Effect of Water-Retaining Additives on Some Properties of Self-Compacting Concretes. Part 2. Rheological Characteristics of Concrete Mixes and Strength of Self-Compacting Concretes

Estimation of the effect of water-retaining additives on the rheological characteristics of self-compacting mixes and physical-chemical properties of self-compacting concretes (SCC) is made. The effect of increasing spreadability is noted after certain period of time for heavy and fine concrete mixes on the cement PTS500 DO N with the complex of additives of superplasticizer+stabilizer under the condition of providing the equal mobility. Such nature of the action of water-retaining additive improves the keeping – ability of the mix to self-compaction – by two times. When introducing the complex of superplasticizer-stabilizer in the light concrete self-compacting mix, the effect of increasing spreadability is absent and t the reduction in the average density of the mix occurs. The analysis of curves of change in the flowability of concrete mixes shows the ambiguous effect of water-retaining additives and testifies the necessity of additional experimental verification of their interaction with the cement of a concrete type. The kinetics of the change in shear yield stress of self-compacting mixes with water-retaining additives confirms the mechanism of action of stabilizers which is reducing the velocity of cement hydration and increasing the keeping of mixes. In the course of studies, the high water-retaining effect of stabilizers which leads to the growth of water consumption of concrete mixes and reduction in the strength of concrete is established. When supplying SCC with the complex of additives, superplasticizer+water-retaining additive, it is necessary to present the curve of change in flowability of the mix in time.

L.I. KASTORNYKH, Candidate of Science (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.),
I.A. DETOCHENKO, Master student,
E.S. ARININA, Master student

Don State Technical University (1, Gagarina Square, Rostov-on-Don, 344010, Russian Federation)

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