Institute of Materials and Structures

Development of sustainable technologies for production of porous, energy effective and innovative product such as foam concrete is in accordance with the requirements of sustainable development. In the present investigation foam concrete, produced applying mixing technology with effect of cavitation, with properties characterized by a low density and specific pore structure, without additional thermal treatment, has been developed. The basic properties of foam concrete, such as water absorption, compressive strength, density and thermal conductivity have been investigated in depending from the mixing parameters, kind and amount of additive. Experimental results showed less values of water absorption and less thermal conductivity of foam concrete comparing to aerated gas concrete. Using of modifying admixtures is the way to improve compressive strength and decrease value of water absorption of foam concrete.

For experimental and numerical investigation of the repaired pipeline prototype, the small-scale vessel model was produced. At the first stage of the experiment, the deformed state of the vessel with an artificially created surface defect was studied by the tensometry method. At the second stage, a fiberglass wrap was installed on the steel vessel together with the system of strain gages. The prototype of the pipeline was loaded with internal pressure. Finite-element modeling of both stages of the experiment was performed to compare the theoretical and experimental data.

Two optimization problems are formulated to improve the effectiveness and productivity of pultrusion processes, to preserve the quality of pultruded profiles, and to take into account the ambient industrial shop temperature and requirements of process technologists. To solve these problems, an optimization methodology using designed computer experiments and the response surface technique was developed. The effects of room temperature and curing allowed behind the die exit on the energy consumption and pull speed were investigated. A more accurate and realistic process optimization was achieved by the temperature control strategy with heater switch-on and-off operations. This indirect optimization methodology allowed us to develop interactive technological maps on the basis of an accessible-to-all Excel code for technologists working in industrial shops. As an example, demonstrating the effectiveness of the methodology developed and utilization of the interactive technological map, the optimization of a real pultrusion process, producing two rod profiles with ears simultaneously, is carried out.