DOI: 10.5061/dryad.0000000bq
title: Study on the improvement of grouting stone properties in coal mine goafs using combined denitrifying bacteria

description: Grouting can effectively reduce residual deformation of coal mine goafs,
 but fly ash grouting materials suffer from poor flowability and slow early
 strength development. Microbially Induced Calcite Precipitation(MICP),
 with its high environmental compatibility and minimal disturbance to
 geotechnical bodies, effectively improves the injectability of grouting
 slurry in goafs. This study combined Castellaniella denitrificans and
 Sporosarcina pasteurii to induce calcite precipitation, preparing
 cement-fly ash slurry with varying water-solid ratios, solid ratios, and
 denitrifying bacteria concentrations. The physical properties of the
 slurry and the mechanical properties of the grouted stone bodies under
 sealed curing conditions were measured. Results showed that the strength
 of the stone bodies cured by MICP increased rapidly within 7 days, and the
 strength reached the standard 2.03 MPa at 28 days under conditions of low
 solid ratio and high water-solid ratio. At a water-solid ratio of 1:1.2
 and a solid ratio of 15%, initial and final setting times were 97.46 and
 127.31 hours, respectively, indicating that MICP enhances slurry fluidity,
 providing more time for grouting construction in goafs. Dual-bacteria MICP
 improves stone body performance by enhancing cohesive, frictional, and
 interlocking forces, with the best compressive strength at a denitrifying
 bacteria concentration with an optical density of 0.8 at 600 nm
 wavelength.
description: # Study on the improvement of grouting stone properties in coal mine goafs
 using combined denitrifying bacteria
 [https://doi.org/10.5061/dryad.0000000bq](https://doi.org/10.5061/dryad.0000000bq) This study combined *Castellaniella denitrificans* and *Sporosarcina pasteurii* to induce calcite precipitation, preparing cement-fly ash slurry with varying water-solid ratios, solid ratios, and denitrifying bacteria concentrations. The physical properties of the slurry and the mechanical properties of the grouted stone bodies under sealed curing conditions were measured. This dataset supports the study on the use of combined denitrifying bacteria, *Castellaniella denitrificans* and *Sporosarcina pasteurii*, to induce calcite precipitation for improving the properties of grouted stone bodies in coal mine goafs through Microbially Induced Calcite Precipitation (MICP). It includes a test programme, measurements of the physical properties of the slurry, and the mechanical properties of the stone. ## **Description of the data and file structure** **Columns:** Water-Solid Ratio: The ratio of the total mass of liquid to the total mass of solid in the slurry. Solid Ratio: The ratio of the mass of cement to the mass of fly ash in the slurry. Concentration of Denitrifying Bacteria: The concentration of denitrifying bacteria used. Density: The density of the slurry. Plastic Viscosity: The viscosity of the slurry in its plastic state. Stone Rate: The rate at which stones form in the slurry. Precipitation Rate: The rate of calcite precipitation. Initial Setting Time: The time taken for the slurry to begin setting. Final Setting Time: The time taken for the slurry to be completely set. 7d UCS: Unconfined Compressive Strength of the stone body after 7 days. 28d UCS: Unconfined Compressive Strength of the stone body after 28 days. ## **Sharing/Access information** There are no other publicly accessible locations for this study data ## **Data Collection** The data was collected from experiments conducted to measure the physical and mechanical properties of grouting slurry and stone bodies under various conditions using Microbially Induced Calcite Precipitation (MICP) with *Castellaniella denitrificans* and *Sporosarcina pasteurii*. ## **Code/Software** No specific code or software was used to generate this data, but standard laboratory procedures for measuring density, viscosity, setting times, stone rate, precipitation rate, and unconfined compressive strength were employed. ### **Usage Notes** * Users of this data should be familiar with basic concepts of geotechnical engineering and microbiologically induced calcite precipitation. * The data is structured to allow analysis of the effects of varying water-solid ratios, solid ratios, and denitrifying bacteria concentrations on the properties of grouting materials and grouted stone bodies. ## **Abbreviations** * **UCS**: Unconfined Compressive Strength * **MICP**: Microbially Induced Calcite Precipitation For any further questions or clarifications, please contact the corresponding author of the study at 13658040318@163.com.