. Building Roads on a Mass-production Basis
Page 21
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THOSE in control of the construction 1 of our roads still have a lot to learn regarding the building of these iii a speedy and economic manner, or, at least, if they have the knowledge, it ha i not hitherto been applied to a really appreciable extent.
Many road engineers made an, extensive tour of practically the whole of the German Autobahnen some two years before the war, and there they had an opportunity of inspecting the methods of construction, including the employment of really. marvellous machines, such as that which we illus trate, and which was photographed by the Editor of "The Commercial Motor."
This is used for laying the concrete after the bed has been -prepared and practically finishes the job in one com bined operation, the whole width of the one-way track being laid, tamped and smoothed at one passage of the equipment. Afterwards, when the concrete has partially hardened, it is cut into the requisite number of slabs, and the spaces filled with bituminous material to allow for expansion in both directions.
An interesting point about the method is that, in case of sinirage, which does sometimes occur with a new road, the slabs are lifted independently and additional foundation material packed under them, but this is usually necessary only where the roads pass through country where the ground is of a yielding nature Before the machine is put into action, narrow trenches are dug at the sides of the intended road; and these are filled with concrete, upon which are laid, steel rails. This task must be carried out with great care, as upon the correct laying of these rails depends the accuracy of road construction, for the outfit runs upon them.
The machine carries 'its own oilengined power plant, concrete mixer, trip-operated, heavy, vertical rams (which pound the concrete as it is laid), the distributors for the rough and surfacing concrete and, finally, the smoothing-off blades which leave the surface in beautiful condition. Machines of this type travel at almost a constant speed and can lay a mile or so of road in a day, provided that the materials be available and the foundation be prepared.
Our remarks regarding it are from memory, but may be sufficient to indi: cate its extraordinary efficiency. We suggest that when the time comes to build those new exclusively' motor roads, for which we are all hoping, attention will be given to the possible employment of machines of this type_