GB357603A - - Google Patents

Abstract

Aggregate is coated with a bituminous material together with rubber and a liquefier for the bituminous material with, if desired, the addition of lime, the weight of the rubber being from 0,2 to 2 per cent of the bituminous material. The rubber may be used raw, as latex, or in solution in a hydro-carbon oil. Liquefiers include gasoline, kerosene, naphtha or light coal tar solvents. The liquefier may be emulsified prior to its addition. In examples, the aggregate has added to it (1) liquefier, then rubber or latex, then asphalt, (2) latex, then liquefier, then asphalt, (3) latex, then emulsified liquefier, then asphalt; "fines" being added to the coated material in each case, in the proportion of 4 to 8 per cent of the mixture. Rubber being soluble in hot asphalt, a rubberized asphalt may be used as a stock solution. A pavement may be laid of a bituminous composition made as above, in any desired number of courses, preferably two; a foundation course consisting of a large aggregate with 3 to 6 per cent of the bituminous material, and a wearing course with smaller aggregate having from 5 to 8 per cent of the bituminous material. This may be covered by a sealing course having sand or fines as aggregate and with from 1 to 3 per cent of the bituminous material. No further fines are added to the coated aggregate of the last course. Reference has been directed by the Comptroller to Specifications 198,136, 216,245, and 216,602, [all in Class 22, Cements &c.].