EXPERIMENTAL STUDY ON ECOFRIENDLY POLYPROPYLENE FIBRE REINFORCED CONCRETE USING FOUNDRY SAND

Transcription

1 EXPERIMENTAL STUDY ON ECOFRIENDLY POLYPROPYLENE FIBRE REINFORCED CONCRETE USING FOUNDRY SAND B. Selvarani and R. Angeline Prabhavathy DMI College of Engineering, Hindustan University, Chennai, India ABSTRACT This paper presents the results of an experimental investigation carried out to evaluate the mechanical properties of ecofriendly concrete with foundry sand and polypropylene fibres in which fine aggregate was partially replaced with foundry sand by weight. M3 grade of concrete was designed using Portland pozzolana cement (PPC) for control concrete. The experimental investigation was carried out with the optimum dosage of 1. Kg/m³ of Polypropylene fibres in concrete. The percentage of replacement was %, 1%, 2% and 3 % by weight of fine aggregate. The mechanical properties such as compressive strength, split tensile strength and flexural strength were studied. The compressive strength, split tensile strength and flexural strength were determined at and. The laboratory results showed that the addition of Polypropylene fibres and foundry sand in concrete increased the compressive strength with partial replacement of waste foundry sand and polypropylene fibres. The split tensile strength increased with increase in percentage of waste foundry sand up to 2%. The combination of waste foundry sand with polypropylene fibres showed a rise in the strength parameters and the highest strength was obtained at 1% replacement in the case of compressive and flexural strengths and it is comparable with conventional concrete. Keywords: portland pozzolana cement, foundry sand, polypropylene fibres. INTRODUCTION Metal foundries use large amounts of sand as a part of the metal casting process. Foundries successfully recycle and reuse the sand many times during the casting process. The problem arising from technological and industrial development is the disposal of waste material. Foundry sand consists primarily of silica sand, with a thin film of burnt carbon, residual binder and dust. Foundry sand can be used as a partial replacement of fine aggregate in concrete. The successful utilization of waste as fine aggregate will turn this waste material into a valuable resource. Making eco-friendly concrete from recycled materials saves energy and conserves resources which lead to a safe sustainable and economical environment. Fibre reinforced concrete can offer a convenient, practical and economical method for overcoming micro cracks. In this study, the effect of using foundry sand as replacement for fine aggregate on ppc concrete with polypropylene fibres on the compressive strength, split tensile strength and flexural strength on M3 is investigated. Khatib et al. [14] investigated the mechanical and fresh properties of concrete containing waste foundry sand (WFS).The workability decreased as the foundry sand content increased. The Compressive strength of concrete also decreased with increasing amounts of Waste foundry sand. Gurpreet Singh and Siddique [15] performed experimental investigations to evaluate the strength and durability properties of concrete mixtures, in which natural sand was partially replaced with waste foundry sand. Test results obtained showed that, concrete mixtures made with waste foundry sand exhibited higher compressive strength than control concrete. Higher value of split tensile strength was observed at 15% WFS. Monosi, Sani and Tittarelli [16] investigated the properties of mortars and concretes containing different dosages of used foundry sand (UFS) as partial replacement of sand in both fresh and hardened conditions. It was concluded that UFS reduced the workability when added as replacement for natural sand at the same water cement ratio and higher amount of superplasticizer was required in order to maintain the same workability. Murahari, and Rao showed that the increase of mechanical properties such as compressive and flexural strength resulting from the addition of polypropylene fibres was relatively high. Topcu and Canbaz [5] studied the effect of steel and polypropylene fibres on the mechanical properties of concrete containing fly ash. Addition of fibres provided better performance for the concrete while fly ash in the mixture adjusted the workability and the strength-loss caused by fibres and improved the strength gain. Research Significance The effect of adding polypropylene fibres and partially replacing the fine aggregate with waste foundry sand on the mechanical properties of concrete has been studied. The purpose of this research is to study the effect of adding polypropylene fibres on the compressive strength by flexural strength and split tensile strength by partially replacing the fine aggregate with waste foundry sand in ppc concrete. MATERIALS AND METHODS Waste foundry sand Waste Foundry sand is a waste material obtained from ferrous and nоn-ferrous metal cast industries. About 3/4 of the total by product consists of sand. Foundries recycle and reuse the sand many times and this causes reduction in strength. It is then removed and it is called as Waste Foundry sand. Foundry industries use high quality silica sand when compared to natural sand. There are clear 9229

2 economic and environmental gains and hence it is used for partially replacing the natural sand. It is having a particle size passing 4.75mm sieve size. The Physical properties and Chemical Composition of waste foundry sand are presented in Tables 1 and 4. Table-1. Physical properties of foundry sand. Property Results Specific gravity 2.45 Bulk density (kg/m³) 2589 Absorption (%).45 Fine aggregates: Natural sand Locally available river sand was used as Fine aggregate conforming to Zone-II as per IS 383:197. The fine aggregate used was clean, inert and free from organic matter, silt and clay. The tests were conducted as per IS: The specific gravity of the fine aggregates was 2.65 and its water absorption was 1.5%. The Fine aggregate was dried before use. The properties of the fine aggregate are presented in Table-6. Cement In this study, Portland pozzolana cement (fly ash based) of single batch was used conforming to IS 1489 (part I)1991 specification. The Physical Properties and Chemical composition of PPC are listed in Tables 2 and 3. Table-2. Physical Properties of Portland Pozzolana Cement. Properties Result Value Standard consistency % 31 % Initial setting time Final setting time Soundness( lechatelier expansion) 19 minutes 325 minutes.5 mm Fineness (% retained on 9 μ sieve ) 3.5 % 7th day Compressive strength 28th day Compressive strength 32 MPa 43 MPa Specific gravity 2.9 Table-3. Chemical composition of Portland Pozzolana Cement. Component Mass % Silica dioxide (SiO 2 ) 23.7 Alumina oxide (Al 2 O 3 ) 12.4 Calcium Oxide (Cao) 48. Magnesium Oxide (Mgo) 1.83 Iron Oxide (Fe 2 O 3 ) 2.1 Loss of ignition 1. Table-4. Chemical Composition of waste foundry sand. Constituents Values in % Cao.14 SiO Al 2 O Mgo.93 P 2 O 5.1 Fe 2 O 3.94 K 2 O.25 Na 2 O.19 Loss of ignition 2.19 Figure-1 shows the polypropylene fibres used in this study Figure-1. Foundry sand. Water Water is important as it contributes in chemical reaction with cement. Water should be clean free from salt, acids alkalis and other destructive materials. The clean potable water was used for mixing and curing of concrete specimens Super plasticizer Conplast SP43 is a super plasticizing admixture which gives high water reduction without loss of workability and produce high quality concrete of reduced permeability. Conplast SP43 was used in this study. Coarse aggregate Locally available coarse aggregates of size ranging from 12 mm to 2 mm were used. The aggregates were of good quality and contained well graded cubical 923

3 shaped units. The coarse aggregates have been tested as per IS 2386:1963. The properties are shown in Table-5. The specific gravity of the coarse aggregates was found to be 2.67, and the water absorption of the coarse aggregates was.5%. It has a particle size passing 4.75mm sieve size. Table-5. Material Properties of Coarse Aggregates. S. No Property Conventional Aggregate 1 Max. nominal size (mm) 2. 2 Bulk Density (loose) in kg/m³ Bulk Density (Rodded) in kg/m³ Impact Value 18.3% 5 Crushing Value 21.1% 6 Water Absorption.5% Table-6. Physical Properties of Aggregates. S. No Characteristic Value River sand (FA) Coarse aggregate 1 Specific gravity Fineness modulus Void ratio Porosity Unit weight(kn/m 3 ) Polypropylene fibres The Polypropylene fibres utilized as a part of this study has the following properties as provided by the supplier. Recron 3S fibres were used as a reinforcement material. It arrests shrinkage cracks and increases resistance to water penetration, abrasion and impact. It makes concrete homogenous and improves the ductility, compressive strength, and flexural strength together with improving the ability to absorb more energy. Use of uniformly dispersed Recron fibres reduces bleeding and segregation, resulting in a more homogeneous mix. This leads to better strength and reduced permeability which improves the durability. Figure-2 show the polypropylene fibres used in this study Figure-2. Polypropylene fibres. Addition of Polypropylene fibres to concrete enhances the longevity of the structure by controlling micro cracks due to shrinkage during curing. Also, these fibres reduce water permeability. Incorporating fibres in concrete increases the flexural strength due to its higher modulus of elasticity compared to that of concrete or mortar binder. Its post cracking behaviour helps to continue to absorb energy as fibres pull out. The properties are shown in Table-7. Table-7. Properties of Polypropylene Fibres. Parameter Cut length Shape of fibre Specification 6 mm or 12 mm Special for improved holding of cement aggregates Tensile strength 4-6 kg/cm 2 Melting point > 25 C Concrete - Use gms per cubic metre Plaster - Use 6 125gms Dosage rate per cement bag in 1:4 cement/sand ratio, optimize as per need Test specimen details Fine aggregate was replaced with different percentages of foundry sand. The percentage of replacement was, 1, 2 and 3% by weight of fine aggregate. Polypropylene fibres were added at the optimum dosage of 1. Kg/m 3 in concrete. The strength properties of mixes were compared with that of conventional concrete mix specimens and tested for workablility and strength tests such as compressive 9231

4 strength, split tensile strength, and flexural strength tests at two different curing periods ( to ). The Mix proportion of M 3 grade concrete are presented in Tables 8 and 9. Mix Designation Foundry sand fraction of fine agg Cement kg/m³ Table-8. Mix proportion for M 3 grade. Foundry sand kg/m³ FA kg/m³ CA kg/m³ Water lts /m³ Recron 3s fibre kg/m³ M-WOF % M-WF % M1-WOF 1% M1-WF 1% M2-WOF 2% M2-WF 2% M3-WOF 3% M3-WF 3% Slump In mm Slump test Slump tests were conducted for concrete with and without fibres and waste foundry sand. When % foundry sand was used without fibres, the slump obtained was 98 mm. The results showed a continuous decrease in slump value of concrete by partial replacement of sand with waste foundry sand when compared with conventional concrete. A decrease in the workability was caused due to the presence of fine particles in the waste foundry sand as the percentage of waste foundry sand increased. Curing of test specimens After casting, the test specimens were dried for 24 hours. The cubes with moulds were left undisturbed in the laboratory under ambient conditions. The cubes were then cured in the curing tank, fully immersed under water bath. The specimens were cured for. After curing, the specimens were tested in the compression testing machine. Figure 3 and 4 show the specimens of Concrete Cubes and Cylinders. Figure-3. Specimens of concrete cubes. Figure-4. Specimens of concrete cylinders. Compressive strength test The Compressive strength of concrete mix with waste foundry sand replacement was determined at 7days and. The test results are shown in Table

5 Mix designation Table-9. Compressive strength of the specimens. Foundry sand % Slump test (mm) Compressive strength (mpa) 28days M-WOF M-WF M1-WOF M1-WF M2-WOF M2-WF M3-WOF M3-WF Figure 5 shows the testing of Compressive strength on cubes Figure-7. Compressive strength of various mixes at and. Figure-5. Compressive strength test on cubes. Figure-6 shows the Comparision of Compressive strengths of various mixes with and without Fibres Figure-6. Comparison of compressive strengths of various mixes with and without Fibres. The Compressive strength of various mixes at 7 days and shown in Figure 7 The strengths of various mix proportions at 7 days and curing were found out. The Compressve strength increased from 33.2 N/mm 2 to 38.4 N/mm 2 for. In this investigation, M1-WF (1% WFS) achieved maximum strength at and curing. Hence natural sand can be replaced by WFS up to 1 %. The waste foundry sand contains high percentage silica which forms good calcium silicate hydrate (C-S-H) gel. Split tensile strength The test results of split tensile strength of M3 grade concrete in which fine aggregate was replaced by waste foundry sand are given in the Table 11. Table-1. Split Tensile strength of the specimens. Mix N/mm 2 N/mm 2 M-WOF M-WF M1-WOF M1-WF M2-WOF M2-WF M3-WOF M3-WF

6 Figure-8 show the testing of Cylindrical specimens for finding the Split tensile strength. WF and M1-WF. The flexural strengths of the various mixes are shown in Table 12. Table-11. Flexural Strength of the specimens. Figure-8. Testing of cylindrical specimens. Figure-9 show the comparison of Split tensile strength of various mixes with and without fibre. Figure- 1 show the Split tensile strength of various mixes at 7 days and Figure-9. Comparison of split tensile strength of various mixes with and without fibres. MIX N/mm 2 N/mm 2 M-WOF M-WF M1-WOF M1-WF M2-WOF M2-WF M3-WOF M3-WF Figure-11 show the comparison of Flexural strength of various mixes with and without fibre. Figure- 12 show the Flexural strength of various mixes at and Figure-11. Comparison of flexural strength of various mixes with and without Fibres Figure-1. Split tensile strength of various mixes at and. 2 1 The Split tensile strength for mix M-WOF (%) was obtained as 2.59 N/mm 2 and 3.1 N/mm 2 at 7 and 28 days. The combination of waste foundry sand with polypropylene fibres showed an increase in the Split tensile strength compared to mix M-WF. For 2% replacement of waste foundry sand, an increase in the Split tensile strength was observed when compared with M- WOF at 7 and. M2-WF mix gave a Split tensile strength of 14.7 % and 2.1 % more than the mixes M- Figure-12. Flexural strengths of various mixes at and. The flexural strength of various mix proportions at and were found out. The flexural 9234

7 strength increased from 3.46 N/mm 2 to 3.72 N/mm 2 for 7 days and 4.13 N/mm 2 to 4.48 N/mm 2 for 28days. In this investigation, M1-WF (1% WFS) achieved maximum flexural strength. The flexural strengths obtained by M1- WF mix is 4.1 % and 6.9 % more than the mix M-WF and M1-WOF. CONCLUSIONS An experimental investigation was carried out to study the effect of adding polypropylene fibres and partially replacing the fine aggregate with waste foundry sand on the mechanical properties of ppc concrete. Based on the investigation, the following conclusions are drawn. a) The compressive strength increased from 33.2 N/mm² to 38.4 N/mm 2 for. The compressive strength obtained by M1-WF mix was 9.7% and 5.3% more than the M-WF and M1-WOF mix. b) The split tensile strength increased from 3.1 N/mm² to 3.58 N/mm² for. Maximum split tensile strength at 2% replacement of WFS was observed for both 7 and. M2-WF mix had a split tensile strength of 14.7% and 2.1 % more than the mix M- WF and M1-WF. c) The combination of waste foundry sand and polypropylene fibres showed an increase in split tensile strength. d) The flexural strength increased from 4.13 N/mm² to 4.48 N/mm² at. Maximum flexural strength was observed for M1-WF (1% WFS). The flexural strengths obtained by M1-WF mix was 4.1 % and 6.9 % more than the mix M-WF and M1-WOF. e) The combination of waste foundry sand with polypropylene fibres showed a rise in the strength parameters and the highest compressive and flexural strength was obtained at 1% replacement. Environmental effects from wastes and disposal problems of waste can be reduced through the use of the waste foundry sand. REFERENCES [1] Eknath P. Salokhe, D.B. Desai. Application of Foundry Waste Sand in Manufacture of Concrete. IOSR Journal of Mechanical and Civil Engineering, ISSN: , pp [2] Pranita Bhandari, Dr. K. M. Tajne Use of Foundry Sand in Conventional Concrete. International Journal of Latest Trends in Engineering and Technology (IJLTET), ISSN: X, 6(3): [3] Ravindra N. Patil Pravin R. Mehetre, Kailash. T. Phalak Development of concrete with partial replacement of Fine Aggregate by Waste Foundry. International Journal of Modern Trends in Engineering and Research (IJMTER), ISSN: , 2(7): [4] Mr. Ganesh B. Salunke A Review on Utilization of Waste Foundry Sand for Producing Economical and Sustainable Concrete. International Journal of Advance Engineering and Research Development (IJAERD), ISSN: , 2(4): [5] Jayaram R, Vijayan.V, ManojKumar R Experimental Studies on Fibre Reinforced Concrete with Addition of Foundry Sand. International Journal of innovative Research and Studies (IJIRS), ISSN: , 3(3): [6] Muhammad Nawazish Husain,Praveen Aggarwal Application of Recron 3S Fibre in Improving Silty Sub grade Behaviour. IOSR Journal of Mechanical and Civil Engineering. 12(2): [7] T.Sandeep Recron medium strength fibre reinforced concrete. International Journal of Scientific and Engineering Research. 3(4): [8] M. Sivaraja, N. Kandasamy, Velmani and Sudhakaran Pillai. 21. Study on Durability of Natural Fibre Concrete Composites using Mechanical Strength and Micro structural Properties. Indian Academy of Sciences. 33(6): [9] R. Aiswarya, G. Venkatesan, A. Rukesh, R. Kirubanandan, G. Jenitha An Experimental study on the Behaviour of Concrete by addition of Bamboo as Fibre and comparing it with the Conventional Concrete. International Journal of Applied Engineering Research. 1(53): [1] R.Aiswarya, G. Venkatesan, R. Regupathi, R.G. Jenitha Effect of copper slag and recycled aggregate in the behaviour of concrete composite. International Journal of Applied Engineering Research, 215, 1(53): International Journal of Scientific & Engineering Research. 7(12), ISSN [11] IS 456:2 Plain and Reinforced Concrete. 9235

8 [12] IS 2386: Part 1 Method of Test for Aggregate for Concrete. [13] IS1262:29 Concrete Mix Proportioning Guide lines. [14] IS 431 Part 4 Methods of Physical Tests for Hydraulic Cement (Determination of Consistency of Standard Cement Paste) [15] IS 431 Part 5 Methods of Physical Tests for Hydraulic Cement (Determination of Initial and Final Setting Times) [16] Qian CX, Stroeven P. 2. Development of hybrid polypropylene-steel fiber-reinforced concrete. Cement Concrete Res. 3: [17] Bureau of Indian Standards (BIS) Specification for Portland Pozzolana cement. IS: 1489 (Part 1), BIS, New Delhi, India. [18] Bureau of Indian Standards (BIS) Specification for coarse and fine aggregate from natural sources for concrete. IS: 383, BIS, New Delhi, India. [19] Bureau of Indian Standards (BIS) Methods of test for strength of concrete. IS: 516, BIS, New Delhi, India. [2] Bureau of Indian Standards (BIS) Splitting tensile strength of concrete: Method of test. IS: 5816, BIS, New Delhi, India. [21] Javed S., Lovell C. W. 1994b. Use of waste foundry sand in civil engineering. Transp. Res. Rec. p [22] Transportation Research Board, Washington, D.C. pp