MODERN ROAD MAKING

Dominion, Volume 16, Issue 156, 20 March 1923, Page 8

MODERN ROAD MAKING

BITUMEN AND CONCRETE. Sir,—ln your issue of March 6 there is a report covering an interview granted by your City Council to a deputation from the Chamber of Commerce and the Automobile ClubWith all due deference to vour city engineer (Mr. W. 11. Morton), I am convinced that a mistake is being made when bitumen is being adopted for the main thoroughfares of so important a city as Wellington. It is claimed that bitumen has superior wearing qualities, and that it is more easily repairable. Now. Sir, it has been proven in the United States of America that concrete will outwear bitumen many' times over, and that the upkeep is very small when compared with that class of road Tiepairs 1o concrete can and are being carried out satisfactorily. The writer has travelled over hundreds of miles of concrete roads in the U.S.A, and Canada, and examined among others a- piece of concrete road that had been down for nine years on one of. the main roads leading out of Detroit (a city of one_million inhabitants), and by actual measurement there was less than three-eighths of an inch of wear covering the whole of that period. Concrete roads have long passed the experimental stage, as evidenced by the fact that there are now over 40,000 miles in use in America; the State of Illinois this year alone is constructing over 600 miles, and Pennsylvania is close up with over 500 miles. The Americans have long since learned that no material will stand the' present-day heaVy traffic so well as concrete. As regards Portland. Oregon, the great Pacific highway leading from San Diego in the south of California through Portland to Vancouver is now all built of concrete; and the time is within sight when it will he possible to travel from Portland on the one coast to New York on the other on n concrete road. ■Vearer home you find that the Aucklifid City Council has proven the staK'lity and economy of concrete, and their last February report states that the cost now stands at 12s- (twelve shillings) per square yard. It is admitted that in the early days some failures were experienced in California, but it is also admitted that those failures were, duo in part- to the use of an inferior sandstone aggregate and in part to a desire to cover too much surface, i. 0., making a road only four inches thick instead of from six to seven inches. But what branch of engineering ha's deviated from the old groove without soro£ failures? It is the failures that make stepping-stones to success for those who dare and do. —I am, etc., T.H.W. New Plymouth.