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The Advantages Of Macadam

The Advantages Of Macadam image
Parent Issue
Day
23
Month
April
Year
1890
Copyright
Public Domain
OCR Text

At a reeeiit meeting of the Pennsylvania State grange at Harrisburg, Worthy Past Lecturor S. R. Downing delivered an address of interest to all who care for the improvenient and preserration of highways. In the course of his remarks Mr. Downing said: A not very ready musician knows how tiresome it may be to conipass a new tune and how easy to lapse into the old airs. And so with new ideas, policios or economics. The old idea is cherished, f oudled and embraced until thore is jealousy of the new. Tlius, when an essayist points out tliat a macadam road is not a pike, tliat a niacadam can be built for less than pikes have cost, i hal a macadam costs less for repair, and that it is the most economie road, souie very gooil people will not so much as wrestlo with the new saying, but, clinging to the oíd ideal, will argüe that inasniuch as pikos are rough, macadains must be rough; inasniuch as pikesare built below frost, macadams must be so built; that inasmuch as the hand hammered pike has cost as much as $5,000 per mile, and, because of its ooarse construction, $100 per mile annually for repair, that consequently a machine crusher, roller made macadam structure must cost the same ($5,000 per milo) for the making and the same (100 per mile) for annual repair. It is beeoming usual to cali pikes macadamized roads. A macadam road is not a pike, in that the macadam s infinitely better and less expensive than roads heretofore called pikes. The iinperfections of a piko are: First- In that it is composod of loose stone in its making and repairing. ïhus the pressure a pike receives from passing wheels deepens into ruts. A rut once made, although filled and réfllled, will reappear. Second - Pikes have been constructed of hammered stone. Hammered stono is too coarse for the best euperstructure of roads. The originator of the macadam principie stated before a committee of the house of commons tliat a stone road wasasavingof repair iti ratio with the fineness of the stone used. Thus a bod of one inch stone would cost in repafa .i such bed but one-half of that of a bed of two inch stone. Again, a pike composed of handbroken stone may have cost $5,000 per mile for building, and $100 per mile annually for repair - $5,000 per mile for building, because the stone was liandbroken, at $1 per perch, and 100 annually for repair, because the superstructure was coarse and loose. Thus ruts are 3tarted and are expensive to erase. The experience of macadam buüders teaches that a rut will follow a rut, that is if a stone lied is laid upon a rutted clay base ruts will appear in the stone bed directly over those of the clay foundation. Thus one rut in a pike is the predecessor of an endless series of ruts and an endless bill of costs. On the other hand, a macadam structure avoids these imperfections of a pike in that (first) its superstructure is composed of small stone and stone siftings oi chips, and (second) while wheels press the unknitted, loose surface of a pike, and reach solidity withiu one track at two inches below the general surface, thus forming ruts, the roller used in macadam structure does exactly what wheela do, but further, it presses the ?ntire surface of the bed, so fat as wheels an penétrate, in ruts, and tlius inakes the entire bed as solid as the base of a rut. Thus, again, a macadam is so uniformly resistant of wheel pressure that ruts cannot be produced in some macadam within a period probably of ten years. A crusher turning out 80 perches of 3tone per day will earn in a day, at 15 sents per perch, $12, which will easily pay for the cost of running a crusher per iay. The difference between $1 per perch for hand broken stone and 15 cents for crushed stone is 85 cents. In the realization of this gain of 85 cents by the use of a crusher we can reasonably con:lude that a macadam ought to be built for less than half the cost of hammored pikes. Then again, as to the economy of a macadam over that of a pike. A macadam being virtually rut and water proof, and continuing so for ten years, what will it cost to repair a macadam per mile annually during ten years? I think rou will reply, really nothing. But will a macadam resist wheel pressure for, say, ten years? In answer we ire furnished proof in an eight-year-old macadam leading from the Pennsylvania railroad f reight and passenger station at Devon, Chester county. Mr. Charlea Paiste, superintendent for the Devon Land corupany, tells me that this macadam has endured all thetraffic from the railroad, being equal at times to two tons at a draft, and yet this macadam has not cost a cent for repair for eigbt years, and, as I savv for myself , has not as yet a rut. The question then arisca, rhis macadam being as good as it w;is eight years ago, will it not endure eigbt vears more without a cent for repair?

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Subjects
Old News
Ann Arbor Courier