Arizona republican., 1910-12-28
PAVING FACTS AND FIGURES
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 the taxpayers We were advised that since the construction of this pave ment nothing whatever has been paid for maintenance, due to wear. This pavement is laid on a gravelly Ioam soil
 In 1904 the cost of this pavement, including excavation and grading, was slS0 per square yard. but a pavement laid under the same specifi- cations in 1910 cost $l.57h per square yard. In each case the contractor was Fairchild, Gilmore, Whitton Company of Los Angeles, California.
 In Riverside we were advised that the variations in temperature were pratically the same as in Phoenix, although the summer heat does not last so long. We were advised that turing the summer period the pave nent softens somewhat, not to the detrimcnt of the same. On the tracks of the Southern Pacific Railway We inspected d cross section of this pave mcnt laid about a year since, and founi the work apparently in exact compliance with the specifications and If very substantial construction. A photograph which We took of this cross section is attached hereto.
 While thus is referred to as a sheet asphalt pavement. the wearing surface is really a combination of stone dust, asphaltum ahd sharp sand in the pro- portions Snown on the attached speci- fications ,.umbercd 25 There were nG indicate that thiS wearing sur face has lmCSled or CraWled after six years use. due aTpa"enIly to the great care with which the specifications hay" b'Cn drawn and the careful in specii''n of the construction This good result is obtained by leaving the surface of the concrete rough. so thtt the one inch of sharp rock bind eI mike; with the asphaltum ties the wearing surface co the concrete base.
 In the residence district of Riverside, W. fonnd an exceptionally fine system of oii maCadam reads. so well con strCctei as tu Take it difficult tO tell when we passed rom the oil macadam tO the asphale- concrete pavement
 These oil macadam pavements in the in the residence districts have proven exceptionally satisfactory in Riverside and are now laid under specifications No. 24. a copy of which is hereto attached and made part hereof, which are the result of many years of careful study of the best construction Of oil macadam roads.
 We were fortunate in being able to inspect several cross sections of this road where excavations were made for water pipes and other purposes. and T picture of a cross section is hereto attached. The same thoroughness in construction and compliance with the specifications were observed in this road as in the asphalt pave ment.
 In a portion of the residence streets the oil macadam road is 90 feet in width from curb to curb, and is com posed of a layer of inches of lime | stone rock. which is filled with lime l stone screenings. compactly rolled until | the rock has been so compacted as to | leave almost no vOidS. on this is laid i a thin carpet of liquid asphaltum or asphaltic oil, containing so per cent of | asphaltum hot, with the best results | under pressure and thus forced into l the stone base a short distance. This | OH IN dpplitu III StNtIdl tbdASs lilAcu with screenings and finely rolled | This wearing surface of oil and | being not to exceed one half inch in thickness.
 We inspected many roads of this | character. which had been in use for from three to seven years, and | found that they were still in excel lent condition and the cost of main tenance slight.
 It is usually necessary to renew the surface of the road at the end of three years. at a cost of about $l5O a mile, after which no further repair is necessary for about six years. If this carpet of asphaltic oil is main- tained the base remains unimpaired.
 These roads are dustless. requiring no watering. will stand a heavy traf- flee, are easily cleaned. and have given great satisfaction to the tax payers. On streets which are not heavily travelled these oil macadam roads are sometimes constructed with a five-inch base. and in some cases on a four-inch base, with entire sat- sfaction.
 The cost of these oil macadam roads in Riverside varies from B cents to 20 cents per square yard. depending