Study on the improvement of grouting stone properties in coal mine goafs using combined denitrifying bacteria

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...., , , # 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...