Some physical properties of the tested sands. Table 1 In terms of the reagent concentrations, Al Qabany et al. (2012) and Okwadha and Li (2010), among others, report that a bacterial-cell so- lution concentration of the order of 10° cellsm1~+ combined with 0.5 M urea-calcium chloride cementation solution achieves quality results in terms of the urea hydrolysis rate and amount of precipitated calcite. On Fig. 2. Shear strength assessment of crustal sand layer using Torvane device. Fig. 5. Shear strength development for singly MICP spray-treated carbonate sand C material using a one-to-one mixture of 0.5M cementation solution mixed with bacterial-cell solution having an OD¢oo value of 1.5. Fig. 4. Shear strength development for single MICP spray treatment of silica sand using 0.5-M cementation solution mixed with bacterial-cell solutions of various concentrations quantified in terms of their ODgoo values; (a) sand A; (b) sand B. Fig. 3. Experimental setup of wind tunnel used in the present investigation; (a) schematic diagram of the apparatus; (b) photograph of its two diffusers (foreground) and wind blower outlet (background). Fig. 6. Single- and double-MICP spray treatments of sand A and C materials using 0.5 M cementation solution mixed with bacterial-cell solution having an ODeoo value of 1.5. Fig. 8. Outdoor and laboratory experiments involving single MICP spray treatment of sand A tray-specimens treated with 0.5-M cementation solution mixed with bacterial-cell solution having an OD¢oo value of 1.5. Fig. 7. Effect of daily moisture addition on crustal shear strength development for single MICP spray treatment using 0.5M cementation solution mixed with bacterial-cell solutions of various concentrations: (a) sand A; (b) sand B.
