126 



REIBLING. 



Concrete cubes from Garcar Bridge, Cebu. 



Mark on cubes. 



Age, in 

 days. 



Dimen- 

 sions, in 



Initial 

 crack. 



Ultimate 

 strength. 



Strength, in 



pounds, per square 



inch. 



Remarks. 



inches. 



First 

 crack. 



Ultimate. 







, 49,730 



65, 000 



1,381 



1,806 



The mortar is rich. 















There were a 

















number of bro- 

















ken stones, espe- 



Class "A" con- 

 crete, South 

 Arch ring, 

 C a r c a r 

 Bridge, 

 Province of 

 Cebu, proj- 

 ect R-16 



61 



6X6X6 



55, 500 



J 



63, 800 



■ 

 • 



1,542 



1.772 



cially the large 

 ones. This cube 

 contains 3 stones 

 about 3 inches in 

 diameter. 

 This cube is the 

 same as the above 

 except that it 

 does not contain 

 large stones of 3 

 inches in di- 

 ameter: 









35, 300 



48,600 



980 



1,350 



The mortarisgood. 

 About one-half of 















the stones were 















broken. The 

















stones used were 

















rather soft. 









37,750 



39, 650 



1,048 



1,101 



Do. 



i 







44,700 



63,150 



1,242 



1,754 



The mortar is good . 

 Small sized 

 stones were used. 

 This cube w a s 

 well proportion- 















ed. A small per- 















centage of the 

















stones were 



, 















broken. 



Cubes stored two weeks in water and then in open air. 



The same gravel was crushed with a weaker mortar (Class "B" con- 

 crete) and gave results as recorded below. The extremely low strength 

 at the "first crack" illustrates the greatest danger in the use of poor 

 gravel. 



