38 THE BUREAU OF SCIENCE 



the investigators has given us a more reliable product in the 

 Philippine Islands. The importance in relation to safe construc- 

 tion and to the saving of money to be effected by carrying on 

 such work is very great. During one fiscal year, 71,778,675 

 kilograms, or a value of f*=l,524,600, of Portland cement were 

 imported into the Philippine Islands. At a low estimate the 

 total cost of the corresponding concrete was six times the cost 

 of the cement, or 1*^9,147,600. A gain or loss of 1 per cent in 

 the efficiency of this material in durability and strength rep- 

 resents a money value of ?91,476. 



Our investigation proved that the efficiency of Portland cement 

 is obtained at a corresponding expense to the manufacturer, and 

 cements should be purchased on a basis of quality rather than 

 upon a mere consideration of quantity, and the information 

 gained from this research work enabled us to suggest "a bonus 

 system for the purchase of Portland cement," the enforcement 

 of which, it is believed, would secure the best cement at a rea- 

 sonable cost and eliminate the necessity of occasionally rejecting 

 cements as has heretofore occurred. 



Our investigations with regard to the manufacture of Portland 

 cement from local raw materials have proved that there is an 

 abundance of calcareous and siliceous material in certain desir- 

 able localities which are well suited for the manufacture of 

 Portland cement on a commercial scale. As there is no cement 

 plant in the Philippine Islands, all of the Portland cement used 

 in this country has been imported, and the high cost for shipping 

 and transportation makes our concrete construction expensive. 

 The average cost of Portland cement in the United States is 

 about T2 per barrel, but the local Government on large contracts 

 now pays from ?5.50 to ?=6.50 per barrel. 



63. Concrete. — Careful, systematic inspection of the sand, 

 gravel, and stone, as well as of the cement used in all concrete 

 construction, is necessary to secure satisfactory permanent re- 

 sults, and reliable and economic practice in concrete construction 

 cannot be assured until the quality and concrete efficiency of 

 the available aggregates — sands, gravels, and crushed stones — 

 have been thoroughly investigated. The Bureau of Science has 

 shown that many of the aggregates which have been used for this 

 purpose are of poor quality, and that adequate consideration is 

 not given to the fact that the nature of the aggregate is fully 

 as important as the quality of the cement. Our investigations 

 indicate the necessity of adopting standard methods for testing 

 concrete and aggregates and a thorough and systematic study 



