Table 1: Physical properties of Al-Qatif clay.

Property Range Material passing sieve no. 200 >90% Liquid limit 130–150 Plastic limit 60–70 Plasticity index 70–80 Maximum dry density 1.150–1.200 gm/cm3 Optimum moisture content 32–40%. Swell per cent (ASTM D4546) 16–18% Swelling pressure (ASTM D4546) 5.000–8.000 kg/cm2 (γ = 1.200 gm/cm3)

After Dafalla et al. [4].