Laboratory Grouting Tests using Ultrafine Cement Based Grouts of Smooth Surface Particles by Dry Impact Blending Method

Cement is a basic material for dam foundation grouting. Cement particles have nonspherical and irregular shapes. Based on the findings in Particle Engineering, spherical particles can be effectively injected into cracks than nonspherical particles. If the cement particles are spherical or have smooth surfaces, dam foundation grouting will be more effective, so we carried out laboratory grouting tests and investigated the effects of cement particles with smoothened surfaces on injection of cement based grouts. In this paper, we used ultrafine cement as grout materials and the surfaces of ultrafine cement particles were smoothened by dry impact blending method. We evaluated the shape of cement particles by electron-microscope and image analysis. We conducted laboratory grouting tests using 50μm crack width model and we found that ultrafine cement grout with smoothened surfaces could be injected well in the low injection pressure condition.