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Abstract: This paper intends to express the physical model ClinConc in a more engineer-friendly way. Through the numerical evaluation it has been found that there exist good correlations between the time-dependent factors for chloride binding and for diffusion coefficient, and between the laboratory measured diffusion coefficient and the apparent one, the latter is a result of the combined effects of material properties and environmental actions. Therefore, the ClinConc model can be expressed by the similar error function as used in many empiric models, but with the proper physical procedures, that is, modeling free chloride transport taking free chloride as diffusion potential and then calculating the total chloride content taking into account the non-linear chloride binding. The modeled chloride profiles are in good agreement with the measured ones, even though further study is needed to clarify the expansion coefficient for the concrete containing silica fume and other pozzolanic additions. [Copyright &y& Elsevier]

Abstract: This paper describes the development of a hybrid model for a concrete batching and mixing plant. The model is sufficiently detailed so as to ensure that it can be used to establish the control system within an industrial monitoring and control framework. Since the concrete batching and mixing plants are hybrid systems, Global Automata were used to build the model of the physical system, since they provide greater “modeling power” being suitable for modeling of a wider variety of systems than other types of automata. Various modeling methods based on the classical hybrid systems theory are rather applied in research works with academic orientation and usually are far from the engineers of industry. A fundamental objective of this work was to adopt a development environment which will be familiar to the industrial people. The developed model entails a hierarchical structure with an automaton as supervisor and several other interactive automata describing the subsystems of the plant. The model was then used to understand the influence of various design and operating parameters on plant performance. The model was also used to establish the control strategy. Both were implemented in a SCADA (Supervisory Control and Data Acquisition) environment which monitors and controls the overall operation of the plant. This framework has been applied on a real plant of West Greece with success in all realistic tests concerning either the control operation or the model validation. [Copyright &y& Elsevier]