红黏土综合浆水化进程及结石体微观形貌研究

Study on hydration process of red clay cement grout and micro-morphology of grout stone

为研究西南乌蒙山区红黏土所配制红黏土综合浆的水化进程和结石体微观形貌,采用直接法测定了红黏土综合浆的水化热特征,并采用扫描电镜分析了红黏土水泥浆水化产物的微结构特征,研究了水泥和结构添加剂对红黏土综合浆水化产物的影响。根据红黏土综合浆等温放热曲线,可将红黏土综合浆的水化进程分为加速期、减速期和稳定期,并通过回归分析获得了浆液水化动力学方程。观察不同龄期红黏土综合浆结石体的扫描电镜图片,发现3 d龄期结石体骨架结构较为蓬松,形成部分小块C-S-H凝胶;7 d龄期时形成大量C-S-H凝胶,结石体趋向形成1个整体;28 d时结石体各水化产物已基本形成,相互搭接形成整体结构。研究表明:水泥是浆液水化反应的基础;结构添加剂的加入提高了水泥的水化反应速度,从而提高了浆液的早期强度;过高原浆密度会降低水泥水化速度。

In order to study the hydration process of red clay cement grout prepared by red clay in the southwest Wumeng mountain area in southwest China and the micro-morphology of the grout stone,the hydration heat characteristics of red clay cement grout were measured by direct method,and the microstructure characteristics of the hydration products of red clay cement grout were analyzed by scanning electron microscope(SEM),and the effects of cement and structural additives on the hydration products of red clay cement grout were studied.According to the isothermal heat release curve of red clay cement slurry,the hydration process of red clay cement slurry can be divided into acceleration period,deceleration period and stability period,and the slurry hydration kinetics equation was obtained through regression analysis.The SEM pictures of the grout stone of red clay cement grout at different ages can be clearly observed:the skeleton structure at 3 d age was relatively fluffy,forming some small pieces of C-S-H gel;at the age of 7 d,a large amount of C-S-H gel was formed,and the stone body tended to form a whole.At 28 d age,the hydration products of the stone body had basically formed and overlapped with each other to form an overall structure.The research showed that cement is the basis of the hydration reaction for the red clay cement grout.The addition of structural additives improves the hydration reaction speed of cement,thus improves the early strength of grout.