CONCRETE ON THE ROADS.

Kaipara and Waitemata Echo, 10 August 1916, Page 3

CONCRETE ON THE ROADS.

CONCRETE ON THE FARM.

Full Particulars of a Most Welcome Innovation, as supplied in a Pamphlet issued by the Portland Cement Company,

Auckland

(Continued from last week and to be continued weekly).

AN ENGLISH EXAMPLE,

In the November, 1915, issue of an English trade journal, " Concrete and Constructional Engineering," a number of English roads recently laid, down in concrete are described and illustrated. The following extract will give an idea of the method of construction and the cost of a reinforced concrete road from 6in to Bin thick. About half that thickness of reinforced concrete should be ample for an ordinarycountry road in th'.s country, but, as a general rule, reinforcement is not necessary for country roads, the recognised safe road being from 5 to Bins of solid concrete.

Roberts Lane, Saltney, Chester (From '" Concrete and Constructional Engineering."):—

In our August number of last year we published a description, with photographs, of one of the first reinforced concrete roads that had been constructed in this country. We allude to the Roberts Lane Road at Saltney, in the environments of Chester, made in 1912, under the personal supervision of Mr Matthews Jones, the Borough Surveyor. Briefly described, this road, which is 950 ft in length and 20ft broad, was excavated to a depth of 8 to 10 inches, then on top of the clay subsoil 2 inches of cinders were placed to bind it. On this I\i to clinches of concrete, then across the road the reinforcement of the Expanded Metal Co.'s rib expanded steel No. 8 was laid. Covering this was concrete to a depth of V/i to 4H inches. The concrete was made of five parts of broken granite %in up to small 2in (mixed) and sharp sand, to one of cement. The road was closed for about three weeks, and for, part of the time kept well watered. After being open to traffic, the road remained for nearly a year without anything being done to it, when it was tar sprayed and sprinkled with granite chippings, at a cost of lHd per yard. This treatment is carried out once a year, so that the maintenance is a very light one.

When this road was inspected in May of 1914 the surface was in perfect condition. In the spring of this year the tar spraying, etc., was done, and when seen again in August last the surface was still in complete order, and there was not the slightest sign of the dressing lifting in any way. On this point it is well worth remembering that when the tar spraying and chippings were first put down the concrete was thoroughly dry and set.

The traffic on this road fifteen months since was computed to be about 60 tons per day—not heavy—but undoubtedly this has increased, and will still further do so as the . property in and arbundvthis district is developed. The; original cost of this road, including the excavation, was 3/10 per yard, and the cost of maintaining the surface has already been mentioned.

REMARKS

It will be noted that the depth of this road, including the binding and reinforcement, is from 8 to 10 inches, anc( that it was constructed at a cost of 3/10 per yard which is a very cheap road indeed for that thickness, After three years 1 traffic passing over it at the rate of over 60 tons a day, the surface was stiU in complete prd.er when last inspected in August, 1915. From this and other evidence to be presented, it will be seen that the plain concrete road is §, success without a.ny covering;, tjut it is $ustoma.ry \n many cases to, put a thm layer qf t§r. an,d. coarse sa^d qr screenings on top of the hardened concrete. There is no necessity for wood blocks, sheet asphalt, or any other of the expensive toppings which have in the past been used at great expense for city streets.

A road such as we, have described }s r\ot nearly as slippery j^s is Queen Street, Auckland, for instance, on a wet day, nor is it any more noisy under horse traffic. It is clean and sanitary, will not harbour germs or odours from, animal droppings, and will nqt wear, into, holes o,r depressions.

If nrqpevly cqns.tr-ucted with good, n3ater.ia.ls it gives a hard, smooth surfa,ce v with sufficient " grip "• fqr- h,o,rse traffic even Qn giades p,f 10% and, qy§*\

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