ASPHALTE PAVEMENTS.

Hawke's Bay Herald, Volume XXI, Issue 5439, 21 July 1879, Page 3

ASPHALTE PAVEMENTS.

j Tn view of the probability of ' asphalte ' pavement being soon extensively laid in Napier we publish the following from an Australian contemporary '■ — The tar pavements of Melbourne are made as follows : — Bluestone metal is first prepared of throe sizes, viz., the ordinary 2h inch metal, strictly broken to gauge; coarse screenings, being that which has been ' screened out of the first by a screen with bars half an inch apart ; and fine screenings, tlie refuse of! the above after being i passed through a sieve which retains . everything coarser thnin sand. Mix these with gas tar (cold) on a platform, :or in some places where the waste . tar will drain away ; this is importaut,- The proportions are as follows : — ' ZVm. metal from 7gal. to Bgal. per cubic yard, the quantity varying with the cleanness of the metal ; the cleaner the metal the less the quantity which will be required. The coascr screenings will take from I4gal. to lGgal. per yard under the same conditions, and the fine screenings j 38gal. It is better that the whole of the metal should be dry before the tar is mixed with it,- but the fine screenings must be so,- artificial drying being resorted to if necessary. It i_ better not to lay the composition in unsettled weather ; and to secure as far as possible a dry bottom, the excavation should not be got out far ahead of the men who are laying tho first coat. The ground is first excavated full 2_tin. below the desired level, after which the space is filled (rather under than up to the 2-Sira. level) with a cooling of the metal. This is then rolled, until it ha» been consolidated about three-quarters of an inch ; after which it is covered with th«r coarse screening^ to the depth of an inch *.' the surface being again rolled and a coat c!«f the finer screenings is then spread to the depth of half-an-inch, after which the Burface is finally rolled until it finishes half-an-inch above the permanent level, from which it will gradually sink to the required height as it consolidates undar the traffic. After the last coat has been rolled the surface is coated with powdered bluestone, or fine sand, in sufficient quantities to keep the feet from adhering, and as this coating, which is only lightly rolled, is liable to be blown away by high winds, or washed away by heavy rains, it must be renewed from time to time, as necessary. The roller requires to tt> somewhat heavy j" that used by the corporation of Melbourne is about 4ft. in diameter, about 18in\ wide, and weighs from 13c\vt. to loewt., and it is better to ram the edges with an iron rammer having a perfectly flat surface in addition. A canvns bag holding water, or a largo swab, must be attached to the roller, the object being to keep the surface of the roller wet whilst the fine coat is being rolled as otherwise it is apt to adhere to tho roller.