Show I I I Rubber Roadways I In answer to an inquiry Consul Gen Gea era cral eral Robert P. P Skin Skinner nor furnishes the following information concerning rubber rub ber bor asphalt pavements in France Francc Experiments covering erin periods of six years have been ma made o with this pavement pave pave- ment meat in several cities throughout France including Paris Paric and ana Lyons and andas andas as far as can be ascertained a have ha given Ji good results result 8 In the city of Marseilles a satisfactory satisfactory tory experiment was made upon the Prado a number of years ago and this spring three or four public places were similarly paved these areas however being devoted to pedestrian traffic ex ex- elusively Innovations of this kind kin make malio slow progress in France but from tho tue character of the men nieu interested in inthe inthe the thc company and the increasing importance import anco ance of the work ork undertaken en rubber asphalt asphalt asphalt as as- paving paying must be he regarded very seriously se so- e. e as a substitute for the more moro usual from of asphalt paving pa I At tho the present time most asphalt paving paving paying pay pay- ing involves in tho the use of costly installations installations for tho the heating of the tho powder a considerable amount of material and a special class of laborers all of which tend to increase the cost Under the new process s it is possible to make make- cold applications of asphalt which are aro said to po possess all the advantages of hot compressed asphalt without its draw draw- backs The material under r description is us a product resulting from th the as association of asphalt and rubber Asphalt is a carbonate car ear bonate bonato of lime impregnated with bitumen bitu bitu- men with which rubber combines under certain cert in conditions thus effecting the cohesion cohesion co co- co hesion of tho the calcareous molecules This product is claimed to bo he more plastic and more adhesive o than pure puro and to resist hi higher her temperatures To obtain the combination of bitumen and rubber they must be b energetically mixed and md more adhesive than pure asphalt reduced to fino fine powder is in the presence pres pres- once ence of rubber swell swelled en and ann softened ba b by bya a solvent Tho The material thus obtained l lis is a brown powder darker than the ori original or on- on iI i- i I ginal nal asphalt and it suffices to compress it in order that it shall set and harden ra rapidly idly It is alleged that when asphalt is is applied applied applied ap ap- ap- ap plied hot the heat of the application comin coming into contact with a concrete foundation containing more mor or less humidity hu hu- vaporizes t the water wate contained therein thou and the steam by its force of expansion escapes thus destroying tho tim compactness o of the combination n. n This h. h s inconvenience does not present itself Inthe in inthe inthe the system under designation which permits per per- mits units tho application of a much thinner layer of ot asphalt and one which unites itself with the th concrete constituting tin a solid mass maS The Tho observations of this form of pavement satisfy tho those e C interest rd ed in the subject t. t that th tim the fc l lf f surface resists or ordinary inary wear more sat sat- than any an- othor Rubber asphalt must bo be applied upon a foundation of first class consisting con con- of pounds of good Portland cement and ono one cubic meter 3 31 cubic feet of and sand the proportions proportions proportions pro pro- portions being hein third one of sand to two two- thirds of pebbles The thickness of the tho foundation should vary varv from fifteen to twenty centimeters 78 inches and it should he be rammed with the hack back backof of shovels used in this work and given gen g en the exact form forum which tho roadway is intended to have without the necessity of making lat later r additions of concrete to bring brine the tho surface to its proper Tho The surface of the tIme concrete should be regular so 50 that the layer of asphalt lIT may mav have bao a uniform thickness I This foundation should remain three to five days cbs according to the season on until it has acquired a 8 sufficient hardness to support tho the ramming of the layer Ia er of as Tho The surface of concrete having been well cleaned is covered with a thin coating of special material which is laid lair on with a n brush upon which tho the rubber asphalt powder is lightly sprin sprin- kled Shortly after the preliminary operations the uni uniform orm layer of rubber asphalt powder d to a thickness of 35 to 4 centimeters to I 57 1 57 inches which i is compressed p I lively by means of a rammer This Thio c lone done tho the surface may mav be opened immediately to travel It is is said aid that by bv this process process pro pro- cess the i top dressing of asphalt when laid on hot may be one half the tIm thickness thickness thick thick- ness necessary when tho tim asphalt is la laon laid on cold As th the tha process is covered b bv by n a pat patent I ent eat and exploited by a particular com coin I pan it is impossible of course to describe de do- scribe the tho system otherwise than in somewhat general terms |