Arizona republican., 1915-06-30

posed of smaller or more finely divid- ed particles The general specification is as follows: Passing a 200 mesh screen D to II per cent, passing q 4O mesh screen Is to 36 per cent; passing a 10 mesh screen 25 to D per cent; passing I4 mesh screen to 22 per cent: passing la mesh screen less than 10 per cent.
 National pavement differs from bitu- lithic and Topeka in that the mineral aggregate is composed of pulVerized earthly material often disintegrated to such degree Of fineness that over I5 per cent will pass through 200 mesh screen. In the cases of the bitulithic and Topeka specifications the asphalt content Of butimen soluble in carbon disulphide between to II per cent In the case of National pavement the asphaltic content consists of II per cent soluble in carbon bisulphic.
 Having outlined briefly the relative composition of bituminous pavemente which | feel aIe specially adapted for use in this city. l desire to say some thing regarding their physical proper ties As this city has laid some 100000 square yards Of bitulithic pavement any comment regarding its adaptability might seem unnecessary at this time I do desire to say. however. that in no city which l visited did I find q more excellent pavement than we have on the streets of Phoenix. Neither did find in any of the cities mentioned above. where bitulithic had been used was the price as low as that which has been and is now being laid for in Phoe- nix. In every locality visited by me the price of cement was much lower than it is in Phoenix. as witness. The case of Dallas, Texas. where large cement plant Is located. cement can be had on the streets for from SEQ to $50 Ter bbl. as against s270 in Phoe- nix.
 I am anneXing to this report pate of the Dallas Daily Times Herald of Monday June 7 1915, wherein adver- Using is being carried of it's paving of two sections Of the city of Dallas where the streets are being paved with bitulithic pavement In the one in stance where the yardage was consid- erably smaller the price per square yard was s240. the largest section was laid for S2.30. It's unequaled success in business districts taken in comparison to pavements inspected by me in the various cities l visited leaves no doubt in my mind that it is the proper pavement to adept as a standard in this city. If any criticism can be offered it might be that in places the proper mix ture was not obtained and as the re- suit therefrom the pavement is softer under our intense heat than that of other sections where evidently a more dense mixture of mineral aggregates was obtained.
 In the matter of Topeka pavement I desire to state that I spent two days in with MT. A. E. Young, city engineer, l made careful inspection of all the To- peka paving laid since it's inception. I also spent sometime in his laboratory and he furnished me with detailed in- formation concerning the manner in which this paving had been laid From the fiIst paving laid to the most recent it was uniformly good. Where extreme care had been exercised in the grading of the mineral aggregates it was a most excellent pavement, and block after block showed TO sign of deterioration or cracks Some of the earlier DOT tions that had been laid had cracked. 1 MT Young informed me that it was simply d matter of experimentation - arrive at the proper mixture, and there ! is no doubt in my mind that proper mixture can be arrived at whereby To- | peka pavement can be laid in Phoenix, and will prove a satisfactory pavement.
 One of the prime motives or reas- ons for my trip of inspection was to investigate what is known as National pavement. At various times my atten ton has been called to this pavement, but I mad newer had occasion to make an investigation until this trip. l had heard it generally spoken of as being mixture of dirt and asphalt which l must confess did not appeal very strongly to me as being a stable mix ture. However, after having inspected National pavement and the process of it's manufacture my opinion was quickly reversed. Instead of being a mixture of dirt and asphalt it is rather a mixture of finely pulverized mineral