Structural-phenomenological analysis of interrelation of microstructure indexes and properties of set cement systems

Abstract

The study of the chemical and physical processes of solidification of polydisperse cement systems until now is based predominantly on empirical approaches. The phenomenological analysis of the interrelation of structure coefficients of set cement systems at the microlevel with their physical-mechanical properties was proposed as one of scientificallypractical approaches to control of physical and chemical processes of structure formation of controlled-quality concretes. The comparison of the quantity indicators of a microstructure of cement rock and its functional properties can be used for the estimation of structural modifications with a variation in the composition of cement systems. The aim of the study was to obtain quantitative data of the structural-phenomenological analysis of set cement systems for determination of interrelation of microstructure indexes with their physical-mechanical properties. For the analysis of the structure of cement systems we used fractal geometry and the theory of passing (percolation)-based methods as well as modern modelling methods and scanning electronic and atomic-power microscopy. Fractal index D and micro-coarseness index S were used for a quantitative estimation of the microstructure of cement rock obtained without an additive and with an organomineral additive. These indexes were compared with the properties of cement rock determined during standard physical-mechanical trials. The calculation of microstructure indicators and determination of the optimal content of the components of the organomineral additive allowed increasing the understanding of the fractal-cluster mechanism of self-organization of cement systems, taking into account the topology of particle distribution. The interrelation between the D and S indicators, compressive resistance and the density of the cement stone was shown. The higher fractal parameter and a relatively low level of micro-coarseness were indicators of the material with improved physical-mechanical properties. The monitoring of changes of D and S indicators can be used to control the structural formation processes of cement systems

Keywords

• polydisperse cement systems
• fractal-cluster microstructures
• electron microscopy
• fractality
• micro-coarseness
• physical-mechanical properties