Advanced Materials Research Online: 2013-05-27 ISSN: 1662-8985, Vol. 701, pp 265-269 doi:10.4028/www.scientific.net/amr.701.265 2013 Trans Tech Publications, Switzerland Use of Plastic Waste (High Density Polyethylene) In Concrete Mixture as Aggregate Replacement Nur Liza Rahim 1,a, Shamshinar Salehuddin 1,b, Norlia Mohamad Ibrahim 1,c Roshazita Che Amat 1,d and Mohd Faizal Ab Jalil 2,e 1 School Of Environmental Engineering, Kompleks Pusat Pengajian Jejawi 3, University Malaysia Perlis, 02600 Arau, Perlis, Malaysia 2 Perlis Department of Environment, Tingkat 2, Bangunan KWSP, Jalan Bukit Lagi, 01000 Kangar, Perlis, Malaysia a nurliza@unimap.edu.my, b shamshinar@unimap.edu.my, c norlia@unimap.edu.my, d roshazita@unimap.edu.my, e faj@doe.gov.my Keywords: Plastic Waste, Recycle Material in Concrete, High Density Polyethylene (HDPE) Abstract. Rapid industrial development causes serious problem all over the world such as depletion of natural aggregates and creates enormous amount of waste material from construction and demolition activities. Quantities of polymer wastes also have been increased these recent years due to the boost in industrialization and the rapid improvement in the standard of living. In Malaysia, most of polymer wastes is abandoned and not recycled. This situation causes serious problems such as wastage of natural resources and environmental pollution. Polymer products such as synthetic fibers, plastics and rubber belong to petrochemical compound and not easily biodegradable even after a long period. One of the ways to reduce this problem is to utilize waste materials in the production of concrete. Use of these materials not only helps in getting them utilize in cement, sand, aggregate, concrete and other construction materials, it helps in reducing the cost of concrete manufacturing, but also has numerous indirect benefits such as reduction in land-fill cost, saving in energy and protecting the environment from possible pollution effects. An experimental research is made on the utilization of plastic waste, High Density Polyethylene (HDPE) as coarse aggregates in concrete with a percentage replacement of 10 %, 20 % and 30 %. The laboratory tests include slump test, compressive strength and water absorption were conducted in this research. The samples content 10 % of HDPE has better performance in term of strength. Introduction Production of solid waste in Malaysia is 1 kg/person per day. In average, approximately 26 million people in the country produce 26 million kilos of solid waste every single day. Plastic waste is the most common solid waste that generate in the country accounting for 7-12 percent by weight and 18-30 percent by volume of the total residential waste generated [1]. Increasing amount of byproducts which are used by municipal and industrial processes has become a major problem for the future. The main aim of environmental protection agencies and governments is to find ways to minimize the problems of disposal and health hazards of these by-products. Plastic has become an inseparable and integral of our lives. Plastic have been used in packaging, automotive and industrial application, medical delivery systems, artificial implants and other uses. With so large and verifying application, plastic contributes to increasing of volume in the solid waste stream. The waste plastic collected from solid wastes is contaminated, assorted mixture of a variety of plastics. This make their identification, segregation and purification become very hard to do. Advantages of using waste or recycled plastics are it will help on reducing the municipal solid wastes being land filled and it became an alternative to pressure-treated lumber that leaches toxic chemical into water. There is many type of waste and recycled plastic that been used in concrete mix. The most common waste or recycled plastic is virgin polypropylene, recycled plastic (melted process), recycled plastic (automobile shredded residue) and recycle plastic (shredded) [2]. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, www.ttp.net. (ID: 130.203.136.75, Pennsylvania State University, University Park, USA-19/02/16,22:54:16)
266 Key Engineering Materials III The productive use of waste materials is one of the ways to alleviate some of the problems of solid waste management. There are several benefits of using waste materials. It helps people save and sustain industrial resources for which it is impossible to renew, as well as having an effect on decreasing the environmental pollution. Because of the environmental and economic reasons, currently there has been a growing trend for the use of the industrial wastes or the by-products as supplementary materials or as an admixture in the production of composite cement and concrete. Using industrial by-products in concrete will lead us to have sustainable concrete design and a greener environment. Materials and Methods HDPE is a semi-crystalline thermoplastic polymer, which belongs to the polyolefin group and is manufactured through the polymerization of ethylene, with the help of catalysts. HDPE is one of the most important plastics [3]. In 2007, the global HDPE market reached a volume of more than 30 million tons, whereby the packaging and construction industries were particularly responsible for driving growth. HDPE is the polyethylene grade with the highest rigidity and the least amount of flexibility. It is well suited for a wide range of applications, like trash canisters, and a multitude of everyday household goods, such as small bottles and clothespins. This light-weight, non-toxic material is easily recyclable and serves increasingly as an alternative for less environmentally friendly substances. Commercial grade HDPE materials have subtle characteristic differences, caused by variations in polymerization technologies, catalyst residues, molecular structures of the polymer chain, and utilized additives. Understanding of these differences and use of the best characteristics makes optimization for specific applications possible. The main objective of this research is to utilize HDPE plastic as coarse aggregate for the production of concrete. The materials used in this study are cement, sand, HDPE, aggregates and water. All the material should be in good condition and quality before uniformly mix in the concrete mixture. The type of cement used in this research is Ordinary Portland Cement. The binder also called cement gel which sacrifices most part of the concrete s properties [4]. Natural coarse aggregate which is with maximum size of 20 mm and natural fine aggregate which is river sand with size 4.75 mm and below are used in this research. The aggregate gives volume to the concrete since this occupies maximum space in the total volume concrete. The aggregate firstly will run sieves analysis for grading it. The aggregate was air dried in room temperature to obtain saturated surface dry condition to ensure that water cement ratio is not affected. HDPE is defined by a density of greater or equal to 0.941 g/cm 3. HDPE has a low degree of branching and thus stronger intermolecular forces and tensile strength [5]. HDPE is a very common plastic. It is used in a variety of applications. Plastic toys, liquid containers, milk and cream bottles, detergent and cleaner bottle and thousands of consumer goods are made out of HDPE. Fig. 1 shows the bottles that have been cut then sieved to get the passing size between 4.75 mm to 20 mm. The dry materials such as cement, sand, HDPE and aggregate were mixed until the entire constituent mix uniformly. The water were gradually added and mixed. Each specimen is produced by using the same method, only the proportion of replacement materials were difference. The ratio 1:2:4 were used in concrete mixture which 1 for cement, 2 for sand and 4 for aggregate with the watercement ratio of 0.55 by mass. Concrete is produced with replacement of 0%, 10%, 20% and 30% of HDPE plastic as coarse aggregate. 45 of cubes concrete size 100 mm x 100 mm x 100 mm each were cast in accordance to relevant standard as shown in Fig. 2.
Advanced Materials Research Vol. 701 267 Figure 1 High Density Polyethylene (HDPE) Figure 2 Concrete De-moulding After 24 Hour Tests conducted on these concretes include slump test, compressive strength and water absorption. Tests were conducted at the age of 7, 14 and 28 days and the results at each testing age are reported as an average. The molds were coated with mineral oil to ensure that no water escaped during filling and to prevent adhesion of concrete. Concrete casting was accomplished in three layers of 33.33 mm each. Each layer was compacted using a vibrating table for 1 15 min until no air bubbles emerged from the surface of the concrete mold. The sample were dried for 24 hour, the sample was removed from the molds and immediately submerged in fresh clean water for curing in the specific time and ready for testing [6]. The flow of the methodology is shown in Fig. 3. Results and Discussion Concrete test is conducted to determine the characteristics and behavior of the concrete. The compressive strength is measured by breaking cube concrete specimen in a compression testing machine. In concrete, strength related to the stress required causing failure and it is defined as the maximum stress the concrete sample can withstand [7]. The compressive strength is calculated from the failure load divided by the cross-sectional area resisting the load. The data as shown in the Fig. 4 reveal that, at all ages the strength of control concrete were higher than the corresponding concrete containing HDPE plastic. The strength of concrete is decreasing linearly with the increasing of HDPE plastic volume in the concrete mixture. From the result, the control concrete (0% HDPE) has exceeded the target strength of 20 N/mm 2 at 14 days and still gains extra strength as it reaches age of 28 days. The compressive strength for samples content 10% of HDPE plastic is lower than the control but still acceptable because it reach the target strength of 20% at the end period of curing, same for the sample content 20% of HDPE. For the samples content 30% of HDPE, the development of their strength are same as 10% and 20% but it does not reach the target strength at age 28 days. The results of the slump test of concrete containing difference proportion of HDPE are shown in Table 1. Referring to the table below, the slump value is increase with the increasing of the HDPE ratio. That means the HDPE will reduce the workability of the concrete when replaced in higher percentage such as 30 % of aggregate weight. The values of slump are 10.0 mm, 12.7 mm, and 15.3 mm for 10 %, 20 %, and 30 % of HDPE, respectively. This result can be attributed to the fact that some particles are angular and others have non-uniform shapes resulting in less fluidity. In addition, the HDPE substituent that used in this research is in solid form, so the solid particles which fill up the voids in the concrete will affect the concrete mix slump.
268 Key Engineering Materials III Recognize Plastic Waste from High Density Polyethylene (HDPE) HDPE are cut/crashed into small pieces Sieving by using the sieve machine (4.75 mm to 20 mm) Mix design for 0%, 10%, 20 % and 30% of HDPE Compression test Optimized crushed HDPE content in concrete Figure 3 Procedure of making PLASCRETE Compressive Strength (MPa) 30 25 20 15 10 5 Compressive Strength VS Curing Period 0 7 Days 14 Days 28 Days 10 % of HDPE 18.964 22.706 26.617 20 % of HDPE 14.161 18.298 22.997 30 % of HDPE 10.835 14.037 18.244 Control 20.236 25.482 28.402 Figure 4 Graph Compressive Strength VS Curing Period Table 1 Result of Slump Test Percentage of HDPE 0% 10% 20% 30% Slump (mm) 10 12.7 15.3 18
Advanced Materials Research Vol. 701 269 The drop in compressive strength due to the addition of HDPE as aggregates may be attributed to lower bond between the cement paste and HDPE in concrete. The higher compressive strength means the good bond between materials in concrete. Less HDPE volume in concrete give good bond between materials in concrete than more HDPE. This is because HDPE has a smooth and shiny surface that is difficult to bind with other materials in concrete. This show that it is better to substitute the HDPE plastic substituent in a lower quantity to ensure the concrete can achieve higher strength. Conclusions HDPE aggregates can be used successfully to replace conventional aggregates in concrete. Laboratory testing showed that the 28-day compressive strength of concrete containing 10% and 20% by volume of aggregate ranged from 22.997 to 26.617 Mpa. The compressive strength of concrete containing HDPE aggregate is retained more or less in comparison with controlled concrete samples. However strength noticeably decreased when the HDPE proportion was more than 20%. The drop in compressive strength due to the addition of HDPE aggregates may be attributed to lower bond between the cement paste and HDPE aggregates and to the low strength of plastic. 20% of HDPE aggregate can be incorporated as coarse aggregate replacement in concrete without any long term detrimental effects and with acceptable strength development properties. References [1] Safan, Agarwal, Solid Wate Recycling, Malaysian Perspective. Frost and Sulivan Market Insight (2007). [2] Siddique. R. Waste Materials and By-Product in Concrete, Spinger (2008). [3] Mandelkern L., Crystallization of Polymers, McGraw Hill, New York (1964). [4] Wiley J. & Son, Concrete Manual (8th edition), New York, London, A Wiley-Interscience Publication (1981). [5] Harper, Charles A., Edward M. Petrie, Plastics Materials and Processes, John Wiley & Sons. (2003). [6] Jabatan Kerja Raya Malaysia, Standard Specification for Building Works. Jabatan Kerja Raya Malaysia. D1-D39 (2005). [7] Mehta P.K and Monteiro P.J.M, Concrete Microstructure, properties and Materials (2006).
Key Engineering Materials III 10.4028/www.scientific.net/AMR.701 Use of Plastic Waste (High Density Polyethylene) in Concrete Mixture as Aggregate Replacement 10.4028/www.scientific.net/AMR.701.265