1. ASTM (2012) Standard test method for laboratory compaction characteristics of soil using standard effort. ASTM D698, West Conshohocken, PA: ASTM
2. ASTM (2014) Standard test method for specific gravity of soil solids by gas pycnometer. ASTM D5550. West Conshohocken, PA: ASTM
3. ASTM (2017) Standard test methods for particle-size distribution (gradation) of soils using sieve analysis. ASTM D6913. West Conshohocken, PA: ASTM
4. ASTM (2018a) Standard test method for liquid limit, plastic limit and plasticity index of soils. ASTM D431. West Conshohocken, PA: ASTM
5. ASTM (2018b) Unified soil classification system. ASTM D2487. West Conshohocken, PA: ASTM