Study of Non-Adsorptive Viscosity Agents Applied to Self-Compacting Concrete

A series of viscosity agents, some of which have no tendancy to absorb 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 from bridge structures and compete with the superplasticizers (SP) to occupy at adsorption sites once the agents adsorb on the surface of the cmeent 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.