Microcalorimetric analysis of methylcellulose influence on the hydration process of tricalcium aluminate, alite and their mixture

Abstract

In the paper, the results of investigation concerning the influence of 0.3% addition of hydroxypropyl methylcellulose (MC) of 40 and 70 Pa s viscosity on the hydration process of main clinker phases C 3 S and C 3 A are presented. The course of hydration is documented using microcalorimetry, and formed phases were identified by XRD. The research indicated that methylcellulose inhibited the hydration process of clinker phases, analysed both, separately and in their mixture. Moreover, it was found that the presence of MC admixture also led to the reduction in calcium sulphate dihydrate reactivity in the system.

Effect of viscosity modifier admixture on Portland cement paste hydration and microstructure

“…Specimens 1M and 3M had also their early age properties changed. Both had a slightly longer dormant period, than the reference as also reported by [21]. However, the C 3 S peak obtained for both was also slightly higher than reference samples, meaning that the hydration reactions were significantly accelerated after the extended dormant period.…”

“…However, reactions of blended C 3 A and gypsum powders were sensitive to VMA viscosity. The authors justified their finds stating that C 3 A hydration was more susceptible to lower ions mobility through viscous solutions [21]. Furthermore, the cement hydration delay was explained with the effect of HPMC on the precipitation of calcium hydroxide, the polymer's water absorption capacity [22][23][24], and the methyl content [25].…”