Publikation: Optimizing compressive strength of sand treated with MICP using response surface Methodology

Das Lehrgebiet publiziert in SN Applied Sciences zum Thema: “Optimizing compressive strength of sand treated with MICP using response surface Methodology”.

In the present study, the optimization of the microbiologically induced calcium carbonate precipitation (MICP) to produce biosandstone regarding the compressive strength is shown. In past studies MICP has been optimized regarding factors like urease activity, calcium carbonate precipitation rate and permeability of treated specimens but only in a few cases regarding compressive strength after biocementation. This study gives insight into the influence of the main components that influence the compressive strength of produced biosandstone. For the biosandstone production, quartz sand was treated sequentially with the ureolytic microorganism Sporosarcina pasteurii (ATCC 11859) and a reagent containing urea and calcium chloride. A central composite design (CCD) was employed, and the resulting experimental data applied to a quadratic model. The statistical significance of the model was verified by experimental data (R²=0.9305). Optimized values for the concentration of urea and calcium chloride were 1492 mM and 1391 mM. For the volume of cell suspension during treatment 7.47 mL was determined as the optimum. Specimen treated under these conditions achieved a compressive strength of 1877 ± 240 kPa. This is an improvement of 144 % over specimen treated with a reagent that is commonly used in literature (1000 mM urea/1000 mM CaCl₂).

N. Erdmann, K.M. de Payrebrune, R. Ulber, D. Strieth; Optimizing compressive strength of sand treated with MICP using response surface methodology; SN Applied Sciences (2022) im Druck