Model Analysis of Rheological Properties of Special Self-Compacting Concrete Paste for High-Speed Railway

The rheological properties of special self-compacting concrete paste played a major role on its performance. The Brookfield R/S SST2000 soft solid tester and TAM AIR 8 channel isothermal calorimeter were used to test the rheological properties and hydration heat effect of special self-compacting concrete paste. The initial cement hydration-rheological model was proposed through the systematical experiments with different water-cement ratio and the chemical admixture, combined with the heat of hydration model of Portland cement. The results showed that the hydration-rheological model of cement paste acted as N, according to the two mutation points on the stress-time curve, which could be divided into three stages, i.e. suspension with no structure, flocculation state structure, condensed state structure. To extend structure mutation values corresponding to the point in time, it can improve the rheological properties of loses with time. With the increasing of water content, heat of hydration effect shows positive effect, but the mechanical effect is weakened. The adding of the superplasticizer delayed the hydration exothermic rate and initial hydration shear stress mutation process.