Clay dosage and water/cement ratio of clay-cement grout for optimal engineering performance

Clay-cement grout is widely used in grouting engineering, but the varied field demands are often difficult to satisfy since the properties of the grout are affected by multiple factors and cannot be simply predicted. This Note presents an experimental study to investigate the effect of clay dosage and water/cement ratios on the performance of clay-cement grout. Twenty batches of grout samples were designed by varying the water/cement ratios from 0.5 to 2 and clay dosages from 5% to 45% which are in the ranges commonly used in engineering practice. The results showed that the optimal performance of the clay-cement grout was highly dependent on the clay dosage and water/cement ratio. In general, higher clay dosage and lower water/cement ratio improved the stability and led to lower permeability of the clay-cement grout but led to a poor performance in terms of fluidity and strength. A methodology was proposed for determining the optimum clay dosage and water/cement ratio to fulfill various field demands. The applicability and economic benefits of the presented method were evaluated by a detailed case study which also demonstrated the effectiveness of the framework for the determination of the optimum dosage of ingredients for clay-cement grout.