1. Volumetric specifications, particularly binder content: These pertain to QA/QC specifications that rely solely on the composition of the mix, i.e. percentage of binder, aggregates and air voids in the mix.
2. The stiffness or |E*| at a single temperature and frequency combination: This refers to QA/QC specifications that are based on |E*| values corresponding to a single temperature and frequency combination based on the prevailing traffic and climatic conditions.
3. The stiffness or |E*| at a range of temperature and frequency combinations coupled with performance prediction models, i.e. performance-based specifications: This refers to QA/QC specifications that rely on accurate performance prediction (i.e. rut values (depth) and fatigue percentages) based on thorough SPT results at various combinations of temperatures and frequencies.