Experimental Study on the Effect of Nutrient Solution Calcium Sources on Bio-cemented Sand

Microbial induced carbonate precipitation(MICP),an environmental-friendly foundation treatment technology,can effectively improve the engineering performance of soil.Different nutrient solution components have a significant impact on the stabilization effect.This paper showed the effect of calcium chloride and calcium nitrate,which were chosen as the calcium sources in nutrient solution,on physico-mechanical properties of bio-cemented sand by penetration test,dry density test,water absorption test,and unconfined compressive strength test,respectively.The morphological differences of calcium carbonate precipitates from the two calcium sources were compared by scanning electron microscopy.Results showed that the overall density of the stabilized sand columns with calcium nitrate was higher,and the fractures after failure were smaller than those in calcium chloride stabilized sand under either saturated or dry conditions.Calcium carbonate in the stabilized sand columns with calcium nitrate had lower permeability