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This article discusses the influence of two types of additives on the compressive and flexural strength and elastic modulus of concrete. Two different types of additives (Metakaolin and MC Adhesive) were used to produce concrete with target strengths of 30 to 45 MPa and a reduced modulus of elasticity. With a partial replacement of cement with metakaolin, as well as in the case of the use of a liquid additive MC Adhesive, a decrease in both the bending and compression strength and the modulus of elasticity is observed. At the same time, the addition of metakaolin, replacing 17.5% of cement, reduces these characteristics to the greatest extent. However, the tensile strength in the bending test of concrete with metakaolin decreases slightly. It was found that the addition of metakaolin increases the crack resistance of concrete as a result of a significant decrease in the modulus of elasticity and a slight decrease in the tensile strength of concrete.

The influence of the electrostatic precipitator ash &ldquo, Zolest-bet&rdquo, and silica fume on the sulfate resistance of Portland cement was studied. The evaluation criteria were the expansion, strength, density, and appearance of the samples, hardened in a 5% Na2SO4 solution starting from 3 days of age for 192 days at a temperature of 20 &deg, C and 148 days at 40 &deg, C. The mixture with the silica fume additive had the minimum expansion under the Na2SO4 action, and the mixture with the fly ash &ldquo, additive had the greatest expansion. Zolest-bet ash in pure water shrank the mixture by 0.19 mm/m by the end of the hardening period, and it gave a linear expansion of 0.23 mm/m in a Na2SO4 solution after hardening. The mixture can be considered sulfate resistant at a given value of linear expansion. Despite the greatest expansion, the compressive strength of the samples with the Zolest-bet additive was found to be the highest at hardening in both environments. The flexural strength was found to be the highest after being in Na2SO4 solution. The sulfate resistance of the mixture with silica fume was higher than that of the mixture based on sulfate-resistant cement. This mixture did not have expansion in comparison with the initial length, instead it shrank, while the expansion of sulfate-resistant cement was 0.006% over the control period. The compressive strength of the mixture with the silica fume additive was slightly inferior to the strength of the mixture with Zolest-bet ash.

The subject of research is expanded-clay concrete with additives of ground granulated blast-furnace slag, silica fume, superplasticizer and air-entraining admixture. The heat release of concrete is investigated depending on the concrete composition (cement, water cement ratio, expanded-clay), additives (slag, silica fume) and admixtures (superplasticizer, air-entraining agent). This study is a part of research on the design concrete mixture with strength class C35/45 and high workability for 3D printer. It was confirmed that the cement content and water cement ratio impact on the integral value of the heat release per unit mass of cement. This value decreases with increasing cement content. The reason for this is that the heat generated by concrete, with constant W/C and other equal conditions, increases linearly with increasing the cement content.

Xenon attenuates on-going neuronal injury in both in vitro and in vivo models of hypoxic-ischaemic injury when administered during and after the insult. In the present study, we sought to investigate whether the neuroprotective efficacy of xenon can be observed when administered before an insult, referred to as ‘preconditioning’. In a neuronal–glial cell coculture, preexposure to xenon for 2 h caused a concentration-dependent reduction of lactate dehydrogenase release from cells deprived of oxygen and glucose 24 h later; xenon's preconditioning effect was abolished by cycloheximide, a protein synthesis inhibitor. Preconditioning with xenon decreased propidium iodide staining in a hippocampal slice culture model subjected to oxygen and glucose deprivation. In an in vivo model of neonatal asphyxia involving hypoxic–ischaemic injury to 7-day-old rats, preconditioning with xenon reduced infarction size when assessed 7 days after injury. Furthermore, a sustained improvement in neurologic function was also evident 30 days after injury. Phosphorylated cAMP (cyclic adenosine 3′,5′-monophosphate)-response element binding protein (pCREB) was increased by xenon exposure. Also, the prosurvival proteins Bcl-2 and brain-derived neurotrophic factor were upregulated by xenon treatment. These studies provide evidence for xenon's preconditioning effect, which might be caused by a pCREB-regulated synthesis of proteins that promote survival against neuronal injury.