Massive concrete structures form a specific group among the whole category of concrete structures, which require a separate aproach to design, construction and control processes. Continuous progress in material science and technology, measurement devices and techniques, numerical modelling and computation and, last but not least, data analysis stimulates developement of new diagnostic methods, that correspond well to the needs of massive concrete structures evaluation. These new methods allow determination of state of concrete on the structure surface as well as inside the structure. The paper presents a literature survey of described cases of massive concrete structures evaluation from several past years. ...
The paper comprises analysis of significant problems that determine durability of hydrotechnical concrete in structures and comments on activity of international research teams working on design fundamentals of structures duration. Authors on the basis of the EN 1990 standard have computed the characteristic predicted lifetime of the weir structures on the Odra river. Necessity of changes in design requirements for hydrotechnical concrete has been underlined, attempting to gain considerably more durable structures. On the basis of the analysis an evaluation of durability of concrete structures in weirs built since 1975 on the Odra river has been made. ...
The paper presents results of laboratory investigations of temperature change influence on CEM III/A 32,5 NW/NA portland cement paste setting start and end time. Experiments were performed on pastes of water-cement ratio equal 0,25 – 0,29; 0,35; 0,45; 0,55 at temperature equal 0°C, +5°C, +10°C, +20°C. Strong thermosensitivity of the tested cement pastes was clearly found, that was evidenced by increase of both setting start and setting end time. The empirical relations between the cement paste setting time and curing temperature and watercement ratio were established. ...
