Adhesiveness of bitumen emulsion

In all cases where bitumen is used, the need for good adhesiveness of bitumen with aggregate surface is of the greatest importance. 

The factors that affect the adhesiveness of the emulsion and thus of the bitumen with the aggregates are as follows the emulsifier type and quantity, the bitumen quality and grade, the pH of the aqueous solution of the emulsifier and the type of aggregates. 

A sufficient quantity of the selected emulsifier should be included in the emulsion so that a sufficient number of free molecules of the emulsifier exist. The pH of the aqueous solution of the emulsifier should fluctuate depending, mainly, on the chemical composition of the bitumen and the type of aggregates. Regarding the effect of the aggregate type on the adhesiveness of the emulsion/bitumen, it should be stated that cationic emulsions adhere very well to all types of aggregates for the production of bituminous mixtures. In contrast, anionic ones adhere better only to limestone aggregates. 

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CEN EN 13614. 2011. Bitumen and bituminous binders - Determination of adhesivity of bitumen emulsions by water immersion test - Aggregate method. Brussels CEN. 

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