The Montgomery advertiser., 1906-11-05

The following paper presented at meeting Of Alabama Good Roads Asso- ciation. Birmingham. by Edgar B. ay' of the Engineering Department, Uni versity of Alabama: to enter into detailed description of the occurrence of chert in Alabama, nor to discuss its physical propertaaeds building in the state but simply to call attention to a road material, 1ouh0 in inexhaustible supply within the what has been done, what may be done with this material which MT sam U: Lancaster says seems to have been been prepared in natures laboratory espe- cfaIly for road building.
 Chert As . Road Building Material
 Chert is found in the lower car doiomite of the Silurian. In the form CT 1t is generally in more or less regu- lar beds or sheets; in the latter, usual There are extensive chert quarries or banks in Alabama, near Florence. Fit. Payne. Birmingham. Leeds, Bessemer' Hnn,ssSn; ;sa snS tow9s. aeks0h fn the T Brmingham district, it is found overlying the red sandstone, which forms the covering, the pig vein of 3be red limestone. The chert of the sub-car- boniferous/ formation contains be- the bank chert is sometimes compare lively soft until # is spread pss on nettse tse roadway than the bard material The chert from the SGurian formation, IS harder and moSe expensive to quarry ,sri. snd does ss tS faom a the upper lorna tion. All. .xfie cherts of the State are easily --q1arried. however, by plastlns -and the Jumps reduced dr to bM proRel RSollinS' fe Chert is one of the hardest of rocks but 1t does not usually occur in cor con- T sidsrab,e npra GTantibsisst ebert Often grade m perceptibly into pure limestone. or beds, but Is generally mixed with more or less sandstone or limestone; ,;,sr so vhaI at cconchoidai fracture. and in color rang, es from pure white to black; neutral Mt,aa gray; brown s,ss orysetIy yeitIEw, in ouality and % ap pearance in it's natural beds. upon ex- posture becomes hard and tough. offer- fer rns elas AaDf%n ana iron oRide between the eleay age joints are easily s,u,as and crnships Sn9dp,y Sind together readily and make cheap roads that wear well and are smooth CT than roads built entirely Of lime l teriai to satisfy as many conditions; if not more than, any other materiai that
 s lsW g frst cost o r0as as t is easily mined The total cost on board cars al pits. in the Birmingham district does not exceed twenty-five cents per Sff requires no preparation. except breaking up of the larger masses which is usually done by roillhs or py mapping hammers: =. it IS more durable than any form of chert or macadam road. It.. f.
 ii produces a road surface, that Is su1oth. of considerable elasticity. but hard enough to have low trac-
 chert road does not rut under any condition of traffic An examination of fhe highways in Jefferson County Alabama. which have been built of chert, and were constructed over twenty years aFo, and many or then, that these roads are smooth and in have had practically no repairs.
 Chert does not produce slippery road surface. and it affords d good foothold to draw heavy loads.
 makes comDarativelv noiseless road and Yields neither dust nor mud
 It makes an impervious roadbed and being smooth drains rapidlY.
 Of light color, if does not absorb heat excessively The color of the surface is pleasing and does not pro- duce glare. where a good quality of bank gravel Is available for binder. it is not nec- eesary to go to the trouble and ex- pense of cutting out suh~rade" It is. however. essential that the surface course contains a sufficient ouantitv ot bond will soon be broken, the material