Coefficient of expansion of concrete 1:2:4 is 0.0000055 per 

 deg. F. 



Coefficient of expansion of concrete as determined by 

 Prof. William D. Pence, University of Purdue. 



Results of Experiments Made by Prof. Wm. D. Pence, 



Perdue University, to Determine Coefficient of 



Expansion of Portland Cement Mortar. 



Coefficient of expansion of wrought iron is 0.0000068. 



Coefficient of expansion of steel is O.OOIKKHM. 



Concrete in tension is more variable than concrete in 

 compression. This is due to the adhesion between the 

 cement and the aggregate. 



Well made concrete of 1:2:4 mix at the age of 1 month 

 runs from 2,000 to 4,000 Ib. per sq. in. when tested in the 

 form of 4 in. cubes. 1:1:3 cinder cubes, 1,000 Ib. A work- 

 ing value ranges from 500 to 750 Ib. per sq. in. 



Prof. Hatt found concrete to be able to stand 300 Ib. per 

 sq. in. in tension. In reinforced work the tension of the 

 concrete is neglected. 



Shear of concrete can be figured from 50 to 65 Ib. per 

 sq. in. This is lower than that given by Feret; it is 

 about what M. Considere gives. 



Prof. Bach obtained the following table from the equa- 



E c * (See Marsh, Page 225, for de- 







tion 



tailed description.) 



A mortar of 1:1% has the greatest strength. Table on 

 page 28. 



