206 



ANNALS NEW YORK ACADEMY OF SCIENCES 



25 pounds for a period of 11 months. Parallel specimens were stored in 

 damp sand during this period and allowed to attain their full normal 

 strength. The table following shows the leakage and final strength of 

 the specimens : 



Table 15 



Percolation through Concrete Specimens 



Months of percolation 



Brands of cement and grams of water passing in 10 m 



inutes 



A 



B 



c 



D 



E 



F 



% 



1 



146 



155 



56 



37 



72 

 71 

 68 

 57 

 40 



"l3 



8 



286 

 125 

 70 

 47 

 28 

 12 

 28 

 46 

 43 



' "7 



13 



63 

 22 

 90 

 52 

 37 

 31 

 34 

 14 

 12 



"io 



10 



164 



179 



167 



161 



65 



15 



11 



6 



2 



*5 



1 



76 

 16 

 11 

 11 



7 

 17 

 26 

 16 



5 



"i 

 2 



230 

 82 

 85 

 82 

 45 

 39 

 33 

 21 

 11 



"ii 



19 



2 





4 



5 



6 



7 



8 



9 



10 



11 





Table 16 



Comparison of Strength before and after Permeability Test 





A 



B 



c 



D 



E 



F 



Compressive strength of specimens 

 at the end of period 



770 7 



1080 



29 



490 



1210 



60 



640 

 1230 



48 



890 



1125 



21 



750 



1220 



39 



590 



1090 



46 



Compressive strength of untreated 

 specimens, pounds per square inch. . 



Loss of strength through percolation 

 ( per cent) 





7 One specimen crushed. Other results are average of two specimens. 



Effect of the direction of flow through concrete. — Concrete seems to 

 offer less resistance to the flow of water when the direction of the flow is 

 parallel to the bed than when at right angles to it. A test covering this 

 point was made with 8-inch cubes of concrete of the proportions 1:4:14, 

 fine and coarse aggregate being a standard crushed bluestone. 



