MECHANICAL PROPERTIES OF STEEL FIBER REINFORCED GEOPOLYMER CONCRETE INCORPORATED WITH FLY-ASH & GGBS

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1 International Journal of Civil Engineering and Technology (IJCIET) Volume 9, Issue 3, March 2018, pp , Article ID: IJCIET_09_03_078 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed MECHANICAL PROPERTIES OF STEEL FIBER REINFORCED GEOPOLYMER CONCRETE INCORPORATED WITH FLY-ASH & GGBS Tadepalli Naga Srinu PG Student Marri Laxman Reddy Institute of Technology & Management Hyderabad Telangana, India Kallempudi Murali Assistant Professor, Marri Laxman Reddy Institute of Technology & Management Hyderabad Telangana, India ABSTRACT As the concrete industry is going on expanding the various alterations and development are given insight due development of infrastructure in present trend the demand for special concretes are increased. The production of concrete mainly consists of cement aggregates etc in this present experimental work the strength aimed was for 40 N/mm 2.[2][3].In this experimental work the cement is completely replaced by flash and GGBS at equal proportions incorporated with steel fibers of standard length 1mm diameter of 50mm aspect ratio of 50 the type of steel fibers used is crimpled form as we knew concrete is weak in tension and strong in compression to counter the stress produced to balance and make the concrete withstand with tension steel fibers are added maximum up to 2% take by weight of binder i.e GGBS and low calcium based flash supplied by local thermal plant. The maximum increase in strength was observed at 1.5% of incorporation of steel fibers. The addition of steel fibers had shown good increase in compressive flexural and split tensile strength. The use of fly-ash and ggbs help in reducing the air pollution by eliminating carbondioxide and carbon monoxide which is produced in manufacturing of cement. [8]. KEY WORDS: Geopolymer, Steel Fibers, SP 430, Sodium silicate, Sodium hydroxide, Fly-ash & GGBS. Cite this Article: Tadepalli Naga Srinu and Kallempudi Murali, Mechanical Properties of Steel Fiber Reinforced Geopolymer Concrete Incorporated with Fly-Ash & GGBS, International Journal of Civil Engineering and Technology, 9(3), 2018, pp

2 Mechanical Properties of Steel Fiber Reinforced Geopolymer Concrete Incorporated with Fly-Ash & GGBS 1. INTRODUCTION: Geopolymer concrete is termed to be highly durable in nature and it can even withstand in any aggressive environments and existing temperatures at present. Addition of steel fibers, GGBS in low calcium based fly-ash based geopolymer concrete [4] shows a particular raise in the compressive strength and durability properties. Low calcium Fly ash based geopolymer concrete tends to be highly economic over Portland cement concrete helps in reduction of harmful gases which are responsible for the exploitation of environment and affects the greenhouse industry. The binder materials like fly-ash [1], the filler materials like GGBS helps in amputating the heat produced while constructing geopolymer concrete it is also termed as cool & green concrete generally. As it is free from toxic pollutant like CO 2 which results in deterioration of the environment. Alkaline activators in geopolymer concrete like sodium hydroxide sodium silicate play a important role in assisting the mechanical properties of steel fiber blended geopolymer concrete. Regarding geopolymer concrete: Davidovits (1988, 1994) had suggested an alkaline liquid could be satisfied to react with the silicon (Si) and the aluminum (Al) materials in parent compounds the materials such as Fly-ash & also GGBS to initiate bind take major role in chemical reaction process which takes place it is termed as Polymerization process, he conveyed the word Geopolymer to represent these binders. This Geopolymerization reaction [2] represents the chemical reaction between alumino silicate oxides with alkali poly silicates which result in yielding polymeric Si O Al bonds. Water will be swelled out from the mixture throughout the addition of super plasticizer and curing process. A important phenomenon is that added water helps in promoting and enhancing the workability of fiber reinforced geopolymer concrete. 2. MATERIALS: Different ingredients used in manufacturing of fiber reinforced geopolymer concrete for the current experimental work are presented in this sector. Fly-ash (class F) [1] was obtained from vardhaman RMC plant, Hyderabad, power plant produced ground blast furnace slag (GGBS) in powdered form and steel fibers of hooked end with aspect ratio of 50 diameter of 0.45mm length 25 mm available locally was used along with fly ash as additive material.[3]. Locally available River sand was imported as fine aggregates passing through nominal IS sieve 4.75mm was taken. Uncrushed, crushed or partially crushed rock based gravel or stone were used as coarse aggregate which should be enough hard, strong, dense, durable, clear and free from veins and adherent coatings which should helps in resisting axial load and were retained on IS sieve 20mm. required and less amount Water is been used for mixing and curing was fresh distilled water.[4] Sodium silicate is also known as water glass or liquid glass, available in (gel) form. In this present experimental investigation sodium silicate 2.5 (ratio between Na 2 O to SiO 2 ) was utilized. As per the recommendation of professors Sodium Silicate liquid used in this study was provided in liquid state were by Chemicals industries, Hyderabad. Generally the sodium hydroxides are available in solid state by form of flakes. In this present investigation the sodium hydroxide pellets of purity 98.5 % were utilized. The super plasticizer used was Conplast SP430 supplied by M/s Fosroc Chemical (India) Pvt. Ltd Material properties: Table 1 Chemical compositions of low calcium based fly-ash and GGBS Particulars Class F fly ash GGBS % Silica(SiO 2 ) % Alumina(Al 2 O 3 ) % Iron Oxide(Fe 2 O 3 ) editor@iaeme.com

3 Tadepalli Naga Srinu and Kallempudi Murali % Lime (CaO) % Magnesia (MgO) % Titanium Oxide (TiO 2 ) % Sulphur Trioxide (SO 3 ) Loss on Ignition The properties of Binder materials like low calcium Fly-ash class F and GGBS are cited in table no [1]. Table 2 Physical Properties of Fly-ash class F and GGBS Property Fly-ash GGBS Specific gravity Bulk density Kg/m Appearance grey Grayish white Particle size 30 microns 25 microns Fineness(m 2 /kg) Properties of Aggregates: The different Properties of Aggregates are cited in table no [3]. Table 3 Properties of coarse aggregate and fine Aggregates Sno Properties Coarse aggregate River sand 1. Specific gravity Bulk Density Fineness modulus Water absorption 0.45% 1% 2.3. Properties of steel fibers: The Properties of Steel Fibers are cited in table. No. [4]. Material Property Type of Fiber steel Diameter 0.5 mm Length 25mm Aspect Ratio 50 Color grey 2.4. Properties of Alkaline Activators (Sodium Silicate and Sodium Hydroxide): The properties of alkaline activators are cited in Table. No. [5]. Table 5 Properties of Alkaline Activators Property Sodium Silicate Sodium Hydroxide Appearance Gel Pellets Density Melting Point 1088 C 318 C Solubility Insoluble In Alcohol Insoluble In Acetone Refractive Index ,473-1, editor@iaeme.com

4 Mechanical Properties of Steel Fiber Reinforced Geopolymer Concrete Incorporated with Fly-Ash & GGBS 3. MIX DESIGN: Stipulations Adopted For Geopolymer Concrete Mix Design for G40- Assumed As there are no Specific code specifications for geopolymer concrete the proportions are calculated and adopted as per Design criteria suggested by a geopolymer concrete Scholar Dr.K. Ramujee.[1]. Unit weight of Geopolymer concrete is 2400 kg/m 3 The Mass of Combined aggregate as 0.75% of the mass of Concrete i. e, 0.75 x 2400 = 1800 kg/m 3 Taking mass of Coarse aggregate as 65% to the mass of combined Aggregate= (65x 1800)/100 =1170 kg/m 3 Then taking mass of Fine aggregate as 35% to the mass of Combined aggregate= (35x 1800)/100 =630 kg/m 3 Mass of Fly ash and alkaline Liquid = = 600 kg/m 3 Considering alkaline liquid to fly ash ratio as 0.35 Mass of fly ash= (600)/ (1+0.35) = kg/m 3 Mass of alkaline liquid= = kg/m 3 Considering Mass of Na2SiO3 solution= = kg/m 3 Now calculating the total amount of mass of water and mass of solids in the sodium hydroxide and sodium silicate solution: Sodium Hydroxide solution (NaOH): 10 X 40 (molecular weight) = 400 grams of sodium hydroxide solids per one liter of sodium hydroxide solution. The water content in the NaOH solution in observed as 63.5%. The mass of NaOH solution = (155.56)/ (1+2) =51.85 kg/m 3 The Mass of Water= (63.5/100) x (51.85) = Kg Mass of solids = = Kg Sodium Silicate Solution (Na 2 SiO 3 ): The water content in the silicate solution in observed as 63.5%. The Mass of Water= (63.5/100) x (103.71) = Kg Mass of solid = = 37.86Kg Total mass of water: Mass of water in NaOH solution + mass of water in Na 2 SiO 3.Solution= = Kg Total mass of solids: Mass of solids in NaOH solution + mass of solids in Na 2 SiO 3 solution + mass of Fly ash = = Kg Ratio of water to Geopolymer Solids = 98.77/501.2= editor@iaeme.com

5 Tadepalli Naga Srinu and Kallempudi Murali Mix id fly-ash GGBS Table 6 Mix Proportions of Steel Fiber Reinforced Geopolymer Concrete Coarse aggregate Fine aggregate Steel Fibers(Kg/m 3 ) Sodium silicate Sodium hydroxide M1 (0%) M2(0.5%) M3 (1%) M4(1.5%) M5(2.0%) RESULTS AND DISCUSSIONS: 4.1. Slump Cone Test: A concrete is said to be workable if it s easily settled and well compacted and finished without any type of swelling. Workability is a property of freshly mixed concrete as concrete is a mixture of cement, aggregate, water & admixtures. A mold for slump test is a frustum shape of a cone, 300 mm (12 in) of height. The base plate is 200 mm (8in) in diameter and it has a smaller opening at the top of 100 mm (4 in). The base plate is placed on a smooth surface and the container is filled with concrete in three layers. The results of slump cone test are cited in table no [5]. Table 6 Results of Slump Cone Test Mix ID Slump value (mm) FRGPC 0% 125 FRGPC (0.5%) 111 FRGPC (1%) 94 FRGPC (1.5%) 85 FRGPC (2%) Compressive Strength: Compressive strength is the most important property of concrete. The specimens were tested on 2000kN As per IS: The geopolymer concrete mixes were formulated in such a way that the fibers were varied replaced partially with 0.5%, 1%, 1.5%, and 2%. And Fly and GGBS were included in the mix at equal proportions. The compressive strength values are cited in table [6]. Table 7 Compressive Strength Results (N/mm 2 ) MIX ID 7 DAYS 28 DAYS % % % % SP editor@iaeme.com

6 Mechanical Properties of Steel Fiber Reinforced Geopolymer Concrete Incorporated with Fly-Ash & GGBS Figure 1 Compressive Strength Apparatus Compressive Strength (N/mm 2 ) 0 0.5% 1% 1.5% 2% 7 days days Figure 2 Compressive Strength Variation 4.3. Flexural Strength: Flexural strength is also known as bending strength, it is a mechanical property which is defined as a material's ability to resist deformation under load or stress in a material just before it yields in a flexure test. The flexural strength of 100*100*500mm beams was tested as per IS: The results for flexural strength are cited in table no [7]. Table.8 Flexural Strength Results (N/mm 2 ) MIXID 7 DAYS 28 DAYS % % % % editor@iaeme.com

7 Tadepalli Naga Srinu and Kallempudi Murali Figure 3 Flexural Strength Apparatus 0 Flexural Strength (N/mm 2 ) 0.5% 1% 1.5% 2% 7 DAYS DAYS Figure 4 Flexural Strength Variation 4.4. Split Tensile Strength: The variation of split tensile strength measured at the end of 7 days and 28 days.the specimens were tested on 2000 kn As per IS The results for split tensile strength are cited in table no [8]. Table 9 Split Tensile Results (N/mm 2 ) MIX ID 7 DAYS 28 DAYS % % % % Figure 6 Split Tensile Strength Apparatus editor@iaeme.com

8 Mechanical Properties of Steel Fiber Reinforced Geopolymer Concrete Incorporated with Fly-Ash & GGBS Split Tensile Strength (N/mm 2 ) 0 0.5% 1% 1.5% 2% 7 DAYS DAYS Figure 7 Split Tensile Strength Variation 5. CONCLUSIONS: 1. Incorporation of steel fibers had enhanced the mechanical properties of geopolymer concrete. 2. The split tensile strength has shown better performance compared to compressive & flexural strengths. 3. The increase in compressive strength in comparison with control mix is nearly 20% in split tensile it was observed as 40% and nearly 35% in flexural strength. 4. Use of binder s fly ash GGBS in equal proportions had shown good increase in split tensile & Flexural strength of fiber reinforced geopolymer concrete better than compressive strength. 5. The decrease in water content favors the formation of geopolymerization process, which demands for increase of concentration of Sodium hydroxide and sodium silicate silicates. Hence increase in concentration of NaOH results in increase of compressive strength. 6. It is recommended to add naphthalene based instead of carboxylic based Super plasticizers for high strength Geopolymer concretes, which is analogous to Conventional concrete of higher grades to secure required workability. 7. Dosage of steel fibers has decreased crack width of specimens while compared to control mix which was the reason for increase in compressive strength. REFERENCES: [1] Development of Low Calcium Fly-ash Based Geopolymer Concrete Dr.K. Ramujee IACSIT International Journal of Engineering and Technology, Vol. 6, No. 1, February [2] J. Davidovits, Geopolymer chemistry and properties, in Proc. Geopolymer '88, First European Conference on Soft Mineralogy, The Geopolymer Institute, Compiegne, France, 1988, pp [3] A. M. Neville, Properties of Concrete, Fourth and Final ed., Pearson Education, Longman Group Essex, England, [4] D.N.Kumar DR.K. Ramujee Durability Characteristics of Fiber Reinforced Geopolymer Concrete Incorporated with Fly-ash and GGBS. International research Journal of engineering and Technology vol: 4 issue 11Nov editor@iaeme.com

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