TARRED ROADS.

Taranaki Herald, Volume LXIII, Issue 144827, 3 November 1915, Page 4

TARRED ROADS.

EXPERIMENTS TO BE UNDERTAKEN. BY TARANAKI COUNTY COUNCIL. At the monthly meeting of the Taranaki County Council to-day. Mr. R.„W. Fisher, county engineer, submitted, the following report: fn company -with your • chairman I visited the Eltham. Hawora. and Wnimate West Counties on October 22. for the purpose of iuspecting the result of tar treatment on the various roads. At Eltham we were met. by Mr. Basham, countv engineer, who accompanied us to the central depot where the material is prepared and the method explained. In this county “Restar” has been most extensively used, “Restar has ben most extensively used, with good results. Two' methods of application have been resorted to. One method adopted is pouring “Restar” on the surface of the roan after' first carefully sweeping the road to remove all dust and afterwards pouring the “Restar” on after heating to a certain temperature; the road then receives .a coat of shingle. The second method is to scarin' the road and. after adding a light coating of new metal, lightly roll the road with a steam roller and apply the “Restar” by pouring it on hot until tho preparation has run into the interstices of the metal,- This in turn receives a further light rolling, after which top dressing of hot tar is applied, followed by a light coating *of shingle, and the road is then ready for traffic. The latter method, although more expensive in primary cost, gives - best results and is the one 'that is being , generally adopted for tho roads in that county. Mr. Basham took us over the j Hunt<tr Road, which was laid nhoUtj four years since in accordance with the last method described, but in this case ! tar from the gasworks, dehydrated to eliminate tho light oils and ammomacal liquor which exists in all tars, was applied. The road*, in'*spite of no expenditure in maintenance for the past four years, showed a surface equal to and better in many cases than tho more expensive proprietary bituminous mixtures.

The Hnwera County Council has not as yet adopted tarring to any great extent. The council, however, have on order a plant which will cost them £I2OO. which is expected to arrive from England in tho course of a month or two. The oounty engineer (Mr. Moggridge) gave -us all tnc information m his power and explained the he had adopted. "Soltar” has been used .011 portions of these roads, and inspection does not show ‘any. material difference between that preparation and “Restar," hut I understand that the quality of tho various consignments of “Soltar” varies, and tome arc not good. Tho ordinary gas, tar dehydrated rs.tq, be adopted generally'th this Comity.' ‘ At Manaia we were met by -Mr. M'Phillips, chairman of the Waimate West County Council. This comity is just embarking bn an Extensive scheme of tarred roads. A length of the mo in road between' Manaia and Hawora'has been put down with-ordinary, gas. tnr obtained from the Wellington Gasworks,

I and has worn out very badly on the sidesv This is attributed to an “error of judgment” in preparing the tar, and . this contention is supported by the fart that a portion of the road which has I been laid with tar from precisely the | same consignment as that used in the defective length has made an excellentjob equal to any we were shown. The method adopted here is that of tarsealing.

The question of cost is difficult ui arrive at in any of the three couutier. j visited, as it differed considerably in ! each district; and this is only natural, l as cost is affected by local conditions;, such as distance of carting materia!, etc., and it ,- s only by means of a pracr tical trial that this can be ascertained. I am glad to have had the opportunity of making this inspection, as it confirms my opinion, based on personal experience. tnat equally good results can be obtained by using tar from the gasworks. 1 might mention .that in, 1908 I superintended the construction of a road-in one of the principal thoroughfares in the city of Bombay, India, which was laid with distilled tar from the gasworks. The street in question carries traffic in 24 hours equal to the South Rond in a month, the nature ot the traffic being exceedingly heavy and consisting to a great extent of bullock wagons conveying heavy bales of cotton from the Bombay cotton mills. 1 recommend that the portions of the reads to bo treated shall be first scarified and. where necessary, new metal added to the extent of. say. 8 cubic yards per chain, and after this has been rolled lightly boiling tar properly prepared, to bo procured from the gasworks. poured m This should he rolled to consolidate it and a top dressing of tar applied and lightly swept over with ordinary brooms, after which it should receive, a coating of fine shingle, which in its turn should receive a light rolling.

I this method of pouring the tar into the unblinded metal as against tar spraying, in that by adopting this principle the material will he bound in at the edges, whereas in the spraying method the edges are the first to give out. as it is here that the greatest wear takes place, and in most of the roads where tar sealing has been resorted to my contention is exemplified.

As an approximate estimate I give SJd per square yard, equivalent to. say. X 3 18s per chain, or ££l2 per mile.

I wish to point nut to you that unless the road surface is properly prepared to ‘receive , the tar by scarifying and bringing it to an even surface the inequalities which exist in the ordinary metal roads ore not minimised and the jolts and pools of standing water will «till make their presence felt. As regards maintenance. I would point out that -whatever system of tar treatment is adopted there is the annual maintenance charge to be fared, which in the case of ordinary tar 1 estimate at- £1 per chain. As regards this county there is a considerable mileage of roads which T consider should be wider metalled before it is ready for treatment. - Tn conclusion we have to thank Mr. Basham (county.engineer, Eltham). Air. Aloggridge. (county engineer, Hawera). Mr. ADPhilHps (county chairman, Manaia). and St r. JLnpdell (county engineer, Stratford, formerly of AVaimnto AVcst) for the courtesy extended to-us. • It was decided to give ©ffect -to the engineer’s recommendations.