초록 ▼

The addition of aqueous dilutions of a sulfonic acid source of 0.2% to 0.8% acid concentration to an aggregate or to a composition of asphalt and aggregate in hot asphalt plants enables a decrease in the amount of asphalt required in comparison to compositions not so treated while achieving comparab

The addition of aqueous dilutions of a sulfonic acid source of 0.2% to 0.8% acid concentration to an aggregate or to a composition of asphalt and aggregate in hot asphalt plants enables a decrease in the amount of asphalt required in comparison to compositions not so treated while achieving comparable strengths and durability when the composition is laid down as road paving material. The improved distribution of asphalt reduces usage by 10% to 40% and permits the incorporation of additional finely divided material to achieve higher strengths, or, inversely, to permit a higher percentage of voids to exist in the completed materials so as to provide for a porous paving material with suitable strength. The use of water in quantities of from 1,000 gallons to 3,000 gallons per 100 tons of aggregate and a sulfonic acid source in quantities of from 0.5 to 8 gallons per 100 tons of aggregate to provide an aggregate-acid-water composition having an initial pH of less than 3.5 makes possible a more economical operation of a hot mix plant, a better control over the quality of the end product, a reduction of the dust nuisance usually associated with such operations and a substantial extension of the use of available asphalt supplies. The use of sulfonic acid sources eliminates the need for adding various fluxing and reclamation agents, petroleum hydrocarbons, oils and asphalt as is standard practice in processes wherein existing asphaltic surfacing is being recycled or reused in hot mix plants, by heater planers and other standard roadbuilding and maintenance equipment as well as in the Mendenhall, Cutler and McConnaughay processes. By utilizing standard roadbuilding and maintenance equipment and supplemental sources of heat, any existing asphaltic surfacing, regardless of thickness or the extent of oxidation or deterioration, may be recycled in situ and reused entirely as new surfacing or, at the discretion of the engineer, used in part as valuable stabilizing material in the base. Paving asphalts may be applied to rock, gravel, sand and soils present in the road bed in conjunction with heat, hot water or steam and a sulfonic acid source so as to achieve compositions satisfactory for use as either paving materials or asphalt stabilized base.

대표청구항 ▼

A treated aggregate composition comprising an aggregate of stone and finely divided particles; water in an amount of at least 1000 gallons per 100 tons of aggregate and a sulfonic acid source selected from the group consisting of sulfuric acid sludge, spent sulfuric sludge, and spent sulfuric acid

A treated aggregate composition comprising an aggregate of stone and finely divided particles; water in an amount of at least 1000 gallons per 100 tons of aggregate and a sulfonic acid source selected from the group consisting of sulfuric acid sludge, spent sulfuric sludge, and spent sulfuric acid in an amount such that the pH of the composition is less than 3.5. A method of coating aggregate with asphalt to form an asphaltic concrete composition comprising contacting an aggregate of stone and finely divided particles with water in an amount of at least 1,000 gallons of water per 100 tons of aggregate, combining a sulfonic acid source selected from the group consisting of sulfuric acid sludge, spent sulfuric sludge, and spent sulfuric acid with said water to form a mixture of aggregate in an acid-water solution, said mixture having a pH less than 3.5, and combining asphalt with said aggregate in an amount sufficient to substantially completely coat said aggregate. Method of claim 29 wherein the sulfonic acid solution is at a temperature of at least 200°F.