Rubber Roads.

Hokitika Guardian, 19 October 1922, Page 3

Rubber Roads.

(By nil Engineer.)

London is shortly to have rulibcir roads. Although this will ho a distinct departure in road engineering, experiments have now been conducted for many years with a view to discovering an entirely new type of surface which will he equally suitable for horse and for motor traffic. If tlm rubber road justifies all the .claims made for it, it will not only solve the noise problem, which has been baffling experts for years, hut will reduce wear and tear of all forms of road transport vehicles to a minimum. It is also nntiepnited that the rubber block will give about 15 years’ wear, which is about double that of wood paving. In the endeavour to find an ideal road surface, engineers havo experimented with some, novel materials which include such widely different substances such, as iron, glass, and cork. Cnst-irjon used in conjunction with concrete' forming, what may lie described as an armoured road, has been tried for some time past in

France. A road of this type has been laid at Lyons and lias proved quite satisfactory, having carried exceptionally heavy traffic with a minimum amount of wear. French road-makers have also produced a glass road surface l , which has been found to possess distinct advantages and hard wearing qualities. The bricks are composed of a material consisting .ol waste glass, such as old broken bottles. This material is devitrilrcd and subjected to a heavy pressure* in moulds. The bricks are thus rendered very tough and extremely durable, and owing to their gritty nature are not liable to become slippery through wear or in wet weather. They are, moreover, capable of resisting a crushing strain of four tons to the- square inch. The cost at the time the* first glass road was laid was stated to he 10s per square yard.

Continental engineers have al>o obtained! good results with cork paving blocks. They have been found lo possess the advantage of being non-absor-bent, noiseless, durable, not liable to expand and on tract when laid, sanitary and lion-slippery when worn. The most important question to ho considered by road-makers at the piesent time* is that of providing surfaces suited not only to the nature of tho traffic passim' over them, lmt to the particular locality where extra strain is imposed. For example, (lurin ' the busiest hours, omnibuses pass Charing Cross to the number of 598 per hour, or approximately one every 6 seconds. This fact provides an interesting instance* oi localised road (lete*rienation. “|>ot holes” arc chiefly caused by concussion. The stopping and starting of heavy vehicles and tlm constant strain caused by changing gear at the head and foot of inclines wears away the ha idlest road surface in a short time. Moreover, at the* point where two different types of roads meet a ridgi is often formed owing to the different level of the surface. Consequently traffic passes over the .tom with a bump and drops oil to the lower surface with c-ernsiderable impact. tlm continual pounding speedily causing “pot holes” and other inegularities.