CONCRETE ROADING.

Taranaki Daily News, 31 July 1919, Page 6

CONCRETE ROADING.

WORKS IN UNITED STATES. An, address 011 concrete roads was given by the Mayor of Auckland, Mr J. H. (Jimson, at a meeting at Oneliunga week, the Mayor of Oneliunga, Mr J. Park, presiding. Mr Gunson said he had dealt fully in Itfs previous address with the concrete work in the city, and i.ts relations to the Manukau road proposals. His object was to place before the ratepayers the latest information as ,to the cost and construction of concrete roads. This he had obtained from Mr W. It Hamer; engineer to the Auckland Harbor Board, who had recently returned from America. Mr Hamer luid carried out more concrete work than anyone else in New Zealand, and in 1904 introduced the system of concrete construction of the Auckland wharves. He was, therefore, an authority on the subject, and well qualified to speak of ,the most modern methods of concrete work in the United States. Mr Hamer found that in California!, for concrete roads throughout the S.tate, the following loans were authorised:—l9o9, £3,COO,000; .1915, £3,000,000. These two loans had been practically expended, and a further loan had jnst been authorised of £7,000,000. There were 4500 miles of concrete roads .in the State. The general practice liad been to form a 24ft subgrade, 15ft wide, of concrete to a thickness of 4|in, leaving 3ft shoulders on either side of the concrete. In many parts oiled crushed rock was topped off on the concreting. The cost of this in jthe past had been approximately £2200 a mile. Four to four and a half inches was the thickness of concrete laid generally throughout the State of California. From San Francisco to Los Angeles, a distance of 441 miles, there was a concrete road of 4%in standing excellently. Tar-top-ping was formerly used, but the concrete was standing so well that the use of the former had been discontinued. CALIFORNIAN CAR TAX. In California there was a motor-car tax of ,£2 a car a year. Mr Gunson said local bodies in New Zealand had no power to levy such a tax, but be hoped the municipal conference would adopt the remit- favoring one. Besides aiding local bodies in their road construction work, the tax would result in a boon to motorists. Engineers in California .advised Mr Hamer that the interest and cost of maintenance of concrete roads was less than water-bound roads- The coun,ties spent annually £4,000,000 on maintenance of roads. Shingle concrete was bound to be not successful and had been abandoned in favor of cube chips. The cartage contracts in California over these roads had dropped from 26J to 12 cents a ,ton a mile. With the 100!) loan of £3,»00,000, 2800 miles of concrete were laid, 4£in thick, at a cost of £1240 a mile. In one day 050 ft of concrete, 15ft wide, was laid by 20 men, whose wages were £1 Is a day. The cost of this was about £4OOO a mile, including fillings for the valeys, which had been considerable, but on flat sections ,the cost had run out at £2200 a mile. ' All the concrete roads in Redwood City, California, were 4Jin thick. They had started with Gin. Experiments had been so successful that they, were dropping into line with other centres, and now generally adopted 4£in, In 1910, in another centfe, test speeds were held as follows: —I6J miles on concrete, 4A miles 011 earth, and fly 2 miles on gravel, while the oil consumption on concrete was only half that 011 gravel.

EXPERIENCE AT SEATTLE.

In Seattle, right in the heart of the city, (Jin hud been laid, with 2Jin of sheet asphalt. The engineer of Seattle stated that ordinary concrete Cin thick made as nearly a perfect road as could be made, and that they were now abandoning "any topping on the concrete, not even asphalt or tar, aa the results with the concrete had been so good. They were very particular about the grading of their sand. New York had just appropriated a loan of £20,000,000 for roads, and a vigorous policy was now being launched there in furtherance of the concrete loads agitation. In other parts of the States they were carrving out concrete work four inches thick at 3s to 4s a square yard, in many places no metal at all being used as a foundation. The concrete was simply laid on solid earth surface after being rolled. In Seattle there were many miles of streets laid' of sin concrete.