# Zeolite-Modified Acrylate Grouts: Synergistic Water-Sealing Performance with Cement Slurry Combined Grouting for Water-Rich Sandy Cobble Tunnels

## TL;DR

This paper introduces a new grouting material combining zeolite and acrylate to improve water sealing in tunnels built in water-rich sandy cobble strata.

## Contribution

The study proposes a novel zeolite-acrylate composite grout with optimized parameters for enhanced water-sealing performance in challenging geological conditions.

## Key findings

- Zeolite addition reduces gel time by up to 23% but excessive content delays solidification.
- Bond strength shows a non-monotonic trend with zeolite dosage, initially decreasing then increasing.
- SEM analysis confirms strong interfacial bonding between the composite and surrounding materials.

## Abstract

Water seepage in shield tunnels in water-rich sandy cobble strata threatens construction safety and long-term durability. Grouting, a widely used remedial technique, depends on material performance. Among common grouts, conventional acrylate (AC) grouts have inherent limitations in strata. This study develops an enhanced zeolite-acrylate composite grouting material by incorporating zeolite powder into the AC matrix. Systematic experiments assessed the impacts of zeolite dosage, slurry ratio, and water use ratio on gel time, water absorption expansion rate, and bond strength, with interfacial characteristics analyzed via SEM. Results indicate zeolite addition shortens gel time by up to 23% (excessive content retards solidification); 24-h expansion rate ranges 63–111%; bond strength shows a non-monotonic trend with zeolite dosage (initial decline then rise), and higher water content weakens adhesion. Scanning electron microscopy (SEM) confirms robust interfacial bonding. Proposed reference field parameters (water use ratio 5:1–6:1, slurry ratio 5:1–6:1, zeolite dosage 0.5–1.0%) require flexible adjustment according to on–site conditions. Notably, gel time is not inherently better when shorter in practice, but tailored to specific construction scenarios. Rigorous tests verify the composite’s superior seepage control capacity with ultrafine cement grout, providing theoretical and practical guidance for grouting design in complex hydrogeological environments.