Title: Study of Non-Adsorptive Viscosity Agents Applied to Self-Compacting Concrete
Author(s): H. Yammamuro, T. lzumi and T. Mizunuma
Publication: Symposium Paper
Appears on pages(s): 427-444
Keywords: Admixtures; adsorption; concretes; particle size distribution; portland
cement; rheological properties; superplasticizers
A series of viscosity agents, some of which have no tendency to adsorb onto cement particles, has been studied for self-compacting concrete. It was found that the mortar rheology of self-compacting concrete is controlled by the adsorption nature of viscosity agents. The adsorptive viscosity agents such as cellulose derivatives form bridge structures and compete with the super-plasticizers (SP) to occupy at adsorption sites once the agents adsorb on the surface of the cement particles in the mortar. This reduces the fluidity of the mortar. A use of the non-adsorptive viscosity agents, on the other hand, accomplishes the adequate fluidity and viscosity of the mortar. In addition, the adsorption sites on the cement particles are reserved for the SP even such agents are used. In order to understand how the viscosity agents work, the adsorption amounts, the zeta potentials and the particle size distributions were observed, while the interaction between the admixtures were examined.