Surface Seeded Fine Aggregate Concrete for Stone Aesthetics

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Solution Overview

Problem

Existing methods for producing exposed aggregate concrete surfaces, such as integrally and surface seeded methods, result in rough and jagged finishes that fail to mimic the aesthetics of marble, stone, or granite, and are limited by the alkali-silica reaction (ASR) which causes cracking and adhesion issues, especially when trying to achieve fine, medium, and coarse grain textures of natural quarried stone.

Innovation Solution

A surface seeded fine aggregate method that involves preparing a subgrade with moist fill sand and reinforcement, pouring a concrete mixture, and broadcasting fine sand or aggregate over 5% to 60% of the exposed surface, followed by mixing into the cement paste, applying a surface retarder, and forming a vapor barrier to achieve a smooth, durable, and aesthetically appealing surface that simulates quarried stone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If large aggregate (1/2 inch to 1 inch) is used in integrally exposed aggregate method, then aggregate exposure is achieved, but surface becomes extremely rough and jagged

Engineering Contradiction:

Improveaggregate exposureVSAvoidsurface flatness

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent changes the critical parameter of aggregate size from traditional large sizes (1/2 inch to 1 inch) to fine aggregate sizes (no larger than 3/8 inch, preferably no larger than 1/4 inch). This parameter change enables aggregate exposure while achieving a flat, smooth surface finish that resembles natural stone, resolving the contradiction between aggregate exposure and surface flatness.

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If aggregate size is reduced to achieve flatter surface, then surface flatness improves, but alkali-silica reaction (ASR) causes cracking and adhesion issues

Engineering Contradiction:

Improvesurface flatnessVSAvoidconcrete integrity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent introduces an intermediary substance - a liquid membrane-forming composition (retarder) - that is applied to the concrete surface before broadcasting fine aggregate. This intermediary layer prevents the alkali-silica reaction between alkalis in cement and silica in aggregate, eliminating cracking and adhesion issues while allowing fine aggregate to be used for achieving flat surfaces.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potentially harmful alkali-silica reaction into a beneficial outcome by using the liquid membrane-forming composition to control and direct the chemical interaction. The retarder allows controlled reaction that strengthens the bond between fine aggregate and concrete substrate while preventing harmful expansion and cracking.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Manufacturing precision

If fine aggregate is broadcast over entire surface, then complete coverage is achieved, but material usage and labor costs increase

Engineering Contradiction:

Improvesurface coverageVSAvoidmaterial efficiency

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent applies local quality by broadcasting fine aggregate selectively only in areas where stone-like appearance is desired (5% to 60% of the total surface area), rather than covering the entire surface. This localized application maintains the aesthetic effect while significantly reducing material consumption and labor costs.

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method produces a flat, durable surface that effectively mimics the textures and appearance of natural quarried stone, suitable for high traffic areas, while reducing the impact of ASR and minimizing material usage and labor costs by broadcasting materials over only a portion of the surface.

Implementation Method 1

a liquid membrane-forming composition is applied to the exposed surface of the concrete mixture to retard hydration of the cement

Methodology Applied

Scientific EffectHydration retardation:

Implementation Method 2

The aggregate or fine sand may be pneumaticaly broadcast over the exposed surface of the concrete mixture

Methodology Applied

Scientific EffectPneumatic transport:

Implementation Method 3

As the concrete cures, the aggregate becomes adhered to the top surface of the concrete

Methodology Applied

Scientific EffectCement hydration:

Data Source

PatentUS7607859B2Surface seeded fine aggregate concrete simulating quarried stone

Publication Date: 2009.10.27 SHAW CRAFTSMEN CONCRETE LLC

AI summary

A method of surface seeded fine aggregate to produce simulated quarried stone. The method comprises preparing a subgrade, pouring a concrete mixture over the subgrate, and broadcasting one of fine sand and aggregate over 5% to 60% of an exposed surface of the concrete mixture. Alternatively, both the fine sand and the aggregate can be broadcast over 5% to 60% of the exposed surface of the concrete mixture to obtain a desired aesthetic effect as provided by the quarried stone.