Phindile Mathenjwa, AECI Specialty Chemicals
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Abstract
There are several factors that affect the performance of the emulsion such as the acidity in Anionic emulsions. Asphalt from varying crude oil sources (such as Paraffinic and Naphthenic) and processes impact the ability of a slow setting emulsified asphalt to mix with a finely divided high surface area material such as Portland Cement and crusher dust.
The acidity in Naphthenic bitumen is beneficial in Cationic emulsions, but it has a negative impact on Anionic slow set emulsions. It influences the slow setting properties to rapid setting.
Water can also possess chemical ionic constituents that can be detrimental when calcium ion attack from the cement mixes with the slow set emulsion, which can lead to breaking the emulsified asphalt.
The exercise was done to illustrate the structural build-up of a continuous calcium polymer that forms thixotropic properties in Anionic slow set emulsion by propagation of the calcium soap gel polymer, which is beneficial for slurry seal and waterproofing sealant applications. The effect of having the chain-stopper in the emulsion system introduced by the presence of an acid (e.g. Naphthenic acid), can be detrimental when mixing cement with slow set asphalt emulsion.
About the Author
Phindile Mathenjwa is a Technical Manager at AECI Specialty Chemicals. She has BTech in Chemistry, BSc Environment Management, and BCom in Management. In 2015 she received an award as one of the top three students in the Foundational Management Development Programme at the Gordon Institute of Business Science. Phindile was employed by NCS Resins prior to joining AECI in 2014. She works with distributors in Asia, Australia and the US, developing new business opportunities and troubleshooting in road science for customers worldwide.
