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Mortars and concretes mixed with asphaltic oils
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TOPICS
Mortars and Concretes Mixed with Asphaltic Oils. A. TAYLOR and T. SANBORN. (P rot. Amer. Sot. Civil Eng., xxxix, 355.)-Page’s statements concerning oil-mixed concrete were subjected to a thorough investigation, and the following conclusions were reached as regards asphaltic oils: (I) Oil-mixed concrete containing 5, IO, or 15 per cent. of oil is more permeable under pressures of 20 to 60 pounds per square inch than ordinary concrete, and oil-mixed mortar containing IO per cent. of oil is more permeable than plain mortar under pressure of IO to 20 pounds per square inch. (2) O’Il- mixed mortars containing up to 25 per cent. of oil show slightly less absorption of water than plain mortar, except that with the most viscous oils the mortar becomes more absorptive, and absorption is not an index of the permeability. The absorption decreases with the increase in the quantity of oil. (3) froth the tensile and the crushing strengths of oil-mixed mortars are considerably less than those of plain mortars, the strengths decreasing with the increasing quantities of oil, and the progressive deterioration with increase of oil being more marked in the case of crushing than of tensile strengths. (4) The strength decreases with the viscosity of the oils, and with the most viscous oils it requires considerably more water to keep a mixture at the normal consistence than is required in the fluid oil mixtures. (5) The relative decrease in strength with increasing quantities of oil in mortars is less in 50 days than in 28 days. Density of Aluminum. F. J. RISLEE. (Faraday Sot., May 7, 1913.)-The density of aluminum varies considerably, according to the previous treatment, and under certain ‘conditions the density of the cast metal may exceed that of the worked metal, though the density of the worked metal increases again on annealing. The worked metal etched with hydrofluoric acid shows under the microscope a structureless surface, with flow lines in the direction of the work. Cast aluminum under similar conditions is very distinctly crystalline. Moulding Aluminum Alloys. ANON. (Bra,ss World, ix, 5, r68.)-For all aluminum alloys, both the light alloys in which aluminum is the chief constituent or aluminum bronzes, the moulding sand must be worked as dry as possible. Wet sand causes the metal to boil and thus produces dross. It is unnecessary to skin drv the mould, but the sand should be as dry as it can be worked and not rammed too hard. 229
TOPICS
Mortars and Concretes Mixed with Asphaltic Oils. A. TAYLOR and T. SANBORN. (P rot. Amer. Sot. Civil Eng., xxxix, 355.)-Page’s statements concerning oil-mixed concrete were subjected to a thorough investigation, and the following conclusions were reached as regards asphaltic oils: (I) Oil-mixed concrete containing 5, IO, or 15 per cent. of oil is more permeable under pressures of 20 to 60 pounds per square inch than ordinary concrete, and oil-mixed mortar containing IO per cent. of oil is more permeable than plain mortar under pressure of IO to 20 pounds per square inch. (2) O’Il- mixed mortars containing up to 25 per cent. of oil show slightly less absorption of water than plain mortar, except that with the most viscous oils the mortar becomes more absorptive, and absorption is not an index of the permeability. The absorption decreases with the increase in the quantity of oil. (3) froth the tensile and the crushing strengths of oil-mixed mortars are considerably less than those of plain mortars, the strengths decreasing with the increasing quantities of oil, and the progressive deterioration with increase of oil being more marked in the case of crushing than of tensile strengths. (4) The strength decreases with the viscosity of the oils, and with the most viscous oils it requires considerably more water to keep a mixture at the normal consistence than is required in the fluid oil mixtures. (5) The relative decrease in strength with increasing quantities of oil in mortars is less in 50 days than in 28 days. Density of Aluminum. F. J. RISLEE. (Faraday Sot., May 7, 1913.)-The density of aluminum varies considerably, according to the previous treatment, and under certain ‘conditions the density of the cast metal may exceed that of the worked metal, though the density of the worked metal increases again on annealing. The worked metal etched with hydrofluoric acid shows under the microscope a structureless surface, with flow lines in the direction of the work. Cast aluminum under similar conditions is very distinctly crystalline. Moulding Aluminum Alloys. ANON. (Bra,ss World, ix, 5, r68.)-For all aluminum alloys, both the light alloys in which aluminum is the chief constituent or aluminum bronzes, the moulding sand must be worked as dry as possible. Wet sand causes the metal to boil and thus produces dross. It is unnecessary to skin drv the mould, but the sand should be as dry as it can be worked and not rammed too hard. 229