Effects of Aluminum Sulfate and Quicklime/Fluorgypsum Ratio on the Properties of Calcium Sulfoaluminate (CSA) Cement-Based Double Liquid Grouting Materials.

Yuli Wang,Jie Yu,Junjie Wang,Xuemao Guan

doi:10.3390/ma12081222

Abstract

Grouting materials are used frequently in grouting reinforcement projects, such as mining and coastal engineering. Double liquid grouting materials are mostly used because of the fast setting and high early strength properties when the two slurries are mixed together but high fluidity when the two slurries are separated. In our study, double liquid grouting materials were developed from CSA cement (slurry A), quicklime and fluorgypsum (slurry B). Aluminum sulfate was added in slurry B in order to counteract any adverse effects caused by the fluorgypsum, such as the decreased early compressive strength and the prolonged setting time. The effects of aluminum sulfate content and the quicklime/fluorgypsum ratio on the setting time, hydration heat, and compressive strength of the double liquid grouting materials were investigated, and the hydration products were characterized through thermogravimetry-differential thermal analysis (TG-DTA), X-ray Diffraction (XRD), and Scanning Electron Microscope (SEM) tests. The results show that the addition of aluminum sulfate can shorten the setting time and increase compressive strength at both early and later ages. Considering the setting time and compressive strength of double liquid grouting material at the same time, the optimum content of aluminum sulfate was found to be 2%, and the optimum ratio of quicklime/fluorgypsum was found to be 2:8. The values of the optimum content of aluminum sulfate and ratio of quicklime/fluorgypsum were verified from theoretical analysis.

Highlights

Grouting materials can be used to strengthen and consolidate the loose rocks around mining wells or strengthen the marine bed in coastal engineering [1]
When the two slurries were mixed together, the influence of aluminum sulfate and quicklime on the setting time of the double liquid grouting materials is shown in Figures 1 and 2
The ettringite formed through reaction between aluminum sulfate and quicklime in slurry B contributed significantly to the early strength development of the double liquid grouting materials

Summary

Introduction

Grouting materials can be used to strengthen and consolidate the loose rocks around mining wells or strengthen the marine bed in coastal engineering [1]. The requirements of grouting materials include high liquidity, fast setting and high early strength. A single liquid grouting material does not meet all these requirements, this is because a single liquid grouting material with a high liquidity might not have a fast setting ability, and there could be leakage from the cracks in the rocks in this case [2,3,4]. Double liquid grouting materials are composed of two separate slurries (usually named as slurry A and slurry B) [4,5], which have a very high liquidity separately but harden quickly when they are mixed together. The two slurries are injected separately into the rocks and they meet each other and harden quickly at the target location

Methods

Results

Discussion

Conclusion