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This paper presents the results of experimental program focused on change of compressive strength of concrete exposed to elevated temperature. The change of compressive strength was studied for several types of concrete with different properties (common concrete, air-entrained concrete, concrete with polypropylene fibres, high performance concrete with steel fibres and concrete with basalt fibres). The samples were exposed to high temperatures up to 1000 0C at, the compressive strength was measured at the elevated temperature. This paper presents results of this experiment and comparison of experimental results with available data from literature and valid Eurocodes.

This paper presents achievements in the field of the numerical simulation of the fibrere reinforced concrete (FRC) and ultra-high performance fibre reinforced concrete (UHPFRC). The numerical simulations were performed to verify results of two experimental programmes focused on the blast resistance of FRC and UHPFRC. The response of the FRC and UHPFRC slabs to the contact and near-field blast was studied in these two experiments. As the detail behaviour of specimens could not be observed because of the blast load, the numerical models were prepared. The accuracy of the numerical models was evaluated based on the comparison of numerical and experimental results. Different approaches for blast simulation were tested and compared. The results indicate that the various phenomena (e.g. overpressure propagation, stress cumulation, crack propagation and damage extend) can be successfully simulated. However, the comparison of the soffit velocity, measured with the PDV unit and numerical model showed shortcomings of the numerical model. These numerical model inaccuracies are discussed and their reasons presented.

This paper follows the line of contributions from earlier conferences and informs about more results of experimental program focused on the resistance of plain and fibre reinforced concrete elements against adjacent and contact blast. Concurrently, a detailed analysis of element response is carried out using ultra high speed cameras.

Fiber-reinforced concrete (FRC) has mechanical properties that enhance its suitability for use in structures subjected to high strain rates, e.g. blast or impact loading. The fracture energy value is the decisive material characteristic for assessing the damage to concrete structures due to loadings with high strain rates. An analytical description of the force-deflection diagram of FRC can be a very efficient instrument for making a preliminary estimate of the fracture and mechanical properties of FRC. On the basis of our experiments and experiments from other authors, a tool for an analytical description of the force-deflection diagram for various strength classes, fiber types, etc. is proposed and evaluated.

The paper describes approach for the description of punching-shear resistance of concrete slab specimens subjected to close blast. The procedure is based on a combination of standardized approaches, a rich experimental program and numerical modeling. The approach aims to quantify the close blast behavior in the means of the velocity of the loading, strain-rate dependent material characteristics and simplify it to allow practical use.

Paper compares and discusses two different layouts of testing of mechanical and fracture properties of FRC, the three-point bending test and four-point bending test. The basis is extensive experimental program and analytical and statistical evaluation.

Because of the progress in cementitious composites material engineering, modern concrete structures are designed as more slender in comparison to previous years. For structures subjected to cyclic loadings it means higher stress ranges and thus higher probability of fatigue failure. These types of structures are often located in places of severe environment (bridges, crane tracks in chemical plants etc.). The paper presents an experimental research focused on the effect of coupled deterioration by aggressive environment and cyclic loading on the concrete specimens. The evaluation of the deteriorative effect of aggressive environment is based on kinetics of chemical reaction between concrete and aggressive solution of hydrochloric acid.