Effect of physical particle characteristics on the consolidation of cementitious suspensions

Reference Presenter Authors
(Institution)
Abstract
04-050 Marcel Hark Maciel Maciel, M.H.(University of São Paulo); Romano, R.C.(University of São Paulo); Pileggi, R.G.(University of São Paulo); The physical particle characteristics have direct effect on the consolidation of cementitious suspensions. The greater fineness leads to a higher solubility of the particles, accelerating the kinetics of reaction, as well as results in larger surface forces between them. However, it is not frequently found in literature papers reporting both the physical and chemical effects on the consolidation process in the early hydration. An alternative is to consider the relationship between the suspension stiffening and the approximation between the particles, considering some parameters that connecting the hydration and the corresponding particle physical characteristic. Then, measuring the specific surface area (SSA), which is related to the hydrates formation, the real density, and considering the solid content, it is possible to calculate the interparticle separation distance (IPS). This work was aimed to evaluate and detailing the effect of the change of the SSA and particle size distribution of the cement on the consolidation by the calculation of the IPS over time. A clinker was milled together with a fixed content of gypsum in a planetary ball mill, obtaining three distinct particle size distribution: i. similar to found in cement industry, ii. coarse and iii. finer than cement. In the first five hours of hydration, the consolidation process was evaluated by oscillatory rheometry tests by the evolution of the storage modulus (G’). The SSA and real density were obtained after the hydration stoppage at set periods, while the particle size distribution was measured in suspension along the hydration. The results indicate that the consolidation stage is greatly enhanced when the cement particles becoming finer. Comparing that increase with the IPS at set periods it was observed a clear correlation, demonstrating the potential of this approach in the study of cementitious suspensions consolidation.
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