The Birmingham age-herald., 1914-11-08

| At the July, iJ14 meeting of the Amer l ican Society for Testing Materials, W. A. Aiken presented paper on "Blast Fur mace Slags as Aggregate in Concrete" |" He used a 1:2:4 mixture of standard Le- l high Valley, Portland cement, "Jersey gravel" sand, and %-inch crushed sag. | nodded into 800 6-inch cubes. Preliminary | tests had shown that slag was stronger | than stone and gravel. so 1t alone was used in the regular tests. Tabulated re- l suits follow:
 Compression tests on slx-inch slag-con- 1 crete cubes:
 Time. 2S days; tests. 100; general aver age cofnpressive strength pounds per l square inch, 1561; 73 per cent averaged | 153s; ? per cont below general average 29 per cent averaged 1730. Il per cent above general average; ' per cent averaged 1344, 1 Il per cent below general average. Time, 90 days; tests, 100; general aver age compressive strength, pounds per square inch 1852: 7S per cent averaged l 1922, per cent below general average; l 15 per cent averaged 21S5. 12 per cent above general average: per cent aver aged 1754, per cent below general ave- arge.
 Time, six months; tests. 100; general average, 25s9; 73 per cent averaged 25SS, same as the general average; IA per cent averaged 305S, IS per cent above general
 
 rer cent below general average. Time, nine months: tests, 100; general average compressive strength. pounds per suuarye inch, 2s41; 72 per cent averaged 2s74, 1 per cent above general average; 8 per cent averaged 1867. is per cent above general average; 20 per cent averaged 2514, 12 per cent below general average. Time, one year; tests, 100; general aver age compressive strength. pounds per square inch. 2797; S4 per cent averaged 2S12, 1 per cent above general average; 6 per cent averaged 534. 2s per cent above general average: 10 per cent averaged 2S42, Is per cent below general average
 The average weight of the concrete was 14e.S pounds per cubic foot. This test will be continued and 10 blocks crushed every six months for six years
 A continuous coating of cement Is a perfect protection of iron against cor rcsion. Unless both water and carbon die xide come in contact with steel there can be no rusting action.
 Structural iron buried in slag concrete for a score of years at Ensey. Ala, is found to be perfectly preserved. In the ruins of Pompeii, iron uncorpded, has been dug from the lava where it has been buried for centuries.
 Cement
 The trade recognizes three classes of hydraulic (hardens after mixing with water) cement: Portland, Natural and Puzzalon or slag.
 Slag Is used sometimes as part of Portland cement but this is not to be confounded with regular slag cement. The essential ingredients of hydraulic cements are calcium carbonate, silica and alumina. Basic slag sand Is dried. ground and.7 per cent of this added to 25 per cent screened freshly burnt lime makes mixture equal to Portland. Is lighter but does not set so quickly.
 Slag cement is especially applicable to sea wall construction. underground work, inside of dams, etc.
 Blocks, Brick, Rubber, Etc.
 Large hollow building blocks can be made on the site and of the following dimensions: S2. 24, 1s or 8 inchees long by inches high by 8, 10 or 12 inches thick. Blocks are also used for street paving.
 Bricks are made of 10 parts grant, lated slag to of lime. Where refractory material Is needed as in lime kilns. boiler furnaces. stacks and hot-blast stoves slag bricks can be used.
 They are manufactured extensively in Europe.
 Bubble consists of large pieces of slag set in cement. Due to its variety of colors and shapes, slag can be util- ized for striking architectural effects