Emulsified Asphalt
This article is about highway and transport engineering, this time we talk about the Emulsified asphalt
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Emulsified asphalt is a mixture of asphalt cement, water, and an emulsifying agent. These three constituents are fed simultaneously into a colloid mill to produce extremely small globules of (5-10ยต) of asphalt cement, which are suspended in the water. The emulsified agent imparts the electric charges (cationic or anionic) to the surface of the asphalt particles, which causes them to repel one another; thus the asphalt particles do not coalesce. The emulsified asphalt thus produced is quite stable and could have a shelf life of several months.
The two most common types of emulsified asphalts are anionic and cationic, a classification dependent on the emulsified agent. The anionic type contains electronegatively charged asphalt globules, and the cationic type contains electropositively charged asphalt globules.
The choice of anionic or cationic emulsions is important when considering various types of aggregates. The anionic emulsions carry a negative charge and are effective in coating electropositive aggregates such as limestone. The positive charge in a cationic emulsion reacts favorably with an electronegative aggregate, such as the highly siliceous aggregates.
(source: Wright, P.H, with contributions by James S. Lai, Peter S.Parsonson, Michael Meyer., Highway Engineering, 6th edition ,John Wiley & Sons, Inc.New York, 1996.)
The two most common types of emulsified asphalts are anionic and cationic, a classification dependent on the emulsified agent. The anionic type contains electronegatively charged asphalt globules, and the cationic type contains electropositively charged asphalt globules.
The choice of anionic or cationic emulsions is important when considering various types of aggregates. The anionic emulsions carry a negative charge and are effective in coating electropositive aggregates such as limestone. The positive charge in a cationic emulsion reacts favorably with an electronegative aggregate, such as the highly siliceous aggregates.
(source: Wright, P.H, with contributions by James S. Lai, Peter S.Parsonson, Michael Meyer., Highway Engineering, 6th edition ,John Wiley & Sons, Inc.New York, 1996.)
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