SOUTHERN JOURNAL OF SCIENCES

During the construction of concrete structures of small cross-sections, the release of heat during cementhardening has no harmful effects. With the increasing temperature of the hardening cement mass, the rate ofcement hydration increases. This increases the rate of release of its heat of hydration of cement. Theconsequence of the accelerated process of hydration of the binder is a more intensive increase in the strengthof cement stone than in the case of hardening under normal conditions. This fact is widely used in practice forthe intensification of the hardening of concrete. When structures with small cross-sections are being built, theheat released during hardening is relatively quickly transferred to the surrounding space and does not cause asignificant increase in temperature. In structures made of massive concrete (with a large cross-section), thisheat is stored in the interior of the array for a long time, which causes a rather large rise in temperature and itsslow drop. This is due to the fact that heat transfer to the external environment is hampered here by theconsiderable thickness of the massif and the rapid rate of concreting, mechanized laying of large masses ofconcrete. As a result, a temperature difference is created between the internal and external parts of thestructure and harmful internal stresses arise that can cause cracking in the hardened concrete. This leads to aviolation of its solidity. The faster cement hydrates, the sooner and more heat is released. The types of cementswith a high content of tricalcium silicate and aluminate emit more heat and rather than types of cement with ahigh content of dicalcium silicate and tetra-calcium aluminoferrite. However, the latter has a lower strength. Theincrease in strength resulting from the hydration process is inevitably associated with the release of heat into theenvironment. C

Introduction: Thermal insulating coatings are increasingly being introduced into construction practice for internal and external finishing enclosing structures and pipelines. Thermal insulation coatings are usually made based on polymer binder and mineral fillers. The durability and stability of the properties of heat-insulating materials depend on the type of binder. As a rule, polymers are used as a binder: epoxy resin; silicone rubber; urea-formaldehyde resins; aqueous dispersed polymers - styrene-butadiene, polyvinyl acetate, and acrylate (acrylic and styrene-acrylic). The quality indicator of binders can be assessed by the influence of the seasonality of climatic impact, and as a result, the best elastic strength characteristics of binders can be established after one month to a year of field tests. Aim: To determine the influence of climatic factors on the change in the elastic-strength indicators of epoxy polymers binders used in liquid thermal insulation coatings. Methods: A tensile testing machine of the AGS-X series with the TRAPEZIUM X software was used for mechanical tests. The tests were carried out in accordance with GOST 11262-2017 (ISO 527-2: 2012) "Plastics. Tensile test method". Results and Discussion: The paper discusses the results of experimental studies of the compositions of polymer binders and their resistance to various climatic factors, which will later be used as a polymer binder for thermal insulation coatings based on fine mineral granular systems. Conclusions: When analyzing the changes in the characteristics of polymer samples after exposure to climatic factors, it was found that compositions based on Etal-247 epoxy resin, cured with amine hardeners Etal-1440N, Etal-1460, Etal-1472, and Etal-45M, demonstrate the best elastic strength characteristics after one year of full-scale tests. The high stability of the indicators under consideration allows us to conclude that the use of Etal-247 resin as a base leads to creating of the most climate-resistant epoxy coatings.

Throughout this article, a study on the characteristics of the compaction test by the Proctor Method, regulated by ABNT NBR-7182, which is used to verify the degree of soil compaction, will be approached in order to broaden the discussion and raise points that demonstrate the urgent need to make it more accurate, efficient and safe. Through qualitative and quantitative research carried out by the authors of this article, it sought to collect data through a questionnaire for professionals in the field of geotechnics in the “Quadrilátero Ferrífero” region in Minas Gerais. In addition to other relevant data for the topic, it was raised that of the 22 professionals from the participating region, 72.7% of the total belief that the manual compaction test can be manipulated by an operator during the test execution, failing to generate results reliable, thus showing the importance of the proposed theme. In this way, we initially sought to correlate the Compaction Energy formula idealized by Ralph Proctor with Isaac Newton’s Gravitational Potential Energy formula and, through it, present the resizing, which may enable the construction of manual, semi-automatic human propulsion machines (not or making the automated ones that depend on electricity available to the market. In conclusion, from the mathematical calculations, it was possible to evidence the use of Newton’s Gravitational Potential Energy to constructnew equipment to carry out this test.