 bulk density and stability
> Maximum value of stability was considered as criteria for optimum waste plastic content
Studies were carried out on Bituminous mixes using 60/70 grade bitumen having average Marshall Stability Value (MSV) of 1300 kg at optimum bitumen content of 5.0 % by weight of the mix. Further studies on mixes were carried out using the modified binder obtained by the addition of varying proportions of processed plastic bags (percentage by weight of bitumen) with the conventional 80 /100 grade bitumen. The optimum modified binder content fulfilling the Marshall Mix design criteria was found to be 5.0 % by weight of the mix, consisting of 8.0 % by weight of processed plastic added to the bitumen. The average MSV of the mix using the modified binder was found to be as high as 1750 kg at this optimum binder content, resulting in about three fold increase in stability of the BC mix, which contains 4.6 % bitumen plus 8 % processed plastic by weight of bitumen, i.e., 0.4 % processed plastic by weight of the mix.
In order to evaluate the ability of the mix prepared with the above-modified bitumen to withstand adverse soaking condition under water, Marshall Stability tests were conducted after soaking in water at 60 Co for 24 hours. The average MSV of the BC mix with modified binder (using 8 % processed plastic by weight of bitumen, as above) was found to increase by about 2.6 times of the mix with ordinary bitumen. Further laboratory studies carried out on the BC mixes using this modified binder also indicated note worthy increase in fatigue life under repeated application of loads.
COMPARISON OF TWO MIXES:
VOLUMETRIC PROPERTIES OF MIXES:-
Volumetric properties of Mixes
Properties Modified Mix (Waste plastic) 8 % by wt of bitumen Conventional Mix
Marshall Stability (kg) 1700 1350
Bulk Density(gm/cc) 2.374 2.350
Air Voids (%) 4.4 3.5
VFB (%) 73 76
Flow (mm) 4 4
VMA (%) 16.5 15.6
Retained Stability (%) 98 88
II. POST TESTING OF WASTE PLASTIC BITUMINOUS MIXES:-
A) PERFORMANCE STUDIES OF THE MIXES
i. Indirect Tensile Strength
ii. Rutting Test
I. INDIRECT TENSILE STRENGTH:-
Use this test method to determine the tensile strength of compacted bituminous mixtures.
As the figure shown below tensile strength of the Waste Plastic Bituminous Mixes is greater then Conventional Mix
II. RUTTING TEST:-
Wheel tracking is used to assess the resistance to rutting of asphalt materials under conditions which simulate the effect of traffic.
A loaded wheel tracks a sample under specified conditions of speed and temperature while the development of the rut is monitored continuously during the test. The rut resistance can be quantified as the rate of rutting during the test or the rut depth at the conclusion of the test.
Graphical representation of rutting test
Test specimens can be either slabs prepared in the laboratory or 20cm diameter cores cut from the highway.
COMPARISON BETWEEN ORDINARY BITUMINOUS ROADS AND WASTE PLASTIC BITUMINOUS ROADS:-
SL. NO PROPERTIES PLASTIC ROAD ORDINARY ROAD
VALUE MORE LESS
2. BINDING PROPERTY BETTER GOOD
3. SOFTENING POINT LESS MORE
4. PENETRATION VALUE MORE LESS
5. TENSILE STRENGTH HIGH LESS
6. RUTTING LESS MORE
7. STRIPPING(POT HOLES) NO MORE
8. SEEPAGE OF WATER NO YES
9. DURABILITY OF THE ROADS BETTER GOOD
10. COST OF PAVEMENT LESS NORMAL
11. MAINTENANCE COST ALMOST NIL MORE
12. ENVIRONMENT FRIENDLY YES NO
ADVANTAGE OF WASTE PLASTIC BITUMINOUS MIX:-
1) Stronger road with increased Marshall Stability Value
2) Better resistance towards rain water and water stagnation
3) No stripping and no potholes.
4) Increase binding and better bonding of the mix.
5) Reduction in pores in aggregate and hence less rutting and raveling.
6) No leaching of plastics.
7) No effect of radiation like UV.
8) The strength of the road is increased by 100%.
9) The load withstanding property increases. It helps to satisfy today's need of increased road transport.
10)For 1km X 3.75m road, 1 ton of plastic (10 lakh carry bags) is used and 1 ton of bitumen is saved.
11) Value addition to the waste plastics (cost per kilogram increa