ROAD CONSTRUCTION.

Hawera Star, Volume XLV, 14 July 1925, Page 5

ROAD CONSTRUCTION.

METHODS IN SOUTH TARANAKI. Much interesting detail concerning the bitumen surfaces which have been laid down in various Manawata, Wanganui and Taranaki local body areas is embodied in the report presented on Wednesday to the Wellington and Suburban Highways Board by the committee which recently toured those districts. Details with reference to local bodies in this district are appended: PATEA COUNTY. The treatment generally in use is the penetration method, but the grouting material is bitumen, not tar, as in Wanganui. The foundation is metal sin thick, rolled and consolidated. This is covered with 3in of graded metal, grouted with bitumen. The whole is top-dressed with a sealing coat of bitumen and metal chips. The second layer of metal and the sealing coat costs 4s 6d per square yard; total cost (including foundation), 8s per square yard; cost of metal delivered, 17s 6d per cubic yard; cost of bitumen. £lO per ton. The approximate quantity ot bitumen used for penetration purposes is one and a half gallons to the square yard. * HAWERA BOROUGH. The surface treatment of roads in this borough has been - chiefly in _ the form of tar macadam machine-mixed, with a sealing coat of tar or sealing coat treatment with tar and bitumen. The maintenance consists of the application every two or three years afterwards of a bitumen coat. The total mileage of road surfaced in the borough is 40 miles. ELTHAM COUNTY. Road construction of a permanent nature in this county has been eonfied to tar sealing and bitumen sealing. It is estimated by the county engineer that tar-sealed surfaces require a maintenance coat after every 18 months or a bitumen coat every two or three rears. The estimated cost of both methods of treatment was from 4d to 6d ner square yard. In this county were found roads that had been laid for 14 years with regular tar-sealing treatment until two years ago, when they received a top-dressing of bitumen. These roads appear to be in remarkably good condition and present well-sealed surfaces. The grade on portion of these roads is one in nine. The surfacing treatments. in> Stratford County has been' on similar lines to those adopted in Eltham County. EGMONT COUNTY. The treatment generally in use is penetration with bitumen, and consists of laying and rolling 4in of graded metal and the grouting thereof with about 11 gallons of bitumen to the square yard. The width of the. paving is 16ft. The cross-fall is 1 in 24. The cost of the metal is 18s per cubic yard, bitumen at £lO per ton. The cost of the finished pavement is 5s 2d per square yard.