Hardening of concrete in the conditions of a construction site under constantly changing temperature and humidity conditions does not provide the desired performance properties of concrete and reinforced concrete structures. An assessment was made of the influence of the conditions of hardening of concrete samples at a water-cement ratio (W / C) of 0.45 and a hardening of 28 days. The hardening of concrete samples took place under conditions of a normal hardening chamber (air temperature T = 20 ± 50С, humidity W = 90 ± 2%), samples in water when completely immersed in a bath at water temperature T = 20 ± 30С and samples immersed in a plastic bag , hardening in the conditions of the air environment of the laboratory (T=20±50C). The samples gain the greatest strength when hardening completely immersed in water, and the smallest when hardening in an insulating polyethylene sheath.
Keywords: concrete scrap, fractionated crushed stone, water-cement ratio, hardening conditions, clinker hydration, strength development kinetics, moisture migration
In this paper, we propose a technique for calculation of the thickness. This technique is allowed to determine the thickness of a sleeping bag based on data on the equivalent coefficient of thermal conductivity of a sleeping bag package and data of heat production of person during the sleep. The values and trends in the variation of the relative discrepancy between the calculated and experimental thickness of the sleeping bags as a function of temperature are explained by the possible differences in the data on the thermal conductivity of the down, and by the necessity to introduce thermal insulation coefficients for individual parts of the body.
Keywords: Key words: sleeping bag thickness, down, thermal conductivity, thermal insulation