PERMANENT ROADING.

Hauraki Plains Gazette, Volume XXXIII, Issue 4478, 11 October 1922, Page 2

PERMANENT ROADING.

SCHEME FOR THE PLAINS!.

EXPERIMENTS TO BE MADE.

Details of a scheme and estimates for permanent reading were given by Mr C. Skitrop, consulting engineer to Messrs Ellis and Company, Auckland, in, the following report, submitted to Monday’s meeting of the Hauraki Plains County Council: “As you are no doubt interested in the question of laying down good motor roads at a reasonable cost and with the least possible expenditure tor maintenance I take this opportunity of explaining what I have done in the way of laying down bituminous asphalt roads and the results obtained. In 1913, when engineer to the New Plymouth Borough Council, I laid down a portion of Brougham Street in union asphalt under the penetration system, and up to May of this year it had 1 cost nothing for maintenance and was still Ln good order. In 1916 I laid down Victoria Street. Cambridge,, in the same manner and with the same materialThere has been no expenditure for maintenance since.”

Details of other works were also given maintenance so far costing nothing. “Taranaki counties this year are laving down 400 tons of union asphalt on the tarred roads in order to reduce the maintenance cost of these roads,” the report continued. “The maintenance cost on the Eltham-Ohouaki road before it was tar-.sealed was approximately £3OO per mile per, annum. By tar-sealing this expenditure was reduced to £l5O per mile per annum. This season the engineer, has surfacesealed a portion with union asphalt, and expects to reduce the maintenance cost at least to £75 per mile per annum. There are three methods in general, use in laying union asphalt roads. They are the hat mix system, the penetration system, and the sur-face-sealing system. The surfacesealing system is that which has been generally used by Taranaki local bodies, and with good results. It could, however, not be applied to any of your roads, which I have been over, as it would be impossible to clean the surface sufficiently for the asphalt to adhere to it. Tjie penetration system is that which wouldjsuit your condition better than either of the others. It consists in scarifying the old metal surface and tarring it to the required shape and covering it with two, three, or four inches of broken metal, as the case may require. The new surface is then rolled perfectly hard and the union asphalt sprayed into the interstices of the metal (under pres.sure) at the rate of one and a quarter gallons to the square yard. The surface is then covered with thin metal chips or other approved material at tlie rate of one cubic yard to 50 square yards of road surface. The traffic is then allowed- free use of the road for three to six months, when the surface is swept clean and surface .sealed with one quarter of a gallon union asphalt to the square yard and covered wit)h’> chips -or coarse sand at the rate of one cubic yard to 7'5 square yards 'of road surface. This class of road should require no further treatment for at least six years, when it. may require surface-sealing.

“I consider the following method would give you good solid- motor roads at a reasonable Cost. First scarify your present road surface and form to the required grades and camber, taking care not. to disturb the old clay foundation unless absolutely necessary. Then cover with four inches of broken metal 3 tp 4in gauge, and roll thoroughly, making up all soft spots that may be found, then cover with three inches of metal broken to a two-inchi gauge, roll again with eight to ten-ton roller until it scarcely leaves a mark on the surface. Then spray with union asphalt as explained under the penetration system. The cost of this class of road would be approximately at per inch 12ft width.

“Scarifying and forming 80 chains at 30te, £l2O ; metal, 3 to 4in gauge, 4in thick, 782 cubic yards at 18s, £703 16s: metal, 2in gauge, 3in thick, 586 cubic yards at 20s, £586 ; metall chips, two coats, 246 cubic yards at 20s, £246 ; rolling 80 chains at 40s, £l6O ; union asphalt, two dressings, 1U gallons, 44 tons at £ll, £484; labour spraying £88; firewood., £22. Total £2409 16s. Area treated 7040 square yards, 6s 10d per square yard.. This estimate may be reduced by using the old metal at present on the. road for foundation.’’ DISCUSSED IN COUNCIL, Mr Skitrop waited on the Council and said that if the Council did not cut through the clay foundations the roads should carry almost any traffic. In some cases the roads would need to be regraded, but not too much. He bad had experience with soft country like the Hauraki Plains. If there was timber" in the roads the timber would- rot some day and the road would sink. Cr. Mayn: Then that’s an argument to take the timber out. Mr Skitrop said some of the Taranaki roads were only 12ft. About 15ft would do for main roads. The more traffic there was pn the roads the better he would like it. Or. Mayn : I suppose you people are not of a speculative nature ?

Mr Skitrop: We are. Cr. Mayn then suggested putting down a strip as a trial. Mr Skitrop said the main road ’o Paeroa would stand the traffic. Cr. Parfitt: Would you consider putting down a test piece ? Mr Skitrop: We would not call it a test piece. We would put it down for you. He further said there would be no failure so long as it was carried out in a systematic manner. If the foundations would not stand 10 tons the metal should be rolled in until they did stand it.

Or. Mayn asked if the firm would put down a test piece. Mr Skitrop said he thought that the firm would not do it, but they would give the Council every assistance and show the Council how to do it if the Council, would pay for the material aiid somebody pay for his time. Cr. Parfitt asked what kind of a foundation was a couple of feet of clay and a cushion of peat and then

more clay. Mr Skitrop said that the road would carry a ten-tpn roller it would carry any traffic. A ten-ton roller was the test. Crs. Mayn and Harris contended that the firm should find the bitumen for an experimental piece. Mr Skitrop said he would see his firm about it. He thought the company would provide a machine. Cr. Parfitt suggested putting down a small strip in the Ngatea township. Another councillor: But it's not a county road. - It .was suggested that about IO 1 chains near Cr. Chatfield’s farm be put down as an experiment. Cr. Harris said Waitakaruru was prepared to pay for an experimental piece.

Cr. Parfitt, said he would like to see some put on peat land. Cr. Mayn : Would you do a piece in each riding on those conditions. Mr Skitrop: Yes. Four inches of metal with union asphalt was bettei' than a foot of metal without it.