Press enter after choosing selection

Macadamized Roads

Macadamized Roads image
Parent Issue
Day
15
Month
October
Year
1890
Copyright
Public Domain
OCR Text

Country roadmaking has become a science, and the matter of a general reform of the roads on a tinifórin systom bids fir to becorae a political questiou in soine states and many minor localities. The most surprising fact so far developed in the recently revived discussion is that very few people (certainly in il more than ono in a thousand) whose business involves much hauling have any idea of thu enormous loss caused by bad roads. Sir John Macheill by many cafeful experiments showed that the units of force needed to move a certain weight in a wagon variad as follows: On a very amooth. hail aurface 2 On a dry and clean roujth stol road 5 On name, very diutty .... 8 On Mam, wet and inuddy 10 On a wet and muddy road 32 That is, he estimatea that bad roads cost about 1,500 per cent. of waste labor! John Loudon Macadam traveled about 30,000 miles to inspect and study the roads of Qreat Britain, and in 1816 introduced his mettíod, Which gained favor so rapidly thát of the 25,600 miles of public roads in the klngdom 18,000 were maéadamized within a dozen years. His systein, hö wever, was thönght by some to be defectivo in one particular - a very important one in England - the method of preparing the foundation. Mr. Thomas Telford added the system of laying a rock foundation and giving the road a tolerably high central crown, so th;it system should properly be called the Telford-Macadam method. The improved or Telford-Macadam method is as follows: The grade should have a rise of at least one inch in thirty toward the center, and the ditches le not less thañ a foot deep, ïnêasuring from a cross section that is the base of the constructed road. On this base (which is thu natural earth and should first be hard rolled) is laid a bed of stone, eight inches deep in the center and diminishing to six inches at the sides; the stones should not be'inore than eight incheá or less than six inches wide; the smaller ones' should be inserted by liand, so as to wedge the whole mass very tightly together. The stone surface is then rainmed and ponnded till it is fairly smoöth. On this foundation course comes a layer of stones, varying from threo inches (the largest) to ono inch (tho smallest). These need not necessarily be machine broken, but may be rëfuse froin the screened stone or rakings. This layer should be tour inches deep, and should be f ree from dirt and well rammed or rolled down. The surface layer of broken stone should bethree inches deep, and should be selected wi th considerable care. Every stone in it should have passed through a two-ineh ring before it is laid, and stones which are wedge shaped, or otherwise do not approach uniformity of measurement, should have no place. After this layer has been carefully prepared it is superficially rolled. Screened gravel or sand is then thrown on, and thorough rolling completes the process. The cost would be about three times that of the common gravel road, and, though some latitude ia allowed in the thickness of the upper layers, yet it is laid down that each should be at least three inches thick, except the sand. The entire depth therefore of the rock, pebble and gravel structure would be abput fif teen inches. Various modifications of the system are therefore ptoposed because of a desire to economize. The argumenta advanced in Englnnd for tho Telford-Macadam system are very forcible, one of the strongest being the drainage secured by setting the longest stones in such a way as to leave the structure quite porous below and yet very firm. In the United States, however, more than one engineer declares Ui.iL 'tf HflUïi ö11 tUluagli tlio radbed it breaks up at times any how; the substratum of rock does not prevent it." Before the days of Telford and Macadam Great Britain had ihe same wretched system that still prevails in many parts of the United States, a system which requires the peoplé of many a thinly inhabited and poor farming región to keep up the road between two populous towns. "Requires" them to do itisonlythe legal expreasion, for they notoriously do not do it - a fact attested by ten thousand popular jokes on "western roads." The so called turnpikes of Ohio and "macadainized roads" of Indiana are practically the same thing - a gravel road only, requiring frequent "patching," but hardening and improving by time, provided the hauling is not too heavy at the start. It certainly seems time for a general reform of the country roads all over the nation.

Article

Subjects
Old News
Ann Arbor Courier