Studies on the Improvement of Characteristics of Bitumen with Use of Waste Plastic

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1 Website: (SN , O 9001:2008 Certified Journal, Volume 3, Issue 3, March 2013) Studies on the Improvement of Characteristics of Bitumen with Use of Waste Plastic Sandhya Dixit 1, Prof. Deepak Rastogi 2 1 Student Scholar, ME Civil, Madhav Institute Of Technology And Science (MITS), Gwalior 2 Professor Department Of Civil Engineering, Madhav Institute Of Technology And Science (MITS), Gwalior Abstract In India plenty of Industrial waste is generated by industrial activity, such as that of factories, mills and mines. In addition to this industrial waste, municipal waste in the form of garbage containing nonbio degradable materials is also produced within the municipal limits. This is a major source of environmental pollution and its proper disposal in challenging problem in order to safeguard the environment for future generation. The use of discarded waste plastics in the road construction was one or the important steps taken in this direction. Use of suitable road waste material in the construction of roads in the country, will not only bring out significant saving on road material cost, but simultaneously shall help in tackling the problem of such waste material. India is far behind the target of road construction of National Highways, State Highways and village roads. The dream of connecting every village with a fair weather road in far distant. The use of plastic bottles, containers and packing strips is increasing day by day and disposal is a big problem. Since these products are non bio degradable, these are likely to remain in the environment for many years creating environmental problems and health hazards. This paper has been developed to discuss in detail as to how the municipal solid waste can be handled and used successfully in the construction of roads thus mitigating the environmental problems and economise the cost of construction of roads within the country. Keywords Bitumen modification with waste plastic, Improvement in characteristics of bitumen with use of waste plastic, Plastic waste in road construction, Study on use of plastic waste in road construction, Uses of plastic waste in road construction I. INTROUDUCTION The growth in various types of industries together with population growth has resulted in an enormous increase in production of various types of waste material world over. The creation and disposal of nonbiodegradable waste materials such as Plastics, Blast Furnace Slag, Fly ash, Steel Slag, Scrap Tyres etc. have been posing problems in the developed as well as developing countries. Plastic is everywhere in today s lifestyle. Use this nonbiodegradable product is growing rapidly and creating the problem of its disposal. Disposal of plastic waste, particularly plastic bags are a menace and has become a serious problem, especially in urban areas, in terms of its misuse its dumping in the dustbins, clogging of drains, reduced soil fertility and aesthetic problems etc. The phenomenal increase in the volume of vehicular traffic on our roads, including commercial vehicles combined with perpetual overloading of transport vehicles and significant variation in daily and seasonal temperature in various parts of the country calls for improved performance of the road pavements and consequently better quality of bitumen. Modified bitumen obtained through mixing of elastomeric as well as plastomeric substances possesses better quality than normal bitumen. Therefore, there is an urgent need of alternate use of waste in bituminous mix, to improve the properties of the binder offers, as such, very promising alternative. Use of plastic in road construction is not new. It is already in use as PVC or HDPE pipe mat crossings built by cabling together PVC (Polyvinyl chloride) or HDPE (High density polyethylene) pipes to form plastic mats. Recent studies in this direction have shown some hope in terms of using plastic waste in road construction, i.e. plastic roads. The life of Pavement surfacing using the waste plastic is expected to increase substantially in comparison the use of conventional bituminous mix. The laboratory studies conducted by some research institutes regarding utilization of waste plastic bags in bituminous mixes have proved that these enhance the properties of mix. Also the performance tests have proved that the fatigue life is doubled and resistance to rutting and water damages increases when plastic waste is used. Different process, viz. dry and wet process have been tried out for blending the waste plastic with aggregate and bitumen. In the dry process, waste plastic is added to aggregate heated uniformly at a temperature of c. The dry process gives a blend with better binding property, a larger surface area of aggregate is available for mixing. Aggregate coated with plastic waste and plain bitumen show zero stripping even after 72h. Other properties like soundness, moisture absorption and voids formation are also minimized and no pot hole formation is observed on roads processed in this way. 895

2 Website: (SN , O 9001:2008 Certified Journal, Volume 3, Issue 3, March 2013) In the wet process, shredded waste plastic is mixed with hot bitumen at a temperature c. with the help of powerful mechanical stirrers. The stabilizers are also added to the bitumen during heating. The mix is then laid on the road. In this process, mixing of higher percentages of is however, difficult because of the difference in viscosities of molten plastic waste and bitumen. Modifier Plastic bag fibers were used as a modifier in this study. The waste plastic bags were shredded into fibers of size 20mm x 3mm. The density, melting point and tensile strength of the fibers were g/cc, c. and 210 MP a respectively. Fig. 1 shows the plastic fibres. II. OBJECIVES OF THE STUDY The present study aimed at preparation of bitumen modified with waste plastic fibers and to find the variation of conventional properties. The major objectives of the study are as follows. To study the physical properties of neat bitumen and modified with plastic fibers obtained from waste plastic bags. To find out the optimum percentage of waste plastic bag fibers. To perform tests on bituminous mixes prepared using the optimum fibers content calculated. A Material III. EXPERIMENTAL PROGRAMME Bitumen 60/70 and 80/100 penetration grade bitumen were used for the present study. The physical properties of bitumen described as 73:1992 are given in Table I. Designation Penetration at 25 o c,100g, 5s, d mm Softening point. 0 c Ductility at 27 0 c cm Specific Gravity 27 0 c, g/cc Flash point, 0 c Table I Physical properties of 60/70 and 80/100 bitumen Test Result Permissible limits as per 73: /70 80/100 60/70 80/ Test Method 1203: : : : :1978 Fig. 1. Plastic Fibres Aggregates aggregates were tested for physical requirements, and test results are shown in the Table II. Table II Properties of coarse aggregates Properties Test Method MoRTH Specification Specific Gravity a) Coarse Agg. (20mm) b) Coarse Agg. (10 & 4.75mm) c) Fine Agg. Aggregate Impact value Los Angeles Abrasion value Result (IV) Max 30% % 2386 (IV) Max 30% % Water Absorption 2386 (III) Max 2% 0.6 % Combined flakiness 2386 (I) Max 30% 24 % and Elongation Index B Preparation of Modified Binders About 350g. of bitumen was heated to c. to a fluid condition. The mixing was performed in the laboratory with a mechanical stirrer at a frequency of 1550 rpm. After the mixing temperature was reached, 0.1 percent fiber by weight of binder was added slowly in order to avoid agglomeration of the material. The typical time used for preparation of the blend was 1 hour. After the blend was prepared, it was allowed to settle for 1 hour. Similar procedure was adopted for other proportion of mixes. The percentage of modifier varied from 0.1% to 0.9%. 896

3 Website: (SN , O 9001:2008 Certified Journal, Volume 3, Issue 3, March 2013) C Test results and discussions Different percentages of modifier (waste plastic fibers) added to 60/70 and 80/100 grades of bitumen affected the physical properties of the binder in terms of penetration, softening point, ductility and Specific Gravity which is presented in Table III. Bituminous Binder + % Modifier 60/70 Bitumen 60/ % 60/ % 60/ % 60/ % 60/ % 60/ % 60/ % 60/ % 60/ % 80/100 Bitumen 80/ % 80/ % 80/ % 80/ % 80/ % 80/ % 80/ % 80/ % 80/ % Penetration (dmm) Penetration Test Results Table III Softening Point ( 0 c) Ductility (cm) Specific gravity The Penetration values are decreasing significantly when 60/70 and 80/100 bitumen are mixed with the modifier and this variation is much more in 80/100 modified bitumen. When 0.6 percent of modifier is added to 80/100 grade, the penetration decreases, and this is equal to the 60/70 grade bitumen. Thus there is a significant decrease in penetration values for modified blends, indication the improvement in their temperature susceptibility resistant characteristics. Softening point test results The softening point increase in percentage of modifiers and this is so because the bitumen becomes increasingly viscous. Softening point for 60/70 bitumen increase to more than 55 0 c by addition of 0.7, 0.8 and 0.9 percent fibers. Therefore 0.6 percent should be the upper limit for 60/70 bitumen. The results show that 80/100 and 60/70 bitumen modified with lower percentage of plastic fibers can be used in road construction satisfactorily, but with higher modification i.e. 0.7 percent to 0.9 percent should not be used in road construction, but may be used as a roofing material. Ductility test results The binders possessing high ductility have good cementing qualities in the road surface and adhere well to aggregates. It may be seen that he ductility values for 80/100 and 60/70 bitumen modified with 0.7, 0.8 percent and 0.9 percent modifiers are very low compared to original binders. The ductility values decrease with increase in percentage of modifier, but the rate of decrease is less when added beyond 0.5 percent. The ductility value less than 50cm (80/100 modified with 0.5 to 0.9 percent fibres and 60/70 modified with 0.4 to 0.9 percent fibres) should not be used in road constructions, but may be used as crack and joint filler materials. Specific gravity test results Higher Penetration grade bitumen and cut back bitumen have lower range specific gravity values. In case the bitumen contains mineral impurity, the specific gravity will be higher. It may be observed that he specific gravity values increase significantly by modifying the bitumen. The values for neat 60/70 and 80/100 bitumen are and respectively which increases to and after 0.9% modification. The effective utilization of the waste plastic bags for the preparation of modified bitumen will result in substantial increase in the scrap value for this otherwise undesirable waste material. These waste plastic bags will not, therefore be thrown out along with the garbage instead they will get collected and sold by the consumers themselves or other agencies, due to the attractive scrap value. Polymer coated aggregates blended with bitumen also show higher Marshall value and better stripping values, thereby indicating that the mix is more suited for road laying. The durability of the roads laid out with shredded plastic waste is much more compared with these asphalted with the ordinary mix. Roads laid with plastic waste mix are found to be better than the conventional ones. The binding property of plastic makes the road last longer besides, giving added strength to withstand more loads also. Rainwater will not seep through because of the plastic in the tar which will result in lesser road repairs. The cost of plastic road construction may be slightly higher compared to the conventional method. However, this should not deter the adoption of the technology as the benefits are much higher than the cost. Considering the improvements as outlined before, the salient features of the waste plasticbitumen mix road may be categorized as under: 897

4 Website: (SN , O 9001:2008 Certified Journal, Volume 3, Issue 3, March 2013) Higher strength Resistances towards water stagnation, i.e. no potholes are formed. Less bleeding during the summer Higher marshal stability Burning of plastic waste could be avoided It does not involve any extra machinery Lower maintenance costs Reduction in consumption of bituminous mix and No toxic gas emissions Plastic roads would be a boon for India s hot and extremely humid climate where temperatures frequently cross 50 0 c and torrential rains create havoc, leaving most of the roads with big potholes. This technology would help to produce better roads with longer service life and would also be economical as there would be considerable savings in the ever increasing cost of bitumen. IV. ROAD CONSTRUCTION SCENARIO Process of construction of flexible pavement: Process 1: The roads were laid using both mini hot mix plant and central mixing plant. The aggregate mix prepared as per IRC specification, was heated in the cylindrical drum to degrees. It was then transferred to the pudding compartment where the plastic waste size between 1.18 mm and 4.36 mm was added. As the temperature of the aggregate were around c and the softening temperature of plastic waste using quantitatively was around c the plastic waste got softened and got coated over the aggregate within 30 to 45 seconds. Immediately the hot bitumen 60/70 grade was added and mixed in the pudding chamber. The bitumen got coated over the aggregates. As the plastics and the bitumen were in the liquid state they got mixed. the mixture was transferred to the road and it was spread and compacted using 8 ton roller. Process 2: For the construction of long distance roads it is very important that the plastics coated aggregate should be tried with central mixing plant. This was successfully tried at Salem, Tanjore, Mumbai, Trisool and Madurai. Unising a mechanical device the plastics waste was mixed with the aggregate at the cylindrical drum before the addition of bitumen. This was done at Trisool, Chennai in the presence of DRDA Engineers. The material collected at the tipper was uniform and had a temperature of 140 o C. this was transported to the spot and the road was laid using paver and 8 ton roller. The spreading was good and the laying was easy. 898 During the process the materials got mixed at; (1) at the tipper (2) During the transfer form tipper to paver and (3) by the pavers during spreading for road laying. This ensures better distribution of plastics and help better binding. V. MARSHALL TEST RESULTS ON BITUMINOUS MIXES. The Marshall stability is a measure of structural strength of a bituminous mix. Higher the stability of the mix, greater will be the strength of surfacing. From the values given in table IV, it can be seen that the Marshall stability increases from 920 Kg to 1000 Kg when the bitumen content is increased from 5 percent to 5.5 % and then it decreases to a value of 890 Kg. at 6% bitumen content. The increase in stability is due to the improvements in the physical properties of bitumen and the coating of the aggregates with the plastic fibres. The Optimum Binder Content (OBC) was found to be 5.4%, Marshall test was also conducted on bituminous mixes prepared with 0% fibre content. Here also, the Marshall stability increased with an increase in the bitumen content. At 5.4% bitumen content and 0.5% fibre, the value of Marshall Stability is 995 Kg. whereas it is 980 Kg. for an unmodified mix. Thus a higher value is obtained for modified mix at compared to an unmodified one. G t Table IV Marshall Test Results on Modified Bituminous Mixes Properties Sample1 Sample 2 Sample 3 Sample 4 Sample 5 Bitumen Content (%) Fibre Content (%) Thickness (mm) 68.5 Weight in air (g) Weight in water (g) Marshall Stability (Kg) Flow Value (mm) 2.8 Theoretical Specific Gravity, G t (g/cc) Bulk Specific Gravity G b (g/cc) VMA (%) VFB (%) Air Voids Vv (%)

5 Website: (SN , O 9001:2008 Certified Journal, Volume 3, Issue 3, March 2013) VI. ECONOMIC ANALYSES A huge quantity of plastic waste have been used as modifying agents. However, the high cost of these polymers compared to bitumen means that the amount of polymer needed to improve pavement performance should be as small as possible. This major restriction could be avoided by using waste materials like plastics. From an environmental and economic standpoint, the use of waste plastic fiberes as a bitumenmodifying agent may contribute to solving a waste disposal problem and to improving the quality of road pavements. VII. CONCLUSIONS The following conclusions are drawn based on the results obtained tin the present study The properties of bitumen such as penetration softening point improved with the addition of the waste fiber. There is a significant decrease in penetration values for modified blends, indicating the improvement in their temperature susceptibility resistant characteristics. The softening point increase with increase in percentage of fibre and this is so because the bitumen becomes increasingly viscous. The results show that bitumen modified with lower percentage of fibres can be used in road construction satisfactorily, but higher percentage of fibers i.e. more than 0.7 % may be used as a roofing material. The ductility value decreases with increase in percentage of modifier, but the rate of decrease is less when fiber is added beyond 0.5 percent. The ductility value less than 50cm should not be used in road constructions, but may be used as crack and joint filler materials. The optimum dose of the fibre was found to be 0.6 percent on the basis of performance grade 70. From the Marshall test results, it is concluded that the marshall stability value increases with an increase in bitumen content from 5% to 5.5% then it decreases. The optimum binder content was found to be 5.4 %.Also higher value of Marshall stability was found for a modified mix as compared to an unmodified one. From an environmental and economic standpoint, the use of waste plastic fibres, as a bitumen modifying agent may contribute to solving a waste disposal problem and to improving the quality of road pavements. The properties of bitumen can be enhanced by adding small amounts of the modifier. Therefore modified bituminous materials can bring real benefits to highway construction, maintenance, in terms of better and longer lasting roads, and savings in total road life costing. REFERENCES [1 ] IRC:SP: , Guidelines on use Polymer and Rubber Modified Bitumen in Road Construction, Indian Road Congress, New Delhi. [2 ] : , Polymer and Rubber Modified Bitumen Specification, Bureau of Indian Standards, New Delhi. [3 ] Jew, P. and Woodhams, R. T.1986, PE Modified Bitumens for Paving Applications, Proceedings of the Association of Asphalt Paving Technologists, Vol. 55, pp [4 ] Lenoble, C. and Nahas, N.C. 1994, Dynamic Rheology and Hot Mix Performance of PMA, Journal of Association of Asphalt Paving Technologists, Vol. 63, pp [5 ] Mecado, E.A., Martin, A., Spiegelmen, C. and Glover, C.J. 2005, Factors Affecting Binder Properties between Production and Construction, Journal of Materials in Civil Engineering, ASCE, Vol. 17, pp [6 ] Murphy M., Mahony M.O., Lycett C. and Jamieson I 2001, Recycled Polymers for Use as Bitumen Modifiers, Journal of Material in Civil Engineering, ASCE, Vol. 13, pp [7 ] Panda M. and Mazumdar M. 1999, Engineering Properties of EVA Modified Bitumen Binder for Paving Mixes, Journal of Materials in Civil Engineering, ASCE, Vol. 11, pp [8 ] Qi, X., Sebaaly, P.E. and Epps, J.A. 1995, Evaluation of Polymer Modified Asphalt Concrete Mixes, Journal of Materials in Civil Engineering, ASCE, Vol. 7, pp [9 ] Read J. and Whiteoak D., The shell Bitumen Handbook, Fifth Edition, Thomas Telford, pp [10 ] Standard Data Book for Analysis of Rates for Roads 2004, Indian Roads Congress, New Delhi. [11 ] Indicative operational Guidelines on construction Polymer Bitumen Road Central Pollution Control Board, Ministry of Environment and Forests. [12 ] Highway Engineering by S K Khanna, CEg Justo, New Chand & Bros., Roorkee (U.A.), Eighth edition, [13 ] Field studies on Flexible Pavement Overlaid using Waste Plastic Coated Aggregated, National Transport Planning and Research Centre, Trivandrum: June [14 ] Manual for the construction and supervision of Bituminous works, published by IRC on behalf of the Government of India, Ministry of Road Transport and Highways, New Delhi, [15 ] Specification for Road and Bridge works, published by IRC, New Delhi, [16 ] Google search climatic condition Test sites position in Earth Test sites. [17 ] Nabil Mustafa, Plastics Waste Management Canadian Plastics Institute, Toronto, Ontario, Canada, Marcel Dekker, Inc [18 ] S K Garg, Environmental Engineering, Vol. II Khanna Publishers,

6 Website: (SN , O 9001:2008 Certified Journal, Volume 3, Issue 3, March 2013) [19 ] Dr. R Vasudevan Utilization of waste plastics for flexible pavement, Indian Highways (Indian Road Congress), (July 2006). [20 ] Sri Ram Institute for Industrial Research, Plastics Processing and Environmental Aspects, New Delhi 7. [21 ] Pavan Kumar & Rashi Garg, Laboratory studies on waste plastic fiber modified bitumen Highway Research Journal, (JanJune 2010) Vol. 3, No