BITUMEN STREETS

Dominion, Volume 7, Issue 2177, 17 June 1914, Page 4

BITUMEN STREETS

.' IMPORTANT POSSIBILITIES MR. F. G. MACE INTERVIEWED CASE AGAINST WOOD BLOCKS DEVELOPMENTS ABROAD Very definite kleao'on tlie subjcct of street and road construction are hold by Mr. F. G. Mace (of the contracting firm of Messrs. Mace and Nicholson), who has just returned from a visit .extending over a period of ten months to_ Encland and the Continent of Europe. Mr. Mace made it his business, amongst other things to conduct exhaustivo inquiries into the latest methods of street and road construction, and his practical knowledge, of course, enabled him to pursue these inquiries effectively. In England and other Countries lie mot many of' the foremost authorities and specialists occupied in this important branch of civil engineering; and, besides being admitted to their laboratories (Where he gleaned a gi'eafc deal of valuable information) he was enabled to inspect .in all its details the practical work of constructing roads and streets according to the latest and most approved scientific methods. 'As a result of these extended inquiries, Mr. Mace is decidedly of opinion that Now Zealand lias a great deal to learn from the countries which he has lately visited. so far as the making and' maintenance of roads and streets is concerned. Notably, lie contends that wood-block-ing, which in Wellington and various other. Now Zealand cities and towns, is regarded as the best material for firstclass streets, is not by any means entitled 'to this premier position. His researches abroad' have convinced Mr. Mace that streets composed of a surface of bitumen laid on a foundation of concrete or of tarred ' macadam -would be much moro cheaply constructed in New Zealand cities and towns than wood-blocked streets,;and would.also bo rastly superior • from every point of view. ■ .

"Tho city of Wellington is proposing to spend a very large amount on street improvements," Mr. Mare remarked to a reporter, "and better streets could be constructed at fifty per cent. less cost if bitumen roadways'were adopted iu preferencei to w;ood-blocks," Imported Export Suggested. It is absolutely necessary 'in the interests' of economy and efficiency, -Mr.-Mac-e considers, that, the authorities concerned with . the construction of streets and roads in this country should be made acquainted with tho up-toKlato and scicntitio methods . which are in vog'no; in ' England, Europe', and America; To that end he suggests that tho Government'should import an expert of European experience to adnse the various local authorities and their engineers.:. The incidental cost, he maintains, v.culd bo trifling in view of the. immense benefit-s to bo gained by the country at large from tho adoption and application of modem methods.

An Extended Investigation. of Mr.. Mace's lg®hwpi!S4sSlß& ed from tho array of facts and suggestions which h0.., laid- before I'ifE DojiiNtoN" representative who "interviewed him yesterday. . "During my absence abroad,'.' ho xcniarked, ''I have visited .sorao thirty jargo cities and have lost,no. opportun-. 'itiy of observing tho different methods ' obtaining in tJie construction both of city streets and country roitils; .and' if the results of my experienoe prove of value I am only too williiig' to -impart any information I may .possess. I may. say that 1 made a .particular-study; of. methods and made 'many '.special. jourKeys to investigate in places where I learned that any engineer adopting new methods of street construction. Aided by a lifetime's practical experience as a contractor,, and with leisure to pursue my : 'investiga-' . tions, 1 venture to say, without wishing to appear in the least egotistical, that the conclusions I have arrived at are both practical and irrefutable. Streets and Traffic. "In the course of my investigations 1 came into contact with many engineers, some of whom are on'tho top' rung of the ladder both as engineers and as authors of books' on this im-' portant question of road construction, who very kindly took pains tb impart to. me all the useful information on tho subject in their possession. I may'say that the city or county engineer or surveyor as he is sometimes termed .is impressed.first with this important fact: that a road or street and tho vehicles which run upon it are component parts of the same machine. Just as a railway is constructed to sustain tho rolling stock designed for it, so a road-bed must be designed to meet tho evervarying requirements of traffic; in short the professional brain of the trained engineer is bent on evolving a road or street suitable for the'traffic it is now, ■or likely/to be, called upon to sustain, and to get away from thv idea of suiting the traffic to tho road. It is'recognised that the road must be suited to the traffic, this, of course, within certain reasonablo limits. Tho engineers whom I met for the most part seemed to me to be very capable men; jvieing ■with easlv other in healthy rivalry as to who could turn out the best road suitable for the traffic, and,at tho lowest possible, cost to the taxpayer. •"The .secret of cood engineering i 3 to carry out works t-o fulfil all requireiraents at tho lowest cost."

Methods in London. "Tlint there obtains a great variety of methods goes without saying. Method ndopted in London, for instance, with its wonderful traffic, would be ridiculous for a country road, both from an economical point of view or from that of utility. Speaking 'now of city streets jn which we in Wellington arc most 'interested, the streets may he considered as first, second, and third-class, cach requiring in detail different treatment, though in principle the samo. The tendency throughout, England is to standardise methods; still in London today tliß street-making is not of a uniform character. There are, right in the centre of London, streets being made of ordinary water-hound macadam, such as obt.nins in 'Wellington (only I must ,say differently constructed), and where from observation I should say tho traffic is ns heavy, except probably over tho- waterfront. Local Methods Criticised. "The methods adopted here in tho construction of macadam roads would ho scouted there; the creat difference heinc; in the binding material, used. Tho i binding material in England is entirely of screenings or chips, with a snriuklmg of sand: these together being thoroughly rolled into the coarser material until ,the road service is as watertight as it is [possible to make a macadtim road with -natural materials. The secret of good.' road-inakilin: lies in' the scaling ■of the surface against, an excess of moisture.- J. Walker Smith, of Edinburgh, .in .his excellent work 011 'Dustloss ''Roads,'' speaking of macadam roads, says:- 'The binding is undoubtedly the crux of the whole question of efficient, road-making and maintenance; the binding .makes,-or mars the macadamised 'road, and' it is, and ever has been the

weak spot in i'uo ordinary timcadtun roads. . . Tfis; o( Macarinm, "The- saJne nvitlmr (who, b,v tii-o wji'v, is a groat advoca-te of th.t? use of tarred macadam}, savs this: 'in iueutjoui.iiE t»e defects ?.if the oniisinry myeadam SSVtiico, oiie iiiu>.'l bp nriiidftii of tj'to fact tlaat for ordinary light ksn'se-drnwn vehkics, and for fivtMniJo )>4r hour* motor tralJre, tliero could bo nothing to provide a jjood f'oottiokl for hoKfts and v/heellk'ild to tJie sitoel-tii'ed. nioturs, than a weli-naade and ivoil-roaintaiiist} macadam road. It is Jnst saffiewirtlj' resilient apd.Bot too resijicnt, ta unit the st-eel-tinsl motor vchfelc, ai'd Rj'obably for such purposes as the so a road often spoken »f but rarely seen, comiliosod of hartl ntaeadam osocedhiK:l,v well rolled and bound Willi its wn chip--Pj"K?. £3io least lxis.sib.'c sd,mixture of binding •as ofdiuarity ttiidcrstood, would bo a v«ry satisfftetory soiutioii of the problem.' Dust and Mud. "In Wellington, and so far as I jenofr elscwliero iii the Dominion, the bintlin" of our macadam roreds is of soft ehno.v material, k'li, in .;(■(?-- solv-es into mud pure and gimpsle, and in dry weather mts e!oiid« of d>ist, and not only adds to th? itkcflinfort of tie public, but enormously increaiso.s til(s cost oi ma)irttri>aj:ce, s:;-ico it otlVrs iko resistance to tfec ftsocssire admission of moisture to tlio. ctjrv-: of the road, . wcll-rtiade n;:i< adnm road*' i.s unt to bo dispiswl; j.ivtk'Oil, the grade Oi the roadway exceeds 1 ill 35 t.iie ordinary mai.iadam fonit of rnad has notbeen supplanted by aiiy of tlw more modern and adnmoed liie'tiiods. Xr»it!,or wood-blocking, rocfc bitumcii nor otWr bitumen. mathotls are pmeticaMe ws grades exceeding IWi 35. tiiWefo-ro for first, Eecond', or third etes streets, v f |,em tho grade oxt-eds 1 in 35 waior-boimd macadam lWist. still be tl» method, of construction, hut tjie-Sij sl>Qu.ld ■r , X'! ; t:titi'ly bo constructed. on tJie fiesi nrineiplcs as to binding, <te . ■ First-class Streets.

Aon- wo cor,ip to ilic construction of nrst-class streets on saitabte grades and foundations. Of course it infest he taken tor granted t!mt m ail forms of construction good are lhere arc praatkaj.i'y t\wi t& choose Iront—iMflol ''blocks and bituinei! surfaces. WI»e» 1 (say bihimeii, 1 do not retyr to oteHnary eaal tar. Tar. of itself is clean, out of the running p.xcbp't for the coneroto uiiderlyhi-g the bitumen or as a . dust Jwyer. Nw wetid bte"!is t-ij London have a tarred surface. It would be unthinkable. I (lid. a-roi see a single tar-sprinkler in lx).vid'<ju, They iLty V' ho seen on count;-.v roads, but never <i'n ivood-blockiiig.j in the l.)ommt<m: As to the merits ®t tits two sHeUi<«is—wood blocks of bittynen-stirfor.i-il streets —I have no hesitation in asserting ; hnl tho bitumen takes the .leading place, from an economical. hiaiuieHajico ajfti sanitary point of view, Aftiad-biocteiuf Costs more iii tire Irst place. 'fnfco jiif; rah, for inst.urce. Wellington ft costs about 20s. per. <sqWo yard. The interest at o per cent. atone oh thai square yard corves to Ls. per aniium. l'lfteen or fcivettiy .years. lw|sa jami!> iiltl most likely iiofc ho to- ichcav it. Even if ft. is, it will cost from Qss to 10s. per square \ aid to repfaae tiie blocks.. It's leugtli of fife under traffic conditions will not equal rack bitunwti by ten years. .1 .have, iu kiv pufrseE,s.iuij a sample of jaftah weed blocks taken from- tho streifis cf .Soi;UiaiU(.toi!. where traffic is heavy, practically vont mil in 18 years. In the sa«e «&y (this i-itfar* ination was gkeu mo % % Southampton City Engine*?.?-) reek bitumen lias been down 2is .years, and lias Hover teen touched, and is still m oxeellsiii eondi.not . §o thick- as vWOOtI blocks in tlio same city (traffic' conditions ar.o equal).have hfipu'. nudoy main.-* tenance for years, awl now present a. surfaco as uneven as Some erf ear WcP lington back .streets, au<l must scon be taken up and. replaced, either with frssl.i four inches t» the. 6ix' si\c-lies of cemcui concrete, foundations,, aiid;- thca applviaig a bita»' fcienous surf.tea/ ' • ! First S'-jst Comriarsd. ' .»"Th©' first "ciog.t (so J was informed) ■of thefo-two. inetltofls is in levam- of tho'. bitniuraen. Tht> wood bleaks 18 years' ago ,cc>st 18s. .per square yard, 28 years ago tho bitiiaieh road eost iOs." per square yard. To43av wood has g&ne up, and rock bita.neft dowa, llfltik "bitiMlieii. in London uo-day costs lUs. Ctl. per yard, as agaiiisfr lto. 28 ye&r* ago. Jar-' rah now costs. per spare yawl. At Heaton Moor, ii-ear 'Si'ttekprjrt, x Maiidu.'s T ; ter, a concrete, and liium-.ci-. Mad t;>xe 95...6 d. per. square yard, and so far has been clow# Kl years, unci lias cost ■absolutely notiiii:;', far maiftwiiauce. Koft woods are noaf substituted for jarraiii, but as soft wood !k;s Jisstf / be e)ieiHi<s- - treated; the tost...pei- toleek is lwti very materially redueai. .Mon'over, under heavy trafiie tiie soft wood eann.at have the sam«! kngfcli <;!' life as jurrah.. I have '.with ftio eS soft woodblocks taken from tiip streets, ef Louden, absolutely worn <jaJ, ia 10 years. Anotliar Form ot Street. "So. far, we havi! emixiderod omly rock bitumen, the.t ft process of eoycring the concrete foundations with a 'coating of bituftUm, ajipiied at a high temperature i.'iiO degrees Fa.hr.), and. rammed home u'i'tli hoi tjiols inaSe fai-t-lio purpose. Tisere is.j howevor, auotlier method of itioto recent introduction, and, lo iuy nand. nn inl-nitt lv more prictieal aiid seans'B.Keai process,, which costs at least S3 per cent, fes than the rock biai::,e:i. It fioasists of a tar. concrete i'onndattor.i (tarred i®aea-' dam), with a bitumen surfaee deposited whilst hot,'and rolled ivfth; a special roller. This Ratimd oi>taiai.s hi i'Hiham, one of the largest; btoOHgfcs in .'London.'.'. I avaifod .niysslf s| tiie opportunity olfersd. m.c ; . to see the process., the c'oiiiponeiit parts of tba Citutoim niixturo, tho jiiix-ing, laysjlq;, avid rolling—in short, tiie jusgress iho material from the cagraek's- iabeiaitiyy to the finished I say without tke slightest hesitetio'n that this method offers to us out hero ovevj possible inducement for its adojpti'in, it is-'fijFty per cent, cheaper thnn wood-blfioks a.iid admits of -a rtfasoiwb'o c-ross-iall j[pr crown), which ,K ; fl(idA|e.s!rs do 'l'i.o't.. The bitumen roadway, tiKnrffirt.-. shsjtfe tho water more easily, is Unshod with every shower of i-ain. If distebfiij by necessary pipft4B;vili.g pi- - otlte* works incidental to eity pnguteoriiijs at- ti-ac-tion, it is easily i-eiakl, Also, it is much more saurt-j.ry, stt import ant tionRideration whe.rn imidi of the. traifie is horse-drawn. Tho Fnlliaivi B'Srwugh ISisgiirevt (an .exceedingly cS.pabfc miifii is steadily cohvortinc all Ims sttcftts, toth woogU block and oi-diaary niaiviulam., into bitumen roadwaysi. He has seventy pities of streets under his eaiitroJ! A iiieinh.-r of his works coUSiaittec> assuveil .mo that by .the adoption of this moi hod their enginoer had frKKi.ii the last five yecirs saved tho soriTCihiiic li.lco £20,000. He afhlod tlwf, the fee'envgh was the only oiie lii. Ijo-nttei, that liii-fi not found it neee-sawy-' h> • raise tiw rates this year tu tn incet th-u cost of reiiairins the exi' noirtinai-A da-c----age douo to tfco vosuls Uy jwwe'ivilfi've.n vehicles, partica'arlj- muler enmibn, The samo bordugj-j hap this this year voted £11.000 for the convviswi of its rui'.siadamised streets, as t'iW.v.wcar out, into bitumei). roadways.. I saw oiui seetioii of street ill this ho.iwali, "ks<jing; i«to a large ra'ihVisy goods sited,, srliere tiie traffic would- iti ii!l e<ntal CO tons per foot of width pf-r dny. Tkis section was conEtrfcoti«(J as deserfbedand had been down for tlww ycai'S uhder what may safely he e)a?'s«fi as'extraordinary heai-y ti-Rflie. 'i"'h« road sitrfiwo was intact and its eomiition 9p|«r®ittly as -good as when it was first laid, 'the life of this class, of street is estimated o_t. thirty .years, At the. feud of. wMcb time only tho tap hitumen sutisee aeea

be risicwcit. In'the boroiigh of Fulhaiu oiit ul a _iota.l of sfcvoiity, mite oi' ?yt)cots ten mites are wood-blocked and yeven riiiles have alro'Uly biißii converted to bitumen ami the 'process 0 f ym,. i*eriiiou us steadily yoitig ou. Local.c.oi> ditions Ivuve to ix; taken ijiioatioij, for what may he practical in one pkii-o may not -be miiversally itpyiieaWe> but the eomfitipiis in .KiigtaiKl, with ii.s foijs, di'iKislinj! ruins, wiiitei' frosts and summer heats (often'intense) may i>B considered quite severe cm road surfaces. As u, tlvo heat. a. teiiiperature of 128 ileyreris Fahrenheit iVas {cgistefed in Lwm!an'- toing Hie sujhmof'of HilO, and isi 1911 a tcn:perst:.ire of 182 degrees was recorded. \\<i may, 1 think, take it. for granted that cuir ciimatie towliiitiiis are not so severe as tliose df luglaiwl and therefore methods adopted there With uuqe siiiied sufieeSs timy safely he intradtteotl licre.

What Might Have 3een 'Saved. "Had inorc modern me'tliods lieini a-duptecf even in rcrferewco to aot already•• wood-blocked sti'aeU, I venture to say tlia't a siiving of £'50,01)0' in i'irsi etats inight iiave rts»li«d -amJ road surfaces i}tute equalling, it not superior id, tfefisc (vhic'h now eii'st would Ijava been rilitaiticd. lam roughly listinrnttaig that we have 100,000 styuarp yaf«Js af wnorlblftcking m mir sti'-oeta winvlt has been laid at Ji cost of" approximately £1 >,\c-r yard. Halvever, • iu; paM is and the present occiMiics our aUentkyn. Oar main object should be tile adiiptkn of a l'ifthod wiiifh will cambij'ie. a mininram cost with full effimwrny. These i touiremen's ftri' uiicjuestione.bly .met by tho bitumen road. Tin- time is not ia'r distant when. every city and provincial iosvii in the I)onmii.::i will adojit this term of road as aiiswcring in the bi-j-.h----«st, jw.ssiMe' dogr'M 'thcs demafflds of economy, sanitation, and. durability, fiitu-mi«on:-s sircs'ts are How under construction in Sydttoy arid the process is also being adapted! in Bn<;nos Ayrcs, and Moute Vkteo, In Koi til America bitumen roads arc rapidly coming iht<> favour and they'hav» long existed and are

. still being tViistriKted i:i Cennaiiy, I >Swed':ii, i)emrti:rk, and France:. Move ( than., 170,t;r}0,u'l0 oquare yards of roaclway have bee:!' laid in the Univou States of Ainciica with hiiunien. ' In tlir State y trf l&tta the city of Wnterioo'has SSSfQ® , square yards of bitumen roadway. ( . Cluirics City, 40 9 008 square yard:-., i Btooat.fi'dd City .66,000 square yards, and j; .so on. .' ;