Thermal properties of building materials at elevated temperatures

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Thermal properties of building materials at elevated temperatures

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Thermal Properties &Building

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by X.F. Hu, T.T. Lie, G.M. Polomark and J.W. MacLaurin

Internal Report No. 643 Date of issue: March 1993

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This is an internal report of the lnstitute for Research in Construction. Although not intended for general distribution, it may be cited as a reference in other publications

THERMAL PROPERTIES OF BUILDING MATERIALS AT ELEVATED TEMPERATURES

ABSTRACT

The results of measurements of thermal properties at elevated temperatures of construction materials, commonly used in China, are given. Tabulated values, graphs and equations are given for the specific heat, mass loss, thermal conductivity and thermal expansion of the materials as a function of temperature, up to 1000°C.

THERMAL PROPERTIES OF BUILDING MATERIALS AT ELEVATED TEMPERATURES

1 INTRODUCTION

Numerous mathematical models for the calculation of the fire resistance of structural members have been developed in recent years. To be able to calculate and vredict the behaviour of these members during fire exposure, it

&

essential to know, at elevated terdperatures, the

fundamental thermal and mechanical properties of which the members are composed.

For more than twenty years, the National Fire Laboratory of the Institute for Research in Construction, National Research Council of Canada has been engaged in research to predict the fire

resistance of structural members. As a part of this research, measurements were made of the thermal properties of various building materials [I].

Rapid advances in facilities and techniques for measuring thermal properties of building materials have made it possible to improve the precision and increase the tem~erature ranee of the measurements. In this bauer, the tesimethods -md the results of measuremeits on 30 segcted . A -

construction materials, commonly used in China, are described. These materials are listed in Table I.

The measurements were made with the objective of providing data for a joint Sino-Canada research project on fire resistance evaluation. The data can be used as input for existing computer programs for the calculation of the fire resistance of the members being investigated in this project 12-41. In addition, the data can also be used in programs under development for the calculation of the f ~ e resistance of various building members, such as columns, walls, floors and beams.

2 METHODS AND INSTRUMENTS

The following methods and instruments were used to measure the thermal properties of the selected building mate&

2 . 1 Specific Heat (Cp)

The specific heat of a material is the amount of heat required to raise the temperature of one unit mass of a material 1°C. In this study, the specific heat will be expressed in J/kg°C.

Usually, the specific heat of a material is temperature-dependent. If, in addition, the material becomes unstable, i.e., undergoes a "reaction", which can be decomposition or transition, etc., the heat necessary to raise the temperature of the material is affected by the heat contributed by the reaction, which results in a peak in the curve of specific heat vs temperature.

In this report, the specific heat at constant pressure (Cp) was measured using a DuPont Differential Scanning Calorimeter @SC) for temperatures up to 6W°C. The DSC measurements were carried out with a scanning rate of 10°Clmin and a sample size of 30-40 mg in a nitrogen atmosphere. For measuring the specific heat at temperatures up to 1000°C, a DuPont 1600°C high temperature Differential Thermal Analyzer @TA) was used.

For materials that do not undergo reactions, the specific heat was measured by carrying out two runs; namely, one with powdered sapphire (AkO3) as the calibration material and one with the sample. A stepwise heating program (namely, a period of constant material temperature followed by a period of temperature rise, which is followed again by a period of constant material

temperature, etc.), through the temperature range from 400°C to 1000°C, was used during the measurements. Since, in this case, the specifc heat of the materials is proportional to the temperature difference measured by the DTA, the specific heat of the samples was calculated by comparing the temperature difference (Wmg) obtained during the test with the samples in the temperature range between 600°C and 1000°C with that obtained during the test with powdered sapphire (A1203).

For materials that undergo reactions, as well as carrying out the stepwise DTA runs for the Cn measurements mentioned above, the heat of fusion of the materials was taken into account in

tlk specific heat calculation. ~ e a s k m e n t s of the heat of fusion of the materials were carried out according to the method described in Reference [6].

A heating rate of 10°Umin was used in the DTA measurements, unless otherwise specified. Heating rates of SOUmin and 20°Umin were also used to compare the effect of the heating rate on the specific heat The results of carbonate aggregate concrete measurements show that the curves shifted to the left by about 20 to 25OC when the rate was decreased from 1O0Umin to SoUmin and shiffed to the right by about 25OC when the rate was increased from 1O0Umin to 20°Umin. The results also showed that the peak areas increase with decreasing rate of heating, Figures 1 through

12 show the linear fits of the Specific Heat versus Temperature. The Figures also include the raw data in tabular form.

2 . 2 Mass Loss

Mass loss of materials was measured by a DuPont 951 Thermogravimetric Analyzer. A scanning rate of 20°Umin in a nitrogen atmosphere was used and specimens weighed between 30 and 40 mg. Figures 13 to 24 show the results of the mass loss measurements.

2 . 3 Thermal Conductivity

The thermal conductivity of the materials was measured using a TC-31 Thermal

Conductivity Meter made by Kyoto Electronics. Results of the tl~ermal conductivity measurements are shown in Figures 25 to 36.

2 . 4 Thermal Expansion

The thermal expansion curve was produced by a Theta Dilatory Apparatus with a computer- controlled program. The specimens tested were 30 to 40 mm long and 10 to 12 rnm square in cross-section. The rate of heating was 10Wmin in static air from room temperature to 1000°C for inorganic materials and to 200°C for organic materials. Results of the thermal expansion tests are shown in Figures 37 to 48.

3 RESULTS AND DISCUSSION

Since the measurement of specific heat of materials at high temperatures (over 700°C) is stilt

a

subject to be explored by thermal analysts, data on the specific heat of materials at elevated temperatures is rarely found in the literature. The method for measuring the specific heat at high temperatures used in

this

_{report has not yet been found in the literature. The specific heats of two}

types of concrete, i.e., siliceous and carbonate aggregate, measured in

this

_{project have been used}

as data input for the calculation of the fire resistance of building components. Results of these calculations show that they agree well with experimental observations [7].

4 MATERIALS DESCRIPTION

Most of the building materials selected and measured in this paper are commonly used in and commercially available in China (Table 1). The identification of the materials is given below where that information is available. The descriptions of the materials are listed in the same order given in the figures section.

Figure 1

Name of Material: Carbonate Aggregate Concrete

Material Identification: Composed of M25 Portland Cement, Sand, Carbonate Rock and Water.

Batch Ingredients (by weight): M25 Portland Cement 1

Sand 2.6

Rock (egg size) 4.16

Water 0.56

Density: 2443 kg/m3

Figure 2

Name of Materiak Siliceous Aggregate Concrete

Material Identification: Composed of #425 Portland Cement, Sand, Siliceous Rock and Water.

Batch Ingredientsmy weight): M25 Portland Cement 1

Sand 2.6

Siliceous Rock 4.16

Water 0.56

Density: 2365 kg/m3

Figure 3

Name of Material: #525 Ordinary Portland Cement Concrete

Material Identification: Composed of #525 Ordinary Portland Cement, Sea Sand medium size), Carbonate Rock (5-20 mm continues particles) and Water. . .

Batch Ingredients (by weight): #525 Ordinary Poatand Cement 1

Sea Sand 2.12

Carbonate Rock 3.75

Water 0.24

Figure 4

Name of Materiak M25 Portland Blast Furnace Cement Concrete

Material IdenWlcation: Composed of #425 Portland Blast Furnace Cement (#300), Sea Sand, Carbonate Rock (5-20 mm continues particles) and Water. Figure 5

Name of Materiak Fire Brick

Material Identillcation: Composed of Aluminous Clinker, Clay and Water. Batch Ingredients: Aluminous Clinker 50%

clay 50%

Water 8%

Figure 6 Name of Material: Material Identification: Batch Ingredients: Density: Figure 7 Name of Material: Material Identification: Figure 8 Name of Materiat Material Identillcation: Figure 9 Name of Material: Material Identification: Figure 10 Name of Material: Supplier: Figure 11 Name of Material. Material Identjfication: Density Figure 12 Name of Material: Material Identification:

Standard Clay Brick

Composed of Clay, Furnace Ash, Coal Stone, etc.

clay 4

Furnace Ash 1

Coal Stone (fine powder)

Baking Temperature: 900-950°C 700-980 kglm3

Gypsum Board

Composed of CaSOz, 2H20, CaSOa MgC03, R203, K20, Fe203, Al203, paper powder and starch.

Fire Retardant Gypsum Board

Composed of C a s e , 2H20, CaS04, MgCO3, R203, K20, Fe203, N203. fire retarding agent, paper powder and starch.

Light Heat-Insulating Brick

Composed of SiOz (70), A1203 (151, Fez03 (5.5), CaO (3). MgO (2), R2O (4.5).

Grdnite (nalural)

Zibo Granite Factory, Shandong Province, China.

Glass Fibre Reinforced Inorganic Board

Glass Fibre Reiiorced Ma~nesium Oxvchloride Cement

Fire Retardant Glass Fibre-Reinforced Polyester Board Glass Fibre Reinforced Polyester with Al(OH)3 as Filler.

TABLE 1. LIST OF TESTED MATERIALS AND FIGURES

1. Carbonate Aggregate Concrete: Figures 1,13,25,37 2 . Siliceous Aggregate Concrete: Figures 2, 14,26,38

3 . #525 Ordinary Portland Cement Concrete: Figures 3,15,27,39

4. #425 Portland Blast Furnace Cement: Figures 4, 16,28,40

5 . Fire Brick: Figures 5, 17,29,41

6. Standard Clay Brick: Figures 6,18,30,42 7. Gypsum Board: Figures 7, 19,31,43

8. Fire Retarding Gypsum Board: Figures 8,20,32,44 9. Light Heat-Insulating Brick: Figures 9,21,33,45

10. Granite: Figures 10,22,34,46

11. Glass Fibre Reinforced Inorganic Board: Figures 11,23,35,47

REFERENCES

Harmathy,T.Z., Properties of Building Materiats at Elevated Temperatures, DBR Paper No. 1080, National Research Council of Canada, NRCC 20956, Ottawa, March 1983. Lie, T.T., Calculation of the Fire Resistance of Composite Concrete Floor and Roof Slabs, Fire Technology, Vol. 14, No. 1, 1978.

Sultan, M.A., Lie, T.T. and Lin, J., Heat Transfer Analysis for Fire-Exposed Concrete Slab-Beam Assemblies, IRC Internal Report No. 605, National Research Council of Canada, Institute for Research in Construction, Ottawa, Ontario, 1991.

Lie, T.T. and Irwin, RJ., Evaluation of the Fire Resistance of Reinforced Concrete

Columns with Rectangular Cross-Section, IRC Internal Report No. 601, National Research Council of Canada, Institute for Research in Construction, Ottawa, Ontario, 1990.

DuPont Co., DSC Heat Capacity Data Analysis Program Manual, Version 1.0 for use with the Thermal Analyst 2000/2100, Issued January 1991.

Miller, G.W. and Wood, J.L., Journal of Thermal Analysis, Vol. 2, 1970, pp. 71-74. Zhu, J.L. and Lie, T.T., Fire Resistance Evaluation of Reinforced Concrete Columns, IRC Internal Report, National Research Council of Canada, Institute for Research in

Figure 1

Specific Heat of Carbonate Aggregate Concrete as a Function of

Temperature

Temperature "C 50 570 610 690 800 880 900 920

940

Specific Heat J/kg"C 1138 1165 1378 8489 lo00 507 507 540 510

1400-

u

1200- 0 & 600- V) 400- 200-

o+

0 200 400 600 800 1000 Temperature, "C Figure 2

Specific Heat of Siliceous Ag,gegate Concrete as a Function of Temperature Temperature "C 114 500 570 600 680 740 770 88 1 982 Specific Heat J/kg0C 903 603 1178 603 423 1418 400 400 400

0

200

400

600

800

1000

Temperature.

"C

Figure

3

Temperature, OC

Figure 4

Specific Heat of #425 Portland Blast Furnace Cement Concrete as a

1000-

2

800-

3

600--

8

400-

l

200-

0.

0

200

400

600

800

1000

Temperature, O C Figure 5

Figure 6

Temperature,

"c

Figure 7

Temperature, "C

Figure 8

1000-

5'

800-

3'

k J

600--

3

x

1

rn

400--

200--

01-

0

200

400

600

800

1000

Temperature, Figure 9

1600~

P

1200- M 24

.

CI d a 800-

2

0

s

₀

'

400.- CA 0. 0 200 400 600 800 1000 Temperature, "C Figure 10

Temperature, "C

/

Temperature

/

Specific Heat

I

Figure 11

Specific Heat of Glass Fibre Reinforced Inorganic Board as a Function of Temperature

Temperature, "C O°C< T 9 0 0 ° C Cp = 767.3+4.77T 200°c< T

asoOc

c p = -31473.96+155.96~ 280°C< T OIO°C. Cp = 96648.7-312.1T 310°C< T 5600°C 'Cp = 5476.95-10.56T Figure 12

Specific Heat of Fire Retardant Glass Fibre Reinforced-Polyester Board as a Function of Temperature

Figure 13

Figure

14

O°CS

T

S520°C MlMo = 1.00000-0.00007T

520°C~

T

59oOoC M/Mo

=

1.16725-0.00038T

900°Cc T S1OOO°C MlMo

=

0.861 11-0.00004T

Figure 15

Figure 16

Mass Loss

of #425 Portland Blast Furnace Cement Concrete as a Function of Temperature

Temperature, OC

Figure 17

rP

g

9 5 -

z

90. 0 200 400 600 800 loo0 Temperature,

T

Figure 18

Figure 19

75-1 I

0 200 400 600 800 lo00

Temperature. "C

Figure 20

Temperature, OC

Figure 21

Figure 22

Figure- 23

Mass

Loss

of

Glass

Fibre Reinforced Inorganic Board as a Function of Temperature

0

0

0 200 ₄₀₀ 600 _{800 1000}

Temperature, OC

Figure 24

Temperature, OC

Figure25

Figure 26

Thermal Conductivity of ~liceous Aggregate Concrete as a Function

Figure 27

Thermal Conductivity of #525 Ordinary Portland Cement Concrete as a Function of Temperature.

Temperature, "C

Figun: 28

Thermal Conductivity of #425 Portland Blast Furnace Cement Concrete as

Temperature.

"c

Figure 29

Figure 30

Figure 3 1

Temperature, "C

Figure 32

Thennal Conductivity of

Fi

Retarding

Gypsum

Board as a Function

1- 0.8- 0.6- 0.4- 0.2- 0-r 0 200 400 600 800 lo00 Temperature, "C Figure 33

Figure 34

Temperature, "C

Figure 35

Thermal Conductivity of Glass Fibre Reinforced Inorganic Board as a Function of Temperature Temperature "C 21 61 130 180 Thermal Conductivity Wlm°C 0.791 0.792 0.789 0567

Temperature, "C

Figure 36

Thermal Conductivity of Fire Retardant GFR-Polyester Board as a Function of Temperature Temperature OC 21 61 130 180 Thermal Conductivity Wlm"C 0.79 1 0.792 0.789 0.567

Temperature, "C

Figure 37

Thermal Expansion of Carbonate Aggregate Concrete as a Function of Temperature

Temperature, "C

Figure 38

Temperature, OC

o0a

T ~ 1 0 0 0 ~ ~ &iLo

=

0.000012T

Figure 39

Thermal Exuansion of #525 Ordinary Portland Cement Concrete as a Function of~emperature

Temperature.

"C

Figure 40

Thermal

Expansion of #425 Portland Blast Furnace Cement Concrete as

a

Figure 41

.

Temperature. "C

o0e

T ~1000°C

.

ALL0

=

0.0000001T

Figure

42

Temperature, "C

Figure

43

0-

*

-2-

s

_-4-

-6-

-8

7

0

200

400

600

800

1000

Temperature,

OC

Figure 44

Figure 45

Temperature, "C

Figure

46

-0.41

0 200 400 600 800 1000

Temperature, O C

Figure 47

Thermal Expansion of Glass Fibre Reinforced Inorganic Board as a Function of Temperature

Temperature,

"C

Figure 48