EXPERIMENTAL INVESTIGATION OF HOLLOW CORE SLAB USING DIFFERENT FIBRE

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1 International Journal of Civil Engineering and Technology (IJCIET) Volume 9, Issue 11, November 2018, pp , Article ID: IJCIET_09_11_116 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed EXPERIMENTAL INVESTIGATION OF HOLLOW CORE SLAB USING DIFFERENT FIBRE R. Yuvanesh Kumar, K. Vinobalaji and M. Naveen Prasad Civil Engineering Department, PSNA College of Engineering and Technology, Dindigul, Tamilnadu, India ABSTRACT Total weight of the building mainly depends on the reinforced concrete. Large portions of building s weight caused due to dead load. In order to reduce the self weight, hollow core slabs are used. Hollow core slab makes the slab much lighter than the massive solid concrete floor slab of equal thickness and strength. Concrete being brittle is strong in compression but very week in tension, this weakness makes it to crack at the tensile end. The tensile property can be induced by adding fibres. Fibres have the ability to arrest cracks, increased extensibility and tensile strength. Fibres are able to the matrix together even after extensive cracking. This Study investigates the hollow core slab incorporated with different fibres like steel, polypropylene and glass fibre. M20 grade of concrete is used for this investigation. Keywords: Dead load, hollow core slab, tension Cite this Article: R. Yuvanesh Kumar, K. Vinobalaji and M. Naveen Prasad, Experimental Investigation of Hollow Core Slab using Different Fibre, International Journal of Civil Engineering and Technology, 9(11), 2018, pp INTRODUCTION Concrete is a mixture of paste and aggregates. The paste composed of Portland cement and water, coats the surface of fine and coarse aggregates. Through a chemical reaction called hydration, the paste hardens and gains strength to form the rock-like mass known as concrete. Concrete has relatively high compressive strength but low tensile strength. The concrete elements subjected to tensile stresses must be reinforced with steel.the elasticity of concrete is relatively constant at low stress levels but starts decreasing at higher stress levels as matrix cracking develops. Concrete has a very low coefficient of thermal expansion and it leads to shrinkage. All the concrete structure will crack to extent due to shrinkage and tension. In order to control the cracks in concrete, fibres are used. Fibres are usually used in concrete to control plastic shrinkage and drying shrinkage cracking. The addition of fibres in the matrix editor@iaeme.com

2 Experimental Investigation of Hollow Core Slab using Different Fibre has many important effects. Most notable among them is improved fracture strength, toughness, impact resistance, flexural strength resistance to fatigue. Concrete slabs are rigid structures made up of concrete with the small height when compared to other dimensions. Total weight of the building mainly depends on the reinforced concrete. Large portions of building s weight caused due to dead load, reducing self weight reduces the total cost of construction. In order to reduce the self weight, hollow core slabs are used. Hollow core slab makes the slab much lighter than a massive solid concrete floor slab of equal thickness or strength. This type of slabs are more economical because of its lower self weight i.e., less material is used for casting. Precast concrete is linked with low seismic zones and more economical construction because of fast building assembly lower self weight that is less material. Reduced weight and less cost of material. It has tubular voids extending the full length of the slab, typically with a diameter equal to the 2/3 to 3/4 of the slab. This makes the slab much lighter than massive floor slabs of equal thickness or strength Research Gap and Objective of the work Much research has been done to reduce the dead load of building and arrest the crack by using fibres. By various study following conclusion has been made. Hollow core slab is used to reduced the self weight of structural member (Slab). Steel fibres can be used up to 1% which improves the flexural strength and split tensile strength of concrete. Polypropylene can be used up to 0.45% which enhances the tensile strength of concrete. Glass fibre can be used up to 0.50% which improves the flexural and split tensile strength of concrete. By adding the fibre to the mix will have ductile failures. Objective of this project to reduce the self weight of the slab by providing hollow through the length of the slab. To improve the ductile property of the hollow core slab by using different fibres like glass, steel and polypropylene. To study the flexural behavior of the hollow core slab by using different fibres. To compare the flexural behavior of hollow core slabs incorporated with different fibres. 2. MATERIAL PROPERTIES Fibres three different fibres like glass, polypropylene and steel fibres were used in this study. Properties of the fibres and typical images shown in Table 1 and Figure 1 Table 1 Properties of fibre PROPERTIES STEEL GLASS POLYPROPYLENE FIBRE FIBRE FIBRE Type Hooked end Recron 3s E-glass Length(mm) Tensile strength(mpa) 800 to to to1700 Specific Gravity Figure 1 Steel, polypropylene and glass fibre editor@iaeme.com

3 R. Yuvanesh Kumar, K. Vinobalaji and M. Naveen Prasad Grade of cement OPC 53 grade is used. 20mm size of coarse aggregate is used. River sand is used for this study. 3. MIX DESIGN Based on the initial test results, mix design was arrived for M 20 grade of concrete according to IS 10262: 2009 details of Mix Proportion given in Table 2. Grade of concrete = M 20 Type of cement = OPC 53 grade Nominal size of aggregate = 20mm Minimum cement content = 300 kg/m³ Maximum water cement content = 0.55 Workability = 100mm (slump) Exposure condition = Mild Method of concrete placing = Normal Maximum cement content = 450 kg/m³ 3.1. Test data Specific gravity of cement = 3.16 Specific gravity of coarse aggregate = 2.77 Specific gravity of fine aggregate = 2.64 Surface moisture = Nil Table 2 Mix proportion w/c ratio Cement kg/m³ Fine aggregate kg/m³ Coarse aggregate kg/m³ EXPERIMENTAL METHODOLOGY AND ANALYSIS OF RESULT Cube of size 150mmx150mmx150mm, cylinder of size dia 150 mm and 300mm heights, prism of size 500mmx100mmx100mm were casted of different proportions of glass, steel and polypropylene fibre. 4 solid slab and 4 hollow core slab of size 1200mmx3000x120mm were casted for optimum proportion of glass, polypropylene and steel fibre.50 mm diameter pvc pipe is used to provide hollow throughout the length of the slab Design for Slab Size of slab 1200mmx300mmx120mm Span/ depth = 35x 0.8 = /depth = 28 D = 120 mm W = 35kN Fac load = 1.5x 35 =52.5 kn Moment = wl 2 /8 =9.45 knm = 0.87 Ast fy d (1- (Ast xfy)/(fck x b x d)) M u editor@iaeme.com

4 Experimental Investigation of Hollow Core Slab using Different Fibre 9.45x10 6 = Ast Ast 2 Ast = mm 2 /m Using 10 mm dia bars at spacing 260mm c/c Minimum reinforcement: 0.12%bD = 0.12% bd = 144 mm 2 /m Using 8 mm dia bars at spacing 130mm c/c 4.2. Compression Test Result Compressive strength is calculated using the formula P/A N/mm GLASS FIBRE Varied fibre content of 0.03%, 0.06%, and 0.09% to volume of concrete the cubes were casted to determine the optimum value for compressive strength Shown in Graph 1 Graph 1 Compressive strength vs % of Glass fibre content Polypropylene Fibre Varied fibre content of 0.10%, 0.20%, and 0.30% to volume of concrete the cubes were casted to determine the optimum value for compressive strength. Shown in Graph 2 Graph 2 Compressive strength vs % of polypropylene fibre content editor@iaeme.com

5 R. Yuvanesh Kumar, K. Vinobalaji and M. Naveen Prasad Steel Fibre Varied fibre content of 0.30%, 0.60%, and 0.90% to volume of concrete the cubes were casted to determine the optimum value for compressive strength Shown in Graph 3 Graph 3 Compressive strength vs % of Steel fibre content 4.3. Split Tensile Test Split tensile strength of the concrete is calculated using the formula 2P/3.14xdxl Glass Fibre Varied fibre content of 0.03%, 0.06%, and 0.09% to volume of concrete the cylinder were casted to determine the optimum value for Split tensile strength Shown in Graph 4 Graph 4 Split tensile strength vs % of Glass fibre content Polypropylene Fibre Varied fibre content of 0.10%, 0.20%, and 0.30% to volume of concrete the cylinder were casted to determine the optimum value for split tensile strength Shown in Graph editor@iaeme.com

6 Experimental Investigation of Hollow Core Slab using Different Fibre Graph 5 Split tensile strength vs % of Polypropylene fibre content Steel Fibre Varied fibre content of 0.30%, 0.60%, and 0.90% to volume of concrete the cylinder were casted to determine the optimum value for split tensile strength Shown in Graph Flexural Strength Glass Fibre Graph 6 Split tensile strength vs % of Steel fibre content Graph 7 Flexural strength vs % of Glass fibre content editor@iaeme.com

7 R. Yuvanesh Kumar, K. Vinobalaji and M. Naveen Prasad Polypropylene Fibre Steel Fibre Graph 8 Flexural strength vs % of Polypropylene fibre content Graph 9 Flexural strength vs % of Steel fibre content 5. RESULT AND DISUSSION It is observed that compressive strength increases up to 12.95% with addition of 0.06% glass fibre to the volume of concrete.compressive strength increases up to 15.62% with addition of 0.30% polypropylene fibre to the volume of concrete. Compressive strength increases up to 17.53% with a addition of 0.90% steel fibre to the volume of concrete. Split tensile strength increases up to 0.62% with addition of 0.06% glass fibre to the volume of concrete. Split tensile strength increases up to 53.75% with a addition of 0.30 % polypropylene fibre to the volume of concrete. Split tensile strength increases up to 62 % with a addition of 0.60% steel fibre to the volume of concrete. Flexural strength increases up to 6.96% with addition of 0.06% glass fibre. Flexural strength increases up to 9% with addition of 0.30% polypropylene fibre. Flexural strength increases up to 10% with addition of steel fibre. 6. CONCLUSION With addition of fibre there is no increase in the compressive strength of concrete. Steel fibres are added to improve the tensile and flexural strength. It was found that steel fibre reinforced concrete with hooked end has better performance than the straight fibre of equal length. It provides better anchorage and aspect ratio than the straight fibre with equivalent editor@iaeme.com

8 Experimental Investigation of Hollow Core Slab using Different Fibre length. Aspect ratio is generally limited to an optimum value to achieve good workability and strength Inclusion of polypropylene fibres reduces the water permeability, increases the flexural strength due to its high modulus of elasticity. Glass fibre which improves the flexural and split tensile strength of concrete. By adding the fibre to the mix will have ductile failures. Hollow core slab reduces the dead weight to a great extent. REFERENCES [1] Ahmet B. Kizilkanat Et Al(2015), Mechanical Properties And Fracture Behavior Of Basalt And Glass Fibre Reinforced Concrete: An Experimental Study, Construction And Building Materials,Volume-100,Pp [2] Ibrahim I.S. And Che Bakar. M.B. (2011), Effects of Mechanical Properties Of Industrialised Steel Fibres Addition To Normal Weight Concrete, Procedia Engineering, Volume 14, Pp [3] IS : 2009 For Concrete Mix Proportioning Guidelines (First Revision) [4] IS 456 : 2000 For Plain And Reinforced Concrete Code of Practice (Fourth Revision) [5] Messaoud Saidani Et Al (2016), Behaviour of Different Types of Fibre Reinforced Concrete Without Admixture, Engineering Structures, Volume-113,Pp [6] Nanang Gunawan Wariyatno Et Al (2017), Flexural Behaviour Of Precast Hollow Core Slab Using Pvc Pipe And Styrofoam With Different Reinforcement, Procedra Engineering, Volume-171, Pp [7] Vahid Afroughsabeta Et Al (2015), Mechanical And Durability Properties Of High Strength Concrete Containing Steel And Polypropylene Fibres, Construction And Building Materials, Volume-94, Pp [8] Vladimir Guilherme Haach Et Al (2017), Possibilities Of Using Ultrasound For The Technological Control Of Concrete Of Hollow-Core Slabs, Construction And Building Materials,Volume-133, Pp editor@iaeme.com