ALTERING THE PROPERTIES OF CONCRETE BY ALTERING THE QUALITY OR GEOMETRY OF THE INTERGRANULAR CONTACT OF FILLER MATERIALS

• US 3,754,954 A
• Filed: 08/10/1971
• Issued: 08/28/1973
• Est. Priority Date: 08/10/1971
• Status: Expired due to Term

• Current Assignee: Lester H. Gabriel, Wilfred Willis
• Original Assignee: Lester H. Gabriel, Wilfred Willis
• Inventors: Gabriel, Lester H., Willis, Wilfred
• Primary Examiner(s): Poer, James E.
• Application Number:
  US05/170,490
• Time in Patent Office: 749 Days
• Field of Search: 106/97,98
• US Class Current: 106/674
• CPC Class Codes: C04B 20/0076 characterised by the grain distribution
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: C04B 38/08 by adding porous substances
• CPC Class Codes: C04B 40/00 Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability active ingredients C04B22/00 - C04B24/00; hardening of a well-defined composition C04B26/00 - C04B28/00; making porous, cellular or lightening C04B38/00; mechanical aspects B28, e.g. conditioning the materials prior to shaping B28B17/02

Abstract

A method for preparing and molding concrete so as to impart great strength per weight, minimize or otherwise alter shrinkage and creep, reduce porosity and give a superior as-molded surface. Aggregates are dry mixed with cement (or cement-filler mixture) in a preparation such that the bulk volume of dry cement (or cement-filler mixture) is approximately equal to the volume of void space which the aggregates would have if the cement were not present. A mold is filled with the resultant dry mixture, the ingredients of which are so proportioned that a particular geometry of particle contact is achieved upon compaction. The quality and geometry of this contact (coupled with the properties of the particular filler materials) determine the properties of the finished product. Then, with no disturbance to this compacted preordered structure of particle contact, water is injected and distributed by a self-metering process dependent upon capillary action which itself is dependent upon the geometry of particle contact. With the assistance or opposition of gravitational forces and with or without increased pressure differential, this water is introduced in a manner such that the water sweeps the air from the remaining voids and ejects that air into the atmosphere. The resultant wet, compact mixture is then cured in the mold or forms.

Claims

2. The concrete or mortar of claim 1 wherein all the aggregate in said concrete is fine aggregate.

3. The concrete or mortar of claim 1 containing a cure accelerator.

4. The concrete or mortar of claim 3 wherein said cure accelerator is calcium chloride.

5. Concrete having simultaneously greater strength per weight, low shrinkage, low porosity and a superior as-molded surface, comprising a cured compacted mixture of graded fine and coarse aggregates with hydrated cement in a preparation such that the amount of cement is approximately equal to and no greater than the amount of void space of the compacted fine aggregates, said cement being compacted to a density approaching a maximum for the dry state and being located almost entirely in the voids between said fine aggregate particles so that the fine aggregate particles bear substantially directly on other fine aggregate particles and the combined volume of said fine aggregate and cement being no less than the volume of the void space that would lie between the particles of said coarse aggregate were said coarse aggregate compacted by itself.

6. The concrete of claim 5 wherein one component of said aggregate is much lighter in weight than another component thereof and the lighter-weight component is small enough in particle size relative to the particle size of said other component so that the forces of apparent viscous drag in the fluid-like dry mixture of cement and aggregate from which said concrete is made exceed the apparent buoyancy forces In the dry mixture so that said dry mixture remains geometrically stable and is constrained when water is infused to convert said dry mixture to said concrete.

7. The concrete of claim 5 wherin one componet of said aggregate is much lighter in weight than another component thereof and the size and quantity of the lightweight component are such that as a consequence of proper compaction, it fits completely and for all time is constrained, within the void spaces of said other component, the quantity and proportion of said other component being such that the particles thereof touch each other in the completed mix.

8. A lightweight concrete having good strength, and good strength-weight ratio, comprising a mixture of cement and optimally graded aggregates, wherein one component of said aggregate is much lighter in weight and smaller in particle size than another component thereof, the lighter-weight component being small enough relative to the particle size of the other component so that the forces of apparent viscous drag in the fluid-like dry mixture of cement and aggregate from which said concrete is made exceed the apparent buoyancy forces in the dry mixture so that said dry mixture remains geometrically stable and is constrained when water is infused to convert said dry mixture to said concrete.

9. A lightweight concrete having good strength, and good strength-weight ratio, comprising a mixture of cement and optimally graded aggregates, wherein one component of said aggregate is much lighter in weight than another component thereof and the size and quantity of the lightweight component are such that as a consequence of proper compaction, it fits completely, and for all time is constrained, within the void spaces of said other component, the quantity and proportion of said other component being such that the particles thereof touch each other in the completed mix.

10. The lightweight concrete of claim 8 wherein said lighter-weight component consists of material chosen from the group consisting of foamed silica, foamed ceramic, foamed polystyrene, phenolic microballoons, sawdust, wood flour, cotton linters, and organic fibers.

11. The concrete or mortar of claim 1 wherein said cement contains filler consisting of particles in the order of less than one micron in diameter, said particles fitting within the voids between the particles of said cement, thereby reducing the porosity of the concrete or mortar.