US Patent 7087665 Quick-setting cationic aqueous emulsions using pre-treated rubber modified asphalt cement

Cationic aqueous emulsions of rubber modified asphalt cement (RMAC) useable for paving, seal coat, slurry seal, roofing, coating and other applications. First, a RMAC is prepared by combining 45 to 90% by weight asphalt with about 5% to about 55% by weight solid recycled rubber (e.g., crumb rubber from used vehicle tires) under conditions that cause at least a substantial portion of the solid rubber to become liquified or otherwise incorporated into the asphalt. The RMAC may be treated with dodecyl benzenesulfonic acid (DDBSA) which causes reaction(s) to occur and results in a lowering of the viscosity of the RMAC. The RMAC (or DDBSA-treated RMAC) may then be emulsified in an aqueous medium to provide an aqueous emulsion.