水泥浆触变性评价方法的探索

Study on Evaluation of Thixotropy of Cement Slurry

通过实验分析了目前常用的触变性评价方法——静切力法和滞后环法,对其合理性进行了讨论;并结合触变水泥浆的现场应用,提出了水泥浆触变性评价应涵盖流动性、胶凝强度发展情况以及施工安全性3个方面,针对常用触变性评价方法存在的问题,探索了一种评价水泥浆触变性的新方法。该方法采用精度高的旋转黏度计在转速极低的情况下测量水泥浆不同时刻的剪切力,几乎消除了剪切力对胶凝强度的影响,通过程序控制可实现对样品的连续测量。此方法可准确反映不同温度下水泥浆胶凝强度发展的快慢和大小,从而可更好地指导触变水泥浆体系的开发和现场应用。

Gel strength method and hysteresis loop method are commonly used in the evaluation of thixotropy of cement slurry.These two methods have recently been studied.Taking field application of thixotropic cement slurries into consideration,it was suggested that the evaluation should cover mobility and progress of gel strength of cement slurry,and operation safety.Based on the study,a new evaluation method was developed,employing a high accuracy rotational viscometer to measure the shear strengths of cement slurry at different times in very low shear rates.The influence of shear force on gel strength is almost eliminated.Continual measurement can be realized through program control.Using this method,the change of gel strengths of cement slurry with temperature can be studied,thus helping develop better cement slurry formulation for field application.