FORMS FOR SPECIFICATIONS, ETC., FOR ROAD MATERIALS. 



29 



pockets, cracks, or marked laminations. Kiln marks shall not 



exceed of an inch, and the wearing surface shall show 



but slight kiln marks. 



Representative samples of the brick shall meet the following 

 requirements when subjected to the rattler test : 



Average loss by abrasion on one or more tests, not more 



than per cent. 



Maximum difference in per cent loss by abrasion when more 

 than one representative sample is tested, not more than 



per cent. 



A maximum of three tests will be used as a basis for re- 

 jection. 

 The bricks shall meet the following requirements : 



Length to inches. 



Width, to inches. 



Depth, to inches. 



Variations among bricks from a single plant shall not exceed 

 the following limits : 



Variation in length, inch. 



Variation in width, inch. 



Variation in depth, inch. 



If the edges of the bricks are rounded, the radius shall not 



exceed of an inch. 



Only bricks with lugs on one side, raised not less than of 



an inch, nor more than of an inch, shall be used. 



The bricks shall be subjected to inspection subsequent to de- 

 livery at the place of use, prior to and during laying, in order 

 to cull out and reject upon variations from the general and 

 dimensions clauses and upon the following grounds : 



All bricks which are broken through, or chipped in such man- 

 ner that neither wearing surface remains substantially intact, 

 or in such manner that the lower or bearing surface is reduced 

 in area by more than one-fifth. 



All bricks which are cracked to a depth greater than -inch 



on any surface, or which are cracked on the wearing surface. 



All bricks which are so off-size or so misshaped, bent, twisted, 

 or kiln-marked that they will not form a proper surface or align 

 properly with other bricks. 



All bricks which are obviously too soft and too poorly vitrified 

 to endure street wear. 



Bricks shall be sampled in accordance with the method de- 

 scribed on page of these specifications, and tested in 



accordance with the method described or referred to on page 

 of these specifications, test No. . 



Battler test. 



Dimensions. 



Visual 

 spection. 



Methods of 

 sampl In; and 

 testing. 



Note. — The committee does not recommend an absorption test 

 for general use in specifications. If special conditions make such 

 a test necessary, it may be specified. 



