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Materials For Roads

Materials For Roads image
Parent Issue
Day
23
Month
July
Year
1890
Copyright
Public Domain
OCR Text

There are many proporties requisito in a good rond making material. Hardbeas, tongknesa and ability to withstand the vreather are oaeentisl and shoBld be carefnUy considerad. Thomas Codriugton, i his book on the maintonanee of inacadamized roads, said: "The.sc three qualifications are by no UH-ans always found together. Thns fiint. thougb hard, is often brittle, and some schistose or slaty rocks, although hard and tQUgb when quarried, often disintegrate when exposed to the weather. Anntlicr qnality of importance is that of binding wi-ii, and t.liis is rarely fonnd in coihbinaticin with extremo hardness and toughness. Materials well Consolidated together and united in a ma.xs rosist cruflb mud) botter than when loose, and good binding property enablos a stone compaiatively weak to weai better than n harder slmii' which doesimt bind. The igneous and silicions rocks, as a rule, have but little binding property. The sandy detritus which is forined from their wear, and in which the Individual stones are bedded in the road, has no cohesión or elasticity boyond that which tnoisture gives it and whicli it eoioseuently loses when dry. The materials, therefore, work loose in dry weather and stones at the surfaco are displaced. Limostones, on the other hand. fumish a inortar like detritus which h;is ;onsiderable cohesión excopt when softened by sxcessive inoisture. "For very heavy traflic hardness and toughness are of more importanee tlian good binding properties, and the best road materials are trapa, basalfs and preenstones. ürdinary granite is generally an inferior road material, frorn the bri' tleness of the feldspar, and gneiss is no botter. "Copper slag and f urnace einders from iron works may be used with advantage where they are procurable and when no stone stTong enough to stand heavy traffic can be got. They are both very durabla, but care is required in the selection of the tougher sorts. They liave no binding proporties, and on this account are soinetimes used with limestone. A rougli surface will, however, ahvuys result from the unequal wear of two materials so different in hardness. Limestone scrapings or red ashes laid 0:1 as a binding material aid consolidation very mucli and also prevent the injury to horses' feet from the sharp edges of the fresh laid slag, which is so much complained of. "Field stone gathered from the surface of the land and river stonu from the beds of streams and rivers are largely used in district where quarries do not furnish a stone fit for road purposes. They both consist of the harder parts of stones derived from various and often distant sources which have withstood the weathoring and woar by wliich the spfter portions have perished. Stones thus derived are not of uniform hardness, and from their unequal wear roads made of them are not so smooth as whon a material of one quality is used. "For traffic not very heavy the harder limestones have great advantages from their binding propertie3, in which the igneous and silicious rocks are deficiënt, and which euables a comparativel)' weah stone to wear better than harder stones, which do not consolidato so weU, The best limestones aro the carboniferous or mountain limestone, the Devonian and some from the older Silurian rocks. "Limestone binds quickly and well, the detritus producing a sort of mortar which cements the whole together and forms a very smooth road. The wear takes place nlmost entirely on the surface, and although it naay be considerable, the road shows no signs of weakness until the thickness is so far reduced that it is no longer able to bear the weight of tho traffic. Au unusually heavy load then breaks up the crust, and the road goes to pieces vith little waming. "The relativo strength and durability of various road materials is a difficult matter to determine. No test but actual wear in the road can be fully relied on, and though it is easy to see that one stone wears twice or three times as long as another, it is almost impossible to take into account all the circumstances under which they are exposed to wear." An Ideal Prairie Road. A rural subscriber to The Burlington Hawkeye writes to his paper as follows: If I were to make an ideal road for this prairie country it would be something like this: I would have sixteen f eet made solid with some material in the middle of the road, and on each side about the same width of dirt road for several miles out of the city. Farther away the hard road might be narrowed to eight or ten feet. The reason for tliis plan is that there is no road as good as a dirt road when dry and smooth. In dry weather the travel would be on the dirt road, saving the hard track, and vice versa in wet, weather, saving both. The writer has had some experiunce in that line in the days gone by, when we had a plank road from Middlotown to Burlington. In iiiuddy times we all went on the plank road; in dry weather the dirt road was used. If some of our wise men would frame some law to improve our roads they would confera great benefit to county and state. Indiana has made her thoroughfares so yon can travel from one part to another without muddying your vehielo, while Ohio still goes floundering through the mud. Which are the wisest statesmen? I think it would be better to pay our road tax in cash instead of working. There would be as much wisdom in saying I should preach out my titlies, teach out my school tax, board out my poor tax, as to demand me to work out my road tax. The benefits from a home market are many and various. My mind was directed to this some two years ago, when hay was selling in Burlington for $16 a ton, when we were feeding good hay to cattle and realizing about $6 because we would have lost all profit in hauling our hay over the wretched roads.

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Subjects
Old News
Ann Arbor Courier