Why does bitumen emulsion definition differ between laboratory standards and field specifications?

Lab standards aim for repeatable measurement under controlled conditions, so they focus on properties like residue, viscosity, sieve, and stability using standardized temperatures and equipment. Field specifications must account for weather, surface condition, aggregate chemistry, and application method, so they emphasize breaking behavior, adhesion, and cure under realistic conditions. A product can meet lab limits yet fail in the field if aggregate compatibility is poor or if application temperature is outside the practical window. Field definitions therefore add performance clauses and handling constraints that labs do not fully capture.