Abstract: A coating for a reinforcing material, such as metal rebar, that increases the adhesion between the reinforcing material and a matrix, such as a cement-based mortar or concrete, in which the reinforcing material is embedded. The coating may comprise a glass frit mixed with a refractory material, such as dry Type I-II portland cement. The coating is bonded, typically by heat, to the surface of the reinforcing material. The reaction of the refractory component, e.g., portland cement, when the reinforcement, e.g., metal re-bar, is embedded in a matrix, e.g., fresh mortar or concrete, prevents the formation of soft precipitates at the interface of the matrix and its reinforcement. One coating comprises portland cement Type I-II combined with a commercial alkali-resistant glass frit. This coating is applied to a steel rebar and fired to bond to the rebar.

Abstract: A coating for a reinforcing material, such as metal rebar, that increases the adhesion between the reinforcing material and a matrix, such as a cement-based mortar or concrete, in which the reinforcing material is embedded. The coating may comprise a glass frit mixed with a refractory material, such as dry Type I-II portland cement. The coating is bonded, typically by heat, to the surface of the reinforcing material. The reaction of the refractory component, e.g., portland cement, when the reinforcement, e.g., metal re-bar, is embedded in a matrix, e.g., fresh mortar or concrete, prevents the formation of soft precipitates at the interface of the matrix and its reinforcement. One coating comprises portland cement Type I-II combined with a commercial alkali-resistant glass frit. This coating is applied to a steel rebar and fired to bond to the rebar.

Abstract: A method of coarse enameling material, such as the surface of conventional rebar, which increases adhesion between the surface and a matrix, such as a cement-based mortar or concrete, in which the material is embedded. In one embodiment, a glass fit is fired onto a surface to achieve an enamel finish, the finish is then cooled and heat softened. A refractory material, such as dry portland cement, is applied to the heat softened enamel, and the resultant coarse coating is then fired and cooled to produce a final hard coarse enameled surface. The reaction of the refractory component in the coarse enameled surface upon insertion in fresh mortar or concrete prevents the formation of soft precipitates at the interface of the cementitious matrix and the coarse-enameled reinforcement. One embodiment involves adding portland cement Type I-II to a softened glass frit as a final coating over an initial base coating that if fired on the steel to prevent corrosion of the underlying steel.

Abstract: High-flexural-strength concrete is produced by mixing wet hydraulic cement-sand mixture with coarse, flat, tabular aggregate, pouring the resulting mixture into a form in a shallow layer, vibrating the form containing the mixture, thereby orienting the coarse aggregate particles, pouring another shallow layer of the mixture into the form, again vibrating the form, and repeating these processes until the form has been filled to the desired level. The mixture then is allowed to cure. Cast-in-place items are prepared by placing thin layers or lifts of oriented, tabular-aggregate concrete into conventional forms and vibrating each lift using flat-plate vibrators.

Abstract: A low-temperature method for producing coated hazardous waste pellets which re used as the aggregate in a concrete wasteform is characterized by combining hazardous waste with a chemically setting organic polymer to form a mixture which is formed into pellets. The pellets are first coated with epoxy and then coated with a silicate-based powder. The liquid concrete-pellet mixture is then placed in molds which can be rotated to concentrate the pellets away from the perimeter of the wasteform. The double-coated hazardous waste pellets have improved bonding when used as a coarse aggregate in a concrete mixture. The resulting wasteform is self-supporting and needs no external container for transportation, storage, or disposal.

Abstract: A method of containing hazardous and toxic wastes includes the steps of irporating the dried waste, in a salt form, in melted polymer, such as asphalt, and forming the waste salt and asphalt blend into aggregate pellets. The pellets are coated with a powdered coating material that is compatible with a portland cement-based mortar or other cementitious material which is used. The coated particles are mixed with mortar to form a polymer-aggregate concrete and cast into wasteforms for storage or burial. If it is desirable to produce a waste form with a continuous layer of mortar on the exterior of the concrete monolith the mold can be placed on a turntable and spun, or otherwise exposed to a centrifugal force to force the mortar to the outside of the mold. Centrifugal separation is possible because the polymer-waste mixture typically has a specific gravity near 1.5 while that of the cementitious mixture is typically greater than 2.0.