US Government As Represented by the Secretary of the Army

USA As Represented by Secretary of the Navy

Judy C Tom

Philip Garcin Malone

Melvin C Sykes

William N Brabston

Dennis L Bean

Lillian D Wakeley

Donald M Walley

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.

Use of oriented tabular aggregate in manufacture of

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.

Low-temperature method for containing thermally degradable hazardous

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.

Method of containing and isolating toxic or hazardous wastes

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Vicksburg, MS, United States of America

Judy C Tom