Microfluidic study in a meter-long reactive path reveals how the medium's structural heterogeneity shapes MICP-induced biocementation.

Microbially induced calcium carbonate (CaCO) precipitation (MICP) is one of the major sustainable alternatives to the artificial cementation of granular media. MICP consists of injecting the soil with bacterial- and calcium-rich solutions sequentially to form calcite bonds among the soil particles that improve the strength and stiffness of soils. The performance of MICP is governed by the underlying microscale processes of bacterial growth, reactive transport of solutes, reaction rates, crystal nucleation and growth.

Evaluating [Formula: see text] breakthrough in a shaly a caprock material: a multi-scale experimental approach.

The potential of underground [Formula: see text] storage relies on the sealing efficiency of an overlaying caprock that acts as a geological barrier. Shales are considered as potential caprock formations thanks to their favourable hydro-mechanical properties. In this work the sealing capacity of Opalinus Clay shale to [Formula: see text] injection is studied by means of capillary entry-pressure and volumetric response.

Controlling the calcium carbonate microstructure of engineered living building materials.

The fabrication of responsive soft materials that enable the controlled release of microbial induced calcium carbonate (CaCO) precipitation (MICP) would be highly desirable for the creation of living materials that can be used, for example, as self-healing construction materials. To obtain a tight control over the mechanical properties of these materials, needed for civil engineering applications, the amount, location, and structure of the forming minerals must be precisely tuned; this requires good control over the dynamic functionality of bacteria. Despite recent advances in the self-healing of concrete cracks and the understanding of the role of synthesis conditions on the CaCO polymorphic regulation, the degree of control over the CaCO remains insufficient to meet these requirements.

Direct currents stimulate carbonate mineralization for soil improvement under various chemical conditions.

The present study integrates direct electric currents into traditional calcium carbonate mineralization to investigate electrochemical interactions and the subsequent crystalline growth of CaCO bonds in sand. A specific line of focus refers to the effect of three chemical reactive species involved in the stimulated geo-chemo-electric system, namely CaCl, Ca(CHCOO) and Ca(CHCH(OH)COO). By altering treatment conditions and the applied electric field, we capture distinctive trends related to the: (i) overall reaction efficiencies and distribution of CaCO crystals is sand samples; (ii) promotion of CaCO mineralization due to DC (iii) crystallographic and textural properties of mineralized bonds.

3-D micro-architecture and mechanical response of soil cemented via microbial-induced calcite precipitation.

We introduce the application of microbial-induced calcite precipitation via the ureolytic soil bacterium Sporosarcina Pasteurii in freeze-dried form, as a means of enhancing overall MICP efficiency and reproducibility for geotechnical engineering applications. We show that the execution of urea hydrolysis and CaCO precipitation persist as a "cell-free" mechanism upon the complete breakdown of rehydrated cell clusters. Further, strength and stiffness parameters of bio-cemented sands are determined.