Breaking behavior of cationic bitumen emulsions

Abstract

Abstract The formulations were developed for road over-stabilized cationic bitumen emulsions on hydrochloric acid and cation-active emulsifiers. There were determined the physical-mechanical properties of the bitumen emulsions produced, while special at-tention was paid to the emulsions breaking behavior. There was defined the influ-ence of the emulsifier content and type upon the bitumen emulsions’ physical-mechanical indices, as well as upon the breaking behavior – by four methods: break-ing value, miscibility with open-grade and dense-grade mixes, fines mixing time, mixing stability with cement. The emulsifier content makes the most impressive in-fluence upon such bitumen emulsion property as stability during storage: residue on sieving (sieve No 014). The results obtained for bitumen emulsions breaking behav-ior (by various testing methods) show the substantial correlation, especially if to compare the breaking value and mixing stability with cement. The miscibility with open-grade and dense-grade mixes provides not just for estimation of a visual cover-ing and combining of emulsion with aggregate, while fines mixing time in all the emulsions tested was more than 300 seconds. Therefore it was defined that the most expedient testing methods for breaking behavior (such ones, which allow defining whether an emulsion is either slow-setting or over-stabilized) are as follows: breaking value and mixing stability with cement. With growth of emulsifier content the break-ing value increases, while mixing stability with cement decreases. Besides, upon the replacement of emulsifier, intended for slow-setting emulsions for the other emulsi-fier, recommended for over-stabilized emulsions, the breaking value substantially in-creases, while the mixing stability with cement rapidly decreases.