Show SURFACE OF ROADS methods to be employed in construction st depends on con editions to be met FOUR SETS ARE summarized location design drainage grading etc are important each fea ture described separately and in full prepared by the united states depart ment of agriculture the proper method to employ in constructing a bund sand clay road surface depends o 01 01 1 the conditions to be met in general thre are four distinct sets lot f conditions all of which may occur tt u the locality or cun eta on different sections of the same road these are lis case 1 where the original roadbed Is sandy and it Is desired to construct jie the surface by i clay case o 0 Z 2 where here tho the original roadbed 1 compos composed td of clay and it la Is dest ed ito construct the surface by admixing ennd I 1 cube u 3 where it Is desired to construct the surface of or othir natural san band dclay clay mixture without ad mixing any of the roadbed material materi pl I 1 case 4 where it la Is desired to supply the tile clay and sand band separ sepa atly and mix mir the two materials in together gether in place to form forra tho the surface before the different cases separately the general ends which all of the construction method should aim to attain mill III be summarized briefly 1 the questions of location design drainage grading etc are if anything more important in the case of sand clay roads than in the tho case of earth rth broadb 2 the amount of clay contained in a fluis lied san nand clay dclay road surface should be only slightly more than sufficient to fill the voids in the sand ordinarily about one lart of clay to two parta darts of sand gives satisfactory results though the proper proportion for any particular casie can be determined best by experiment 8 9 for average country road traffic and a roadbed the depth of a san band dclay clay surface should be about eight inches after it la Is compacted if chan band aud aad pure clar were used to maki the mix mixture turp the respective depths of the bund layer and the ciny clay layer required would be approximately eight inches and four inches men measured loose it la in customary cuoton iary to decrease the surface thickness from center to bide sides with mith a feather edge extending out over the shoulders but thie this practice makes it necessary for roost most of the traffic to use the center of abi th can best bp be de described separately for each of the four bets sets of aboe cae 1 to construct a sand cley clay surface by admixing clay with mith and sand from the tile roadbed fart grade tile th roadbed in ili the manner already d ascribed scribed for earth bet construction but keep the tile crown hat on the portion to be surfaced then spread clay over that part of the roadway which the sur fact face Is 1 to cour tn to such dath that when hen it iq 1 mixed with the band sand of the roadbed a surface about eight inches talk after will mill bo be ob i iho ibe loose depth of clay ony mua sary to secure a finished mirauce eight inches thick will mill vary vury from four our inched to six elz inches according to thu the amount of nal sand the clay contains after tho the caa cini has bet ban n barad ad plow up mild sand from front beneath la in 11 qu trinity to make the net flet proportion of sand to clay about 2 to 1 ordinary Ord Inart aa 13 the plow furrows should extend down town into tho the band and from tour four to rix In indies lies depending on tile a of he tile roadbed and lie the amount of eard bard originally present in the lay clay hut but it 1 Is better to hano too tot little than too much mitch band lecaue le caus it Is 1 easier to add sand from the roadbed than to haul additional clay next harrow the surface with a disk harow the tile operations of plowing and rind harrowing barrow lne until the rand sand and clay are mixed thoroughly ind and uniformly then shape up tip the surface with mith n grading mathine or rond drag and penult permit branic upon it tho the oret soaking min rain plow and harrow the surface again until the surfacing material practically beco becomes al e 8 mud after which shape up tho and keep it in eliapo shape by repeated drak drag ring until it has ha dried out add Is thoroughly compacted watch ther therod opil carefully for sacral 4 utter it it W flat or 61 1 I shift crowned I 1 IMP IM vy P I 1 1 it l V I 1 it AC 7 tt TT j S whon ready to the inter material mat trial lail 1 1 I I 1 3 W s1 sa se tut I 1 for thit ats h L ik 1 chois selim showing material mater tal spread ebo on th the roa le J 1 t k re for m u na I 1 T W e iu m Si n aisi yi y r cross section of road 44 1 TYPICAL CROSS SECTIONS SHOWING METHOD of constructing SOD CUY ROAD BY MIXING SAND OR WITH THE I 1 hoac hed MATERIAL W be at feast 1 R feet for forstik a nak track frack road roa roaland jand and Teer 5 alil not ki less than hai erect 5 ctet lur doub double be 44 not leas than 14 fut ff t kis ku than soctt i H crown hariu from ato td it e foot for level yada to va 1 the th root for a F i d I 1 la Is drat first constructed to correct den of band or clay und and to keep the surface in shape case 2 to obstruct t a bandy sandy clay road rond by admixing sand with clay from froin the roadbed the process la is exactly similar to that described for vase 1 except that sand ie Is spread over the graded roadbed nd n v d ciny clay Is plowed up froia from beneath to mix ith it the depth to malch the sand should bo be spi ad for an elgh tInch finished our face usually cartes varies froni from four to eight inches according to the amount of mild contained originally in the clay of the roadbed the depth to which the he plow furrows should extend down into the clay usually varies from about three inches to about the inches and depends on the band sand content of the ciny clay and the lie of the road bed it should bo be borne j I 1 etal that in this case it t la to better to iwu lint e a sur plus of blind than a surplus of 0 clay in the surface eur faco bienusa the former Is more easily corrected caso case 3 8 figure 2 illustrates the two principal steps involved in constructing a sand clay surface with trip soll or other natural ennd sand lay tiny mixture the roadbed should be graded in the tile usual may ay except lint that the portion to r i W 41 v i jy gaa k cross section ready to receive the material irater lal S S w 4 sa s1 j r t ir re to t fi w iii 1 t cren af f completed comp road TYPICAL CROSS SECTIONS SHOW SHOWING 1110 METHOD OF A ASANO SAND OAY clay ROAD USING TOPSOIL OR OTHER NATURAL MIXTURE W chauy lit b at f eaf 10 fett for binalo mai imek nod roa 15 lot oat ass ml ahel att I 1 tor double frach Vi should U rot not itu 1 than 14 re reet et ond AM W ariot riot less than rest H crown varies arrom affo I 1 ia the th fod foot for level brads fc ral ta to I 1 ito to th 01 fl ol is emde ot 5 X a road and heavy vehicles using the fedge edge of the surface are liable to break through the surfacing material 4 0 in constructing a band sand clay face the two constituent maala should be thoroughly and intimately mixed together la in nil all in mak g artificial mixture mixtures much plowing and harrowing are required 1 5 no matter nhat method la Is tol fol elwed inked in constructing a sand day clay ear our face traffie u usually mut must be depended upon to puddle and compact the sur bur facing material and the road never should be considered complete until after it hae has been subjected to trade traffic for a considerable period during this the surface hould should be kept n by repeated drugging and it if rip astary additional tand or clay should be supplied at point points which how show eaknes at owing to these rna ma te celuh luls not having been mixed in proper i aber feature features of cf the truc loo be surfaced should be trenched out with the grading machine to receive the surfacing material the material should be spread to euch a depth that it will be at least eight inches thick at the center when compacted caw 4 C where it Is necessary cesary to brine bring the fond and clay on the road separately and mix mir them lo 10 place the method employed should be a combination of the methods already fla 1 I ascribed bed that la Is a trench should be formed with the grading machine to receive iho the bottom layer of materne mater mate ent nl chich may be cither either the sand or the clay clad and the top layer should then be bf fprd and the mixing done as de 11 in case I 1 or cas case 2 the depths of the respective inders aa should be uh suh na as to a completed face at leapt eight c inches thick and the proportion should be axel in lie ills cantier already dowl tied in lie the th othor cates |