Papers by Keyword: Carbonation of Concrete

Abstract: The paper deals with the resistance of reinforced concrete against fire and the degradation of reinforced concrete due to high temperatures. In the first part the processes of degradation of concrete are solved due to the evaporation of water and its change of state with respect to the different thermal expansion of aggregates and concrete reinforcement members. The main part is focused on the construction of monolithic and prefabricated structures of industrial chimneys. The most common types of protection of the chimney's internal parts from the exhaust gases are discussed here. Also the possibilities of designing individual expansion joints are described. In the experiment, the problem of chimney damage, with the subsequent description of the chimney diagnostics in the premises of Unipetrol in Litvínov, was solved due to an extraordinary event - explosion of the ethylene unit.

Abstract: Carbonation of the concrete is a process influencing acceleration of the aging of concrete during the time, at reinforced concrete structures it is usually accompanied with corrosion of the reinforcement and disturbances of the covering layer of the concrete. Its consequence is decrease of the static reliability of the reinforced concrete building structures. Carbonation of the construction from common concrete and lightened concrete causes just in the CR damage worth billions of Czech Crowns every year. The paper refers about seriousness of the current technical state of reinforced concrete structures and influence of the most important factors on the course of their degradation caused by carbonation and specifies principles for designing new reinforced concrete constructions.

Abstract: The distribution of surface pressure of columns in concrete bridge with the effect of wind load has been simulated by Ansys software. Carbonation model of concrete in windy environment has been established by analyzing the relationship between the wind pressure, carbonization time and carbonation depth. Furthermore, by Taking air pressure of concrete surface into the carbonation model, there is a good consistency between the test value and the measured value of the actual place. At last, the design method of the durability of concrete structures under wind loads, which is based on concrete durability limit state, has been putted forward to determine the expression of the breakdown coefficient.

Abstract: Currently, durability of concrete structures is a hot area of civil engineering. This paper reviews the background to the study of concrete and the current international research developments. Recent accomplishments in the world are summarized on four levels—environment, materials, components, structure. Finally, directions of future research are also proposed.

Abstract: The purpose of this study is to establish an analytical formulation for determination of the critical chloride content in concrete. In this study, factors affecting the critical chloride content such as mix proportion, environment, chemical evolution of pore solution with time, carbonation and so on are taken into account. The numerical simulation program of cementitious materials, HYMOSTRUC was utilized for the construction of the formulation. This was expressed as a free chloride content in a mass unit of concrete as a time function.