XI, A, 5 



Witt: Philippine Paving-brick Materials 

 Table VII. — Bonding power of Pasig clay. 



219 



M 



ix. 



Tensile strength. 



Clay. 



TufE. 



Kilos per 

 square cen- 

 timeter. 



Pounds per 

 square 

 inch. 



Per cent. 



Per cent. 







100 







12.2 



176 



80 



20 



8.0 



115 



70 



30 



9.2 



132 



60 



40 



8.3 



118 



50 



50 



10.5 



149 



40 



60 



10.5 



151 



30 



70 



10.2 



147 



It is surprising that the tensile strengths of all the mixtures 

 were nearly alike. One might expect that the strength would be 

 less with the lower percentages of clay, but the results obtained 

 show that this is not the case. The general behavior of the 

 various mixtures leads me to believe that most of them could 

 be used in the manufacture of building brick ; but unfortunately 

 the results of the fire tests were such as to eliminate them from 

 consideration as paving-brick materials. This is because the 

 vitrification range is too short. In fact, the test pieces fused 

 almost as soon as they commenced to vitrify. The disadvantage 

 in making building brick from a mixture is the labor required 

 to dry and pulverize the two materials. 



SUMMARY 



1. There is an urgent need, in the Philippines, for a suitable 

 paving material for city streets. Imported materials are not 

 generally available for this work on account of prohibitive 

 freight rates. 



2. The Bureau of Science is searching for a clay or a shale 

 suitable for the manufacture of paving brick. Tests on nine 

 samples have been completed. 



3. The success of the undertaking depends, to a large extent, 

 on cooperation in securing samples. If a sufficient number can 

 be obtained, it seems likely that the right deposit may be located. 



143249 Z 



