A Plant for Expediting Road Maintenance.
Page 62
If you've noticed an error in this article please click here to report it so we can fix it.
("NNE of the most interesting and IL/practicable combination machines for road spraying and re-surfacing, which can be employed both for dressing the roads to prevent wear and for remaking the surface when the wear has gone too far to be remedied by light repairs, is the Fowler plant manufactured by John Fowler and Co. (Leeds), Ltd., Leeds. The outfit consists of Fowler steam-propelled road roller upon which is mounted a tank, a pump and distributing jets for delivering tar, pitch and bitumen mixtures on to the road surface at high pressure and with absolutely even distribution.
Coupled to the roller is a patent gritting machine for spreading stone chippings, grit or sand evenly over the coated surface and while the material is still hot. The work of spreading the material and covering itwith grit is carried out uniformly and for all practical purposes simultaneously.
The advantages of the system are obvious. The high pressure employed forces the binding material into the interstices, so that these are all filled up instead of being merely covered. Distributing the grit while the coating is soft enables it to penetrate and be held by the material instead la forming a loose layer on the surface, whilst the fact that the two tasks are performed together enables the road to be kept open for traffic. Also, after completing each length of road, the roller is immediately available to run back over the finished surface and consolidate the chippings and binder int) a durable, close-packed wearing surface, so that the grit is not thrown off by passing traffic as so often occurs, to the detriment both of the surfacing and of the finish of the vehicles themselves.
The surface that results is not slippery, because the chippiugs protrude from it, providing a good grip. Economy is certainly obtained, for a foreman and six men can run the whole plant, including the loading of the gritting machines and tar tank, and it has been proved that 10,000 square yards can• easily be obtained as a day's output.
For resurfacing work, the penetration system is employed, stone being laid dry on the road surface and partially consolidated, after which the binding material is spread on to the stone at high pressure and forced into all the cracks so that the freshly-laid stone is cemented to the old surface. Immediately after each applicationt of the binding material a coating of stone chippings is thrown over the surface and this is rolled into the cracks between the larger stones, so assisting in rendering the new surface quite homogeneous. It is usual to make three applications of the binding material, spreading the clippings after each. The resulting surface is very hard and durable, and there is no excess of binding material to roll into waves under heavy traffic.
The practical advantages of this method of repair are that the road surveyor can ascertain exactly what type and quality of stone is being used to make the road ; the road metal is easily handled in transport, as itt is dry and so does not tend to set in railway trucks or transport lorries, and, of course, its handling is much cleaner, whilst, if required, quick-setting bituminous mixtures can be employed, so that the resulting road surface more nearly resembles asphalt than tar macadam. The sealing coat applied to the road surface at a later date can be spread by the same plant and by the same method. The roller can be used at any time for ordinary road rolling or scarifying, so that it can be used throughout the year instead of idling during bad weather.