28 



BULLETIN 555, U. S. DEPARTMENT OF AGRICULTURE. 



General. 



Chemical 

 properties. 



Physical prop- 

 erties. 



Modifications 

 la elongation. 



Weight. 



Storage. 



Methods of 

 sampling and 

 testing. 



General. 



SPECIFICATION FOR STEEL REINFORCING RODS. 



Rods shall be (insert form selected) * and (insert method of manu- 

 ^?*?5. e . d . e . s . i 55 d 2: and shall conform to the following chemical and 

 physical requirements. Twisted bars shall be twisted with one 

 complete twist in a length not over 12 times the thickness of the 

 bar. 



Rods shall meet the following chemical requirements^ 

 Phosphorus — 



Bessemer, not more than § per cent. 



Open-hearth, not more than § per cent. 



Rods shall meet the following requirements for physical prop- 

 erties : 



Tension tests — 



Tensile strength, not less than § pounds per square 



inch. 



Yield point, not less than § pounds per square inch. 



Elongation in 8 inches, not less than § per cent. 



Cold bend test without cracking — 



Thickness or diameter under f inch, §°. 



Thickness or diameter £ inch or more §". 



For plain and deformed bars over three-quarters inch in 

 thickness or diameter, a deduction of 1 from the percentages of 

 elongation specified in the foregoing table shall be made for each 

 increase of one-eighth inch in the thickness or diameter abov< 

 three-fourths inch. 



For plain and deformed bars under seven-sixteenths inch in 

 thickness or diameter, a deduction of 1 from the percentages of 

 elongation specified in the foregoing table shall be made for each 

 decrease of one-sixteenth inch in thickness or diameter below 

 seven-sixteenths inch. 



The weight of any lot of bars shall not vary more than 5 per 

 cent from the theoretical weight of that lot. 



Steel rods shall be so stored as to prevent the formation of 

 rust scales and when used on the work they shall be free from 

 dust, dirt, loose rust, paint, oil, or grease. 



Rods shall be sampled in accordance with the methods de- 

 scribed on page , paragraphs , of these specifications, 



and tested in accordance with the methods described or referred 

 to on pages of these specifications, tests Nos. 



SPECIFICATION FOR VITRIFIED PAVING BRICK. 



All brick shall be of a size commercially known as " vitrified 

 block." They shall be thoroughly annealed, tough and durable, 

 regular in size and shape and evenly burned. When broken the 

 bricks shall show a dense, stonelike body, free from lime, air 



• Plain, deformed, hot or cold twisted, as may be desired. 



t Rolled from new billets made by Bessemer or open-hearth process or 

 rolled from standard section tee rails, as may be specified. 



t To be applied only to rods rolled from billets. 



§ The values given in American Society for Testing Materials Standards, 

 1916, serial designation A15-14, for the particular kind of material de- 

 sired, are recommended for insertion in this table. 



