The Influence of Concentrations of Cement Particles on Rheological Behavior and Thixotropy of Portland Cement Paste

E-ISSN： 1662-9779|2018|276|27-34

ISSN： 1012-0394

Source： Solid State Phenomena, Vol.2018, Iss.276, 2018-08, pp. : 27-34

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Abstract

The influence of concentration of cement particles φ_c on rheological behavior (flow behavior, dynamic yield stress, plastic viscosity) and thixotropy of the Portland cement CEM I 42.5 R paste was investigated in this research. Also, thixotropy was evaluated by index of reversible structure of Portland cement paste. Concentration of cement particles φ_c ranged from 0.434 to 0.518. Investigation was carried out using rotational rheometer Rheotest RN4.1 with coaxial cylinders. The tests revealed that as φ_c decreases from 0.518 to 0.434, rheological behavior of Portland cement paste is improved: yield stress decreases from 12.7 Pa to 7.1 Pa as well as plastic viscosity – from 4.3 Pa·s to 0.88 Pa·s. The exponential correlation between φ_c and index of reversible structure of Portland cement paste was found. As φ_c decreases from 0.518 to 0.434, index of reversible structure of Portland cement paste, which describes a thixotropy, decreases from 5291 Pa·min to 977 Pa·min.