The modulus of elasticity of twelve-inch mortar cubes, one volume cement to one volume sand, was, for loads between five hundred and one thousand pounds per square inch, 3,461,000 at seven days and 5,000,000 at seventy-five days.

Metal Companies is given in Table 145. The results are seen to be low, as is the crushing strength. The permanent set in five-inch gaged length for a load of six hundred pounds per square inch is also shown in the table.

Table 145. Modulus Of Elasticity Of Cinder Concrete

Tests of Twelve-inch Cubes, Three Months Old, at Watertown Arsenal.

Portland Cement, Brand.

volume Proportions in Concrete.

Compressive Strength.

Modulus of Elasticity in Thousands, between Loads per Square Inch of

Permanent Set in Five Inch Length after Load of 600 Pounds per Square Inch.

Pounds per Square Inch.

Cement.

Sand.

Cinders.

100 and 600.

100 and 1000.

1000 and 2000.

A

1

1

3

2780

2500

2500

1429

0.0000

B

1

1

3

2368

4167

3214

1190

0.0000

B

1

1

3

2580

2083

1875

1351

0.0001

C

1

1

3

1877

1667

1552

...

0.0001

D

1

1

3

1879

2273

1875

...

0.0001

Mean

1

1

3

2297

2542

2203

...

0.0001

A

1

2

5

1715

1471

1286

...

0.0002

A

1

2

5

1402

1087

957

...

0.0008

B

1

2

5

1263

1087

865

...

0.0024

B

1

2

5

1200

1190

849

...

0.0009

C

1

2

5

917

735

...

...

0.0057

C

1

2

6

871

658

...

...

0.0113

Mean

1

2

5

1228

1038

...

...

0.0035

Note : Tests for Eastern Expanded Metal Companies. "Tests of Metals," 1898.