MODERN ROADING.

Hauraki Plains Gazette, Volume XXXVI, Issue 4911, 4 December 1925, Page 4

MODERN ROADING.

METHODS IN TARANAKI.

PIAKO ENGINEER’S REPORT

A few months ago, the chairman of the Piako County Council. (Mr F. W. Walters) and the county engineer (Mr W. J. Gibbs) paid a visit to Taranaki to inquire into the methods of modern reading adopted .there. The cause of the visit was the result of some uneasiness being felt concerning the No. 1 road, Waitoa, put down in bitumen during the past summer. ThisTOad did not appear .to be standing up to the traffic, and. the council was at a loss to know what was at fault. According to the report the methods, adopted in laying down the Waitoa road compared favourably vith those in vogue in Taranaki, apparently the buily advice other than a, number of minor details being that no more work should be done till, the best months of the summer.

The report, however, contains many interesting observations in connection with road making, and is i as follows : “The first county roads we inspected were Inglewood. We inspected their main highway, new work of last season, and were shown some sections by the county engineer. Their method is penetration. They find tar at prosent useless., They do not roll their penetration course prior to applying bitumen, on account of. crushing the stone. It is rolled well after penetration, and a sealing coat is applied the next season in most cases. “The resident-engineer of the Public Works Department at Stratford likes, oil for the first coat, or tar to absorb any dust. Bitumen is. applied later. He thinks we have gone to a great deal of trouble in preparation of our road, much more than they db, and that there is no better method than that which we adopted. We were shown approved highway specifications which are not so complete and rigid as our own in many respects. He knows our road, and thinks we should not do more until, the best months of the summer. He thinks, aggregate must be thoroughly clean and hard, and absolutely free from dust or clay if bitumen only is to' be used. Road oil or tar will, absorb dust in the first coat. He has adopted the penetration method for all their worrs, but thinks that surface sealing is quite good under certain conditions. “Patca comity has some good roads, put down under the penetration method. “Hawera Borough.—The engineer states that he had some trouble at first with bitumen by placing the same on dusty stone, and had to apply another coat of bitumen straight away to. prevent it breaking up. He thinks th ; at bitumen is very tricky material to handle, and everything must be at its best. Clean hard materials, good foundations., and ideal weather conditions, together with first-class workmanship, to be assured of a successful job, and our method of work was excellent. He also seated that he can find no difference in a well-formed consolidated macadam road sealed and a road that has been penetrated for 2% inches, excepting in costs, the latter being 'the greater of the two. He has. constructed both, and finds, the result the same (a good ' road). He likes road oil for the first coat, to be sealed with bitumen later, and prefers a fine crushed metal with a layer of ehippings between each coat in preference to all 2%-inch metal.

“Waimate West, county engineer uses bitumen for his penetration course. His usual method is to scarify old worn-out macadam roads, apply three or four inches of clean metal, roll, lightly, grout or penetrate with above preparation, and then blind with fine clean gravel. During the summer he sweeps the fines off with a horse broom prior to applying his second or top coat, with bitumen. "Egmont county has put down a short length of Main Highway which is in first-class order. The method adopted is: Old macadam road scarified from 3 to 6 inches, new metal applied, 18 to 20 feet in, width, well banked up at .the sides, rolled lightly, penetrated, and a slight' coating of clean chippings well rolled in. In most cases the second coat is applied at once. A section has been left to be top-dressed during the coming season. “Taranaki county have sealed most of their roads with tar, but use bitiP men for top-dressing and maintenance. For new work they' prefer the penetration method. “Most of the counties and also 'the Public Works Department have adopted the penetration method and are using bitumen. In all cases formation must be of the) best. All aggregate clean and free from dust, and bitumen of approved quality put down in fine hot weather.” —Matamata Record.