Influence of additional components on mechanical and shrinkage properties of high performance cementitious grouting materials

Semi-flexible pavement is a new type of pavement technology with excellent mechanical and road performance. Grouting materials play a crucial role in filling and reinforcing semi-flexible pavements as an important component. In this study, based on sulphoaluminate cement, the effect of mineral admixtures on rheological properties of grouting materials was studied by introducing rheology. High-performance grouting materials for semi-flexible pavements were prepared by varying the ratio of water-cement ratio, early-strength agent and mineral admixture, and their optimal ratios were determined. The research findings indicate that, the grouting materials with the best mechanical properties can be obtained when the water-to-binder ratio is 0.5, and the dosages of lithium carbonate, silica fume, microspheres, and granulated blast furnace slag are 0.2 %, 1.6 %, 5.0 %, and 5.0 %, respectively. The optimal dosage for shrinkage-reducing agents to improve the shrinkage behavior of grouting materials is in the range of 0.10–0.15 %. The accelerated early hydration reaction and improved compactness of the material matrix are the main reasons for the rapid development of the mechanical properties of the grouting materials. Mineral admixtures can undergo a hydration reaction similar to that of cement to produce a rigid gel consisting of very small particles with a laminar structure, which has a positive effect on the development of grouting material properties. The improvement in shrinkage behavior is achieved through the filling effect of silica fume and the micro-expansion effect of plasticizing expanders, which generate small and uniform bubbles.