P J M Larrañaga


Successful Asphalt Paving (conclusion)



Chambers's Journal 1838

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"Asphalte, or Asphaltic Cement."
Chambers's Edinburgh Journal No. 350 (October 13, 1838) : 299-300

It must have been generally observed, from the advertisements issued on the subject in the British journals, that companies have been recently formed in our metropolitan cities for the sale of a substance called Asphalte or Asphaltic Cement, in connection with certain continental mines where that material is procured. It is recommended to public notice as a most valuable cement for building purposes, for covering floors and roofs, for flagging, both out of doors and in doors, and for various other useful objects. Some account of this substance, and of the condition in which it is extracted from the mines, may not be uninteresting to our readers.

The term Asphalte has long been familiar to the world in connection with building. Ancient Babylon was in a great measure composed of a species of pitchy or bituminous stone, called by the name of Asphaltic Stone, which was found extensively in Asia Minor. ...the "Asphaltic Pool"In Palestine, a bituminous earth is procured in abundance at the present day, particularly from the neighborhood of the Dead Sea, which, on account of the impregnation of its waters with bitumen, has often been termed the "Asphaltic Pool." The word Asphaltic, therefore, is used to signify any thing impregnated with bitumen, which is the same combustible substance familiar (under slightly different forms) by the name of tar or pitch, and which is extracted both from minerals and vegetables. an ingenious, learned, and speculative Greek, named Eirinis, discovered a fine bed of Asphaltic rock... On examining the Valley of Travers, in the Prussian province of Neufchatel, about the year 1712, an ingenious, learned, and speculative Greek, named Eirinis, discovered a fine bed of Asphaltic rock, and, probably from some recollections suggested to him by his knowledge of antiquity, began to make experiments upon the value of the rock for cementing purposes. He describes this rock, or Asphalte, as he called it to be "composed of a mineral substance, gelatinous and calorous, more clammy and glutinous than pitch ; not porous, but very solid, as its weight indicates ; and so repelling the influence alike of air, cold, and water, that neither can penetrate it ; it is better adapted than any other substance to cement and bind buildings and structures of every kind ; preserving the timber from the dry rot, from worms, and the ravages of time ; so much so , that exposure to the most inclement extremes of weather only renders it the firmer and the more enduring." Such is the account given by Eirinis of his Asphaltic cement ; and he also states that its efficacy and durability were tried and proved on many buildings in France, Neufchatel, and Switzerland. "Nothing (says he) can be easier than the composition of this cement," and he gives directions for melting it as it is taken from the mine, and stirring it when melted, mixing with it at the same time ten per cent. of pitch, after which it is to be spread on the stone or wood to be coated, previously heated to a slight degree.

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Such was the first attempt made, in modern times, to turn the natural production called Asphalte to service in building. Eirinis was not supported properly, however, and the Val de Travers mines, though occasionaly wrought by succeeding speculators, have only fallen into competent hands within a very recent period. Count de Sassenay, who had acquired the requisite experience by his having been for six years the proprietor and manager of the Seyssel mines, became, in the beginning of 1838, the proprietor of those of the Valley of Travers in Neufchatel. The Seyssel mines, it is to be observed, are also Asphaltic, and had been wrought for a number of years. But, on examination, Count de Sassenay found the Neufchatel mines to contain a finer-grained rock, and with two per cent. more of bitumen in it, than the Seyssel mines. He was therefore led to become the purchaser of the former, and has established a company at Neufchatel, with a capital of forty thousand pounds, for the working of Asphalte, and for its sale in the various countries around.

Count de Sassenay states, in the Introduction to a little pamphlet which supplies us with these particulars, that there are two kinds of mineral matter which go by the name of Asphalte, though erroneously so. The first is an earthy concretion of gritty, loose texture, to which the count gives the name of bituminous molasse, and which he ascribes to the latest or tertiary formation of rocks. The other substance is the true Asphalte, which is solid, of the colour of soot, and is an admixture of bitumen with calcareous or limestone rock of the Jura formation, which belongs to the secondary era. The bitumen is here completely combined or amalgamated with the calcareous material, and this union is productive of a new homogeneous substance, which alone is the true Asphaltic Cement, or Asphalte which alone is the true Asphaltic Cement, or Asphalte. Bituminous molasse is a mineral substance comparatively abundant on the continent, and has been wrought in several places with the view of making the same cement, but has not undergone that natural admixture with calcareous matter which constitutes the true Asphalte, and hence such views have not been realixed. This is not only stated by Count de Sassenay, but by M. Rozet, M. H. Fournel (a noted engineer), and other observers. "Many experiments have been made to imitate the cement we have mentioned (that of Seyssel); but in these operations the want of the calcareous matter has been attempted to be supplied by substances, which, absorbing the bitumen, produce a composition which cannot resist the influence of heat or cold, but is melted by the sun and cracked by the frost." The Val de Travers, where are found the finest kinds, as has been said, of this natural production, formed in all probability under strong volcanic action, leads into the Lake of Neufchatel. Half way up the mountain-sides, the Asphaltic works are carried on. "The operations," says M. Fournel, "are very simple, and consist merely in blasting the rock. The cavities for the powder are perforated by wimbles of about thirty-nine inches in length, one of which a man can work as he would a carpenter's auger. This manner of boring appears to be applicable only to the Asphaltic stone. The labourers can work better in winter than in summer ; because the rock being harder and more condensed in cold weather, the powder has more effect, and the blasting is more extensive." The rock is in blocks or irregular masses, not in strata, and there is reason to believe that the whole mountain is of Asphalte. The manner of preparing the rock for cementing purposes is this. "Ninety-four parts (weight) of the Asphaltic stone, pulverised, are mixed with six parts of bitumen, and melted down in large boilers ; and the mass is then poured off and formed into large rectangular cakes, which are sold as the Asphaltic Cement." It is easily re-melted, and instead of losing, gains quality by the repetition of the process. Of late, however, the plan has been adopted of sending the stone itself to the place where it is to be used, and there melting and mixing it with the tar immediately before use. This saves one melting. The way of using it requires little explanation. When melted, the cement is merely spread over the desired part equally, and in such thickness as circumstances may require. In the coating of places to be trodden much, such as footways, terraces, slabs, &c. it is customary to mix fine river sand with it, which gives it more stability, and a degree of roughness that is not unnecessary.

We have now to ask if the Asphaltic Cement has been extensively tried, and with what issue. Count de Sassenay, when proprietor of the Seyssel mines, obtained permission to use the cement in the fortifications of Cincennes, Douay, Grenoble, and Besançon. It was also found that rats and mice disappeared when the cement was laid down.The minister of war was satisifed by the experiment that it would be highly advantageous to have the roofs, floors, &c. of barrack-rooms coated, both on the score of cleanliness (inasmuch as the cementing was easily washed), and on account of the protection against damp afforded by it. It was also found that rats and mice disappeared when the cement was laid down. On these facts being ascertained, the French minister of war contracted for the use of Asphalte in the various buildings over which he had control. The extensive commissariat magazines at Bercy, and those which supply the garrison of Paris, the roofs, ceilings, and floors of the detached forts at Lyons, the arsenal at Douay, the new barracks at Perrone, those at Mont Louis and other places, were all supplied with Asphaltic coatings in whole or in part. Asphalte was also substitute for the stone pavement in some of the cavalry barracks. The unwearability of the material rendered these experiments most satisfactory. [A staircase, coated with the cement by Eirinis more than a hundred years ago, still remains, and is unmarked, whereas contemporary stone stairs in the same building are hollowed out by foot-marks.] The ministers of the Marine and of the Interior in France followed the example of the War Minister, and coated their convict-prisons and other edifices with the Asphalte, and with equal satisfaction.

These things passed very recently—subsequently, indeed, to the year 1832—when Count de Sassenay became proprietor of the Seyssel mines, from which the Asphaltic cement was procured for the purposes mentioned. It was not until 1835 that any experiment was made upon the use of Asphalte for flagging thoroughfares. At that time the footway of the Pont Royal was coated with the cement, and its durability, under the tread of thirty thousand people daily, has amply justified the trial. Since that time, the footway of the bridge Du Carousel, the footway by the railings of the Tuilleries, other footways, and the basin of the fountain in Richelieu Street, have been coated with the Asphaltic Cement, and it has been found to stand equally well the "summer's heat and the winter's snow." The Belgians have begun also to use the article extensively in public works. In several parts of London, portions of the street for foot passengers have also been laid with asphaltum, by way of experiment, and on a late inspection by us, it seemed to answer all the purpose of flag-stones. Various artificial cements, in imitation of the natural Asphaltic, have been brought before the public, but, on trial, they have been found to crack in winter and to melt in summer—in short, to be totally inefficient in comparison. The Asphaltic Cement has been used with success in joining stone to stone, or metal to stone. As for its use in the caulking of vessels, we are not aware what has been the result of recent experiments on this point. The induration which forms its chief value in coating pavements and such places, might be injurious in the case of vessels, but an additional proportion of tar to the cement would probably amend this fault, and render it useful there also.

We have taken this account of the Asphaltic Cement and its properties, we admit, from parties friendly to, and even interested in, its introduction to general use. But the number and respectability of these parties (including Count de Sassenay, M. Fournel, M. Rozet, and P. Muldoon, Esq.) form a good guarantee for the veracity of the preceding statements. The British public must satisfy themselves, however, upon the subject ; and the establishment of the companies alluded to affords so easy an opportunity of doing so, that various public bodies, as well as private individuals, we are glad to perceive, have already laid down the cement, both in places of public promenade and in the interior of dwelling-houses. Its expense, we understand, is far from being great, even after transportation. Upon the whole, from its apparent power of resisting all extremes of temperature and weather, as well as its extraordinary durability, we are inclined to think the Asphaltic Cement may yet prove a valuable addition to our architectural materials. There would be little difficulty also, it is obvious, in giving it any colour in the melting pot which might suit circumstances or fancy.

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