Experimental Study On Seepage Prevention And Plugging By Microbial-induced Calcium Carbonate Deposition

Concrete as the most widely used building materials, concrete structure has become the world’s most widely used construction groups, but the structure cracked concrete is concrete development stage accompanied by the inevitable question. There are many Stage for concrete seepage repair methods and repair materials, but based on the materials, mostly harmful to the environment, and compatibility of cement-based materials and bad.Microbial-induced calcium deposition technique is a new method for repairing cracks, its environmentally friendly, and good compatibility with the deposition of calcium carbonate cement-based materials. Fix principle that urease produced by microbial metabolism of the urea can be decomposed into ammonium ions and carbonate ions, after the repair parts calcium carbonate and calcium ions can be combined to form calcium carbonate, the latter is deposited in the stacking defects direct or indirectly, crack repair.Pap test using Bacillus induced deposition of calcium carbonate, in order to study the applicability of microbial-induced calcium deposition in the engineering aspects of seepage experimental research mainly in the following areas:1.Of different widths and different lengths of cracks induced by microbial effect of calcium carbonate deposition technique to repair summarize each applicable restoration. The results show that:the direct infusion of bacteria and nutrients in a manner more suited to small cracks; using pre-filled perfusion medium and bacteria and nutrients suitable for a wide fissure way; activity of bacteria is the cause of induced deposition of calcium carbonate; crack length on the block the effect was less affected. 2.Through the use of microbial-induced changes in calcium deposition plugging cracks in the soil permeability indirect research. The results show that:the activity of bacteria is the key to induce deposition of calcium carbonate can reduce soil permeability; foreign soil by reducing the permeability of concrete, concrete block can be achieved indirectly crack closure.3.After microbial-induced calcium deposition technique to repair, compactness of concrete cracks plugging. The use of ultrasonic detector after the repair of cracks were detected before and after plugging compactness contrast, test data show that the deposition of calcium carbonate by microbial induced fracture after blocking technology, to a certain extent, to meet the requirements of compactness.4.Using the same bacterial activity of different concrete crack repair, repair of comparing different bacterial activity crack speed. The results show:Activity-induced deposition of calcium carbonate on a larger speed in a certain range, the closure rate increases with increase activity.