Manual of road construction and maintenance, compiled at the School of Military Engineering

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1908 Excerpt: ...4 inches at the side, the natural subgrade being of clay; so considerable a thickness as 12 inches in the centre would not be necessary where the natural subgrade was harder. The saving in maintenance on a well-bottomed road is considerable. Elsewhere a partial remedy has been tried with good results, namely, to cut out the weak "shoulders," or road haunches only, and relay, after putting in sound foundations, which act as abutments to the roadway covering of fresh metal filled in between them. Experience, however, tends to show that if for a few years a little more stone of rather larger gauge is added to a road than is either usual or actually required to replace the annual wear, the requisite standard of strength can be attained with economy and efficiency. One of the most promising and recent efforts in the renewal of roads is the method introduced by Mr. Arthur Gladwell, surveyor, of Eton R.D.C. The process is a waterproofing system, which will make a strong road of one whose foundation is not liable to destruction by water. It is fully described later, p. 105. In tropical countries, where labour is very scarce in the wet season, as in British Central Africa, road maintenance has to be deferred until the end of the rains. This necessitates very large gangs working a short time. Two or three miles a day of earthen road can be repaired then by 500 to 600 men. The cost of repairing a length of 100 miles of such earthen roads (see Figs. 26 and 27) works out at the rate of £i per mile, 1,500 natives being employed under three Europeans. The best roads in Europe are in France, Switzerland, and Italy, where an admirable system of maintenance and inspection, under a Government staff, is organized. Some of the roads in Austria and Spain are very ...