Bitumen Emulsion Asphalt (Bitumen) Emulsions (Chemistry and Concepts)
Emulsion - Definition
An emulsion is a dispersion of small droplets of one liquid in another liquid. Typical examples include such everyday products as milk, mayonnaise, and cosmetic creams. Emulsions can be formed by any two immiscible liquids but in most emulsions one of the phases is water. Oil-in water (O/W) emulsions are those in which the continuous phase is water and the disperse (droplet) phase is an 'oily' liquid. Water-in-oil (W/O) "inverted" emulsions are those in which the continuous phase is an oil and the disperse phase water. More complex structures are possible such as water-in-oil-in-water (W/O/W) emulsions in which the oil droplets themselves contain smaller droplets of water.
Bitumen (asphalt) emulsions are normally of the O/W type and contain from 40 to 75% bitumen, 0.1-2.5% emulsifier, 25-60% water plus some minor components which are described below. Bitumen emulsions are brown liquids with consistencies from that of milk to double cream which depend mostly on the bitumen content and the particle size. The bitumen droplets range from 0.1-20 micron in diameter and some drops may contain smaller water droplets within them so are better described as W/O/W emulsions. This ‘trapped’ water can influence the physical properties of the emulsion.
Classification of Bitumen Emulsions
Bitumen emulsions are classified according to the charge on the droplets and according to their reactivity.
Cationic emulsions have droplets which carry a positive charge.
Anionic emulsions have negatively charged droplets.
Rapid-setting emulsions set quickly in contact with clean aggregates of low surface area such as the chippings used in chipseals (surface dressings).
Medium setting emulsions set sufficiently less quickly that they can be mixed with aggregates of low surface area such as those used in open graded mixes.
Slow-setting emulsions will mix with aggregates of high surface area. In the naming of emulsions according to the ASTM standards, cationic rapid-,medium- and slow-setting emulsions are denoted by the codes CRS, CMS and CSS, whereas anionic emulsions are called RS, MS, and SS.
In India Mostly cationic Emulsion is used for various application as per IS 8887.
Bitumen Emulsion can be used in customized application like surface dressing/chip sealing /cold mix application (recommended low/medium traffic roads) Bitumen emulsion for preventive maintenance like slurry seal, Microsurfacing, crack seal ,fog seal etc where high level of specification and customization required to perform intended application .We as Nanotech Industries performs key role to the end results and permanence of products to supply -apply & support .