I want to start my work by modification of the bitumen by using recycled HDPE, is there any difference to using virgin HDPE,l and what is the best percentage ?
Dear Dr. Mohamed;
excuse me to tell you first that the question should be reformulated otherwise, for example: "Is there any differences between recycled and virgin HDPE used in the modification of bitumen".
Assuming the same polymer stock samples; it is obvious that there must be differences since the recycled one has lost some of its original specific properties due to processing, ageing, and recycling operations. This is usually covered under the combined effects of the thermal-stress history, which affect (degrade) the basic properties of the polymer. On the other hand, the virgin sample keeps its structure-properties integrity.
From this one can expect for sure a lot of differences between the recycled and the virgin HDPEs on the modification of bitumen. Regards
Dear Dr.BOUAZIZ
Firstly thank you for correcting my question , and thank you for the helpful answer ^_^ good luck
Aged and recycled HDPE will mainly be characterized by smaller polymer chains than the fresh one, and by a few lateral groups oxidized. It may also be slightlty reticulated, i.e. not be purely 1D as before. Finally, it will contain more impurities. So, yes, little differences have to be expected, but not necessarily important for your application.
Alain
During processing of polymers, the polymeric material is exposed to thermal, oxidative as well as shear-induced degradation, causing molecular scission. The physical characteristics of the recycled polymer such as the flow behavior, tensile strength, elongation and impact are different from and generally inferior to those of the virgin polymer. . The effect on the flow behavior has been shown in the following references.
1. A. V. Shenoy, D. R. Saini and V. M. Nadkarni, Estimation of the melt rheology of polymer waste from melt flow index, Polymer., Vol. 24, p. 722 (1983).
2. A. V. Shenoy and D. R. Saini, Thermoplastic Melt Rheology and Processing, Marcel Dekker Inc., New York (1996).
Hence, it is obvious that there will be a difference between recycled and virgin HDPE used in the modification of bitumen. The rutting and fatigue cracking behavior of the modified bitumen using recycled HDPE and using virgin HDPE at the same concentration level will be definitely different. However, one can narrow the difference by determining how much more of the recycled polymer needs to be added to achieve the same level of properties as that of the virgin HDPE. A calculation needs to be then made to see whether that extra quantity added of the recycled polymer in order to achieve the same level of desired property is economically viable. Otherwise, one would have to settle for and accept a lower level of the desired property upon modification of bitumen but with the satisfaction of having found a use for the recycled waste.
Dear Mohammed;
I hope the following attached book will help you in your work. Regards
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