Experimental study on MICP stabilized graded crushed stone base using surface infiltration

ObjectiveThis study investigates the effectiveness of microbial induced carbonate precipitation (MICP) technology in stabilizing graded crushed stone base through surface infiltration.MethodThe influence of MICP technology on road performance of graded crushed stone base was investigated through the unconfined compressive strength test, splitting test, and freeze-thaw cycle test. Additionally, the distribution of calcium carbonate content in crushed stone base was investigated through the acid wash test and microscopic test; while the consolidation mechanism was analyzed by using MICP technology.ResultMICP technology could enhance the compressive strength of graded crushed stone. The enhancement effectiveness was strongly influenced by the volume of infiltration solution and the infiltration times. The 7-day indirect tensile strength and flexural strength of MICP stabilized graded crushed stone specimens were increased by 93.2% and 75.4% respectively in the optimal infiltration solution volume and cycle conditions. The internal calcium carbonate content of MICP specimens initially decreased and then increased with the increase of infiltration depth.ConclusionThe surface infiltration based MICP technology significantly enhances the unconfined compressive strength, flexural strength and frost resistance of graded crushed stone, demonstrating superior mechanical properties and durability. The stabilizing effect of MICP technology on graded crushed stone primarily relies on the binding effect of calcium carbonate crystals generated through mineralization reactions on crushed stones.