Syndicate content

Recent comments

  • Reply to: What does “urban” mean?   1 month 3 weeks ago

    Urban cities should have measurement related to new jobs created, and re-skilling measurements. Re-skilling is important because with change in technology every segment of the work force needs to be re-skilled.

  • Reply to: From plastic to pavement: Another example of creative waste management   9 months 1 week ago

    Very interesting, thanks for sharing the info on this. I would echo Xie Jian's comments about wanting to see a full economic analysis of this, i.e. the direct costs of processing the plastic and laying roads, the indirect and external costs, the expected savings from reduced waste disposal costs and vs. conventional options for plastic recycling, comparison with the costs of conventional road materials and also longer term maintenance costs, etc.

  • Reply to: From plastic to pavement: Another example of creative waste management   9 months 3 weeks ago

    Dear All thank you so much for your comments, apologies for the delay in responding to your comments. I managed to get in touch with the inventor of this method. Dr. R. Vasudevan who shared with me his thoughts on the above. I am going to respond in one long message instead of separate one in order to provide more comprehensive view of this method. technical details are available in case you need it.

    On how to use waste plastics for road construction, Carry bags, cups, thermocoles, foams and flexible films are shredded into small pieces (between 1.6mm – 2.5mm). The granite stone is heated to around 1700c. The shredded plastics waste is added to the stone. It get melted and coated over stone in just 30 seconds. Then the bitumen is added and mixed. The mix is used for road construction. From rural roads to National High ways all types of roads can be laid using this technique.

    on what the main characteristics of the process are
    1.Plastics waste like carry bags, disposal cups, thermocoles, laminated films and polyethylene and polypropylene foams can be used.
    2.There is no need of segregation.
    3.No need for much cleaning
    4.Multi layer films can also be used.
    5.Easy process without any new machinery
    6.Simple process without any industry involvement
    7.No granulation or blending is needed
    8.Land filling and incineration process can be avoided
    9.In situ process
    10.Use of lesser percentage of bitumen and thus savings on bitumen resource
    11.Use of plastics waste for a safe and eco-friendly process
    12.Both Mini Hot Mix Plant and Central Mixing Plant can be used
    13.Only aggregate is polymer coated and bitumen is not modified
    14.Use 60/70 and 80/90 bitumen are possible
    15.No evolution of any toxic gases like dioxin
    16.Fly ash can also be used to give a better performance
    17.Use of each ton of plastic waste avoids the entry of 3 tons of Co2 in to the atmosphere, which otherwise results in global warming
    18.For 1km X 3.75m road, 1 ton of plastic (10 lakh carry bags) is used and 1 ton of bitumen is saved.
    19.Value addition to the waste plastics (cost per kilogram increases from Rs 15 to Rs 30).
    20.Flexible pavement scrap can be reused effectively by coating with plastics waste. This helps to reduce the cost of 50%; saves the use of raw material by 70 – 80% and also the level of the road can be maintained.

    Characteristics of the Plastic Road:
    - Stronger road with increased Marshall Stability Value
    - Better resistance towards rain water and water stagnation
    - No stripping and hence no potholes.
    - Increased binding and better bonding of the mix.
    - Reduction in pores in aggregate and hence less rutting and raveling.
    - No leaching of plastics.
    - No effect of radiation like UV.
    - Can Withstand Heavy Load and Heavy traffic.

    on the Performance of the Plastic oad:
    Monitoring of test roads were carried out using structural evaluation, functional evaluation and conditional evaluation studies. Generally all the roads laid over a period from 2002 to 2006 are performing well. The results obtained for these roads helped to conclude that these roads are performing very well in spite of their age. Under the similar conditions most of the bitumen roads are not performing well at all. These roads have not developed even small cracking and a pothole. The roads were distributed over the different localities of Tamil Nadu exposed to various environmental conditions like temperature, rainfall, etc., yet the roads are performing well.( photos of the roads before and after are available)

    on the growth of the Plastic Road:

    •Patent has been obtained from the Government of India for the plastic tar road laying process – Patent No. A-CH\871; 198254
    •Guidelines published by IRC-2013 IRC-SP:98-2013
    •In the year 2010 the National Rural Road Development Agency in consultation with us, have published a Guidelines for laying plastic tar road laid
    •The latest gazette notification revised plastic waste management rules mention that plastics can be used for making road by local bodies. (Ministry of Environment and forest notification ; dated 4th February 2011; P. No. 21)
    •The current Chief Minister of Tamil Nadu has included in her parties election manifesto that the state will be freed from plastic menace and rural roads will be converted into plastic road using the process developed by the Thiagarajar College of Engineering.
    •Tamil Nadu government implemented this process through DRDA and over 1500km rural roads were laid distributing over all the districts in Tamil Nadu.

  • Reply to: From plastic to pavement: Another example of creative waste management   9 months 3 weeks ago

    Yara, I have no personal experience with mixing waste plastics with bitumen for road construction. As I understand, it is an concept that has pros (reuse of plastics; some possible durability enhancement) as well as cons (not all plastics are suitable, also because of environmental reasons; mixing with bitumen reduces some application properties) and that had some limited piloting / application, but has not yet developed to mainstream use.

    Assuming that technical issues can be overcome, a particular point of attention is how to make contracting agencies and contractors actually use these materials. Application of secondary materials --including recycled construction and demolition waste, but also materials such as coal ash and flue gas treatment products—can entail risks and generally the sector is conservative. Therefore, in addition to solid testing, much effort is needed to get the use of secondary materials firmly included in building codes, material specs, standard contracts, etc. This aspect often needs much more effort than technically (and economically and environmentally) proving that the material is safe and applicable.

    - Frank Van Woerden
    Sr. Environmental Engineer, The World Bank

  • Reply to: From plastic to pavement: Another example of creative waste management   10 months 1 day ago

    This is a very interesting and innovative approach for processing plastic waste. But there are questions and information needed in order to assess whether the approach can be applied to other places. For example, whether is the cost of collecting plastic waste included in the economic evaluation of the approach? What are the requirements for waste stream to be used in the road construction? Is there any pre-treatment cost before using the plastic waste? How flexible is the share of plastic wasted needed in the construction process?