CONCRETE ROADS.

Manawatu Herald, Volume XL, Issue 1861, 6 August 1918, Page 3

CONCRETE ROADS.

MR. G. CHAW’S EXPERIMENT

The outstanding importance of adequate reading provision to meet present-day traffic makes this problem one that is claiming more than ordinary attention from local bodies. Tests of various materials are being made in many parts of New Zealand, and in America particular attention is being paid to concrete for road formations. This material has been used with considerable success from the point of economy and stability, and some months ago Mr G. Craw, of Linton, a member of the Kairanga County Council, obtained the Council’s permission to lay a length of five chains of this, form of road in Rangitikei Line, Palmerston North, as an export merit, and estimated that the road could he laid at a cost of £3O per chain. Mr Craw completed the. work some weeks ago, and it was thrown open to traffic at the las!, meeting of the Kairanga County Council.

Sponkinto n reporler, Mr (Taw said ho considorod the road would stand up lo expectations if; given lair treatment. He did not, however, expect the road being |>nt to such a severe test for at least six months, as it was being subjected to at present. The road was thrown open wiu'ii hardly eight weeks old, and immediately metal drays were put on carting and lipping metal on the surface of the concrete, and when shovelled off naturally left a lot of. loos,'' stones, which were crushed under passing traffic at the great risk of d imaging the surface. As he did not think this a fair test —the concrete being still in a semigreen state —lie asked the roadmen to have the road swept. Although lie could not object to metal dray traffic, he did net anticipate the road being used so ; on and so coni biliously. Howevf. r. no damage could lie noticed, and if the road could idand (he treatment referred to. it would do more than he had expected of it. As regards cost, lie had estimated Ihe road at £3O per chain, and (Ids estima! \ as it proved, did not allow of much of a margin, as the cost worked out at a trille over £29. Mr Craw said he considered a long length canid he laid cheaper in comparison t > a short one, as the cost did not occur in the same proportion, Snell an item as lighting at night, for instance, cost 10s per chain, whereas the same lights would suffice for a mile or two of road. Several other costs occur irj a like proportion. In reference lo (lie laying of a few miles of concrete road, lie would not recommend putting it down in the same design or by the same method as the experimental length, and would recommend first of ail two concrete mixers being used instead of one, which would lessen the cost.- Rut the most important item of all was the haulage of .metal. Horses for this work were ridiculous and money could he saved by the use of mechanical means more in accordance with the times. As to the road itself, he -would net alter the main or bottom course, but the one and ahalf inch top course, he would alter • it and go one hotter by using line broken metal and add sufficient, coarse, sharp sand to make it workable, and put it down four to one of cement. This alteration would not add to the cost when laying a long 'iength, because a stone crusher and plant could be provided for the purpose. The materia! used on the lop* or wearing course of the experimental length was ordinary river metal of good quality put through a three-quarter inch screen and put. down four to one of cement. He could not procure any fine metal for the purpose. liivor metal has a tendency to crumble under constant, heavy wear, although it may- last many years without the necessity for a tar or hi lam m spraying to stop the wear. The advantage of broken metal for this particular purpose is that it would not crumble under traffic, and would be practically everlasting. The experiment will be watched with interest by the district generally, and one and all will wish it. success.