Recycling of Polyethylene Waste to Produce Plastic Cement

Available online at www.sciencedirect.com

ScienceDirect Procedia Manufacturing 8 (2017) 635 – 642

14th Global Conference on Sustainable Manufacturing, GCSM 3-5 October 2016, Stellenbosch, South Africa

Recycling of Polyethylene Waste to Produce Plastic Cement Ahmad K. Jassim* University of Basrah, College of Engineering, Materials Engineering Department, Basrah, Iraq

Abstract Disposal of plastic waste in environment is considered to be a big problem due to its very low biodegradability and presence in large quantities. Therefore, finding alternative methods of disposing waste by using friendly methods are becoming a major research issue. In this research, high density polyethylene waste is mixed with Portland cement to investigate the possibility to produce plastic cement, and study the effect of replacing sand by fine polyethylene waste with different percentage on the properties of product. The experiments were done by using the waste of polyethylene packages include bottle and food crates in the range of 10% to 80% by volume as a short reinforcement structure. The results show that there is a possibility to produce plastic cement from polyethylene waste and Portland cement by using 60% and 40%, respectively. In addition, their density was decreased, ductility increased, and the workability improved, which lead to produce lightweight materials. ©©2017 Authors. Published by Elsevier B.V. B.V. This is an open access article under the CC BY-NC-ND license 2016The The Authors. Published by Elsevier (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of the 14th Global Conference on Sustainable Manufacturing. Peer-review under responsibility of the organizing committee of the 14th Global Conference on Sustainable Manufacturing Keywords: recycling; plastic; polyethylene; waste; cement; disposal.

1. Introduction Humans have always produced trash and disposed of it in some way so solid waste management is not a new issue. What has changed are the types and amounts of waste produced, the methods of disposal, and the human values and perceptions of what should be done with it. The applications of plastic materials and their composites are still growing rapidly due to their low cost and ease of manufacture. Therefore, high amount of waste plastic being accumulated which create big challenges for their disposal [1].

* Corresponding author. Tel.: 009647802251917; E-mail address: [email protected]

2351-9789 © 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the organizing committee of the 14th Global Conference on Sustainable Manufacturing doi:10.1016/j.promfg.2017.02.081

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Ahmad K. Jassim / Procedia Manufacturing 8 (2017) 635 – 642

Despite the suitability of plastic for a wide variety of applications, organizations are faced with the growing problem of finding alternative methods for disposing a large volumes of waste packaging. Disposal of plastic waste in environment is considered to be a big problem due to its very low biodegradability and presence in large quantities [1, 2, 3]. One of the environmental issues in the most region of Iraq is the large number of package made from polyethylene materials such as shampoo sachets, carry–bags, nitro packs, milk and water pouches, and vegetable packages etc., which are deposited in domestic waste and landfills [3]. The largest component of the plastic waste is polypropylene, polyethylene terephthalate, and polystyrene [1]. Today sustainability has got top priority in construction industry. Recently plastics were used to prepare the coarse aggregates thereby providing a sustainable option to deal with the plastic waste. Therefore, recycling of plastic waste is an important topic in order to decrease environmental pollution and prevent waste of resources [3, 4]. Recently, plastic waste is one component of municipal solid waste which is becoming a major research issue to study the possibility of disposal the waste in mass concrete especially in self compacting concrete, light weight concrete, and in pavements. It can be used as a component of a composite construction material, as an inorganic filling material, and aggregate of concrete [2, 3, 4]. Recycling of plastic waste in concrete has advantages since it is widely used and has a long service life, which means that the waste is being removed from the waste stream for a long period. Moreover, using of post-consumer plastic waste in concrete will not only be its safe disposal method but may improve the concrete properties like tensile strength, chemical resistance, drying shrinkage and creep on short and long term basis [1]. The scientist has been discovered new types of engineering that include sustainable engineering and green engineering to reduce energy and natural resources consumptions. The goal of green engineering is to minimize adverse impact while simultaneously maximizing benefits to the economy, society, and the environment. It is focusing on the increasing the efficiency of a process to reduce the amount of pollution generated to be as eco-efficiency. This will shift the industrial processes from linear (open loop) system in which the resource and capital investments move through the system to become waste to ecological closed loop systems where wastes become inputs for new processes [5]. Baboo et al, was found that the workability and compressive strength were reduced due to partially replacement of sand by waste plastic flakes in varying percentages by volume to produce waste plastic mix concrete with plasticizer [2]. Rebeiz, has been investigated the strength properties of unreinforced and reinforced polymer concrete using unsaturated polymer resin based on recycle polyethylene terephthalate plastic waste. The result should that there is a possibility to produce a good quality of precast concrete [6]. Choi et al, and Batayench et al, were investigated the effect of waste polyethylene terephthalate bottles aggregate on properties of concrete. The waste plastic reduced the weight of normal concrete and the compressive strength was reduced too [2, 7, 8]. Pezzi et al, found that the addition of polymeric material in fraction less than 10 % in volume inside of cement matrix does not imply a significant variation of the concrete mechanical features [2, 9]. However, Marzouk et al, found that density and compressive strength of concrete decreased when the polyethylene terephthalate aggregate exceeded 50% by volume of sand [2, 10]. Binici H. et al, has been successfully used polyethylene bottles wastes in cement less concrete production and found that the ductility of concrete was improved [11]. Plastic has different properties such as durable and corrosion resistant, good isolation for cold, heat, and sound, saving energy, economical, has a longer life, and light weight [1, 3]. Therefore, in this research, solid-state recycling process is proposed to realize the direct recycling of polyethylene as the green engineering forming technology. Moreover, it will be used to produce plastic cement directly from solid state to improve the mechanical properties and workability of products. High density polyethylene waste is mixed with Portland cement to investigate the possibility to produce plastic cement, and study the effect of replacing sand by fine polyethylene waste with different percentage on the properties of product.

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2. Experimental work 2.1. Materials Polyethylene is a semi-crystalline material with excellent chemical resistance, good corrosion resistance, and good fatigue and wear resistance. It provides good resistance to organic solvents and strength with low moisture absorption. Moreover, it is light weight material, non-toxic material, resistance to stain, and offers excellent impact resistance and high tensile strength. Polyethylene box or crates have been collected from municipal and landfills as a waste of human activities. Then cutting into small size by using special cutting and grinding machine to get fine particles. The result grinding polyethylene waste are sieving to separate the fine particles from the coarse particles to be ready for mixing with Portland cement and water as shown in figure 1.

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Fig. 1. (a) Polyethylene waste box before cutting and grinding; (b) Grinding polyethylene waste.

2.2. Production Procedure The concrete mix was design to study the effect of replacement of sand by fine polyethylene waste. Portland cement mixed with fine polyethylene wastes and water using different percentages of wastes as shown in table 1. The percentages of materials and water take by volume. Table 1. Concrete mix design for high density polyethylene waste with Portland cement and water . Experiment HDPE Portland cement Water No. % % % 1 15 85 25 2 20 80 25 3 25 75 25 4 30 70 25 5 35 65 25 6 40 60 25 7 50 50 25 8 60 40 25 9 80 20 25

Portland cement and fine polyethylene waste mixed with water to get a homogenous concrete to cast on the small mold. Samples left in the mold until it dried, then put in water for 3-4 days for solidifying and curing to increase their cohesion. After that, samples left from water to dry and test their properties. The second step was putting the samples again in water for 7 and 28 days to study their stability and the effect of water on their properties.

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3. Results 3.1. Shape of products The shape of wet plastic cement that produced from mixing Portland cement with fine polyethylene waste before and after casting and drying are shown in figure 2 and 3, respectively. These materials are mixed and casting without any vibration or press.

Fig. 2. Portland cement and fine polyethylene waste after mix.

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30% HDPE

d) 50% HDPE

b) 35% HDPE

e) 60% HDPE

c ) 40% HDPE

f) 80% HDPE

Fig. 3. Portland cement and fine polyethylene waste mixed after casting and drying with different percentage of HDPE (a) 30% HDPE; (b) 35% HDPE; (c) 40% HDPE; (d) 50% HDPE; (e) 60% HDPE; and (f) 80% HDPE.

3.2. Density Density of plastic cement produced in this work was measured and the results show in table 2. Table 2. Density of plastic cement produced from high density polyethylene waste HDPE with Portland cement and water . Experiment HDPE Portland cement Water Density No. % % % (gm/cm3) 1 15 85 25 1.458 2 20 80 25 1.660 3 25 75 25 1.678 4 30 70 25 1.972 5 35 65 25 1.708 6 40 60 25 1.662 7 50 50 25 1.537 8 60 40 25 1.375


3.3. Moisture Table 3 shows moisture of plastic cement produced in this research after immerged 7 and 28 days in water. The results show after 28 days the moisture percentage will be less than the moisture of plastic cement that immerged 7 days. The best moisture percentage has been got when the polyethylene percentage equal to 25% and 30% in the mixing concrete. Table 3. Moisture percentage of plastic cement produced in this research work and immerged 7 and 28 days in water. Experiment HDPE Moisture % Moisture % No. % After 7 days After 28 days 1 15 10.5 11.6 2 20 23.4 4.00 3 25 14.4 3.60 4 30 13.96 3.79 5 35 15.96 5.08 6 40 15.86 10.73 7 50 19.46 5.04 8 60 17.36 5.42

3.4. Workability Plastic cement with waste polyethylene up to 60% have good workability because it is possible to make hole by using drill machine as shown in figure 4.

Fig. 4. Sample of plastic cement produced in this research with hole.

3.5. Compressive strength Figure 5 – 10 show compressive strength diagrams for plastic cements that produce by mixing fine polyethylene wastes and Portland cement after immerged 7 days in water. The yield points for different specimens have been found which lie in the range of 568 to 971 N after 7 days and from 571 to 2352 N after 28 days as shown in table 4. It is depended on the percentage of fine polyethylene waste. By increasing the waste plastic ratio, the compressive strength values of waste plastic concrete mixtures decrease at each curing age. This trend can be attributed to the decrease in adhesive strength between the surface of the waste plastic and the cement paste. It seems that the bonding between the plastic particles and the cement paste is weak. Table 4. Yield points of plastic cement produced from HDPE waste and Portland cement immerged 7 and 28 days in water. Experiment HDPE Yield point Yield point No. % (N) - 7 days (N) – 28 days 1 15 568 1491 2 25 971 2352 3 30 915 1271 4 35 945 1103 5 40 638 571 6 60 660 788

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Fig. 10. Compressive strength of produced plastic cement with 40 % HDPE and 60 % HDPE after immerged 28 days in water.

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4. Conclusions It is possible to produce plastic cement from waste of polyethylene materials that generated from human activities like food packages or crates. The results show that density of produced plastic cement was differed depending on the percentage of waste polyethylene in the concrete mix design. It is increased with increasing the percentage of waste up to 30% then decreased gradually. The maximum density of product is 1.972 gm/cm3 which is less than the density of cement mortar that produced from sand and Portland cement. The density reduction with 15% of traditional concrete. The moisture of plastic cement that produced in this research was lied in the range of 10.5% to 23.4% for products immerged 7 days in water. However, for products immerged 28 days, the moisture was decreased to be in the range of 3.6% to 11.6%. The best moisture percentage for products is 3.6 and 3.79% for products with 25% and 30% waste polyethylene, respectively. The best compressive strength for product was found in the mixture has 25%, 30%, and 35% polyethylene. The yield points for them are 971, 915, and 945 N, for immerged 7 days, respectively, and 2352 for mixed of 25% and 1271 N 30% after immerged 28 days. The stress-strain behavior is plastic behavior which has several stages of deformation. It works as semi crystalline polymer, flexible concrete and not brittle as Sand-Portland cement concrete. Therefore, their stress – strain diagram exhibited both elastic and plastic deformation before fracture. Moreover, the products with 25% to 30% waste polyethylene have good workability to make holes without any problem. However, when the percentage of waste decrease or increase, the workability will be weak and power was generated during the cutting operation. Solid-state recycling process becomes an effective and powerful methodology to realize the green state forming from recyclable wastes to useful parts. The developed process can be considered as a typical green-forming or environmentally manufacturing process for lightweight materials. It has many benefits including simple, cost and energy saving, and clean recycling because it is not harm the environment. From the above information found that the best and suitable percentage of waste polyethylene is 25 to 35% which give a good properties of mixture. References [1]

[2] [3] [4] [5] [6] [7] [8] [9] [10] [11]

Ganesh Tapkire, Satish Parihar, Pramod Patil, and Hemraj R. Kumavat, Recycling plastic used in concrete paver block, International journal of research in engineering and technology, Vol. 3, issue 9, 2014, p. 3335. Baboo Rai, S. Tabin Rushad, Bhavesh Kr, and B. K. Duggal, Study of waste plastic mix concrete with plasticizer, International scholarly research network, ISRN Civil Engineering, Vol. 1, 2012, p. 1-5. Pramod Sambhaji Patil, Behavior of concrete which is partially replaced with waste plastic, International Journal of Innovative Technology and Exploring Engineering IJITEE, Vol. 4, Issue 11, 2015. Hanifi Binici, Effect of aggregate type on mortors without cement, Europen jornal of engineering and technology, Vol. 1, issue 1, 2013, p. 1-6. James R. Michelcic, Julie beth Zammerman, Environment, Sustainable design, John Weley and Sons Inc., 2010, p. 236-24. K. S. Rebeiz, Precast use of polymer concrete using unsaturated polymer resin based on recycled PET waste, construction and building materials, Vol. 10, issue 3, 1996, p. 215-220. M. Batayneh, I. Marie, and I. Asi, Use of selected waste materials in concrete mixes, Waste Management, Vol. 27, Issue 12, 2007, P. 1870-1876. Y. W. Choi, D. J. Moon, J. S. Chung, and S. K. Cho Effects of waste PET bottles aggregate on the properties of concrete, Cement and concrete research, Vol. 35, issue 4, 2005, p. 776-781. L. Pezzi, P. D. Luca, D. Vunono, F. Chiappetts, and A. Nastro, Concrete products with wastes plastic material (bottole, glass, plate), Materials Science Forum, Vol. 514-516, 2006, p. 1753-1757. O. Y. Marzouk, R. M. Dheilly, and M. Queneude, Valorisation of post-consumer waste plastic in cementitious concrete composites, Waste management, Vol. 27, issue No. 2, 2007, p. 310-318. Binici H., Gemci R. Kaplan H, Physical and mechanical properties of morter without cement, Journal of construction and building materials, Vol. 28, 2012, p. 357-361.