National Institute of Construction Management and Research, Pune-45.

Report on Use of Plastic in Tar Road Construction.

JANAK D. GANDHI-251042. (ACM-SEC-I). PRASAD BOROLE-251021. (ACM-SEC-I).

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Contents
Introduction. Background of Invention.

Salient features of the polymer-wastebitumen mix Road.

Methodology. Characteristics of various materials. Various tests performed on the material. Field Study. Conclusion. Inferences.

1.0 Introduction Salem, an industrial town in TamilNadu, is the first to lay a plastic-tar road in the country. The city Mayor R Suresh Kumar announced recently that the plastic-tar technology would be adopted widely by the Corporation to mitigate the menace of plastic wastes. The Corporation had decided to adopt the polymer-tar technology developed by Dr R Vasudevan, Chemistry Professor, Thyagarajar College of Engineering, Madurai. The technology is such that the plastic waste management finds a ready solution. The bitumen and gravel mix used for laying roads is combined with flakes or granules made from domestic plastic wastes like carry bags, teacups and variety of domestic plastics, a versatile material and a friend to common man become a problem to the environment after its use. Disposal of a variety of plastic wastes in an eco friendly way is the thrust area of todays research. The authors innovative techniques to use the waste plastics and the tyre waste for the construction of flexible pavement, for making pathway blocks, and for making laminated roofing sheets form a good solution for the waste disposal problem of both plastic waste and municipal solid waste. 1.1 Background of the Invention

Polymers are used as additives in asphalts and bitumen for processing in roads or industry, either for improving their use characteristics by modifying the hot rheological properties, or for improving their physicochemical properties (cold brittleness, toughness, flexibility, stability, thermal susceptibility, mechanical resistance to shocks, vibrations, abrasions etc.) In general, the polymers used are thermoplastics (olefin copolymers or polymers), rubbers and in particular thermoplastic elastomers (multiblock copolymers of diolefins and styrene), or to a lesser extent, thermosetting resins (polyurethanes, epoxy resin, phenol formaldehyde). According to the prior art, these polymers can be used alone or in mixed form. For example, it has been proposed to recycle as additives for bitumen, manufacturing waste materials (waxes of polyethylene, atactic polypropylene, and polyvinyl alcohol, powdered vulcanized rubber waste, etc.) or plastic waste obtained from domestic refuse and more particularly plastic packs. In the latter case, the mixtures of polymers essentially contain polyolefins, polyvinyl chloride, and polystyrene and polyethylene terephthalate.

Polymers are added in small quantities (generally 2 to 10% by weight) to bitumen, in the form of "simple" mixtures involving no chemical reaction or interaction between the constituents, or in the form of "complex" mixtures involving a chemical reaction or interaction between the polymer and certain constituents of the bitumen (asphaltenes, malthenes, resins, etc.), optionally in the presence of a third constituent (catalyst or reagent). Usually the polymers are dispersed in the solid or melted state in previously heated bitumen excess and, after stirring; the mixtures are used as they are in the melted state, or cooled to the solid state, and are optionally ground or granulated. Certain processes for the production of a mixture in the melted state of olefin polymeradded road-making bitumen, recommend the addition of at least 5 to 30% by weight of mineral particles, which accelerate the dissolving of the polymer in the bitumen (cf. e.g. U.S. Pat. No. 3,336,252, published Aug. 15, 1967). U.S. Pat. No. 4,028,293 published on Jun. 7, 1977 claims the production of a bitumencontaining material, which is more particularly used in the road-making and building fields and which is obtained by the high temperature reaction (at least at 180 C.) of a mineral compound such as sand or gravel with a polymer or a mixture of polymers obtained from domestic or household refuse. The resulting mixture is then added hot to the bitumen and cooled. A major disadvantage of this method is the final cost of the operation, which involves a high temperature preheating of a large amount of mineral material prior to the addition of the polymer or polymers. 1.2 Salient features of the polymer-waste-bitumen mix Road: Road strength is twice stronger than normal roads. Resistance towards water stagnation i.e. no potholes are formed. Less bleeding during summer. Burning of plastics waste could be avoided. It doesnt involve any extra machinery. It doesnt increase cost of road construction; and It helps to reduce the consumption of bituminous mix vis--vis reduce cost.

2.0 METHODOLOGY

The plastic waste (bags, cups, Thermo Cole) made out of PE, PP, & PS are separated, cleaned if needed and shredded to small pieces (passing through 4.35mm sieve) The aggregate (granite) is heated to 170oC in the Mini hot Mix Plant and the shredded plastic waste is added, it gets softened and coated over the aggregate. Immediately the hot Bitumen (1600C) is added and mixed well. As the polymer and the bitumen are is the molten state (liquid state) they get mixed and the blend is formed at surface of the aggregate. The mixture is transferred to the road and the road is laid. This technique is extended to central

mixing plant too.

PROCEDURE OF MIX Plastic waste cleaning process (1) Shredding required size waste (2) Aggregate heated to 1700 deg (3) Aggregate transferred to puddling chamber (4) Waste plastic mixed with the hot bitumen (5) Bitumen added (6) Aggregate-plastics-bitumen mix (7)

Figure: A block diagram of a manufacturing aggregate-plastic-bitumen mix

Plastic waste cleaning process (1)

shredding required size waste (2)

Aggregate heated to 1700 c (3)

Aggregate transferred to puddling chamber (4)

Waste plastic mixed with hot aggregate (5)

Bitumen added puddling chamber (6)

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Bitumen + aggregate + plastic mix (7) 3.0Characteristics of Materials 3.1 Characteristics of Waste Plastics 3.1.1 Thermal study Thermal behaviors of the polymers namely PE, PP &PS is shown Table 1. Table 1 Thermal Behavior of Polymers Polym er PE PP PS Water (solubilit y) NIL NIL NIL EPT Softeni ng Temp (0C) 100120 140160 110140 Products reported NO NO NO Decom Produc positio ts n Temp reporte (0C) d 270CH4C2H 350 270300 300350
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NIL NIL NIL

Ignition temp range in (0C) >700 >700 >700

Produc ts reporte d CO2 CO2 CO2

C2H6 C6H6

3.2 Characteristics of Plastic Coated Aggregate (Used For Flexible Pavement) Moisture Absorption and Void Measurement For the flexible pavement, hot stone aggregate (1700c) is mixed with hot bitumen (1600c) and the mix is used for road laying. The aggregate is chosen on the basis of its strength, porosity and moisture absorption capacity as per IS coding. The bitumen is chosen on the basis of its binding property, Penetration value and viscoelastic property. The aggregate, when coated with plastics improved its quality with respect to voids, moisture absorption and

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soundness. The coating of plastic decreases the porosity and helps to improve the quality of the aggregate and its performance in the flexible pavement. It is to be noted here that stones with < 2% porosity only allowed by the specification. 3.2.1 Binding property The molten plastics waste exhibits good binding property. Various raw materials like granite stone, ceramics etc . were coated with plastics and then molded into a stable product. On cooling it was tested for compression and bending strengths. TABLE 2 Binding Properties Percentage of plastics coating over aggregate 10 20 25 30 Compression Strength (Tonnes/cm2) 250 270 290 320 325 335 350 390 Bending Strength (Kg/cm2)

The increase in the values of the compression strength and bending strength shows that the plastics can be used as a binder. 3.3 Characteristics of Polymer Modified Bitumen An alternate use of plastic waste is also under study where plastics is mixed with bitumen and used for preparing the mix. The mix was used to study the basic properties of bitumen like softening point, penetration point and ductility. The penetration value was decreased to a very low value and similarly the ductility. More than 3% addition of waste plastics to the bitumen results in a hard polymer modified bitumen with very poor viscoelastic property (The minimum values for a suitable bitumen P.V = 80; Ductility = 50).

Table 3 Properties of Polymer Modified Bitumen % of plastics 1% Ductility (cm) 64 Penetration (mm) 95 Softening point (0C) 54

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2% 55 90 50 3% 20 80 50 5% 11 55 72 10% 7 NIL 75 On comparison it may be inferred that the use of higher percentage of plastics in polymer modified bitumen is not favorable (Table 4). 4.0 Tests on Aggregate 4.1 Soundness Test Soundness test is intended to study the resistance of aggregate to weathering action. The weight loss is attributed to the poor quality of the aggregate. The plastic coated aggregate, did not show any weight loss, thus conforming the improvement in the quality of the aggregate. 4.2 Aggregate Impact Value A study on the effect of plastic coating was extended to study on the aggregate impact value. Aggregate was coated with 1% & 2% plastics by weight and the plastic coated aggregate was Submitted to Aggregate Impact Value test and the values were compared with values for non coated aggregate. Table 4 Aggregate Impact value Percentage of plastics Aggregate Impact value Nil 25.4 1% 21.20 2% 18.50 It is clearly observed that the coating of plastics improves Aggregate Impact Value. Coating of plastics over the stone aggregate improves the quality of the aggregate. Moreover a poor quality of aggregate can be made useful by coating with polymers. (Table 3). This in turn helps to improve the quality of flexible pavement. 4.3 Los Angels Abrasion Test The repeated movement of the vehicle with iron wheeled or rubber tire will produce some wear and tear over the surface of the pavement. This wear and tear percentage of an aggregate is determined with the help of Los Angeles abrasion study. Under this study the percentage of wear and tear values of the plastic coated aggregate is found to be in decreasing order with respect to the percentage of

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plastics (E.g. 37% without plastic, 32% with 1% plastic and 29% with 2% plastic). When the Los Angeles abrasion value of plain aggregate value is compared with the Plastic coated aggregate the values are less for polymer coated aggregate. 5.0 Utilization of Waste Polymers for Flexible Pavement and Easy Disposal of Waste Polymers 5.1 Study on Crumb Rubber Modified Bitumen The waste tires are made into powder by grinding into some special type of grinders. The powder is collected and it is used for modification of bitumen. The bitumen is heated to 100-120oc and the powdered crumb rubber is added to the bitumen and stirred well with help of mechanical stirrer. The mix is stirred at the speed of 3000 RPM to get a homogenous mixture. The stirring is carried out for 2- 3 hours. The crumb rubber blended bitumen is subjected to different tests like penetration point, ductility, softening point. Here we have taken 80/100 bitumen and it is modified with different percentage of crumb rubber powders starting from 1% to 5%. The results of the test are given in Table 5. Table 5 Data on Crumb Rubber Modified Bitumen % of crumb rubber 1% 2% 35 5% 5.2 Field Study % plastics 5 5 5 5 Ductility values (cm) 75 72 70 61 Softening point (deg) 53 54 56 58 Penetration at 250C (mm) 90 88 85 70

More than 1500kms length of Plastic tar road was laid by Tamil Nadu government during 2004-2006. Test road were laid at Mumbai, Pondicheery and Trivandrum. These roads are functioning well without pothole, raveling and rutting. The process requires only 30 seconds for mixing 10% of plastics. The plastic available in the near by area can be used. 5.3 Testing of the Roads As per our discussion above the load withstanding capacity of the road is increased by a large amount. This is proved by conducting various tests on the built plastic tar roads at different places at different times. This test has been carried out with the

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help of National Transport Planning and Research Centre, Trivandrum. The tests show very good results some of the tests are listed below. i) To measure the roughness of the pavement surface. ii) To measure the resistance offered by the pavement surface against skidding of vehicles. iii) To measure the pavement macro texture for the geometrical deposition. iv) To assess the structural evaluation of flexible pavement for the strength of the pavement. v)To Measure the Field Density of the road. vi)To study the Gradation of the laid road. vii) To carry out different tests on recovered bitumen. viii) Examine the condition of the road (cracks, raveling, potholes, rutting, and corrugation edge Break) 6.0 Economy of the Process and the Plastic Waste Available This dry process helps to use good quantity of plastic waste in road construction. A model calculation is given in Table 6. Table 6 Economics of the process Size of the Bitumen Plastics Bitumen Cost reduced road needed needed saved 1km x 3.75m 9 tones 1 tones 1 tones Rs 15,000 A model is being worked using Tirunelveli, a town in TamilNadu. The plastics waste collected is around 650 tones/ annum. The roads available are approximately 400km and their annual requirement of plastic waste to lay plastic road is more than 600 tons. So the total waste generated could be used for road laying. The life of the road is increased and hence the maintenance expenditure is reduced. 6.1 Economics of Road Construction Laying of bitumen road Indian Roads Congress (IRC) Specifications There are different types of bitumen roads. They are, Dense Bituminous Macadam, Bituminous Macadam. These roads differ in 3-ways i.e.
1.

Composition of the aggregate; 2. Type of bitumen used; 3. Thickness of layer.

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Bitumen is a useful binder for road construction. Different grades of bitumen like 30/40, 60/70, and 80/100 are available on the basis of their penetration values and these grades can be used as IRC Specifications. Waste plastics (10% in place of bitumen) can be used for these different types of bitumen roads. The technology of road laying is very much the same as prescribed by the Indian Roads Congress (Section 500, IV revision) Specifications. A detailed description of the material required for laying of Semi Dense Bituminous Concrete (SDBC) 25 mm road (on existing road) is described below: Materials Aggregate (6.7mm) For 1000Mx3.75M (25mm) Road needed Shredded Plastics Required Bitumen replaced (saved) by 10% Plastics Actual Bitumen Required Aggregate (11.2mm) Aggregate (6.7mm) Aggregate Dust 11.250 tons (60/70 grade) bitumen 10% by weight 1.125 tons 10.125 tons 70.875 Cu.M 43.125 Cu.M 23.625 Cu.M

Cost Total cost including material as mentioned above labour charge etc is approx.5.00lakh. The cost may be different from place to place and have to be calculated accordingly. The cost break-up is given below Collection of littered plastics Cost of shredder and other equipment Laying of road with material, labour etc. Total Rs. 0.50 lakh Rs. 0.50 lakh Rs. 4.00 lakh Rs. 5.00 lakh

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7.0 Results and Discussion Table 7 Summary of Results Road Year laid Car parking road Canteen road Mens hostel road Vilachery road Vandiyur road Bitumen road Jan 2007 2004 2005 2005 2003 2003 Average Unevenness Daily Traffic 95 280 180 1000 600 1000 (mm/km) 3200 3000 3010 3250 3100 4700 Skid number 50 55 59 50 66 55 Texture Depth (mm) 0.53 0.55 0.56 0.50 0.47 0.90 Rebound Deflection (mm) 0.70 0.75 0.61 0.70 0.62 1.55

From the skid resistance studies of the five stretches it has been proved that the entire road was having good skid resistance values. the other two outside roads have good texture values. From the surface texture From the deflection studies studies of the five stretches it has been proved that the roads inside the campus and of the five stretches it has been proved that all the stretches are reasonably strong. From the bump integrator studies of the five stretches it has been proved that the unevenness index value of these three road sections are nearly to 3000 mm/km, which indicates a good surface evenness. 8.0 Case Studies Case Study 1 Bitumen Road with Plastics Waste A Successful Experiment in Mumbai [1] Plant at Worli and to use the mixed aggregate for the construction/repair work of Bitumen Road. Accordingly the trial was organized on 6th and 7th December, 2004, waste plastics replaced about 7-8% by weight of bitumen (For new road, this goes up to 15%.). Stripping test conducted after the mixing operation proved that the adhesion of the stone plastics waste bitumen aggregate was good.1st Road Laying/Repairing Place was at New Prabhadevi Road (G-S WARD) 2nd Road Laying/Repairing Place was Opp. Poonam Park, Parsee Lane, Lal Baugh area (F-S Ward). It was observed that Plastics Waste could be successfully mixed with stones

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and bitumen at the high speed asphalt plant and the condition of the bitumen road, when laid properly, was good. Cost of waste plastics was around Rs. 6 per kg vis-vis cost of bitumen being around Rs. 14 per kg. Hence there was a saving in cost of tar road construction. Condition of the road, inspected periodically, was found to be good. Proposal has now been made to MCGM to adopt this technology for constructing bitumen roads in the Mumbai Municipal area. After successful demonstration of the tar road construction where the addition of plastics waste was by manual method, the Brihanmumbai Municipal Corporation (BMC) has now invited ICPE for a large-scale trial using mechanical dosing device for mixing plastics waste with an aggregate at their asphalt plant This asphalt mixture will be used for laying longer stretches of bitumen roads across Mumbai

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Case Study 2 Plastic Bitumen roads in Tamilnadu [2, 4] Salem town shows the way to handle plastic waste Salem, an industrial town in TamilNadu, is the first to lay a plastic-tar road in the country. The city Mayor R. Suresh Kumar announced recently that the plastic-tar technology would be adopted widely by the Corporation to mitigate the menace of plastic wastes. Speaking at the inaugural function of the laying of a 350-metre road on experimental basis using plastic tar technology here, the Mayor said the problem of plastic wastes management posed a major challenge to the City Managers. Hence the Corporation had decided to adopt the polymer-tar technology developed by Dr. R. Vasudevan, Chemistry Professor, Thyagarajar College of Engineering, Madurai. The technology is such that the plastic waste management finds a ready solution. The bitumen and gravel mix used for laying roads is combined with flakes or granules made from domestic plastic wastes like carry bags, teacups and variety of domestic plastics. Public can sell their domestic plastic wastes instead of discarding them into the dust-bin. The Salem Manufacturers Association has shown keen interest in recycling domestic wastes and the Salem Exenora club has already taken steps to promote the concept, the Mayor said. Speaking about his technology, Dr. R. Vasudevan said the bitumen mixed with plastic flakes made from domestic wastes displays better hardness, better resistance to water penetration and hence lasts longer. Domestic wastes falling into categories such as polyethylene, polypropylene and polystyrene can be converted into flakes or granules and be mixed with the aggregate. Alternatively the plastic can be mixed with heated tar and later mixed with the gravel. Polyethylene can be used up to 5 per cent and polystyrene 20 per cent and so on. This project is a combined effort of the Salem Municipal Corporation, Corporators, the Exenora Club, an NGO and the plastic manufacturers. The Kovilpatti Municipality, near Madurai, too has adopted the technology and expressed satisfaction. There is a lesson for Municipal Corporations of all the major cities like Chennai, Bangalore, Delhi and Mumbai that are generating thousands of tonnes of garbage every day.

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TAMBARAM The District Rural Development Agency, which encouraged a woman to take up a plastic recycling unit, is not aware that such a project existed just two years ago. Bharathi, a woman in Kaarapakkam panchayat off Rajiv Gandhi Salai, was the only group to boldly take up the innovative concept. With financial support and encouragement from the DRDA, Kancheepuram, the women members made a foray into an area that most others ignored. They even installed a plastic cutter machine and started procuring plastic waste from scrap iron merchants and other spots where it was generated in large numbers. A member of Bharathi womens group told The Hindu that they faced a lot of problems initially. They used to shell out considerable sums to purchase plastic waste in the form of cans and bottles among others. The first time they tasted success was when the recycled plastic was actually used in a project. The first plastic bitumen road was laid in Tirusulam, connecting the level-crossing near the railway station with the Grand Southern Trunk Road. They also got orders from rural local bodies in the rest of Kancheepuram district. However, over the next few months, the members were unable to sustain the project as they did not get the payment for some of the orders they had got from the government, despite making several trips to the Block Development Offices. With DRDAs declining support for this initiative, the project died silently. Today, a plastic recycling unit is in place at the Zero Waste Centre of Pammal Municipality. A portion of the plastic pieces is procured by the municipality to be added in road laying works. Members of Pammal Exnora Innovators Club said using plastics improved road quality apart from being a simple method to dispose of a portion of plastic waste. Following Table 8 shows list of Plastic-Tar roads in Tamilnadu.

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Table 8 - List of Plastic-Tar roads in Tamilnadu

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Conclusion The present invention relates to a simplified, economic process for the recycling of polymer waste in road-making or industrial bitumen. This process is particularly suitable for the recycling plastic waste. The process according to the invention consists of preparing a polymer residue-rich bituminous mixture, more particularly of plastic waste, which can then advantageously be used in the diluted state for improving the mechanical, stability and use properties of roadmaking or industrial bitumen. The process according to the invention involves five successive stages, namely a grinding of the polymer residues, washing, drying, mixing with palverent bitumen and shaping preferably by extrusion and granulation or by compacting by compression. In more detailed manner, the process consists of shredding of a plastic bags, cups, etc. This mixture contains soil, a few residual metal fragments and various polymers, mainly (e.g. at least 80% by weight) polyvinyl chloride, polypropylene, polyurethane foam and to a lesser extent polyesters and acrylonitril styrene resin. Screening is carried out in such a way as to obtain a particle size below 10 mm and preferably between on average 2 and 4 mm. The palverent mixture is washed with water at a temperature which is preferably between 20 and 60 C. in order to eliminate soil and is dried at a temperature preferably between 80 and 120 C., e.g. by passing into a pulsed air rotary oven.. The mixture contains 95 to 40% by weight polymers and 5 to 60% by weight bitumen or asphalt, the said mixture representing at least 90% by weight of the final bituminous composition.

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The generation of waste plastics is increasing day by day. The major polymers namely polyethylene, polypropylene, polystyrene show adhesion property in their molten state. Stone aggregate is coated with the molten waste plastics. The coating of plastics reduces the porosity, absorption of moisture and improves soundness. The polymer coated aggregate bitumen mix forms better material for flexible pavement construction as the mix shows higher Marshall Stability value and suitable Marshall Coefficient. Hence the use of waste plastics for flexible pavement is one of the best methods for easy disposal of waste plastics. The use of polymer coated aggregate is better than the use of polymer modified bitumen in many respects. Moreover the polymer coated aggregate helps to use Crumb rubber modified bitumen resulting in better result. In India more than 3.3 million km of road is available. If they are constructed as plastic tar road, there will be less waste plastic available on the road. The process is eco friendly. The use of waste plastics in the manufacture of pathway blocks. References 1. Envis-Indian Centre of Plastics In The Environment Management of Plastics, Polymer Waste & Bio-Polymers &Impact of Plastics on Eco-System. Vol-3, Issue-1, Jan-Mar 2005, Pg No 1-2. 2. Envis-Indian Centre of Plastics In The Environment Management of Plastics, Polymer Waste & Bio-Polymers &Impact of Plastics on Eco-System. Oct-02, Issue-9. Daily News Paper, The Hindu, Wed Sep-21,2005,Karnataka Daily News Paper, The Hindu, Wed Oct-07,2007,Tamilnadu Webography 5. file:///C:/Documents%20and%20Settings/user/Desktop/plastic/Ahmedabad %20Roads%20To%20Get%20Eco-Friendly.htm 6. file:///C:/Documents%20and%20Settings/user/Desktop/plastic/Find%20your %20way%20on%20a%20plastic%20road.htm 7. file:///C:/Documents%20and %20Settings/user/Desktop/plastic/plasticroads.htm (INTERNATIONAL PLASTICSTASK FORCE) 8. file:///C:/Documents%20and%20Settings/user/Desktop/plastic/procedure.htm 9. file:///C:/Documents%20and%20Settings/user/Desktop/plastic/Reuse%20of %20plastics%20waste%20in%20Road%20Construction.htm (CENTARL POLLUTION CONTROL BOARD)

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