Total replacement of cement using flyash and silicafume
- 1. TOTAL REPLACEMENT OF CEMENT USING FLYASH AND SILICAFUME Presented by, T.PREM SAI REDDY CEN,IST,JNTUH TELANGANA ,INDIA.
- 2. • Concrete is the most common construction material used in building industry. • Cement is a basic component of concrete used for building and civil engineering construction. • On average approximately 1 ton of cement is produced each year for every human being in the world. • Cement industry is one of the major contributing factors for air pollution with reference to sulphur dioxide (SO2), nitrogen oxide (NOx) and carbon monoxide (CO) as major air pollutants. • Adverse effects on human health and on environment, such as visual impairment, respiratory and cardiovascular disease and depletion of ozone level, acid rain, global warming, water quality deterioration INTRODUCTION:
- 3. OBJECTIVES: •Alternative method to reduce carbon emission •Using by-products such as FLYASH and SILICAFUME. • Attaining bond between the substituent's in the matrix. •Using binding agents like Sodium silicate and Sodium Hydroxide. •Finding the best mix which gives the best suitable in terms of strength and a complete replacement of cement, which may lead to sustainable development.
- 4. MATERIALS AND METHODOLOGY: There are two main constituents of geo-polymers, namely the source materials and the alkaline liquids. FLY ASH: • Fly Ash is a fine residue powder by-product from burning pulverized coal in thermal power generating plants. It is the finest and is the most broadly used material of all the by-products. SILICA FUME: • Silica fume, also known as micro-silica, is an amorphous (non-crystalline) polymorph of silicon dioxide, silica. It is an ultrafine powder collected as a by- product of the silicon and ferrosilicon alloy production and consists of spherical particles
- 5. Property Portland Cement Siliceous (ASTMC618 Class F) Fly-Ash Calcareous (ASTM C618 Class C) Fly-Ash Silica Fume SiO2 content (%) 21.9 52 35 85-97 Al2O3 content (%) 6.9 23 18 --- Fe2O3 content (%) 3 11 6 --- CaO content (%) 63 5 21 <1 MgO content (%) 2.5 --- --- --- SO3 content (%) 1.7 --- --- --- Specific surface(m2/kg) 370 420 420 15,000- 30,000 Specific gravity 3.15 2.38 2.65 2.22 General use in concrete Primary binder Cement replacement Cement replacement Property enhancer
- 6. AGGREGATES: • Shape and particle size distribution of the aggregate is very important as it affects the packing and voids content. • Locally available river sand is used as fine aggregate in the preparation of the cubes. • The sand passing through IS sieve 2.36mm was taken for casting. • The coarse aggregate is the main matrix of the concrete. •The coarse aggregate used is locally crushed granite stone of 20mm size. The aggregate passing through IS 20mm sieve and retaining on 12.5mm sieve were taken for conducting the study.
- 7. ALKALINE ACTIVATORS As the CaO is the major binding property present in cement, the aim of this study is to use alternate binders to produce a cohesive mix between fly-ash and silica fume. The binders used are: SODIUM SILICATE: • Sodium silicate is the common name for compounds with the formula (Na2SiO2)nO . A well-known member of this series is sodium meta-silicate, Na2SiO3. • Also known as water-glass or liquid glass, these materials are available in aqueous solution and in solid form. • It is available in gel form, for good pozzolanic reaction it is mixed with NaOH and it increases workability
- 8. SODIUM HYDROXIDE: •Sodium hydroxide (NaOH), also known as lye and caustic soda, is an inorganic compound. •It is a white solid and highly caustic metallic base and alkali of sodium which is available in pellets, flakes, granules, and as prepared solutions at different concentrations. •Sodium hydroxide forms approximately 50% (by mass) saturated solution with water. •Sodium hydroxide is soluble in water, ethanol, and methanol. This alkali is deliquescent and readily absorbs moisture and carbon dioxide in air. •It homogenise mix, prevent segregation, makes crystalline product which is stable in aggressive environment, reduces porosity, Ionic strength
- 9. SUPER PLASTICIZERS: Naphthalene sulphonate formaldehyde (SNF) and Glenium B233 based super plasticizer was used for fastening the reaction rate. FLYASH SILICA FUME SODIUM SILICATE SODIUM HYDROXIDE
- 10. MECHANISM: • Si and Al atoms in source materials dissolved using alkaline solution. Source materials include fly ash, silica-fume. Gel is formed by applying heat. • This gel binds aggregates and un-reacted source material forming geo-polymer concrete dissolution of Si and Al atoms takes place through the action of OH ions. • Precursor ions condense to form monomers and Poly-condensation of monomers to form polymeric structures • This framework formed is called as polysilates. Sialate stands for silicon-oxo- aluminates building unit chains and rings formed and cross linked through Si-O- Al bridge
- 11. CASTING AND CURING: In the process of preparation of the cubes 5 mix proportions were chosen at which the results that give the higher strength parameters are considered. The results obtained are compared with the conventional concrete to significant the purpose of using fly-ash and silica fume as the source materials. Mix Fly-ash Silica fume 1 100% 0% 2 90% 10% 3 80% 20% 4 70% 30% 5 60% 40%
- 12. CURING: The prepared cubes can be cured by two ways 1.AMBIENT CURING 2. OVEN CURING Ambient curing, involves in placing moulds with the concrete in the sunlight until the tests on respective days are to me performed. In oven curing, moulds containing concrete are to be placed in oven at 60 degrees for 24 hrs or at a time period for the temperature to raise from 60 to 110 degrees. Casted Cubes Cubes in heat Curing
- 13. RESULT AND DISCUSSIONS: •A total of 50 cubes based on the specified mix proportions (i.e. table 5) were prepared and the strength parameters are analysed for 7 days and 28 days of curing period. •The obtained results are compared with the conventional concrete to estimate the level of strength variance between the conventional and geo polymer concrete. • Out of the mentioned mix proportions the mix of 70% fly-ash and 30% silica fume has given the highest strength values, finally providing a best proportionate mix.
- 14. Conventional concrete 7 days 28 days Weight (kg) Peak load(KN) Peak stress (MPa) Weight (kg) Peak load(KN) Peak stress (MPa) Cube 1 8.23 486 21.6 8.324 756 33.6 Cube 2 8.45 515.2 22.9 8.3 783 34.8 Cube 3 8.32 510.7 22.7 8.58 776.2 34.5 Cube 4 8.25 553.5 24.6 8.61 821.25 36.5 Cube 5 8.4 535.5 23.8 8.44 807.75 35.9 Average 23.12 35.06
- 15. GPC using 100% Fly- ash 7 days 28 days Weight (kg) Peak load(KN) Peak stress (MPa) Weight (kg) Peak load(KN) Peak stress (MPa) Cube 1 8.23 722.2 32.1 8.42 778.5 34.6 Cube 2 8.45 636.7 28.3 8.410 855 38 Cube 3 8.32 585 26 8.47 722.2 32.1 Cube 4 8.24 679.5 30.2 8.43 810 36 Cube 5 8.31 765 34 8.45 713.2 31.7 Average 30.12 34.48
- 16. GPC using 90%Fly- ash & 10% Silica fume 7 days 28 days Weight (kg) Peak load(KN) Peak stress (MPa) Weight (kg) Peak load(KN) Peak stress (MPa) Cube 1 8.23 677.2 30.18 8.420 801 35.6 Cube 2 8.45 670.5 29.8 8.410 837 37.2 Cube 3 8.32 688.5 30.6 8.470 861.7 38.3 Cube 4 8.26 699.1 31.1 8.51 819 36.4 Cube 5 8.28 729 32.4 8.47 794.2 35.3 Average 30.8 36.56
- 17. GPC using 80%Fly- ash & 20% Silica fume 7 days 28 days Weight (kg) Peak load(KN) Peak stress (MPa) Weight (kg) Peak load(KN) Peak stress (MPa) Cube 1 8.23 684 30.4 8.42 814.5 36.2 Cube 2 8.45 643.5 28.6 8.41 859.5 38.2 Cube 3 8.32 634.5 28.2 8.47 1021.5 45.4 Cube 4 8.41 668.2 29.7 8.61 841.5 37.4 Cube 5 8.33 693 30.8 8.52 805.5 35.8 Average 29.54 38.6
- 18. GPC using 70%Fly- ash & 30% Silica fume 7 days 28 days Weight (kg) Peak load(KN) Peak stress (MPa) Weight (kg) Peak load(KN) Peak stress (MPa) Cube 1 8.23 733.5 32.6 8.42 875.2 38.9 Cube 2 8.45 762.7 33.9 8.41 891 39.6 Cube 3 8.32 706.5 31.4 8.47 992.2 44.1 Cube 4 8.26 668.2 29.7 8.51 859.5 38.2 Cube 5 8.37 715.5 31.8 8.49 850.5 37.8 Average 31.88 39.78
- 19. GPC using 60%Fly- ash & 40% Silica fume 7 days 28 days Weight (kg) Peak load(KN) Peak stress (MPa) Weight (kg) Peak load(KN) Peak stress (MPa) Cube 1 8.21 643.5 28.6 8.42 744.7 33.1 Cube 2 8.45 609.7 27.1 8.41 846 37.6 Cube 3 8.32 657 29.2 8.47 783 34.8 Cube 4 8.27 684 30.4 8.51 789.7 35.1 Cube 5 8.39 670.5 29.8 8.63 769.5 34.2 Average 29.02 34.96
- 21. ADVANTAGES high compressive strength high tensile strength low creep low drying shrinkage resistant to heat and cold chemically resistant highly durable fire proof
- 22. DISADVANTAGES Difficult to create Requires special handling Chemicals like sodium hydroxide are harmful to humans High cost of alkaline solution Pre-mix only Sold only as pre-mix or pre-caste material Geo-polymerisation process is sensitive Lacks uniformity
- 23. CONCLUSION Geopolymer concrete is a promising construction material due to its low carbon dioxide emission High early strength, low creep and shrinkage, acid resistance, fire resistance makes it better in usage than OPC Wide spread applications in precast industries due to -its high production in short duration -less breakage during transportation Enhanced research along with acceptance required to make it great advantage to the industry
- 24. REFERENCES • Aslani (2015); Thermal Performance Modelling of Geopolymer Concrete, Journal of Materials in Civil Engineering • Shankar H Sanni (2012); Performance of Geopolymer Concrete under severe environmental conditions, International Journal on Civil and Structural Engineering • Ramujee et al (2014), Development of Low Calcium Fly Ash Based Geopolymer Concrete, IACSIT International Journal of Engineering and Technology, Volume 6 • Lloyd et al (2010);Geopolymer concrete: A review of development and opportunities • Bakharev, T., (2005(a)), Resistance of geopolymer materials to acid attack, Cement and Concrete Research, 35, pp 658-670.
- 25. Thank you