Study on hydration cementation and enhancement mechanism of grout-rock interface of PVA modified grouting material
- 1CCTEG Coal Mining Research Institute, Beijing, China
- 2Mining Research Branch, China coal Research Institute, Beijing, China
Abstract
The weakly cemented sandstone aquifer in coal mine is prone to particle softening under mining disturbance and water-rock interaction, which induces the decrease of rock integrity and the development of water conducting channel, leading to the instability and failure of aquifer. To address the low early-age hydration activity of grouts containing a high proportion of coal gangue, discontinuous grout-rock interfacial bonding, and limited adaptability to weakly cemented sandstone, this paper uses cement and coal gangue(CG) as raw materials to prepare modified grouting materials with different polyvinyl alcohol (PVA) content. The uniaxial compression, XRD, FTIR and SEM test methods were used to systematically study the influence of PVA content on the performance of solid waste based slurry, the bearing characteristics of slurry-rock composite, the evolution of hydration products and the interface micro structure. The synergistic enhancement mechanism of PVA induced hydration cementation film coating and slurry-rock interface was revealed. The results show that: (1) High content of CG weakens the early hydration activity of cement slurry system. After PVA is added, the fluidity of slurry increases, the initial and final setting time is further prolonged, and the bleeding rate decreases, indicating that PVA can improve the flow stability and water retention performance of coal-based solid waste slurry. (2) PVA content has obvious dosage dependence on the bearing capacity of the grout rock complex. The peak stresses of the 0%, 0.3%, 0.6% and 1.0% PVA groups are 4.87 ± 0.14 MPa, 5.35 ± 0.06 MPa, 6.04 ± 0.09 MPa and 5.12 ± 0.09 MPa, respectively. The 0.6% PVA group shows relatively better mechanical properties within the test range of this paper. (3) Appropriate amount of PVA can promote the filling of C-S-H gel, AFt rod crystals and C-H flake crystals on the surface of sandstone particles and in the pores and fracture, and adsorb and coordinate through hydroxyl groups to form hydration products and flexible polymer film. The hydration products provide a rigid skeleton, and the PVA flexible film plays a buffering role in the interface bonding and deformation, and synergistically realizes the densification, continuity and toughness enhancement of the weakly cemented sandstone-grout interface. The experimental results show that 0.6% PVA content can achieve a better balance between slurry performance, water retention stability, interface hydration cementation and mechanical bearing capacity, which can provide material design basis for grouting reinforcement of weakly cemented aquifer, thickening of aquiclude and prevention and control of mining-induced water disasters.
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BibTeX
@article{li2026study,
title = {{Study on hydration cementation and enhancement mechanism of grout-rock interface of PVA modified grouting material}},
author = {Youwei Li and Haoyu Hu and Yujun Zhang and Gui Liu},
journal = {PLOS One},
year = {2026},
month = nov,
doi = {10.1371/journal.pone.0362466},
url = {https://doi.org/10.1371/journal.pone.0362466},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Study on hydration cementation and enhancement mechanism of grout-rock interface of PVA modified grouting material
AU - Youwei Li
AU - Haoyu Hu
AU - Yujun Zhang
AU - Gui Liu
PY - 2026
DA - 2026/11/05
JO - PLOS One
DO - 10.1371/journal.pone.0362466
UR - https://doi.org/10.1371/journal.pone.0362466
AB - The weakly cemented sandstone aquifer in coal mine is prone to particle softening under mining disturbance and water-rock interaction, which induces the decrease of rock integrity and the development of water conducting channel, leading to the instability and failure of aquifer. To address the low early-age hydration activity of grouts containing a high proportion of coal gangue, discontinuous grout-rock interfacial bonding, and limited adaptability to weakly cemented sandstone, this paper uses cement and coal gangue(CG) as raw materials to prepare modified grouting materials with different polyvinyl alcohol (PVA) content. The uniaxial compression, XRD, FTIR and SEM test methods were used to systematically study the influence of PVA content on the performance of solid waste based slurry, the bearing characteristics of slurry-rock composite, the evolution of hydration products and the interface micro structure. The synergistic enhancement mechanism of PVA induced hydration cementation film coating and slurry-rock interface was revealed. The results show that: (1) High content of CG weakens the early hydration activity of cement slurry system. After PVA is added, the fluidity of slurry increases, the initial and final setting time is further prolonged, and the bleeding rate decreases, indicating that PVA can improve the flow stability and water retention performance of coal-based solid waste slurry. (2) PVA content has obvious dosage dependence on the bearing capacity of the grout rock complex. The peak stresses of the 0%, 0.3%, 0.6% and 1.0% PVA groups are 4.87 ± 0.14 MPa, 5.35 ± 0.06 MPa, 6.04 ± 0.09 MPa and 5.12 ± 0.09 MPa, respectively. The 0.6% PVA group shows relatively better mechanical properties within the test range of this paper. (3) Appropriate amount of PVA can promote the filling of C-S-H gel, AFt rod crystals and C-H flake crystals on the surface of sandstone particles and in the pores and fracture, and adsorb and coordinate through hydroxyl groups to form hydration products and flexible polymer film. The hydration products provide a rigid skeleton, and the PVA flexible film plays a buffering role in the interface bonding and deformation, and synergistically realizes the densification, continuity and toughness enhancement of the weakly cemented sandstone-grout interface. The experimental results show that 0.6% PVA content can achieve a better balance between slurry performance, water retention stability, interface hydration cementation and mechanical bearing capacity, which can provide material design basis for grouting reinforcement of weakly cemented aquifer, thickening of aquiclude and prevention and control of mining-induced water disasters.
SN - 1932-6203
ER -