Engineering characteristics of compressed earth blocks stabilized with cement and fly ash.

• Fly ash-cement stabilized CSEBs are assessed in terms of compressive, split tensile, flexural and shear strength. • Inclusion of fly ash is effective to reduce the cement content significantly. • Inclusion of FA ≥ 20% with 5% and 7% cement satisfies the strength requirements. • Fly ash is effective in reducing the accumulated loss of mass. • Life cycle analysis suggest that CSEBs are superior to conventional fired clay bricks. Fly ash is a common industrial waste that requires a proper disposal which otherwise will have a detrimental effect on the environment. As such, utilization of fly ash in producing Compressed Stabilized Earth Blocks (CSEB) can provide suitable means to promote sustainability. Work herein focuses on investigating the performance of CSEBs stabilized with cement and fly ash (FA) as an alternative to traditional construction materials, like Fired Clay Bricks (FCB). Strength characteristics of CSEBs have been evaluated in terms of compressive, split tensile, flexural and shear strength. For durability, accumulated loss of mass due to cyclic drying-wetting test, wet strengths, submersion and efflorescence test have been performed. For this study, 270 CSEBs and 192 cylindrical samples are prepared with 0–10% cement and 0–30% FA (All the percentages are by dry mass of soil taken). Addition of 10–30% FA along with cement increases the compressive strength, flexural strength and split tensile strength by different magnitudes depending on the cement content used. Inclusion of FA ≥ 20% with 5% and 7% cement satisfies the strength criterion suggested by different standards. Moreover, FA was effective in reducing the cement content in the mix without sacrificing the strength. Cyclic drying-wetting test shows that with the increase of the amount of FA with cement, accumulated loss of mass reduces, which is in agreement with the observation of microstructural analyses. Strength retention of the samples after cyclic drying-wetting test ranged within 51–88%, showing the durable performance of cement-FA stabilized earth. Results of triaxial test indicate that FA improves the peak deviatoric stress-strain and failure stress-strain irrespective of cement content and confining stress. With the addition of 0–30% FA with 5% and 7% cement, the cohesion parameter varies within 159–315 kPa, and the angle of internal friction varies within 38.1–57.1°, indicating an improved shear response of cement-FA stabilized mixes. Life Cycle Analysis (LCA) shows that considering energy consumption, Global Warming Potential (GWP) and other environmental impacts, CSEBs are superior to the traditional FCBs. [ABSTRACT FROM AUTHOR]