Marshall Stability

The present study investigates the potential use of waste plastic as a modifier for asphalt concrete and cement concrete pavement. Plastic waste, consisting of carry bags, cups etc can be used as a coating over aggregate and this coated stone can be used for road construction. Different ratios of plastic such as Polypropylene (PP), Low Density Polyethylene (LDPE), and High Density Polyethylene (HDPE) by weight of asphalt were blended with 80/100 paving grade asphalt. Unmodified and modified asphalt binders were subjected to rheological test. The performance tests including, Marshall Stability, loss of stability tests were conducted using plastic coated aggregates and polymer modified bitumen on HMA mixtures. Work has been done by using plastic coated aggregates in cement concrete pavements. The results showed better values for asphalt concrete. This is an eco-friendly process.

The asphalt industry has been perpetually challenged by its hazardous emissions
and its contribution to the ongoing climate change and global warming crises. Likewise,
the environment has been cumbered by the challenge of improper disposal of nondegradable
solid wastes especially crumb rubber in form of scrap tyres resulting in
serious environmental degradation. This research investigated the effect of modifying
bitumen with bio-oil from cassava peels upgraded with a nondegradable polymer i.e.
crumb rubber. Performance tests were carried out on the modified bitumen to evaluate
its effect on its rheological properties. The percentage of bio-oil by volume used for
modification of bitumen was 5%, 10%, 15% and 20%. Marshall Stability and flow tests
were also carried out on the bio-asphalt produced. Experimental results of bitumen
modification with cassava peel oil at 5%, 10%, 15% and 20% replacements showed an
increment in flash point of 244°C, 250°C, 252°C & 259°C fire point of 259°C, 265°C,
269°C & 274°C and softening point values of 55°C, 55.5°C, 56.5°C & 57.5°C
respectively of the base bitumen. Due to the high moisture content associated with biooils,
properties such as ductility and viscosity were adversely affected. Upgrading with
crumb rubber caused an improvement in the engineering properties of the base bitumen
with penetration grade at 20% modification showed the resultant blend was 40/50
which is suitable for use on airport pavements. The highest Marshall Stability and Flow
values were obtained at 20% modification with bio-oil upgraded with polymer with
values of 26.5kN and 13.33mm as against 9kN and 10.5mm obtained on the control

In India majority of roads are being constructed by flexible pavements. But the performance of the pavement largely depends on quality and type of materials used, Construction methodology adopted, temperature, climatic conditions etc. Because of these variations in the mentioned parameters, pavements undergo distress/ failure. The different types of failure in flexible pavement are Rutting, Shovelling, Edge breaks, Cracks, Slippage etc. Rutting is a common phenomenon which occurs in flexible pavement surface due to overloading of vehicles and repeated application of wheel load. Rutting is defined as channelized depression in the pavement surface along wheel path due to heavy repetitive traffic load. Design of bituminous paving mixes greatly effects the performance of pavements. In the present laboratory research work, conventional bitumen is used in wearing/ surface course and Modified Bitumen is used in binder course of the layer. Pavement layers are constructed/casted in an Indigenously designed, developed and fabricated equipment called Roller Compactor cum Rut Analyzer (RCRA) and Rutting test was performed. The overall objective is to compare the Marshall properties of the conventional and Modified Bituminous mix and to study the rutting performance of these bituminous mixes. Results shows that bituminous mixes prepared with Modified Bitumen/Binders has a very high Marshall Strength and offers greater resistance to rutting