A Systematic Study on the Influence of Grain Characteristics on Hydraulic and Mechanical Performance of MICP-Treated Porous Media

• Published in: Transport in porous media Vol. 147; no. 2; pp. 305 - 330
• Main Authors: Konstantinou, Charalampos, Wang, Yuze, Biscontin, Giovanna
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.03.2023; Springer Nature B.V
• Subjects: Civil Engineering; Classical and Continuum Physics; Compressive strength; Earth and Environmental Science; Earth Sciences; Environmental engineering; Fluid flow; Geotechnical Engineering & Applied Earth Sciences; Grain size; Granular materials; Hydraulics; Hydrogeology; Hydrology; Hydrology/Water Resources; Industrial Chemistry/Chemical Engineering; Mechanical properties; Particle shape; Particle size; Particle size distribution; Permeability; Porous media; Reduction; Sand; Shape effects; Particle size distribution; Permeability; Porosity; Grain characteristics; Strength; MICP performance
• ISSN: 0169-3913; 1573-1634
• DOI: 10.1007/s11242-023-01909-5

The bio-cementation of sands (microbially induced carbonate precipitation) is an emerging technique that could broaden the horizons in the sectors of hydraulics, hydrology and geo-environmental engineering. It has been used extensively to increase the strength of sands and for controlled permeability reduction. This study focuses on the choice of base materials and presents an extensive program to generate materials with various combinations of properties and assess the effects of grain shape, size and spread of particle size distributions on permeability, unconfined compressive strength and porosity. Better strength enhancement and more controlled permeability reduction is achieved for bio-treated specimens with a moderate number of particle-to-particle contacts ( D 50  = 180–890 μm). Results showed that the grain size has the greatest impact on both strength and permeability with very small ( D 50  = 110 μm) or very large grains ( D 50  = 1810 μm) not being effective in terms of strength enhancement and permeability control. The higher the uniformity coefficient of the base material is ( D 60 / D 10 from 1.4 to 5.6), the greater the effects on the mechanical properties are because of the narrower pore space and the higher number of contact points between particles. Materials with higher uniformity coefficients and larger grain sizes (i.e., D 60 / D 10  = 5.6, D 50  = 2454 μm) provide more controlled strength enhancement and permeability reduction. The particle shape either angular, subrounded, or spherical does not affect much the resulting mechanical properties as long as the grain sizes fall within a region compatible to the bacterial size ( D 50  = 180 and 890 μm). Article Highlights MICP was applied successfully using a wide range of base granular materials. The grain size has the greatest impact on strength and permeability in bio-treatment against grain shape and PSD. Wider particle size distribution and larger grain size leads to controlled alteration of strength and permeability.