46 



Tensile Strength of Morttir Affected by Fineness of 

 Cement. (Eliot C. Clarke.) 



Portland Cement 



Rosendale Cement 



Strength in Pounds 

 per square inch 



n 



Strength in Pounds 

 per square inch 



1:0 

 1:3 

 1:5 



403 



105 



68 



304 

 180 



1:0 

 1:1J 

 1:2 



(5) That the forms will permit no settling, thus pre- 

 venting the breaking of the adhesion between the cement 

 and steel. 



(6) That the steel is placed in the prescribed position. 



(7) That the forms are* not removed in less than 10 

 days and the bottoms of beams and girders and shoring 

 underneath in not less than 4 weeks. In very long girders 

 and thick slabs, not less than 6 weeks. 



(8) Make the material as homogeneous as possible. 



(9) Use 30 to 50 diameters to develop the grip of the 

 bar, and if not able to do so, hook the bar at ends with a 

 6 in. hook. 



(10) Always see that the shear is provided for when 

 concentrated loads occur. 



(11) See that you have enough area in compression, 

 and if not, add steel and inverted U's. 



