculation Molarity NaOH flakes in one lt of water (kg) NaOH flakes in one lt of NaOH solution (kg) 12M 0.480 0.3243 14M 0.560 0.359 16M 0.640 0.390 6. PREPARATION OF TEST SPECIMENS 6.1 Preparation of the Alkaline Solution The Sodium hydroxide flakes were dissolved in water to make the solution. The concentration of the NaOH solution depends on the molarity; 12 M, 14 M, 16 M. The sodium silicate solution was added to this NaOH solution and this mixture of alkaline liquid was prepared one day prior to the casting of the specimens as this is confirmed to have the better results (Hardjito and Rangan)[18] .The alkaline liquid was used after 24 hrs and within 36 hrs .(Hardjito and Rangan)[18] . On the day of casting of the specimens, the alkaline liquid was mixed to binder and aggregates with water added (if necessary) in order to achieve better workability. 6.2 Mixing, Casting and Curing of GPC For mixing, conventional method used for making normal concrete was adopted to prepare geopolymer concrete.The solid constituents viz. GGBS and aggregates were mixed in dry form for about 3-4 minutes. At the end of this mixing ,the liquid component of the geopolymer concrete mixture ,i.e.,combination of the alkaline solution with extra water was added to the solids and the mixing continued for another 3-4 minutes.The fresh GGBS based geopolymer concrete was grey in colour and shiny in appearance. The green mix was cohesive.The workability of the fresh concrete was measured by means of the conventional slump test. The fresh concrete was then poured into the moulds in three layers immediately after mixing and compacted by hand compaction by giving 25 strokes for each layer .After casting the test specimens were covered with HDPE (High Density Polyethelene) sheet, to minimise the water evoporation during the rest period of 24hrs at room temperature. At the end of 24 hrs all the specimens along with the mould were placed inside the hot air oven and cured at 120°c for another 24 hrs. The specimens were taken out from the oven and kept to air- dry at room temperature and after cooling to the room temperature the specimens were de-moulded and tested to determine the various strength properties.
  5. 5. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308 __________________________________________________________________________________________ Volume: 03 Special Issue: 06 | May-2014 | RRDCE - 2014, Available @ http://www.ijret.org 317 Fig 6.1: Fresh GGBS Based Geopolymer Concrete Fig 6.2: Specimens Covered with High Density Polyethelene Sheet Fig 6.3: Specimens Along with Moulds Fig 6.4: Specimens Kept for Curing 7. RESULTS The effects of various salient parameters on the compressive strength of geopolymer concrete are discussed. The parameters considered are,  Compressive strength v/s Binder.  Compressive strength v/s Alkaline liquid ratio. 7.1 Compressive Strength v/s Binder The different binder quantity added in the mixture is shown in the table no.5.1.1for 12 M, 14M and 16M NaOH solutions and study on compressive strengths was made. It is observed from the figure 5.1.1 to5.1.4, that the compressive strength of Geopolymer concrete specimen is more for 7.0 kg binder rather than 6.5 kg and 7.5 kg binder (calculated for 5 cubes) for alkaline liquid to binder ratio of 0.4. This result shows that higher or lower quantity of the binder, yields lower value of compressive strength. Similarly higher or lower ratio of alkaline liquid to binder ratio also yields lower value of compressive strength. A similar trend is same for different molarities of NaOH solution. This effect is due to the reaction with the alumina-silicates present in the industrial waste and the alkaline activators added in the optimum quantity shown above. It is observed that higher value of compressive strength is shown in 12M solution instead of 14M or 16M solutions. This also prevails that higher molarity in NaOH does not help in achieving the compressive strength. However better results are shown in 12M solutions compared to higher molarity NaOH solution.
  6. 6. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308 __________________________________________________________________________________________ Volume: 03 Special Issue: 06 | May-2014 | RRDCE - 2014, Available @ http://www.ijret.org 318 Fig 7.1: Effect on Compressive Strength by Binder Fig 7.2: Effect on Compressive Strength by Binder Fig 7.3: Effect on Compressive Strength by Binder Fig 7.4: Effect on Compressive Strength by Binder 7.2 Compressive Strength v/s Alkaline Liquid Ratio The different alkaline liquid ratio added to the mixture is shown in the table no.5.2.1 for 12M, 14M, 16M NaOH solution and study on compressive strength was made. It is observed from the figure 5.2.1 to 5.2.4 that the compressive strength of GPC specimens is more for Alkaline liquid to binder ratio of 0.4. It is also observed that as the ratio of Na2SiO3/NaOH increases the compressive strength also increases. A similar approach is same for different molarities of NaOH solution. The reason for increase of compressive strength is due to increase of solids (Silicate + NaOH). Fig 7.5: Effect on Compressive Strength by Alkaline Liquid Ratio
  7. 7. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308 __________________________________________________________________________________________ Volume: 03 Special Issue: 06 | May-2014 | RRDCE - 2014, Available @ http://www.ijret.org 319 Fig 7.6: Effect on Compressive Strength by Alkaline Liquid Ratio Fig 7.7: Effect on Compressive Strength by Alkaline Liquid Ratio Fig7.8: Effect of Compressive Strength by Alkaline Liquid Ratio 8. CONCLUSIONS Based on the present experimental investigations the following conclusions are drawn.  Higher concentration of sodium hydroxide in the solution results in lower compressive strength of GGBS based geopolymer concrete.  The compressive strength of geopolymer concrete is more for the higher ratio of sodium silicate to sodium hydroxide solution by mass.  The compressive strength is lower in case of higher or lower ratio of alkaline liquid to binder.  It is evident that more the alkaline liquid concentration (NaOH + Na2SiO3) yields lower compressive strength.  The compressive strength increases with the increased concentration of sodium silicate solution, upto certain ratio.  As water binder ratio increases the compressive strength of GGBS based geopolymer concrete decreases.  There is marginal decrease in the density of GGBS based geopolymer concrete compared to the conventional OPC concrete.  The fresh GGBS based geopolymer concrete hardens at room temperature. REFERENCES [1] Barbosa, V. F. F., Mackenzie, K. J. D. and Thaumaturgo, C., (2000), “Synthesis and characterisation of materials based on inorganic polymers of alumina and silica: sodium polysialate polymers”, International Journal of Inorganic Materials, 2, 309- 317 [2] Bhikshma, V., Koti Reddy, M. and Srinivas Rao, T., “An Experimental Investigation on Properties of Geopolymer Concrete (No Cement Concrete)”, Vol. 13, No. 6 (2012). [3] Cheng, T. W. and Chiu, J. P. (2003). “Fire-resistant Geopolymer Produced by Granulated Blast Furnace Slag” Minerals Engineering 16(3): 205-210. [4] Chindaprasirt, P., Chareerat, T., Siricicatnanon, V. (2007). “Workability and Strength of Coarse High Calcium Fly Ash Geopolymer”. Cement Concrete Compos., 29: 224-229. [5] Davidovits, J. 1984. “Pyramids of Egypt Made of Man- Made Stone, Myth or Fact?” Symposium on Archaeometry 1984. Smithsonian Institution, Washington, DC. [6] Davidovits, J. et al., “Process for Obtaining Geopolymeric Alumino-Silicate and Products Thus Obtained”, US patent USA 5, 342(1994) 595. [7] Davidovits, J. (1999). “Chemistry of Geopolymeric Systems, Terminology. Geopolymer” 99 International Conference, France.

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