GB316017A - Improvements in or relating to the making of roads, paths, and the like - Google Patents

Abstract

316,017. Hines, J. T. July 31, 1928. Macadamized roads. - A road-making or like composition comprises stone or other mineral aggregate bonded with a mixture of commercial bitumen, Trinidad bitumen, or epure, containing clay in a colloidal state and a fluxing oil containing sulphur in combination or free. A fine mineral filler may also be added. The sulphur, which serves to harden the bitumen, is preferably dispersed in a colloidal state in the oil and by varying the amount of sulphur the hardness can be controlled. Three methods of making the composition are (1) spraying the clean dry aggregate with the fluxing oil and then incorporating the bitumen mixture and the mineral filler; (2) mixing the fluxing oil, bitumen, and epure, and applying the mixture to the aggregate; (3) applying the bitumen mixture to the aggregate and the fluxing oil to the mineral filler, and then mixing the two compositions. The oil is preferably applied at a temperature of 110-185‹ F. and the bitumen mixture at a temperature of 240-320‹ F. The mineral filler is preferably stone of the same quality as the aggregate, but cement, limestone dust, or slate dust mav be added. Suitable proportions of the oils and bitumens are from 5 to 10 per cent of fluxing oil containing 2-10 per cent of sulphur, from 40 to 60 per cent of commercial bitumen of 200 penetration, and from 40 to 60 per cent of Trinidad epure having a high content of colloidal clay. In surfacing a road, the composition is spread to a thickness of one and a half times the thickness of the finished layer and is then consolidated with a heavy roller. The' surface is then covered with clean # inch chippings at the rate of about one ton to 135 sq. yards, and the chippings are rolled to give a non- skid surface. On paths and carriage ways, screened gravel' can be used to give a finished surface having the appearance of ordinary gravel.