1. Ampadu SIK, Ackah P, Nimo FO, Boadu F (2017) A laboratory study of horizontal confinement effect on the dynamic cone penetration index of a lateritic soil. Transportation Geotechnics 10:47–61, DOI: https://doi.org/10.1016/j.trgeo.2016.12.002
2. ASTM (2006a) Standard test methods for maximum index density and unit weight of soils using a vibratory Table -D4253-06. ASTM International, West Conshohocken, PA, USA, 15
3. ASTM (2006b) Standard test methods for minimum index density and unit weight of soils and calculation of relative density -D4254-06. ASTM International, West Conshohocken, PA, USA, 9
4. ASTM D1556/D1556M-15e1 (2024) Standard Test Method for Density and Unit Weight of Soil in Place by Sand-Cone Method, DOI: https://doi.org/10.1520/D1556_D1556M-15E01
5. ASTM D1557-12R21 (2021) Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (56,000 ft-lbf/ft3 (2,700 kN-m/m3))