THE VALUE OF BITUMEN.

Hawera & Normanby Star, Volume XLII, Issue XLII, 16 October 1922, Page 4

THE VALUE OF BITUMEN.

DISCUSSED BY ELTHAM COUNTY

COUNCIL

Th<* Eltham County Council are thinking oi using bitumen extensiVeiy on tueu- roads. At tne meeting v« baturuay councillors expressed cUe opinion that bitumen wus quiie pao£ tne experimental stages ana was iar tne best investment. The engineer mentioned that a shipment of pitunien was being landed, ac JNew Plymouth every four niontns, ana there were 40 tons lying at the port which could be supplied right away. He thought that the purchase of bitumen would prove an excellent investment financially, as the tar put on the roads to-day wduld want renewing in the next two or three years. Bitumen or tar work in the Eltham County would begin in earnest in December next. The engineer, in his monthly report, referred to the subject as follows :— Demonstration lengths of Union asphalt or bitumen were laid down ; between September 17th and 22nd; 75 chains was laid down on the length of Eltham Road from "Martin's dip to "Doctor's drop,'' against a 40-chain length of restar laid in the late autumn from "Martin's dip" (inclusive) to- ! wards Eltham. Forty-five chains of I Mountain IRoad (c), extending from I the borough boundary towards Stratj ford, were also treated, and a small patch at the western end of Anderson i Road was coated for experimental purI poses, being sprayed arid blinded twice. ; Quantities used were as follows:— j - Sq. yds. Gal. ! Eltham Road (m.) 8250 1650 j Hunter Road 700 140 'Mountain Road (c.) ... 3960 790 Anderson Road ............ 60 25

•Totals 12,970 2605 The lengths of- Eltham and Hunter lioads treated were of good shape with tne tar carpet in good condition. The lengtii of Mountain Road was of inditterent shape, and the tar carpet had begun to brealc up. The amount of asphalt used on tJiese roads averaged 1-5 gallon per square yard, equivalent to about 8 tons per mile of 15ft road and 7 tons per mile of 12ft road.

The sand used for blinding contained' a large proportion of one-inch pebbles j and the steam roller was run over the work to break up the pebbles, which it j did yery effectually. The weather | was fine but cold; atmospheric shade ' temperature averaged about 55 F.; a' cold southerly wind was blowing most • of the time. My aim was to get the1 bitumen on to the road surface under. treatment at not less than 360deg. F. The asphalt was raised to a tempera-j ture varying from 430 to 500 degrees Fahrenheit, conveyed to the Work in a 400-gallon tank by lorry, and sprayed on to the road by a machine made by Nixon, of New Plymouth, and lent for the purpose. Mr. Skitrop, the inventor of the machine, supervised its | use by the county staff. Considering j the cold weather, and the fact that! I the qa>rrying arrangements were im- 1 provised, the results were " excellent, I j and demonstrated clearly that with, a; small expenditure on plant the high j [temperature difficulty can easily be; overcome. Before handling the [ asphalt in appreciable quantities it j would be necessary to erect a shed for I breaking up the cold material in. Breaking up in the open resulted in 1 chips flying, and' the sun soon melted j these into very objectionable spots for walking on. While the barrels are in the sun the contents are too soft for easy handling. To enable the soft asphalt to be carried long distances the conveyor tank requires lagging with asbestos, and this tank would be very much improved by the introduction of a fire-box, which would enable us to carry more than the one fill for the sprayer and simplify emptying at times when the whole contents could not be drawn off at once. Beyond a radius of six miles one lorry carrying 400 gallons per load would not be able to ■ feed the 200-gallon sprayer fast enough ito keep it \w>rking continuously. Conj tinuous working could be arranged if •.two lorries, each fitted with conveyors, j were employed, or if subsidiary heat- ' ing depots were used beyond the sixmile radius. The quantity of blinding material required may prove to be slightly less than is used with tarspraymg, but a surplus has been left near the demonstration lengths for use should the work soften much when the hot weather comes. The spraying machine used by us holds 200 gallons, or sufficient for spraying 10 chains of road and under ideal conditions it can be emptied in one hour. Theoretcaliy one mile of road can be sprayed per day, but in practice the result would probably average half a mile, or three miles per week. The hot weather which came at the end of the month softened the bitumen, and were the loose blinding had left i the" wheel tracks the surface became sticky and horses were inclined 10 lift I small patches. It has therefore been i found necessary to brush the blinding J back on to the wheel tracks on hot | days. This would-probably not be so j necessary with bitumen sprayed, during the hottest weather, as it will then take hold of a larger proportion of the sand.

The matter of purchasing a bitumen spraying machine (Was held over until the next meeting of the council.