INTERNATIONAL JOURNAL OF CIVIL AND STRUCTURAL ENGINEERING Volume 1, No 3, 2010

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1 ABSTRACT Effect of non bio degradable waste in Concrete slabs Venu Malagavelli 1, Rao.P.N 2 1- Lecturer, Department of Civil Engg, BITS, Pilani Hyderabad Campus, Jawahar Nagar, Shameerpet Mandal, Ranga Reddy District, Andhra Pradesh. 2- Professor Department of Civil Engg, BITS, Pilani Hyderabad Campus, Jawahar Nagar, Shameerpet Mandal, Ranga Reddy District, Andhra Pradesh. venu.bits@gmail.com doi: /ijcser The non-biodegradable waste is creating a lot of problems in the environment and its disposal becoming a great difficulty in the municipalities. Fiber reinforced polymer (FRP) materials are currently produced with different compositions and widely used for strengthening and retrofitting of the concrete structures. Recently considerable research has been directed to characterize the use of polymer fibers in the concrete strengthening applications. An attempt has been made to investigate the concrete (M 30 ) slabs using the two different fibers namely Poly Ethylene Terephthalate (i.e. mineral water bottles) and High Density Poly Propylene (i.e. disposable glasses). In the present analysis, nine samples of slabs are examined and results are presented. It has been observed that the ultimate load carrying capacity increased considerably by using these two fibers. Keywords: Polymer Fibers, Poly Ethylene Terephthalate (PET), High Density Poly Propylene (HDPP), Ultimate load, workability, compressive strength. 1. Introduction Concrete is a heterogeneous composite material made up of cement, sand, coarse aggregate and water mixed in a desired proportion based on the strength requirements. Plain concrete does not withstand as much tensile forces as compared to compression. The main drawback has necessitated civil engineers to make use of conventional reinforcement to increase the tensile strength and ductility of concrete members. The addition of fibers in concrete would act as crack inhibitors and substantially improve the tensile strength, cracking resistance, impact strength, wear and tear, fatigue resistance and ductility of concrete. The concept of using fibers in concrete as reinforcement is not new. For last three decades numerous studies were performed on Fiber Reinforced Concrete (FRC). In the early 1960 s only straight steel fibers were used and the major improvement occurred in the areas of ductility and fracture toughness, even the flexural strength increases were also reported. In the beginning fiber reinforced concrete was primarily used for pavements and industrial floors. Currently, the fiber reinforced cement composite is being used for wide variety of applications including bridges, tunnels, canal linings, hydraulic structures, pipes, explosion resistance structures, safety valves, cladding and rolled compacted concrete. Plain and fiber reinforced concrete slabs were tested under monotonic load by Jeffery et al. In this study five slabs of 2.2mX2.2m in size and nominal thickness of 127mm were casted. Two slabs containing with steel fibers, two slabs with synthetic macro fiber and one plain concrete slab. They found that the significant increase in the flexural strength of fiber reinforced concrete slabs when compared to plain concrete slabs. Vasudevan studied 449

2 utilization of waste polymers for flexible pavements. In this study stone aggregate is coated with the molten waste plastics. The coating of plastics reduces the porosity, absorption of moisture and improves soundness. They found that the use of waste plastics for flexible pavement is one of the best methods for easy disposal of waste plastics. Flexural behavior of small steel fiber reinforced concrete slabs studied by Ali and Majid. They found that the addition of steel fibers in the concrete improves the energy absorption capacity of slabs. Ombres et al studied the behavior of glass fiber reinforced concrete slabs and they found that the ultimate capacity of slabs increases with the amount of GFRP rebars. Andrea and Kanrod conducted the experiments on concrete using different fibers like steel, glass, carbon and hemp. They found that the compressive strength and ductility are increased by using fibers. Strain hardening and multiple cracking behavior of hybrid fiber reinforced cement composites containing different hybrid combinations of steel and polyethylene (PE) fibers under four-point bending are investigated by Shaikh Faiz Uddin Ahmed et al. Hybrid combination of 1.5% steel and 1.0% polyvinyl alcohol (PVA) exhibited best performance in terms of highest flexural strength, 0.5% steel and 2.0% PE exhibited highest deflection and energy absorption capacities. Apparao and Raghu Prasad conducted experimental investigations on the fracture energy and tension softening behavior of high strength concrete with fibers. They found that the addition of steel fibers, the energy absorption capacity of concrete increase very significantly. In the present study two different fibers namely Poly Ethylene Terephthalate (i.e. mineral water bottles) and High Density Poly Propylene (i.e. disposable glasses) used. 2. Materials Cement: Ordinary Portland cement of 43 grade was used. The chemical composition and physical properties of cement were given in table no.1. Table1: Properties of cement Physical properties Test Results Limits as per IS Fineness (m 2 /Kg) min (Specific Surface) Setting Time (Initial) min Setting Time (Final) min Sound Ness By Lechatelier By Auto Clave Compressive strength 3 days 7 days 28 days Chemical Properties LSF [(CaO 0.7SO 3) / (2.8SiO 2+1.2Al 2O Fe 2O 3) ] mm 0.8% 23MPa Min 33MPa Min 43MPa Min to1.02 Max AM (Al 2O 3/Fe 2O 3) Insoluble Residue (% by Mass) 450

3 Magnesia (% by Mass) Sulphuric Anhydrate (By Mass) Total Loss in Ignition (%) Total Chlorides (%) Fine Aggregate: Locally available river sand was used, which is free from organic impurities. The specific gravity of this fine aggregate was 2.62 and the fineness modulus was Table no.2 gives the sieve analysis results and fig.1 shows the grain size distribution curve. Sand is confirming to zone II. IS Sieve Weight retained Table 2: Sieve analysis of fine aggregate %of weight retained Cumulative %of weight retained % of passing Limits as per IS IS Total cumulative % of weight retained Figure 1: Grain size distribution curve for fine aggregate 451

4 Coarse Aggregate: The coarse aggregate used here is 20mm in size, crushed angular shape and free from dust. The specific gravity and fineness modulus were 2.80 and 7.15 respectively. IS Sieve Table 3: Sieve analysis of coarse aggregate Weight %of Cumulative % % of retained weight of weight passing retained retained Limits as per IS , IS µ µ µ Total cumulative % of weight retained Water: Water to be used in the concrete work should be free from oils, acids, alkalies and other organic and inorganic impurities. Table no.4 gives the properties of water used in concrete. Table 4: Properties of water sample S. No Parameter Results Limits as per IS ph Chlorides 30 mg/l 2000 mg/l (PCC) 500 mg/l (RCC) 3 Alkalinity 5 ml < 25ml 4 Sulphates 121 mg/l 400 mg/l 5 Florides 0.02 mg/l 1.5 mg/l 6 Organic Solids 40 mg/l 200 mg/l 7 Inorganic Solids 120 mg/l 3000 mg/l Non biodegradable materials (NBD): NBD materials are non corrosive, resistance to chemical attack, light in weight and easy to handle. For example Fiber plastics, jute plastics, textile waste, polythene covers, disposable glass, water bottles etc. Poly Ethylene Terephthalate (PET): This is a thermo plastic resin of the polyester family that is used to make beverage, food and other liquid containers. PET blends are engineering plastics with excellent processing characteristics and high strength and rigidity for a broad range of applications unlike other plastics. This is most important raw material used in 452

5 manmade fibers. Depending on its processing and thermal history, it may exist both as an amorphous and semi crystalline material. It can be synthesized by transesterification reaction between ethylene glycol and dimethyl terephthalate. It is manufactured under the names Arnite, Impet & rynite, Hostaphan, Melinex & Mylar Films and Darcon Terylene & Treivive fibres. High density Polypropylene Fiber (HDPP): HDPP is a linear polymer with the chemical composition of polypropylene (CH 3 ) N and defined by ASTM D638 as a product of propylene polymerization with a bulk density of 0.036gm/cm 3 or higher. The properties of both the fibers are given in table no.5. Table 5: Properties of PET and HDPP fibers S. Test Test method PET HDPP Unit No 1 Tensile Load ASTMD Kg 2 Elongation at break ASTMD % 3 Density ASTM D792 ASTMD gm/cc 4 Identification CIPET method Polyethylene Terephthalate (PET) Polypropylene (PP) 3. Mix Proportions Mix design is the process of selection suitable ingredients of concrete and determining their proportions with object of producing concrete of certain maximum strength and durability as economical as possible. The concrete mix is designed as per IS , IS and SP 23.The table no.6 gives the materials required for the M 30 grade concrete. Water cement ratio is 0.42 and mix proportions are 1:2.05: Mixing and Casting Table 6: Concrete mix proportion quantities per cum S. Materials Quantity in kg/m 3 No 1 Cement Fine aggregate Coarse aggregate water 147 Mixing has to done carefully so that the uniform dispersion of fibers and prevent the segregation or balling of the fibers. The present experimental study of Fibers includes testing of specimens for compressive strength. Specimens are prepared using design mix with PET & HDPP percentages starting from 0.5 to 6% with an increment of 0.5 by volume of concrete. 453

6 150X150X150 mm concrete cubes prepared for the compressive strength and a total of nine numbers of slabs of size 740X740X50mm with nominal reinforcement (four numbers of 6mm rods in both directions) are prepared for the flexural testing. In this three slabs without fibers, three slabs with 1% fibers and three slabs with 2% fibers. Slab will be provided with nominal reinforcement of 6mm diameter bars of 5 numbers in both directions. 5. Results and Discussions Slump test and compaction factor tests were conducted for finding the workability of the concrete. The results of the both test are shown in below figures Figure 2: Slump test results Figure 3: compaction factor test results From figure no. 2 and 3, both the tests slump and compaction factors are gradually increasing. At 1% fiber maximum slump and maximum compaction factor attained for HDPP fiber and at 2% fiber maximum slump and maximum compaction factor attained for PET fibers. 454

7 Figure 4: Load carrying capacity in compression at the age of 28 days Figure 5: Compressive strength of concrete at the age of 28 days It has been observed from the figure no. 4 and 5 the ultimate load and compressive strength of cubes by using both the fibers with different percentages of fibers is gradually increasing up to 1% fiber and gradually decreasing. The maximum compressive strength of cubes by using HDPP and PET fibers are and N/mm 2 respectively. Slabs are tested for the Flexure strength with/without fibers in the concrete. Table 7: Flexural test results of Slabs with/without fibers Peak Load Peak Displacement Displacement at Peak % of (KN) (mm) load (mm) fiber HDPP PET HDPP PET HDPP PET

8 From the above table, the maximum load carrying capacity is more by using PET fiber when compared to HDPP fiber. Similarly peak displacements are also more for PET fiber when compared to HDPP fiber. 6. Conclusion Based on the present and experimental investigation studies the following conclusions can be drawn 1. Ultimate load carrying capacity of concrete is increased by using fibers when compared to ordinary high performance concrete. 2. Ultimate load carrying capacity concrete increased by 4.62% with 1% HDPP fiber and 9.11% with 1% PET fiber. 3. The compressive strength of concrete increased by 4.2% with 1% HDPP fiber and 5.63% with 1% PET fiber. 4. Load carrying capacity of concrete in flexure is increased by using the both the fibers. Peak load 4.29% (1%) and 1.29% (2%) is more by using PET fibers in the concrete. Similarly in peak displacements are more by using PET fibers. 7. References 1. Jeffery R. Roesler, David A. Lange, Salah A. Altoubat, Klaus-Alexander Rieder and Gregory R. Ulreich, 2003, ASCE Journal of Materials in Civil Engineering, 16(5), pp Vasudevan. R., S.K. Nigam, R. Velkennedy, A. Ramalinga Chandra Sekar and B. Sundarakannan, Utilization of Waste Polymers for Flexible Pavement and Easy Disposal of Waste Polymers International Conference on Sustainable Solid Waste Management, Chennai, India, pp Ali R. Khaloo and Majid Afshari, 2005, Cement & Concrete composites, ELSEVIER Journals, 27, pp Ombres, L., T. Alkhrdaji, and A. Nanni, "Flexural analysis of One-Way Concrete Slabs Reinforced with GFRP Rebars" International Meeting on Composite Materials, PLAST 2000, Milan, Italy, pp Andrea. M. and Kanrod. B., Fiber Added Concrete, 2 nd international PhD symposium in civil engineering, Budapest. 6. Shaikh Faiz Uddin Ahmed, Mohamed Maalej and P. Paramasivam, 2007, Construction and Building Materials, ELSEVIER Journals, 21, pp Apparao. G. and Raghu Prasad. B. K., 2005, Journal of Structural Engineering, SERC Journals, 31(4), pp IS : Recommended Guidelines for Concrete Mix Design. 9. IS : Plain and Reinforced Concrete Code of Practice. 456

9 10. SP 23 Specification for the concrete Mix designs. 11. IS : Methods of Test for Aggregates for Concrete. 12. IS : Specification for Coarse and fine Aggregates from Natural Sources for Concrete (Second revision). 13. IS : 43 Grade Ordinary Portland cement Specification. 457