INFLUENCE OF SELECTED MICRO ADDITIVES CONTENT ON THERMAL PROPERTIES OF GYPSUM

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Bulk density and total porosity of gypsum composites after 35 days

Parameters	Building materials
	Pure gypsum	Gypsum and polymer	Gypsum and microspheres	Gypsum and aerogel
Bulk density (kg/m3)	998	940	921	920
Total porosity (%)	57.5	60.0	60.8	60.9

Constants A, B, C, D, E and F of equations (5–7)

Building materials	Constants
	A	B	R2	C	D	R2	E	F	R2
Pure gypsum	0.0010	0.7176	0.9782	0.5799	2.087	0.9871	0.0005	0.2984	0.9686
Gypsum and polymer	0.0012	0.8886	0.9943	0.6985	2.225	0.9689	0.0006	0.3622	0.9751
Gypsum and microspheres	0.0012	0.8090	0.9947	0.7230	2.275	0.9919	0.0006	0.3476	0.9936
Gypsum and aerogel	0.0013	0.8520	0.9918	0.6521	2.230	0.9965	0.0006	0.3290	0.9833

Values of thermal conductivity λ, specific heat Cp , thermal diffusivity a, standard deviations σ and uncertainty of variation u of the pure gypsum and gypsum with additives polymer, aerogel and microspheres after 35 days

Parameters	Materials
	Pure gypsum	Gypsum and polymer	Gypsum and microspheres	Gypsum and aerogel
Thermal conductivity λ (W/(m⋅K))	0.3004	0.2556	0.2778	0.2821
Standard deviation σλ (W/(m⋅K))	0.0039	0.0069	0.0088	0.0072
Uncertainty uλ (W/(m⋅K))	0.0022	0.0034	0.0044	0.0035
Specific heat Cp (J/(kg⋅K))	1,520	1,597	1,594	1,630
Standard deviation σCp (J/(kg⋅K))	31	14	31	87
Uncertainty uCp (J/(kg⋅K))	11	8	17	49
Thermal diffusivity a (mm2/s)	0.1923	0.1716	0.1930	0.2074
Standard deviation σa (mm2/s)	0.0018	0.0023	0.0087	0.0095
Uncertainty ua (mm2/s)	0.0009	0.0012	0.0044	0.0049