VOL. 8, NO. 4, APRIL 2013 ISSN 1819-6608 ARPN Journal of Engineering and Applied Sciences ©2006-2013 Asian Research Publishing Network (ARPN). All rights reserved. www.arpnjournals.com 290 EFFECT OF POLYTHENE MODIFIED BITUMEN ON PROPERTIES OF HOT MIX ASPHALT Mutiu Akinpelu 1 , Bamidele I. O. Dahunsi 1 , Oladipupo Olafusi 1 , Olufemi Awogboro 1 and Adedeji Quadri 2 1 University of Ibadan, Ibadan, Nigeria 2 Nigerian Building and Road Research Institute, Otta, Nigeria E-Mail: madelodun@yahoo.com ABSTRACT The continuous increase in road traffic couple with an insufficient degree of maintenance due to shortage of funds has caused an accelerated and continuous deterioration of the road network in Nigeria. To alleviate this process, several types of measures are reported to be effective, for instance, securing funds for maintenance, improved roadway design, use of better quality of materials and the use of more effective construction methods. Improving the quality of materials used in road construction had been shown to improve road service performance in the wake of the increase usage. Practical experience over the last four decades have shown that the modification of the bituminous binder with polymer additives offers several benefits in asphalt concrete and has been tested in a number of countries around the World. The use of polythene materials for pure water sachet in the country has received a great boost due to its abundant supply and high resistance to insects, fungi, animals, as well as molds, mildew, rot and many chemicals. However the disposal of the waste polythene materials in large quantities has been a problem all over the country. This study was therefore designed to investigate the effect of polythene as contained in pure water sachet in the asphalt concrete properties. Polythene was added in grinded state as binder modifier. It was introduced to the mixture by melting it in the bitumen used in preparing the asphalt concrete mix. Marshall Mix design method was used, first to determine the optimum bitumen binder content and then further to test the modified mixture properties. In total, 17 samples were prepared (10 samples were used to determine the binder content and the remaining samples were used to investigate the effect of modifying the asphalt mixtures). The optimum asphalt content was 7.0%. Six proportions of polyethylene by weight of the optimum binder content were selected to be tested (2.5, 5.0, 7.5, 10, 12.5 and 15%). The properties tested include bulk density, stability and flow of the concrete mix. The obtained optimum proportion of the modifier is 12.5% by the weight of the optimum bitumen content. It is found to increase the stability, reduce the density and slightly reduce the flow of asphalt concrete specimen. Findings from this study suggest that polythene modifier offers better engineering properties and its usage as bitumen modifier could serve as a means of managing the waste menace. Keywords: waste polythene, bituminous binder, asphalt mixture, optimum binder content, bulk density, stability, flow. 1. INTRODUCTION The use of polyethylene materials for pure water sachet in the country has received a great boost due to its abundant supply and high resistance to insects, fungi, animals, as well as molds, mildew, rot and many chemicals. However the disposal of the waste polythene materials in large quantities has been a problem all over the country. These polythene break down in fire and form hazardous smoke, and toxic fumes or ash, typically containing hydrogen cyanide. Incinerating polythene to recover the high energy used to create them is usually expensive, so most of this polythene reaches the garbage dumps, decaying very slowly. Some recycling is done on them, usually creating pellets for reuse in the industry, but this is done at a much lower scale. The mixing up of these waste pure water sachets with other bio-degradable organic waste materials in the garbage of the urban areas is another problem of great concern. As a result, more research need to be focused towards a better way of managing these waste materials, so as to eliminate the problems usually encountered in the present disposal method. In case it is possible to find useful application for the waste polythene materials, there will be substantial scrap value for this waste product and therefore they will be collected and sold by interested persons, instead of being littered or thrown out in the waste bins or into the road side drains. Asphalt concrete is a composite material commonly used in construction projects such as road surfaces, airports and parking lots. It consists of bitumen, used as a binder and mineral aggregate mixed together, then lay down in layers and compacted [1]. The amount of aggregate in asphalt concrete mixtures is generally 90 to 95 percent by weight and 75 to 85 percent by volume and they are primarily responsible for the load supporting capacity of a pavement. The binder, usually penetration grade bitumen is a viscoelastic material with suitable mechanical and rheological properties for waterproofing and protective coverings for roofs and roads, because of its good adhesion properties to aggregates [2, 3, 4, 5]. Ordinarily, the binder constitutes 5 to 10 percent by weight of the concrete mixture and different grades like 30/40, 60/70 and 80/ 100 are available on the basis of their penetration values. The performance of the road pavement is strongly influenced by the properties of the bituminous binder as bitumen is the continuous phase and the only deformable component [6]. However, Roads produced with bitumen binders are subjected to many harsh environmental