No abstract

The paper describes the study on the operational properties of lightweight composite with density of 150-350 kg/m 3 . It was established that these properties depend on the ratio of porous cement matrix and inclusions of crushed expanded polystyrene packing tare waste per unit volume of the lightweight composite. Studies have demonstrated that when the density of lightweight composite varies in the above mentioned limits, the compressibility amounts to 2.4-0.8 mm, point load -0.38-3.39 kN, dynamic stiffness -35-135 MN/m 3 , and reduction in normalised impact sound pressure level -26-17 dB. The dependences between the established properties and the density of lightweight composite are showed in the equations of regression. Possible versions for the use of lightweight composite in different constructions of floors and roofs are also provided.

The aim of the research was to evaluate an influence of floating floor construction specimen size on weighted reduction in impact sound pressure level ΔL_W. The large size (area ≥ 10 m²) specimens should be used according to LST EN ISO 10140 series standards. The problem is that produce large specimens is expensive and time-consuming process. So more rapid and cheaper way is to use smaller size (area < 10 m²) specimens and perform measurements in real buildings with similar test conditions as in laboratory. For evaluation of the specimen size influence on reduction in impact sound pressure level ΔL_W value sand/cement screed area discreetly was reduced from 13.4 m² down to 0.5 m². The test results showed strong dependence of reduction in weighted impact sound pressure level from specimen size. Relying on the test data it was derived relationship which could be applied for the correction of the determined ΔL_W values when smaller size specimens (area < 10 m²) of floating floor constructions are used.

DOI: http://dx.doi.org/10.5755/j01.ms.18.1.1350

No abstract

Abstract. In many EU countries, the normative requirements for thermal characteristics of roofs are associated only with rating the heat losses through the roofs during the heating period. The problem of overheated premises under the lightweight ventilated roofs, covered with steel sheets, arises in the summer time. During this period of the year, because of the intensive solar radiation and high air temperature, the steel roof coatings heat up during the day and cause additional heat inflows to the premises. One of the most effective means to reduce the additional radiative heat flow from the interior surfaces of the roof coating into the attic is to install radiant barriers with low emissivity coefficient into the roof construction. The experimental research has shown that having heat reflective coatings with low emissivity coefficient (ε = 0.09) installed on the exterior surface of the thermal insulation layer of the ventilated roofs with steel coatings, the heat flow from the roof coating through the roof construction into the interior premises can be reduced on the daily average of 23-25% in the summer time.