Research Paper R.P 1320

   Part of the Journal of Research of the National Institute of Standards and Technology Volume No. 25

   Physical, Mineralogical, and Durability Studies on the Building And Monumental Granites of the United States.

By Saniel W. Kessler, Herbert Insley, and William H. Sligh

* ABSTRACT*

Tests on 116 samples of granite (including the "black granites") from the principal producing districts of the United States gave the range value for various physical properties as follows:

Compressive strength 7,700 to 53,800 lbs. per sq. inch.

Absorption (48 hour immersion) 0.02 to 0.58%

Porosity 0.40 to 3.84 percent.

Weight 157 to 187 lbs. per cubic foot.

The "black granites" (gabbos and bassalts) were indicated to be stronger, denser, and less absorptive than normal granites.

1. 2. 3. 4. 5.
Ser. No. Source Color Texture **Compressive Strength Absorption Density Porosity Wt. per Cu Ft.
25 Ver. Bl. grey Fine 15,600 lbs.psi .20% 2.686 .97% 166
11 Maine Lt. grey Fine 29,600 " .31% 2.658 1.32% 164
55 N. Car. Pink Medium 39,700 " .16% 2.643 1.10% 163
71 Wisc. Dk. grey Medium 13,800 " .05% 2.954 1.45% 181
78 Minn. Pink Coarse 19,000 " .12% 2.754 2.65% 167
89 Minn Pink Medium 29,600 " .11% 2.694 1.41% 165
*115 Calif Dk. grey Fine 53,800 " .04% 3.024 .76 187
116 Calif Dk. grey Fine 34,400 " .07% 2.910 1.03 180
Averages 24,500 " 1.29%
Lowest 5,900 " 0.40% 157

*    Source of Mojave Black Granite Surface Plates

1.  Compressive strength tested on 300,000 lb. hydraulic machine on dry samples, perpendicular to the rift.

2.  Absorption by weight, in percent, for immersion period of 48 hours.

3.  True density, determined in powdered samples suspended in alcohol.

4.  Porosity, total pore space computed from absorption formulas.

5.  Computed by multiplying the bulk density by 62.35

 

   BLACK GRANITE ------

**  Young Modulus (psi x 106) ......................................................................................  8.45 to 13.6

**  Modulus of Rigidity  (psi x 106).................................................................................  4.5 to 5.2

**  Heat Capacity (joules /g) ..........................................................................................  0.72

**  Thermal Expansion Coeff.  (in/in/deg C x 10-6)  .........................................................  5.4

**  "Surface Plates Compared by Physical Tests" by Richard Merriam, Associate Professor,

Dept. of Geology, Univ. of Southern California, Los Angeles, California.