1. AASHTO M 147. Standard specification for materials for aggregate and soil–aggregate subbase base and surface courses.
2. AASHTO T 221-90. (2012). Standard method of test for repetitive static plate load tests of soils and flexible pavement components for use in evaluation and design of airport and highway pavements.
3. AASHTO T 85. Standard method of test for specific gravity and absorption of coarse aggregate.
4. AASHTO T 89. Determining the liquid limit of soils.
5. AASHTO T 90. Determining the plastic limit and plasticity index of soils.