Coated-fine-aggregate, concrete composition and method

• US 9,359,253 B2
• Filed: 07/01/2014
• Issued: 06/07/2016
• Est. Priority Date: 07/01/2014
• Status: Active Grant

• Current Assignee: AquaSmart Enterprises, LLC
• Original Assignee: AquaSmart Enterprises, LLC
• Inventors: Hendrickson, Calder
• Primary Examiner(s): CHIN, HUI H
• Application Number:
  US14/321,441
• Publication Number:
  US 20160002107A1
• Time in Patent Office: 707 Days
• Field of Search: 524/5
• US Class Current: 1/1
• CPC Class Codes: B01J 20/262 obtained otherwise than by reactions only involving carbon to carbon unsaturated bonds, e.g. obtained by polycondensation macromolecular compounds obtained otherwise than by reactions only involving unsaturated carbon-to-carbon bonds per se C08G
• CPC Class Codes: B28B 1/14 by simple casting, the material being neither forcibly fed nor positively compacted for molten material B28B1/54
• CPC Class Codes: B28B 17/02 Conditioning the material prior to shaping for mixtures containing clay or cement B28C
• CPC Class Codes: C04B 14/06 Quartz; Sand
• CPC Class Codes: C04B 16/04 Macromolecular compounds C04B16/02 takes precedence
• CPC Class Codes: C04B 20/1033 obtained by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: C04B 2103/0051 Water-absorbing polymers, hydrophilic polymers
• CPC Class Codes: C04B 24/287 Polyamides
• CPC Class Codes: C04B 28/02 containing hydraulic cements other than calcium sulfates
• CPC Class Codes: C04B 28/14 containing calcium sulfate cements gypsum-paper plates E04C
• CPC Class Codes: C04B 40/0633 Chemical separation of ingredients, e.g. slowly soluble activator
• CPC Class Codes: E04G 21/02 Conveying or working-up concrete or similar masses able to be heaped or cast in connection with finishing work E04F; construction and surfacing of floorings made of similar material to roads or pavements E01C; in connection with barrages E02B7/00; in connection with foundations E02D15/00; composition of concrete C04B; working concrete in general, e.g. mixing machines B28C

Abstract

A concrete composition and method include a portion of fine aggregate bearing a coating of a polymer, which may be a continuous coating layer or a layer of powdered, discrete particles embedded in a binder. The polymeric coating may be a super absorbent polymer (insoluble in water, but absorbing water), or another polymer such as the acrylamides, co-polymers thereof, polyacrylamides, or the like (soluble in water). The coating absorbs water, but particles are too small to form significant voids. Water is absorbed into the concrete mix in far greater proportions (e.g. w/c ratio over 0.5) improving workability, doubling workability time, and improving ultimate compressive stress (strength).

Claims

1. A composition comprising:

coarse aggregate comprising rocks of a comparatively larger size;

fine aggregate comprising granules of sand having an average maximum dimension substantially smaller than the coarse aggregate;

cement; and

polymer coated aggregate comprising a portion of the fine aggregate having the granules individually coated with discrete, individual, and discontinuous particles of a powder comprising a water-absorbing polymer.

2. The composition of claim 1, wherein the polymer coated aggregate constitutes less than about one tenth of the fine aggregate.

3. The composition of claim 2, wherein the powder is bound by a binder to the granules individually, as a substrate.

4. The composition of claim 3, wherein the powder comprises individual particles, each having an outer portion facing away from the substrate, and a contact portion in contact with at least one of the binder and the substrate, the outer portion remaining dry continually from before application to the substrate until mixing into the composition.

5. The composition of claim 4, wherein the powder is formed of a polymer selected from an acrylamide, an acrylamide co-polymer, a polyacrylamide (PAM), and a super absorbent polymer (SAP).

6. The composition of claim 5, wherein the cement is constituted in a fluid phase flowable to lubricate the coarse aggregate and fine aggregate, the cement and fine aggregate substantially filling interstitial space between the rocks of the coarse aggregate.

7. The composition of claim 5 further comprising a binder binding the contact portions of the powder to the substrate.

8. The composition of claim 7, wherein the polymer is water soluble and separable from the substrate by dissolving upon being hydrated by a portion of the water subsequently releasable by the polymer to provide at least one of additional water for workability, water for reaction of cement, water for reduction of surface shrinkage, and slowing of drying of the composition.

9. The composition of claim 8, further comprising, in cured state, voids created by dehydration of the granules and having an average maximum dimension sufficiently small to be effective to maintain strength properties effectively equal to those of the composition absent voids.

10. The composition of claim 1, wherein the proportions of constituents, proportioned in parts by weight, further comprise about two parts cement, about four parts fine aggregate, about four parts coarse aggregate, and about 1.5 parts water, wherein about ten percent of the fine aggregate further bears a coating of the polymer.

11. The composition of claim 1, constituted from parts proportioned by weight, wherein:

the cement constitutes an amount of from about one and a half to about two and a half parts;

the fine aggregate constitutes from about 3 to about 5 parts;

the coarse aggregate constitutes from about 3 to about 5 parts;

the water constitutes from about 1.25 to about 2 parts.

12. A method of combining constituents, the method comprising:

selecting a coarse aggregate comprising rocks of a comparatively larger size;

selecting a fine aggregate comprising granules of sand substantially smaller than the rocks;

selecting a cement;

selecting a polymer comprising a powder having particles, dry, discrete, and comminuted to a size smaller than the granules;

providing a coating comprising a dry dust of the powder adhered, as distinct and individual particles, by a binder to selected individual granules added in to become a portion of the fine aggregate;

mixing the constituents with water.

13. The method of claim 12, wherein:

the water, cement, and fine aggregate effectively completely fill interstitial space between the rocks of the large aggregate;

the coating is a hydrophilic material; and

the method further comprises casting the mixture into a restraint effective to mold the mixture to a shape.

14. The method of claim 13 further comprising:

providing, by the coating, water into the cement effective to maintain fluidity of the mixture for a period greater than one and a half hours; and

curing the constituents to a level of compressive strength undiminished by the water.

15. The method of claim 14, wherein the coating is a water soluble polymer separable from the granules by dissolving with the water, to an extent effective to extend the time to greater than 2 hours.

16. The method of claim 12 further comprising curing by the cement from a liquidous state to a solid state comprising voids created by a difference in volume between the particles containing absorbed water, and the particles dehydrated during curing.

17. The method of claim 16, further comprising providing by the polymer to the cement additional water for increasing the amount of chemical hydration reaction with the cement.

18. The method of claim 12, wherein the polymer is a water soluble, synthetic polymer.

19. The method of claim 18, wherein the synthetic polymer further dissolves proximate the granules sufficiently to separate from the granules during the mixing.

20. The method of claim 12, wherein the polymer is selected from polyacrylamide, a co-polymer of at least one of an acrylate, acrylic, and acrylamide, an acrylamide compound, and a super absorbent polymer.