Comprehensive Effect of the Time and Water-Cement Ratio on the Rheological Properties of Power-Law Cement Grouts

Yang Zhi-Quan,Mi Ya-Peng,Xu Wan-Zhong,Wang Yu-Dong,Guo Yan-Hui,Su Jian-Kun,Ding Yi,Zhang Bi-Hua,Li Shi-Hou,Liu Hao,Yang Yi,Chen Jun-Zhi,Liu Wan-Lin,Zhu Ying-Yan,Daoyi Zhu

doi:10.1155/2021/6636708

Abstract

The rheological properties of cement grouts are significantly affected by the changes of the time and the water-cement ratio, which determine the diffusion state of grouts in rocks and soils and influence the outcome of projects. In this study, Portland cement grouts with water-cement ratios of 0.50, 0.55, 0.60, 0.65, 0.70, and 0.75 at six moments, including 0 minutes, 5 minutes, 10 minutes, 20 minutes, 30 minutes, and 60 minutes, were evaluated to figure out the comprehensive effect of the time and the water-cement ratio on the rheological properties of power-law cement grouts. The results showed that the water-cement ratio had a great influence on both the consistency coefficient and the rheological index of the power-law cement grouts. The former appeared to have a downward trend with the increase of the water-cement ratio, and the latter appeared to have an upward trend. There was a rising tendency between the time and the consistency coefficient, while the rheological index was less affected by time. The difference between its maximum and minimum values was within 5%. Combined with the perspectives of statistical theory, practical applicability, and accuracy, the exponential model was the optimal model for showing the relationship between the comprehensive effects of the time, water-cement ratio, and consistency coefficient of the power-law cement grouts. The linear model was the optimal model of the rheological index based on the comprehensive effect of time and the water-cement ratio. Based on this, a power-law rheological equation with consideration of the comprehensive effect of time and water-cement ratio was established. The research results could not only improve the rheological theory of power-law cement grouts but also provide technical support for engineering practice.

Highlights

In the near surface and mountainous area, the strong activity of geofluid may induce the occurrence of geological disasters such as landslide, debris flow, and collapse, which will lead to heavy casualties, environmental damage, and huge property losses
This research was focused on power-law cement grouts (W/C below 0.75), which are widely used in engineering practice
Experimental research, theory discussion, and numerical analysis were used to discuss the comprehensive effect of time and the water-cement ratio on the rheological properties of power-law cement grouts at room temperature (25°C ± 2°C)

Summary

Introduction

In the near surface and mountainous area, the strong activity of geofluid may induce the occurrence of geological disasters such as landslide, debris flow, and collapse, which will lead to heavy casualties, environmental damage, and huge property losses. As an inorganic cementitious material with low cost and good performance, has been widely used. Setting time (min) Initial time 90 Final time 400. Flexural strength (MPa) 28 d Hang wire Dial Geofluids

Methods

Results

Conclusion