In the paper, the method of a numerical simulation concerning diagonal crack propagation in con-crete beams was presented. Two beams reinforced longitudinally but without shear reinforcement were considered during the Finite Element Method analysis. In particular, a nonlinear method was used to simulate the crack evaluation in the beams. The analysis was performed using the commercial program ANSYS. In the numerical simulation, the limit surface for concrete described by Willam and Warnke was applied to model the failure of concrete. To solve the FEM-system of equations, the Newton-Raphson method was used. As the results of FEM calculations, the trajectories of total stains and numerical images of smeared cracks were obtained for two analyzed beams: the slender beam S5 of leff = 1.8 m and the short beam S3k of leff = 1.1 m. The applied method allowed to generate both flexural vertical cracks and diagonal cracks in the shear regions. Some differences in the evaluation of crack patterns in the beams were observed. The greater number of flexural vertical cracks which penetrated deeper in the beam S5 caused the lower stiffness and the greater deformation in the beam S5 compared to the short beam S3k. Numerical results were compared with the experimental data from the early tests performed by Słowik [3]. The numerical simulation yielded very similar results as the experiments and it confirmed that the character of failure process altered according to the effective length of the member. The proposed numerical procedure was successfully verified and it can be suitable for numerical analyses of diagonal crack propagation in concrete beams.

Cauchy paved the way for constructing models in concrete technology, and elsewhere. He determined the (nonflat) surface area in 3D by measuring random total projections. Analogously, he determined the length of a curved line in 2D by way of measuring the total projections. The paper will present the mathematical expressions, because in many branches of concrete technology, modelling is found based on such Cauchy concepts. These branches – fractography in compression, tension or shear, fibre reinforcement and permeability estimation – will briefly be mentioned to demonstrate this. It has been found that, for the discussed fields of engineering relevance, major model parameters for cementitious materials are similar to those developed by Cauchy in the 19th century. In the paper some previous investigations concerning fractography, fibre reinforcement and fracture roughness will be summarized but basically a new development on porosimetry will be presented. Particularly a new achievement of successful implementation of the methodology (also based on Cauchy) for optimizing permeability estimation will be discussed.

Laboratory and field experiments have been conducted to study mobility of chromium and lead in

floodplain sediments. The main goal of the research was to verify a hypothesis whether changes of chromium

and lead concentration could be used to estimate the relative age of floodplain deposits. The basis for undertaking such research was the presence of weaving industry centers in the Obra River valley between the 16th and

the 19th century and using Cr and Pb compounds in paint recipes. The Cr and Pb contents were also analyzed in

three vertical profiles unaffected by the field experiments. The age of organic sediments in each of the profiles

was determined using the radiocarbon analysis. The results of the laboratory experiments have shown that the

highest contents of the elements were noted in the surface layer of the sediments placed in the column. However,

the contents decreased during the last phase of the experiments and both vertical and horizontal migration of

both elements was observed. A more intensive mobility was observed in the field test. Its cause could be the

changes of the groundwater level, floodplain inundation and pH conditions in alluvial deposits. Such processes

may have influenced migration of the compounds originating from the weaving industry production; Cr and Pb

contents detected in the profiles unaffected by the field experiment were too small to be used for relative dating of alluvial deposits. Moreover, the alluvial deposits with increased contents of the studied elements may be

older than the period of the weaving industry development. Cr and Pb mobility was especially intensive in the

profiles situated within the near bed zone of the floodplain due to regular inundation, and the activity of erosion

and accumulation processes entraining the studied elements back to transport in the river bed.

The subject matter of the research pertains to the improvement of rheological properties of petroleum bitumens by their modification with SBS (styrene-butadiene-styrene) copolymer. The authors have determined selected rheological properties characterising the durability of modified bitumens used in road pavements. The bitumens were modified in laboratory conditions with modified bitumen concentrate of a known SBS copolymer content of 9%. The result was a binder containing the known percentage of the SBS copolymer of 3%, 4.5% and 6%. Rheological properties of the tested bitumens were determined by the use of a DSR dynamic shear rheometer (in a wide temperature range from 40°C to 100°C) and a ductilometer at 5°C. DSR was used for performing MSCR test to determine the resistance of the asphalt mixture with the SBS-modified binder to permanent deformations in the high temperature range (from 40°C to 82°C). The comparison of the values of the dynamic shear modulus |G*| of all the bitumens tested shows that with a growing content of the SBS copolymer in the tested binder the value of |G*| increases, which may indicate greater resistance to permanent deformation of the asphalt pavement. The MSCR test has shown that the increased use of the SBS copolymer addition in the bitumen translates to decreasing values of the non-recoverable creep compliance J_nr. The SBS copolymer accelerates stress relaxation in the bitumen sample, thus increasing pavement resistance to low-temperature cracks. Furthermore, modification reduces the negative impact of ageing on the properties of the binder, manifested by its stiffening and slowdown of relaxation.

Packaging steels are thin gauge flat carbon steels coated with tin or chrome on both sides. They are very important raw materials for the production of steel packaging, which allow food to be stored safely and with an extended shelf life. The publication focuses on the production process of ETP and ECCS steel, as well as the problem of corrosion of steel packaging.

The topic of legislative changes that require the elimination of chromium (VI) compounds from the steel passivation process was also discussed. The packaging steel industry is currently facing the need to develop a new passivation technology. Leading packaging steel manufacturers in cooperation with varnish and paint suppliers have developed chromium (VI) free technologies by implementing chromium (III) compounds and titanium oxide technology.

Authors focus also on new trends and potential development directions for the packaging steel industry.