HARDWOOD RECORD 



Wood Paving in the United States, 



For more than seventy years wood has 

 been used for street paving. In the begin- 

 ning, however, incomplete knowledge and 

 wrong methods led to failure, and it is only 

 within the last ten years, or since the in- 

 troduction of the present creosoted longleaf 

 pine block that wooden pavements have been 

 20 



laid with greater success, writes C. L. Hill 

 in a recent circular issued by the Forest 

 Service. Wood has many qualities which spe- 

 cially adapt it to paving, and with a better 

 knowledge the effect of preservatives upon 

 its durability, it is thought its use for pav- 

 ing wHl increase. Until the beginning of in- 

 vestigations by the Forest Service longleaf 

 pine was about the only wood employed, but 

 the great advance in its cost has rendered its 



use expensive, and accordingly the search for 

 sonic cheaper substitute has been taken up. 



All sorts of blocks have been used in lay- 

 ing pavement, circular, rectangular and 

 others, but by reason of faulty construction 

 and lack of preservative treatment they were 

 long considered practically unsuccessful as 

 a permanent proposition. In the Middle West 

 oak, cypress, white pine, hemlock, Washing- 

 ton cedar, eottouwood, mesquite, osage 

 orange, redwood, fir and tamarack have been 

 tried, without satisfactory results. Jarrah 

 blocks were laid on one street in New York 

 in 1895, but were removed nine years later; 

 although they filled their purpose fairly 

 well, the pavement cost $5 per square yard — 

 too much for general use. 



After these unsuccessful ejcperiments with 

 untreated wood, attention was turned to sonu 

 wood preservative which should prevent de 

 cay, mechanically fill the pores of the wood 

 thus preventing absorption of other fluids, 

 eliminate expansion, increase durability of 

 the block, and tend to maintain sanitary con- 

 ditions. Bepeated experiments have nar- 

 rowed the work down to the use of practic- 

 ally one material, the dead oil of coal tar, 

 or creosote, either pure or mixed with pitch, 

 resin or other material. 



Although creosoted southern pine blocks 

 were laid at Galveston, Texas, about 1873, 

 and gave good service until the great flood 

 of 1900, the example was not followed up 

 and it is only within the past few years that 

 it has received careful attention in this 

 country. Jan. 1, 1906, there were about 1,- 

 400,000 square yards in use in the United 

 States, Indianapolis leading with 404,800 

 square yards, New York with 178,264, and 

 Minneapolis, Toledo and Boston following in 

 order. Of course a great deal has been laid 

 since that date. 



Not only do wood problems have to be 

 dealt with, but also those peculiar to con- 

 struction work of this kind. The success of 

 the modern wooden block pavement is at- 

 tributable to taking infinite pains with all 

 features pertaining to both. The wood is 

 carefully selected as to kind and quality, is 

 cut into blocks of exaci dimensions, carefully 

 seasoned, and then filled with just the re- 

 quisite amount of oil to reduce to a minimum 

 the absorption of water and consequent ex- 

 pansion and contraction of the pavement. 

 The blocks are then laid ij^ith the grain ver- 

 tical, over an accurately surfaced cushion on 

 a solid foundation of cement-concrete. They 

 are closely joinei and in fine work the joints 

 are made water-proof; the result is an ideal 

 pavement as regards noise, smoothness and 

 durability. 



upinions were sought by the Forest Ser- 

 vice engineers of a number of American 

 cities who have had experience with the mod- 

 ern creosoted block, as to comparative quali- 

 ties of the different kinds of pavement. The 

 figures given below are the averages of ten 



replies to the inquiry. Under the percentage 

 column the various qualities desirable in 

 pavements are assigned proportionate values, 

 the total being, of course, 100 points. The 

 pavement ranking first under any given qual- 

 ity is given the full quality percentage, the 

 rest grading down from this value in proper 

 proportion. 



Comparative value of different pavements. 



Per- I 



Pavement Qualities. cent- Gran- 



Ease of maintenance 10 9.5 



Kase ot cleaning 14 lO.ft 



Low traction resistance 14 S.5 



Freedom from slippfiincss (aver- 

 age of condltious) 7 5.5 



Favorableness to tiavel' 4 2.5 



Acceptability^ 4 2.0 



Sanitary quality 13 9.0 



Total number of points 100 71.0 



.\verage cost per square yard 



laid, 1905' $3.26 



As- As- Creo- 



Sand- phalt pbalt Mac- soted 



stone, (sheet), block. Brick. adam. wood. 



17.5 



10.0 



14.0 



7.0 

 12.5 



14. U 

 6.0 



14.0 



73.5 76.0 79.5 74.5 55.0 80.0 



$3.50 ?2.30 $2.29 $2.06 $0.99 $3.10 



iFavorableness to travel is dependent chiefl 

 .V upon smoothness and freedom from dust and 

 mud, secondarily upon the qualities composing 

 -Acceptahility." 



^Acceptability includes noise, reflection of li 

 Sbt. radiation of heat, emission of unpleasant 

 odors, etc. It chiefly concerns the pedestrian a 

 nd the adjoining resident. 



'Cost per square yard includes concrete, but 

 not excavation, curbing, etc. ; except for mac- 

 adam, which Is not usually laid on concrete. 



Eeferring to the accompanying table, the 

 basis of judgment on "cost" should be the 

 returns upon total expense of a pavement 

 during its existence. For creosoted wood, the 

 first cost of which is high, any other method 

 of estimating is unfair, and reduces its 

 standing much below actual service value. 

 Disregarding cost, wood ranks very high in 

 every quality listed, except that it is more 

 slippery and estimated to be somewhat less 

 durable than a few others; however, it is 

 highest in all those qualities which contri- 

 bute to general acceptability. Moreover, the 

 values assigned by the engineers on durabil- 

 ity are generally based upon European ex- 

 perience and report, inasmuch as little of 

 the pavement in the United States has been 

 down long enough to determine its actual 

 endurance. However, in Baltimore in 1901 

 several strips of experimental pavement were 

 laid, including sheet asphalt, creosoted wood 

 and several kinds of brick. After five years' 

 service and the great fire, the wood was in 

 the best condition. After five years' use 

 asphalt and wood block, pavements ou Mich- 

 igan avenue, Chicago, were compared; the 

 latter had worn down only one-eighth of an 

 inch; the asphalt showed an average of one 

 inch; the wooden blocks remained smoother 

 and in all-around better condition. In 1902 



