Development of a new small-scale asphalt emulsion storage stability test

The storage stability of asphalt emulsions is a critical quality control parameter. Existing standards (AASHTO T 59 Sections 16, 11) require testing 1000 millilitres; therefore, this study aimed to develop a test method with lower material requirements. Three asphalt emulsions were evaluated using the existing method and three new methods: flask-pouring, flask-pipette, and burette. Particle size, sieve, residue, and storage stability were measured from the top and bottom at 1, 3, and 7-day storage durations. Results showed stability trends are consistent with the existing 1-day method, while for settlement (3–7 days), the flask-pouring method exhibited the strongest correlation with the existing method (R2 = 0.99) while requiring 70% less material. Flask-pipette and burette methods were prone to clogging during extraction. d99 particle size was an indicator of coalescence, showing up to fivefold increases during testing. The flask-pouring method is a promising laboratory-scale approach to quantify emulsion stability while minimising material requirements.