Hygrothermal analysis of mass concrete by derived finite element

The present thesis deals with problems regarding mass concrete, in which the temperature\ud rises due to the heat of cement hydration during the curing phase. A rise of temperature in\ud concrete may result in cracking of young concrete. In the first part of the thesis cement\ud composition and its influence on the released hydration heat is described. The hydration\ud process is explained by its individual phases which occur during hardening of concrete. Two\ud types of cement are presented, the CEM I 42,5 R and CEM III/B 32,5 N SR-LH. The hydration\ud heat released by those two types of cement differs significantly. Also an analytical expression\ud is given for evaluation of heat release of cement.\ud Next, the discretization of the problem and the derivation of the coupled equations is made for\ud a single finite element. The derived equations are used to form a system of linear algebraic\ud equations, which is needed for calculation of the temperature and moisture distribution. Also\ud the derived equations are used to write a computer program in MATLAB environment. The\ud program is used as a tool for numerical hygrothermal analysis of mass concrete.\ud The last part of the thesis presents the results of three different. The purpose of the first\ud analysis is to investigate the influence of the coupling degree between heat and moisture\ud transfer. While the results of non-coupled and semi-coupled models seem reliable, the results\ud of a fully-coupled model are not realistic and therefore are not used in further analyses. The\ud second analysis confirmed there is not much influence of semi-coupling on temperature fields,\ud so the equations can be solved separately and still give useful results. The third analysis shows\ud the necessity of low heat cement use in mass concrete structures