Effects of Viscosity Type Modifying Admixture on the Properties of Cement-Based Materials

In view of the segregation resistance, stability and pumpability of cement-based materials can be effectively improved by using viscosity modifying admixtures. In order to promote the application of VMAs in cement-based materials, the effects of viscosity type modifying admixture on the properties of cement-based materials, such as the rheological parameters, plastic viscosity of cement paste, workability, bleeding rate of fresh concrete, and compressive strength of hardened concrete were researched in this paper. The results showed that the water retention and cohesiveness of cement paste could be enhanced and the workability of cement-based materials was improved by the introduction of VMA, and then the phenomenon of segregation and bleeding could be improved. Although the early strength of concrete at 3 d and 7 d would be decreased, the strength at 28 d would be increased due to the addition of VMA, and the VMA-2 exhibited superior comprehensive performance.