ASTM C20 Standard Test for Apparent Porosity, Water Absorption, Apparent Specific Gravity, and Bulk Density of Burned Refractory Brick and Shapes by Boiling Water

Scope: 

ASTM C20 involves test methods that help in quality control, research and development, establishing specifications, evaluating compliance with specifications, and providing data for design purposes. A refractory material is a material that is resistant to decomposition by pressure, heat, or chemicals. And even at high temperature it can retain strength and form at. Refractory materials have four primary properties which are determined in ASTM C20, which are the apparent porosity, water absorption, apparent specific gravity, and bulk density. These properties help evaluate and compare refractory products for their quality. Furthermore, in the selection of refractory products and where a product could be used.  

Test procedure:

In ASTM C20, after samples are dried by heating, they are weighed to determine their dry weight, D. Test samples are then suspended in water and boiled for 2 hours. They have to be submerged in water and should not be allowed to touch the heated bottom of the container i.e suspended. Heat is turned off and the samples are suspended in water for a minimum of 12 hours. Suspended in water, the samples are weighed to determine their suspended weight, S. Samples are removed from the water and dried lightly with a moistened cotton cloth to remove all drops of water from the surface and to determine the saturated weight, W. 

Video 01: Testing of bricks porosity, crushing strength, hardness, soundness, water absorption, impact, and structure test

Specimen Size:  

For testing bricks, cut a brick into four equal parts to expose the interior part of the brick. When testing other shapes, the volume has to be 25 to 30 inches. The specimens must show both interior and exterior portions. 

Data: 

1. Exterior Volume, V 

V = W – S

2. Volumes of Open Pores and Impervious Portions

Volume of open pores cm³  = W – D

Volume of impervious portion cm³  = D – S

3. Apparent Porosity, P

P, % = [(W- D/V] x 100

4. Water Absorption, A

A,% = [(W – D)/D] x 100

5. Apparent Specific Gravity, T

T = D/(D – S)

6. Bulk Density, B

B = D/V

Conclusion: 

ASTM C20 determines the properties of refractory products.