Microbially induced stabilized rammed earth: Compressive strength-capillary water absorption Co-relationship

Rammed Earth (RE) is finding more applications as a sustainable construction material with cement as stabilizer. However, RE is susceptible to water absorption through pores, weakening the bond between the soil particles, reducing its strength and lifespan. Increased cement content, though enhances strength, does not effectively fill pores. There are no proven methods to fill pores with cementitious materials in structures like RE. In this study, Microbially Induced Calcium Carbonate Precipitation (MICP) has been adopted during casting to improve the compressive strength of cement-stabilized RE. MICP technique not only enhances the strength but also fills pores, inhibiting capillary water absorption thereby extending the lifespan of RE. The results of tests on MICP-induced specimen indicated that the compressive strength increased by an average of 26 %. The capillary water absorption reduced considerably with the bacterial induction. A relationship between compressive strength and capillary water absorption of RE is arrived. While further study is necessary for microbial stabilization to be used in RE, these preliminary data show promising results.