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Published on January 1, 2005

Pavement Preservation Using the SBR Latex Modified Asphalt Emulsion

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Date Published January 1, 2005

This Report has been authored by:Koichi Takamura at BASF Corp.

Modified asphalt emulsion with the SBR latex is not just an emulsion of polymer-modified asphalt but rather the asphalt emulsion containing dispersed latex particles in the aqueous phase. Menisci of water containing latex particles form among asphalt particles when water starts to evaporate upon application. These latex particles migrate together with water, accumulate in the menisci and form honeycomb structures surrounding the asphalt droplets. These honeycombs are highly elastic with high elongation even at low temperature because of high molecular mass and low glass transition temperature of the latex polymer used. Radial truck tires induce high transverse contact stresses on the pavement, resulting in high near surface lateral stresses, which causes longitudinal surface cracking and near-surface rutting and shoving. These transverse contact stresses could be confined within a thin pavement layer applied as preventative maintenance. The high strain-stresses applied to the asphalt binder would be concentrated into these thin polymer membranes forming the honeycombs. These flexible membranes absorb external stresses without causing fractures to brittle bitumen droplets at low temperature, thus enhancing the fatigue resistance of the asphalt pavement.