The Bridgeport evening farmer., 1916-09-11


 The larger part of the material be- low No. 20 mesh and one-fourth (25 per cent.) of the No. 20 mesh ma terial, or 30 per cent. of the entire aggregate. is ordinary bank sand or fine stone dust, such as is used in all bituminous concrete mixtures. At least 25 per cent. appears to be or dinary sand. The percentage of arr tificially crushed stone in the aggre- gate below No. 20 mesh is difficult to determine in either Bitulithic or To- peka Whatever such percentage may be it appears to be counterbal- anced by the sand and gravel in the aggregate above No. 20 mesh.
 Using the figures of weights per square yard heretofore given. one square yard of pavement 2 inches thick would contain:
 Bitulithic. Sand and dust, 6S.t IDS; stone, 143.bs lbs.
 Topeka, Sand and dust 99.1 lbs; stone, 121.21 IDS.
 Excess sand in I yard of Topeka 30.3 lbs. El
 Excess stone in l yard of Bitu- lithic, 22.37 lbs. G
 Stone, such as is used by Warren Brothers Company, costs delivered in Boston approximately $1.50 per ton. Sand of good quality, suitable for bi- luminous pavement mixtures. costs about 70 cents per ton delivered. From these figures it is apparent that the cost of the mineral aggregate in Bit ulithic. and Topega is for purposes of comparison as follows:
 Bitulithic ......... .13.52 cts. sy. yd. ToYeka, .13.05 cts. sq. yd. Excess cost for Bit
 ulithic ..... ...... AT cts. sq yd.
 The dust for filler is included in these figures. Against this excess for the mineral aggregate of Bitulithic there should be taken into account the comparative cost of the asphalt content in the two mixtures.
 From the Columbia Road analysis. Bitulithic contains approximately |16.82 pounds of asphalt per square yard, costing about 1882 cents. To- peka contains approximately 22 lbs. of asphalt per square yard. costing about 22 cents, an excess cost for To- peka of 5.18 cents per square yard, or considering stone, sand and asphalt, an excess cost for Topeka materials of All cents per square yard over Bitu- lithic. The cost ot the seal-coat. if used, is the same in either case and so need not be considered here. The prices recently submitted for Topeka contemplated the use of a seal-coat. "2nd. As stone is more difficult to handle than is sand, the cost of labor in handling materials at the plant and laying on the street is at least twice as great in Bitulithic as in the other two pavements."
 Any reason fer this statement is diff ficult to imagine, as with the methods employed there is no apprectable diff ference in handling one material over another. Moreover for sheet asphalt as laid in two layers and requiring two operations for mixing and for placing and rolling, the cost of hand ling is of necessity much more than for either Topeka or Bitulithic. Even if the statement were true, the diff ference in the amount of stone be- tween Bitulithic and Topeka is so small as to make any increased ex- pense on that account infinitesimal
 "3rd. The cost of haul Is 50 per cent. greater in the case of Bitulithic because of additional weight of ma- terial moved"
 As already shown, there is no sub- stantial difference in the weight of the material, and in either case a team of horses can easily handle cartload of material; therefore this claim is not well founded.
 "4th. In Bitulithic pavement con- struction a flush-coat of Bituminous Cement and crushed stone is used, which adds materially to the cost and