MULTI-PHYSICAL MODEL FOR DESCRIBING SELF-HEALING MORTAR CONTAINING BIOCHAR- IMMOBILIZED BACTERIA

摘要

This work aims to analytically and numerically describe and predict the ability of a particular kind of bacteria (Bacillus sphaericus) to heal cracks in mortar. The ureolytic bacteria induces microbial calcium carbonate by releasing urease enzyme, which in turn stimulates the degradation of urea into carbonate and ammonium; the carbonate then reacts with the calcium ions (in calcium nitrate) to produce calcite to heal cracks. A novel feature of our study is that the bacteria is immobilized in biochar, which is the solid by-product of pyrolysis. The biochar and bacteria are included in the mortar mixture together with special nutrient solution; the mixture of bacteria and nutrients is called the "spore solution". Our prior (and published) studies found that biochar-immobilized bacteria heal cracks more efficiently. The modeling approach consists of 4 major steps or sub-models.