PERFORMANCE OF POLYETHYLENE TEREPHHTHALATE (PET) WASTE MATERIAL IN CONCRETE ADMIXTURE

Transcription

1 PERFORMANCE OF POLYETHYLENE TEREPHHTHALATE (PET) WASTE MATERIAL IN CONCRETE ADMIXTURE Emedya Murniwaty Samsudin, Hasniza Abu Bakar and Asmaria Hasanuddin Faculty of Civil and Environmental Engineering,University Tun Hussein Onn Malaysia ABSTRACT Concrete is a composite material produced by mixing three primary materials such as cement, sands and aggregates at a certain mixing ratio. Polyethylene Terephthalate Wastes or WPET materials were introduced as an additive into the concrete admixture purposely to reduce the amount of non-compassable material in landfill. This study aims to produce concrete using waste materials from PET as an additives in the concrete mix and to investigates the strength, durability and workability of WPET concrete in accordance to British Standard 1881 (BS1881). In this study, plastic additive were used as a replacement of course aggregates in the concrete mixture by 10%, 20% and 30% respectively. The waste PET concrete then tested to determine the concrete performance with regards to its compressive strength, density and workability by age of concrete 7 days, 14 days and 28 days. Result shows that the additive of 10%, 20%, and 30%, of waste PET in 1:1.75:2.75 concrete mixture design with 0.5 water cement content affects the concrete properties in terms of workability, strength and density of concrete. By increasing the waste PET material into the concrete mixture, the compressive strength of concrete will decrease but the workability was gradually improved. Besides, result for 30% waste PET shows that the replacement of PET materials into the concrete mixture was able to produce a lightweight concrete design mixture. Therefore, replacing of waste PET as a substitution of course aggregates can reduce the use of concrete raw material (aggregates) and able to solved and reduce the amount of non-compassable dumping material in the landfill Field of Research: Concrete,waste materials, Polyethyele Terephthalate (PET), Compressive Strength and Concrete Workability INTRODUCTION Polyethylene terephthalate (PET) is one of the most common consumer plastics used and is widely employed as a raw material to realize products such as blown bottles for soft-drink use and containers for the packaging of food and other consumer goods. PET bottles have taken the place of glass bottles as storing vessel of beverage due to its lightweight and easiness of handling and storage (Mariaenrica, 2010). More than 60 billion tons of plastic waste produce every day around the world and will cause the pollution of environment because it cannot be disposed (Mohd. Adha, 2010). Polymer is one of the most available materials for daily usage because it is anti-corrosion, durable and very light. Therefore, the main factors it has been chose by many because it is available everywhere and this cause the plastic materials appear as one of the largest contributing factors to the solid waste disposal. Plastics wastes are among recycling or the 72

2 reuse of wastes because their disposal has harmful effects on the environment due to their long biodegradation period, and therefore one of the applications of these materials in other industries (Zainab Z. Ismail and A.AL-Hashmi, 2007). The use of aggregates in concrete production should be reduced on environmental factors, which in the production of concrete aggregate consumption of 60-70% of materials used in producing concrete. Awareness of the importance of nature conservation causes quarrying work needs to be reduced for reasons of erosion and air pollution. The use of PET plastic into the concrete as an additive can help reduce the use of aggregates thus can reduce solid waste landfill. In this study, an experiment involved the addition of PET type of plastic used as an additive in concrete to produce eco-friendly concrete. Concrete like other engineering materials needs to be designed for properties like strength, durability, workability and cohesion. 2. OBJECTIVES, SCOPES AND THE IMPORTANCE OF RESEARCH This study aims to achieve the following objectives;- I. To produce concrete using waste materials from polyethylene terephthalate (PET) plastic bottles as an additive in concrete mix. II. To investigate the durability and workability of lightweight concrete in accordance with British Standard 1881 (BS 1881). In specification, the scopes of this study include: I. Compression strength of concrete between actual concrete and concrete which has been modified (the addition of plastic on the concrete mix) in the mixture will set. Produced concrete strength test will be based on BS 1881 and tested on day 7, day -14, and day-to-28. II. III. For this experiment, plastic waste polyethylene terephthalate (PET) were used as a lightweight aggregate in the concrete mix additives. Plastic bottles were cut in the form of small pieces with an average size between 5mm-15mm PET. Plastic content will be added as a percentage of aggregate by added in 10%, 20% and 30% of PET strips into the concrete mixture. The parameters being test in experiment were workability of concrete, density and compressive strength of concrete. Concrete tests conducted by the British Standard BS LITERATURE REVIEW Concrete Admixtures An admixture is a material other than water, aggregates, cement and fiber, added to plastic concrete or mortar to change one or more properties at the fresh or hardened stages. Admixture are introduced before, during or (in some cases) after the mixing of the major ingredients. A number of different types of admixture are available in the market to perform 73

3 functional such as increasing the plasticity, accelerating the setting, improving the strength development and reducing the heat of hydration (Shan Somayaji, 2001). 3.2 Solid Waste Disposal Problems In 2007, it is reported a world s annual consumption of PET drink covers of approximately 10 million tons, which presents perhaps 250 milliards bottles. This number grows about up to 15% every year. Nowadays landfill sites, in general, are becoming overcrowded and expensive for waste disposal, efforts must be made to minimize the quantities of materials that are delivered to landfills. If the production of waste cannot be prevented, then it is attractive to create an alternative use in another process instead of disposal. The benefits of this recycling can be economically advantageous, due lower costs of removing the waste and the reduction of pollution and contamination (G. Li et al., 2004; Senthamarai and Manoharan, 2005). 3.3 Polyethylene Terephthalate (PET) Plastic type s polyethylene terephthalate or PET is the thermoplastic polymer resin used in synthetic fibers, such as beverage bottles, oil bottles, carbonated bottle, medicine bottles and so on. This type of plastic is numbered as a number (1) in accordance with the recycling number used to sign for the types of plastic. Table 1 shows the guide value of the physical and mechanical properties of PET. Physical condition of the plastic is usually colorless and transparent and this type of plastic have a high penetration of light and have low permeability rates of carbon dioxide. PET Bottle is an alternative to glass bottles because it is lightweight and easily handled and stored. Table 1: Guide Value of the Physical and Mechanical Properties of PET (Material Science of Polymers for Engineering, 2003) 3.4 The Use of Waste Plastic in Concrete Recycle of PET Bottles as Fine Aggregates in Concrete. Mariaenrica Frigione from University of Salento Italy attempted to substitute 5% of concrete by weight of fine aggregates (natural sand) with an equal weight of PET 74

4 aggregates. The particles of PET is a granular similar to that of the substituted sand. Test method using six cubic s (side=150mm), three cylinder (height=300mm, diameter 150mm) and three prism (75mm side square cross sections, 285mm long). From Table 2.0 and Table 3.0 has shown the mixture composition for concrete mixture of 0.100m 3 and workability, compressive strength and split tensile strength concrete. The result compressive strength test, the result has shown the value do not different more than ± 0.3 MPa. However, the trend of all results clearly displays the tendency of a small decrease when PET substitute in concrete. Table 2.0: Mixture composition for concrete mixture of 0.100m 3 Table 3.0: Workability, compressive strength and split tensile strength concrete Irrelevant difference in compressive strength at 28 days and 1 year year between reference concretes and mixes containing WPET at low w/c ratio (0.45); the differences become a little significant by increasing the w/c ratio (up to 0.55). It is likely that, due to the bleeding, by increasing the w/c ratio, the interface between WPET and the hydrated cement Portland presents a higher porosity and consequence of the flat shape of the WPET pieces (Mariaenrica, 2010) Use of Waste Plastic in Concrete Mixture as Aggregates Replacement. Research done by Zainab Z. Ismail, Enas A. AL-Hashmi, (2008) aims to determine the efficiency of reusing waste plastic in the production of concrete. Waste plastic of fabriform shape was used as a partial replacement for sand by 10%, 15% and 20%. This study insures that reusing waste plastic as a sand-substitution aggregate in concrete gives a good approach to reduce the cost of materials and solve some of the solid waste problems posed by plastics. The test performance include performing slump, these tests include performing slump, fresh density, dry density, compressive strength, flexural strength, and 75

5 toughness indices. The curing ages of the experiment of 3, 7, 14 and 28 days. The focus of this research will be on the compressive strength and performing slump. Mixture proportioning for this experiment are presented in table 4.0 as P12, P13, and P14 corresponding to the 10%, 15% and 20% addition of waste plastic sand replacement. Table 4: Waste plastic concrete mixture Figure 1: Slump of waste plastic concrete Figure 2: Compressive strength Figure 1 shows the result of the slump tests of waste plastic concrete mixture. In spite of the slump reduction, the waste plastic concrete mixtures have easy workability. Results for compressive strength test are shown in Figure 2. By increase the plastic waste in concrete the value of compressive strength decrease below the plain mixture at each curing period. The conclusion of compressive strength values, all waste plastic concrete mixtures tend to decrease below the values for the reference concrete mixtures with increasing the waste plastic ratio at all curing ages. This may be attributed to the decrease in the adhesive strength between the surface of the waste plastic and cement paste. In addition waste plastic is hydrophobic material which may restrict the hydration of cement (Zainab Z. Ismail, Enas A. Al-Hashmi, 2008). 4. METHODOLOGY Figure 3 illustrates the flow chart of the methodological process for this study and Figure 4 shows the shapes of PET after heating process. 76

6 Figure 3: Methodology Chart Figure 4: Shape of Waste PET plastic after Heating Process The material used in this experiment as follows: i. Cement: type Portland cement was used in all types of aggregate content mixtures. The chemical composite of the cement are presented in Table 5, respectively. i. Aggregates: The fine aggregate was made up of clean river sand. The coarse aggregate was crushed stone aggregate of maximum size 20mm. ii. Waste PET: Waste Plastic PET represents the discarded waste from plastic bottle that were collected at residential college and UTHM area. After the collection of waste PET bottle, Plastic bottles were cut using the machine and sieve the plastic in the form of small pieces with an average size between 5mm- 15mm PET. Plastic content will be added as a percentage of aggregate by added in 10%, 20% and 30% of PET strips into the concrete mixture. 77

7 Table 4: Chemical composition of cement (Mat Lazim, 1987) Compounds Abbreviation % weight Tricalcium silicate 3CaO.Sio2 (C 3 S) 54.1% Dicalcium silicate 2CaO.SiO2 (C 2 S) 16.6% Tricalsium aluminate 3CaO.Al2O3 (C 3 A) 10.8% Tetra calcium aluminoferrite 4CaO.Al2O3.Fe2O3 (C 4 AF)9.1% Gypsum and Others 9.4% (maximum) The compressive strength of PET plastic is very low due to the smoothest surfaces. It needs another solution for it to have a good adhesion force when it muddle up into the concrete mix. This problem can be fixed by heating the PET plastic with fine sand. The process was shown in Figure 4. The entire assortment needs to be arbitration first before the heating process can be carried out on PET plastic and the sands. Reference concrete mixture: concrete mix design according to a ratio 1:1.75:2.75, each mixture consisted of the weight for nine cube mix concrete for cement 3.93kg, sand 6.88kg, and Aggregates 11kg. These mixtures were of 0% waste PET plastic and were cured for 7, 14 and 28 days. Waste plastic concrete mixture the mixture are presented in Table 5 as 2A, 2B and 2C corresponding to the 10%, 20% and 30% addition of waste PET as aggregates replacement. Table 5: Concrete mix design for 9 cubes Symbol Cement (Kg) Aggregates (Kg) Materials Sand (Kg) W.PET (Kg) W.PET (%) W/C or W(C+ WPET) A B C In preparing the concrete cube, 36 cubes of concrete for the cube size 100mm x 100mm x100mm were molded for compressive strength and density test. Table 6: Number of sample for each cube concrete Concrete Sample Plastic (%) Number of Sample 7 days 14 days 28 days Sample 1 0% Sample 2A 10% Sample 2B 20% Sample 2C 30% Total

8 4.3 Test of Specimen i. Batch and mix the material according to BS 1881: Part 125: 1983 (Methods for mixing and sampling fresh concrete in the laboratory) ii. Workability of the designed mix by slump test according BS 1881: Part 102: 1983 (Method for determination of slump) iii. Three cube concrete will be curing at the tank and compressive strength with compression machine at 7, 14 and 28 days, respectively with reference to BS 1881: Part 116: 1983 (Method for determination of compressive strength of concrete cubes), and BS 1881: Part 111: 1983 for curing test specimen. The compressive strength can be used by formula: Maximum Load (N) Compressive Strength = (N/mm 2 ) Cube Area (mm 2 ) 5. RESULT AND DISCUSSION Table 7 shows the result of slump test and compression strength for the concrete control and concrete waste PET was compared and shown in Table 7. Table 7: Result for 1:1.75:2.75 Concrete Properties with WPET Material Symbol W/C WPET (%) Density [kg/m 3 ] Compressive Strength (MPA) 7 days 14days 28 days Slump (mm) A B C

9 .2 Workability of Fresh Concrete The slump test of PET concrete mixture waste outcome was presented in fig. 7 and fig.6. It shows that the increasing of the PET plastic additive waste will decrease the slum of concrete sharply. From the result, it exposed that the workability of mixture concrete is within the real reduction about mm (Tan Boon Tong, 1994). These indicate that the workability of concrete is in satisfactory range. Figure 5: Slump of waste PET concrete Figure 6: Compression strength of concrete From the Fig. 6 represents WPET mixing proportion at 0%, 10%, 20% and 30% the resulting compressive strength of the concrete with elapsed age. Compressive strength of concrete shows an increase that coincides with age regardless of the percentage of WPET. With 0% WPET replacement, the compressive strength at 28 days is about MPa. However, as the percentage of WPET in the mix increases, for example from 10% to 20%, the compressive strength at 28 days is reduced from to 27 MPa. Moreover the higher the percentage of WPET in the mix, the more the compressive strength of the mortar decreases. In particular, when WPET is mixed at 30%, the compressive strength at 28 days shows a 73% 6. CONCLUSION From this research was to evaluate the recyclability of domestic plastic waste as a coarse aggregate for concrete. From the result the main conclusions that can be drawn: I. From the analysis of waste plastic PET as a course aggregates gave that the value of compressive strength is Mpa, for the density of concrete about kg/m 3, and the workability of concrete mixture showed a tendency to decrease below the slump of reference concrete mixture, the mixture easy to work based on the consideration of workability of concrete. II. The compressive of concrete containing the plastic waste PET decreased as a proportion of plastic waste increased. The concrete contained a 10% of waste PET gave a highest strength for age of concrete 28 days, the result strength of concrete is Mpa. The comparisons between reference concrete, the percent of strength decreased 80

10 about 15.5%. The reducing of plastic waste PET will gave increased strength and batter properties. 7. REFERENCES A. M. Mustafa Al Bakri, S. Mohammad Tamizi, A. R. Rafiza, and Y. Zarina,.(2011). Investigation Of HDPE Plastic Waste Aggregate On The Properties Of Concrete. Journal of Asian Scientific Research, 1(7), G. Li, M.A. Stubblefield, G.Garrick, J.Eggers, C. Abadie, B. Huang (2004). Development of Waste Tire Modified Concrete. Cem Concr Res. 34(12), Mariaenrica Frigione.(2010). Recycling Of PET Bottles as Fine Aggregate in Concrete. Waste Management, 30, Mat Lazim Zakaria. (1987). Bahan Dan Binaan. Cetakan Pertama : Dewan Bahasa dan Pustaka Kuala Lumpur 2001 Mohd. Adha Mohd Zain. (2010, Sept 15). Berita harian online. From RM Senthamarai, P.D. Manoharan (2005). Concrete with Ceramic Waste Aggregate. Cem Concr Compo. 27(9-10), Shan Somayaji (2003). Civil Engineering Materials. Second Edition. California Polytechnic State University, San Luis Obispo: Prentice Hall. Tim A.Osswald and Georg Menges. (2003). Materials Science Of Polymers for Engineering, Second Edition. University of Wisconsin Madison : Hanser Publishers, Munich. Yun-Wang Choia, Dae-Joong Moonb, Jee-Seung Chungc, Sun-Kyu Chod, (2005). Effects of Waste PET Bottles Aggregate ontthe Properties of Concrete. Cement and Concrete Research. 35, Zainab, Z. Ismail; Enas, A. AL; Hashmi. (2008). Use of Waste Plastic in Concrete Mixture as Aggregate Replacement. Waste Management 28(11),