Heavy‑duty modified asphalt contains polymer modifier and mineral filler. Under static storage, phase separation, filler settlement and polymer enrichment easily occur, resulting in uneven asphalt quality. Optimizing the structure of asphalt tank agitator and carrying out reasonable speed matching can form a stable circulating flow field inside the tank, restrain solid‑phase precipitation and polymer stratification, and keep the performance of modified asphalt uniform during long‑time storage.

Analyze the mechanism of delamination and precipitation of modified asphalt. The density difference between inorganic filler and asphalt matrix causes solid particles to sink to the tank bottom under gravity. Polymer components tend to gather at the upper layer due to incompatibility with base asphalt. If the agitator structure is unreasonable, dead zones exist at the tank bottom and around the tank wall. Low stirring speed cannot generate enough circulating turbulence to suspend settled particles. Excessive rotating speed produces strong shear force, which breaks the polymer network structure and degrades the modification effect. Frequent high‑speed stirring also increases asphalt aging risk and drives energy consumption up.

Optimize the overall structural form of the agitator. Combine bottom anchor blades and upper axial flow impellers. The anchor blade fits the contour of the tank bottom, eliminates static sediment dead zones and stirs the deposited filler upward. The upper axial‑flow impeller forms vertical up‑and‑down circulation, so that upper enriched polymer mixes fully with the lower slurry. Add scraping edges on the anchor blade to reduce hard caking on the tank wall. The distance between blades and tank plate should be controlled properly; too large a gap leaves sediment, while too small a gap causes friction and blade wear.

Implement staged speed matching according to working conditions. Divide the operation mode into low‑speed holding stirring, medium‑speed circulation mixing and high‑speed homogenization. During normal constant‑temperature storage, adopt continuous low‑speed running to maintain particle suspension without excessive shear. After feeding new modified asphalt, switch to medium‑speed circulation for a certain period to homogenize fresh and original materials. High‑speed stirring is only used for short‑time homogenization before discharging and shall not run continuously for a long time, avoiding polymer degradation.

Optimize installation position and flow‑guiding structure. Set the agitator at the eccentric position of the asphalt tank instead of the central position to prevent the formation of rotating vortex and material circular motion without vertical exchange. Install diversion baffles on part of the tank wall to break tangential swirling flow and strengthen vertical mixing. The baffle height and spacing should be designed according to tank diameter, avoiding local flow stagnation.

Coordinate heating temperature and stirring cycle control. Too high storage temperature accelerates modifier aging, while low viscosity caused by overheating increases settling velocity of solid fillers. Match stirring logic with tank temperature control system. When the temperature fluctuates and asphalt viscosity changes, the controller automatically adjusts the rotating speed. Set intermittent stirring for idle storage to cut energy cost, and avoid long‑term static placement without agitation.

Strengthen regular inspection and performance verification. Sample asphalt from upper, middle and bottom layers of the tank to detect penetration, softening point and segregation degree, judge whether stratification appears. Check blade abrasion, shaft swing and seal leakage periodically. According to the actual segregation test data, continuously adjust blade shape, installation height and speed switching threshold, and form a standardized stirring operation curve for different modified asphalt.