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DOI: 10.15862/21SATS118 (https://doi.org/10.15862/21SATS118)

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Galkin Yu.Yu., Udodov S.A. Phase analysis of the structure of cement stone isolated at its early loading. Russian Journal of Transport Engineering. 2018; 5(1). Available at: https://t-s.today/PDF/21SATS118.pdf (in Russian). DOI: 10.15862/21SATS118

Phase analysis of the structure of cement stone isolated at its early loading

Galkin Yury Yur’evich
Kuban state technological university, Krasnodar, Russia
E-mail: tcmii@mail.ru

Udodov Sergey Alekseevich
Kuban state technological university, Krasnodar, Russia
E-mail: udodov-tec@mail.ru

Abstract. Loading of reinforced concrete structures in the early stages of hardening causes the development of inelastic deformations that fade with time. Considering the intensive flow of shrinkage deformations during this period, an important role is played by taking into account the effect of moisture on the structure of composites subjected to early loading. The review of works on the study of the dependence «moisture of cement stone – deformation of creep» is given. Since the creep strains, in turn, are influenced by the parameters of the early loading (age at the time of loading, the magnitude and duration of the load), it is appropriate to assume a connection between the moisture content of the cement stone being loaded and its properties after the load is removed. Based on the author’s already available data, a comparative analysis of the phase composition of loaded and unloaded samples was performed using XRD and DTA. On the X-ray patterns of loaded samples, the height of the peaks of the main minerals decreases, which may indicate an increase in the degree of hydration. Peaks of ettringite, as well as CSH hydrosilicates, have a higher intensity when analyzing samples after the early loading. Despite the noted aspects, the main peaks related to portlandite, when the load is applied, decrease. An assumption has been made that this phase is bound by sulfate constituents. The arc of amorphousness of the loaded sample lies below the control one, which indicates its lesser amorphicity.

Differential-thermal analysis as a whole correlates well with XRD data. Derivatograms of loaded samples indicate their increased humidity, and the determination of portlandite content by mass loss in the range 430-470  ⁰C showed a decrease in this phase with the early loading of cement stone.

Keywords: early loading; Portland cement; moisture; surface insulation; X-ray phase analysis; differential thermal analysis; calcium hydrosilicates; portlandite; ettringite

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