TARRED MACADAM

Dominion, Volume 14, Issue 205, 25 May 1921, Page 6

TARRED MACADAM

NEW STYLE OF MIXER

AN ASPHALTER FOR OUTLYING DISTRICTS

At a cost of £2OOO th© City Council has imported a Ransome (British) tarred macadam mixer, which is at present being set up at the back of th© destructor on tho old dock site. The acquisition is one of the results of the city engineer’s visit to England. When in Surrey Mr. Morton saw one of the County Council’s mixers a,t work, and decided •that the typo was just the one for Wellington. There are many ways of laying down tarred macadam. One is to lay the

metal in a clean state, and then sprinkle cr hose it -with hoi. tar; another is to shoot the metal through a tar boiler. The "Ransome” is the best known method to date, inasmuch as it covers the two main essentials—it dries iho

metal thoroughly before tit is passed - on to the mixing drum, and, in the » mixer, there is given the accurate quantity of tar to a defined amount of metal, sufficient to completely coat each bit of rock. The machine consists of an elevator (with buckets), a hopper, a drying drum, apd a mixing drum. The whole thing is portable, but in the case of the corporation machine it is being placed on a concrete stand about six feet high, so that carts can back in beneath, and fill up with the hot tarred metal by gravity. In that condition it can he carried four or five miles, and still be hot enough for the purpose intended. In Wellington the drawback has always been the difficulty of working with tar in wet or damp weather. To bo thoroughly efferi.lv* metal in the loose on a road surface must Ire quite dry before tar will adhere to it, and for that reason most of th© asphalting work has had to be done during the summer months. With the "Ransome,” however, , it will be possible .to turn out good tarred metal in any kind of weather. The machine is adaptable to any kind or size of metal, grave?, and slag. As a rule the metal used on the Wellington roads is 2| inches, for heavy work, but it will be possible to use i-inch metal (for footpaths). Tire machine is capable of turning out 6 tons of 2}in. tarred macadam per hour, and 41 tons of Jin. asphalt per hour. The corporation has also imported a handy little asphalt-mixer for use more particularly in the suburbs. This machine, which is on wheels, may bo dragged along by hand and. may be worked by hand-power, so that given thy materials —gravel, slag, or metal chips and tar—it can do all that is necessary on the spot in the case of rtmrill asphalting jobs, which offer difficulties under ordinary circumstances.