Open AccessResearch into the Time Factor in the Formation of Phase Composition of the Cement Stone Structure
Author(s) -
Н И Макридин,
I. N. Maksimova,
D. V. Emelyanov,
D N Barabanov
Publication year - 2021
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/1079/6/062028
Subject(s) - portlandite , cement , alite , hardening (computing) , carbonation , ettringite , materials science , superplasticizer , belite , hydrate , humidity , composite material , mineralogy , portland cement , chemistry , clinker (cement) , thermodynamics , organic chemistry , layer (electronics) , physics
The challenge of obtaining high-quality concretes rests on the specificity of hydration hardening of a cement binder, during which the introduction of even a small amount of this or that component or a change in the hardening conditions may lead to drastic changes in the structure and properties of cement materials. In order to reveal the nature of the influence of plasticizing additives and their introduction procedure, a set of research efforts targeting microstructure and basic mechanical properties was deployed, including the study of changes of cement stone’s structural and mechanical parameters over a long period of hardening (up to 18 years) and the composition of cement stone’s hydration products. The main variable factors dealt with are: the dosage of SP S-3 and the modifier’s introduction procedure during mixing of cement with water. The paper imparts findings on the kinetics of changes in the content of alite, belite and other hydrosilicates in cement stone, as well as portlandite against the duration of samples’ hardening. It was found that for almost all compositions with S-3, there is a decrease in the intensity of calcite reflections (3.029 Å) compared to the control sample, which speaks of a slight decrease in carbonation processes in the presence of a superplasticizer. When the temperature and humidity conditions of hardening change, especially over a long period, structural changes associated, for example, with the destabilization of hydroaluminate phases, decompression caused by the formation of secondary crystalline hydrates of various densities, and the release of hydrate water can be one of the reasons for changing the strength of cement systems over time. These phenomena were analysed throughout its hardening time lasting up to 18 years.