1. Al-Thawadi SM (2011) Ureolytic bacteria and calcium carbonate formation as a mechanism of strength enhancement of sand. J Adv Sci Eng Res 1(1):98–114
2. ASTM (2011) Standard D2487–11. Standard practice for classification of soils for engineering purposes (unified soil classification system). ASTM International, West Conshohocken, PA
3. ASTM (2014) Standard D854: Standard test methods for specific gravity of soil solids by water pycnometer. In: Annual Book of ASTM Standards. ASTM International, West Conshohocken, PA
4. ASTM (2016a) Standard D4253: Standard test methods for maximum index density and unit weight of soils using a vibratory table. In: Annual Book of ASTM Standards. ASTM International, West Conshohocken, PA
5. ASTM (2016b) Standard D4254: Standard test methods for minimum index density and unit weight of soils and calculation of relative density. In Annual Book of ASTM Standards. ASTM International, West Conshohocken, PA