Study of the hygrometric condition of cement stone and concrete

Abstract

Cement systems are thermodynamically non-equilibrium, non-linear systems. Since it is far from equilibrium, it must be characterised by structure formation processes. Here it is necessary to consider the definition of ‘structure formation’. This term is used in two meanings. The first is generally accepted in concrete science -the formation of mechanical bonds between the dispersed particles of a solidifying system as a result of ongoing chemical and physicochemical processes, culminating in the formation of a solid body -the cement stone and concrete. The second meaning of the term describes the emergence of dissipative structures, i.e. the destruction of the initial homogeneity of the system due to the emergence of streams, concentration gradients, chemical waves, etc. By measuring the parameters of the resulting dissipative structures of different formation methods, it is possible to assess the degree of disequilibrium in the solidifying system and hence the directed methods of structure formation and structure optimisation. It should also be noted that a non-linear, non-equilibrium hydration process leading to a concentration potential difference proceeds with equal probability in all directions. Applying a gradient of a high-intensity physical field to the disperse system, one should expect a synchronisation of the fluctuations of the concentration potential of local areas of the disperse system, which will result in a sharp increase of the physical and mechanical properties of the hydration products of the binder and of the concrete in general.