STREET FORMATION.

Star (Christchurch), Issue 11671, 11 April 1916, Page 6

STREET FORMATION.

INTERESTING EXPERIMENTS. A marked improvement has lately been made to the surface of Mercer Street, Wellington, a thoroughfare which badly needed some attention. In order to determine which was the better of two methods, an experiment was conducted as between the methods of laying down a tar and bitumen surface, so* one side of the. road was first tarred and then given a coating of a special bitumen supplied by the Vacuum Oil Company, and on the other side the bitumen was laid down first on the macadam,. and tar was applied as a surface. Some little difficulty was experienced in spreading the bitumen, which had to be laid when very hot, otherwise, it thickened and did not spread very easily. The net results, however, says the " Dominion," are that Mercer Street has now a very good surface, instead of being a corrugated , road. It is understood that the better results have been obtained by spreading tho tar first, as it' fcaJces more kindly to the macadam than does the bitumen. Judging by the fact that the plain tar-spraying method of giving a street a smooth surface has long been discontinued, it was apparently not a success. In Upper Willis Street the city engineer has been trying another method of road formation which he believes may give good results, and be a resistant to the motor traffic. This consists'of a solid foundation of concrete, surfaced with a couple of inches of fine asphalt. The concrete base will, Mr Morton considers, prevent " waving," which is the defect in all street, surfaces without a solid level foundation.