ROAD MAKING.

Waipa Post, Volume V, Issue 242, 29 August 1913, Page 2

ROAD MAKING.

THE discussion on road material and maintenance at the recent International Road Congress was something of a triumph for the bituminous binder, such as tar and pitch. The engineering correspondent of a leading English provincial journal considers that for the most part the only complaint the delegates brought forward against bitumen was that it is costly —admittedly a serious drawback, but that it is, however, a step forward to have established the two principles of roadmaking embodied in the bi-tuminous-bound Macadam road — namely, that the road shall be watertight from its first begin-

ning, and that the cementing material between the road metal shall have a certain amount of resilience. No doubt it is physically possible to make a rigid, say a concrete, road sufficiently strong to carry any traffic which can be put on k, but in practice expense must be considered, and having regard to the fact that wheel loads are both concentrated and moving, it appears reasonable that, in order to make a moderate depth of road material sufficiently permanent, the crust at least should possess resilience. Asphalt possesses such resilience but in order to reduce cost it appears probable that ordinary stone must form the main part of the road crust, and this being virtually unyielding in itself seems to call for a yielding binder or cement. The same writer states that the science of road-making is only just reawakening into life after a long period of stagnation and worse, ,but the signs are hopeful of a marked advance, based partly on systematic observation and tests of different road constructions, but also largely on a keener appreciation of fundamental road phenomena.