Table of Contents
What are warm mix additives?
Organic WMA additives are known to reduce the bitumen viscosity in order to improve workability. These organic additives are mainly waxes (natural or synthetic) and fatty amides, and they are added to warm mix to lower the viscosity of the asphalt binder at temperatures slightly above 90 ◦C and to improve lubrication.
What are additives in asphalt?
Asphalt additives included latex, ethylene vinyl acetate, styrene-butadiene styrene-block (SBS) copolymer, SBS vulcanized with asphalt, manganese organic complex, polyethylene, and carbon black. Certain polymers when blended with the proper grade of asphalt will significantly reduce fatigue cracking.
What is warm mix asphalt technology?
Warm Mix Asphalt (WMA) is the generic term for a variety of technologies that allow producers of Hot Mix Asphalt (HMA) pavement material to lower temperatures at which the material is mixed and placed on the road. It is a proven a technology that can: Reduce paving costs. Extend the paving season.
Which technology allows the manufacture of warm mix asphalts?
Plant production with an asphalt emulsion product called Evotherm™, which uses a chemical additive technology and a “dispersed asphalt technology” delivery system. The addition of a synthetic zeolite called Advera® WMA during mixing at the plant to create a foaming effect in the binder.
What is the difference between warm mix asphalt and hot mix asphalt?
Warm Mix Asphalt is produced and mixed at temperatures roughly between 100 and 150 °C. Hot Mix Asphalt is produced and mixed at temperatures roughly between 120 and 190 °C The production temperatures of Hot Mix Asphalt depend on the bitumen used.
Why and what are the additives used to modify bitumen?
Additives are substances that can be added to the bitumen binder to modify bitumen characteristics and thereby to improve workability, the adhesion to aggregate, and the properties of final asphalt mixture.
What is warm mixture?
HMA is manufactured in a central mixing facility (typically called a hot mix plant) and consists of high quality aggregate and asphalt cement. The two are heated and mixed while hot to completely coat the aggregate with asphalt cement.
How is warm mix asphalt produced?
HMA is the traditional process for constructing asphalt pavements. HMA is manufactured in a central mixing facility (typically called a hot mix plant) and consists of high quality aggregate and asphalt cement. The two are heated and mixed while hot to completely coat the aggregate with asphalt cement.
What is different types of modified bitumen?
Common types of polymer modified bitumen
| type | Generic Examples |
|---|---|
| Fiber | Natural: Asbestos Rock wool Manufactured: Polypropylene Polyester Fiberglass Mineral Cellulose |
| Oxidant | Manganese salts |
| Antioxidant | Lead compounds Carbon Calcium salts |
| Hydrocarbon | Recycling and rejuvenating oils Hard and natural asphalts |
What is an asphalt modifier?
These modifiers are used to reduce rutting and to improve fatigue and thermal cracking resistance. Crumb rubber is an elastomer made from ground tires. Several technologies are in place for using ground tire rubber. This material is used primarily to address rutting.
What is warm asphalt?
Warm mix asphalts help to improve site safety for road surfacing teams. Lower asphalt temperatures reduce fumes and steam on site. This means better visibility and improved safety during night-time and winter working.
What temperature is warm mix asphalt?
What are the different asphalt mixes?
HMA pavement mix types include Open-Graded Friction Courses (OGFC), Stone Matrix Asphalt (SMA), and fine- and coarse graded dense mixes. HMA pavement mixtures are expected to perform over extended periods of time under a variety of traffic and environmental conditions.