Effect of mix design on compressed earth block strength

- Effect of a unique CEB geometry on strength testing methods.
- Effect of mix designs on CEB flexural and compressive strength.
- CEBs with optimized mix designs surpass ASTM strength requirements.

Compressed earth blocks (CEBs) are masonry units that combine soil, stabilizer, and water under pressure to form an earth block. Unit block performance is dependent on the characteristics of soil and the mix design. This paper presents CEB unit strength test methods and results for CEBs produced from 14 mix designs at 7 and 28 day curing times in both saturated and unsaturated conditions. Trends in the effect of mix design on block strength reflect that strength increases with both moisture and cement content in the regimes of applicability for the production machinery. The unsaturated, 28-day unit compressive strengths ranged from 4.92 MPa to 15.72 MPa. The optimal mix contained 10.91% cement and 11.40% water which resulted in an average compressive strength of 15.15 MPa; ASTM C90 mandates a minimum compressive strength of 13.79 MPa.