Non-destructive tests of reinforced concrete chimneys, especially high ones, are an important element in assessing their condition, making it possible to forecast their safe life. Industrial chimneys are often exposed to the strong action of acidic substances, They are negatively exposed to the condensation of the flue gases. Condensate affects the inside of the thermal insulation and penetrates the chimney wall from the outside. This is one reason for the corrosion of concrete and reinforcing steel. Wet thermal insulation settles, and drastically reduces its insulating properties. This leads to an increase in temperature in the reinforced concrete chimney wall and creates additional large variations in temperature fields. This consequently causes a large increase in internal forces, which mainly increase tensile and shear stresses. This results in the appearance of additional cracks in the wall. The acid condensate penetrates these cracks, destroying the concrete cover and reinforcement. Thermographic studies are very helpful in monitoring the changes in temperature and consequently, the risk of concrete and reinforcement corrosion. This simple implication between changes in temperature of the chimney wall and increasing inner forces as shown in this article is particularly important when the chimney cannot be switched off due to the nature of the production process. Methods for interpreting the results of thermovision tests are presented to determine the safety and durability of industrial chimneys.

Rapid technological progress in construction requires that more and more attention should be paid to human security issues. Threats occur both at the stage of building facilities and during their use. Some impacts are easy to identify during construction stage like shocks and vibrations, others are hidden from sight and direct sensing like the harmful effect of chemicals. In addition to accidents that happen on construction sites, there are still objective threats, which may occur throughout the lifetime of the facility. In addition to clearly perceptible ones such as earthquakes, hurricanes, fires, there are hidden threats as well: bacteriological contamination, radiation or chemical interactions that occur in time. This article points to the most common chemical hazards. Examples of chemical threats occurring in construction at the stages of design, construction and use of buildings will be given below.

The products covered by the common name polyurea were first developed and marketed in the United States in the 1980’s In the first period polyurea was used as a protective coating of polyurethane foam used for thermal insulation of roofs, and in the 1990s many other uses were quickly disseminated. In Europe this technology appeared in the second half of the nineties and the market for polyurea applications started to develop very dynamically in the recent years. Polyurea coatings, due to their extremely versatile physical properties such as watertightness, extremely high wear resistance, resistance to chemical and mechanical stresses, high elasticity and stretchability as well as resistance to freeze-thaw cycles, are increasingly popular, and more and more frequently used in the broadly understood construction. As a rule, the growing demand for technology fosters its development and enhances the knowledge of those who use it, so that it is used for its intended purpose, while maintaining security and enforcement procedures. However, in the absence of such knowledge, misconceptions about the use of polyurea spray coating technologies are emerging, both at the design stage and during the execution phase.

This paper presents an experimental investigation of the discharge flow pressure in the vertical silo and the hopper due to the use of insert (top cone with trunk cone bottom). Using the Insert inside the silos is one of the proposed solutions to avoid the problems of having funnel flow pattern, which has a significant effect on the distribution of flow pressure exerted on the silo wall and the hopper. The experiments were performed on a metal cylinder prototype; corn was used as a granular material, and the wall and hopper pressure distribution was measured by a special pressure transducer. The experiments revealed an important result in the flow pressure due to the change in the location of the insert. The experiments were conducted in Damascus University laboratories.

This article investigates the degradation of stiffness in high and standard-strength concrete due to the influence of repeated loading and considers the non-linear behavior arising from localized or natural defects of concrete. The article also refers to the models from existing literature that evaluate the characteristics of concrete by enhancing its physicochemical properties through the application of natural and synthetic fibers. The impact of the service load, which influences the change in concrete stiffness, is illustrated using the elastic–plastic concrete model. The elastic–plastic model of concrete, combined with experimentally determined data such as elastic and residual deformations, simplifies the analysis of concrete beams or surface elements. This model enables static solutions of inelastic materials based on the classical theory of elasticity. The degradation of element stiffness in this model is described by the local increment of the rotation angle. Based on the model we can assume a constant stiffness along the length of the beam before as well as after exceeding the value of the cracking moment. In the case of cyclic loads, it can be assumed that residual deformations have the greatest influence on the displacement values, which in the calculation model are described by the component of the angle of rotation in the crack, describing permanent displacements.