Effects of soil grading and sand content on soil-cement properties

The effect of soil-cement characteristics, unconfined compressive strength (UCS), dry density, and water absorption on the soil grading and sand content of six groups (natural soil, ≤ 2 mm, ≤ 1 mm, ≤ 0.5 mm, ≤ 0.25 mm, and ≤ 0.075 mm) of soil-cement block was studied. The results showed that the characteristics of soil-cement mixed with sand were influenced by soil grading. Better characteristics of soil-cement soil were obtained when the soil particle sizes of soil-cement were less than 0.075 mm of mixed sand. Every soil particle size has optimal sand content. Results showed that the optimal sand content of natural soil is 40%, whereas those of other soil particle sizes are all 55%. The results also showed that the UCS of 28-day ages is 1.79 times that of natural soil for soil-cement mixed with sand of ≤ 0.075 mm particle group, whose water absorption is 50% that of natural soil as the optimal sand content. Finally, the study of clay content showed that there exists an optimal clay content for various size groups, namely, 9.12%, 7.06%, 8.08%, 9.05%, 11.36%, and 13.60% for natural soil, ≤ 2 mm, ≤ 1 mm, ≤ 0.5 mm, ≤ 0.25 mm, and ≤ 0.075 mm, respectively.