Effect of Silica Fume and Nano SiO2 on Properties of High Water Materials

In order to improve workability and strength of new high water materials, the influence of silica fume and nanometer on the physical and mechanical properties of high water materials was studied. By changing the content of silica fume or gas-phase nano-SiO2 in the new high-water materials, the workability of the materials was observed, and the strength of the materials at different ages was measured. The results showed that the increase of nano-SiO2 content significantly shortened the coagulation time of the high-water materials and improved the cohesion of the high-water materials. When the water-cement ratio was 1:1, the optimal content of silica fume was 3%, and the strength of the specimen in seven days was 43.7% higher than that of the original high-water material. At the water-cement ratio of 1.5:1, the optimal content of nano-SiO2 was 2%, and the strength of the specimen in seven days was 21.2% higher than that of the original high-water material. Through SEM scanning the microstructure of the material, it was found that the hydration reaction of the high-water material with nano-sio(2) was more sufficient and the structure was denser.