WOOD RESEARCH Volume 68, Number 3, 2023
Uğur Aras

Possibility of Using Crude and Expanded Vermiculite in Cement-Bonded Particleboard Production

The aim of this study is to investigate the effect of using vermiculite on the thermal, physical and mechanical properties of cement-bonded particleboards. For this purpose, single-layer cementitious particle boards with a final density of 1200 kg/m3 and a size of 550 x 550 x 10 mm were produced using 2 type vermiculites (crude and expanded) at three different ratios (5%, 10% and 15%). The produced boards were examined in terms of thermal (TGA/DTG), physical (moisture content, density, water absorption and thickness swelling), mechanical (modulus of rupture, modulus of elasticity, internal bond strength and screw withdrawal resistance) properties. According to the TGA results, using both types of vermiculite caused an increase in cement hydration products in the boards and increased the thermal resistance. While the use of vermiculite did not significant effect on the density and moisture content of the boards, it increased the dimensional stability of the boards. The values of modulus of rupture and modulus of elasticity increased when the low amount of vermiculite was added. However, with the use of vermiculite in the boards, there was a decrease in the internal bond strength and screw withdrawal resistance values in general. All boards produced using vermiculite met the values specified in EN standards.

WOOD RESEARCH Volume 61, Number 4, 2016
Jaroslav Blažek, Martin Múčka, and Kamil Trgala

Cost and thermal – technical optimization of wooden construction in the passive standard

The article describes the thermal – technical point of four wooden constructions in the passive standard, when one of the constructions was tested in an accredited laboratory 1007.4 thermal – technical diagnostics. The sample was made according to the laboratory´s requirement 1700 x 1700 mm and tested according to the test harmonized standard ČSN EN ISO 8990: 1994 Thermal insulation – Determination of thermal transmission properties in the steady state temperature – calibration and guarded hot box. The object of the tests was to declare heat thermal transmittance value – U value based on the measured surface temperatures (θsi) and energy consumption. Thermal resistance and thermal transmittance were empirically calculated according to the measured and standard values in accordance of the CSN 73 0540: 2011. Thermal protection of buildings. The other three structures will be structurally modified to reflect this normative value Upas 20 = 0.12 – 0.18 (W.m-2 . K-1) and ensure their cost optimization.

WOOD RESEARCH Volume 63, Number 2, 2018
Mingbin Liu, Youfu Sun, Chen Sun, and Xiaolin Yang

Study on thermal insulation and heat transfer properties of wood frame walls

Steady-state heat transfer performance of wood frame wall is an important index to assess its energy efficiency. In order to study the factors that affect the heat transfer coefficient of wood frame wall, the method of improving the thermal insulation property of the wall was studied. In this paper, 12 wall specimens with different structures were manufactured, and the effective heat transfer coefficient was measured by the hot box-heat flow meter test method. The reliability of the theoretical calculation value of thermal resistance was verified by the experimental value. The results showed that the moisture content of Spruce-pine-fir (SPF), insulation materials, spacing and thickness of studs had influence on the heat transfer coefficient of walls. The effective heat transfer coefficient values of three walls ranged from 0.325 to 0.398 W•m-2•K-1, which met the thermal level It of the severe cold area. The linear correlation between the theoretical calculation value and the test value was up to 0.9587, effective thermal resistance value of wood frame wall can be estimated by calculating without extra experiment.