Alkali silica reactivity (ASR) resistant aggregate concrete

Abstract

Improved methods are provided for producing exposed aggregate concrete resistant to alkali silica reactivity. A concrete mixture is poured over a subgrade into a formwork. In a first embodiment, the concrete mixture includes a combination of lithium nitrate solution and concrete. In an alternative embodiment, the concrete mixture is a combination of concrete, aggregate and a lithium nitrate. Once the concrete mixture has been poured, the upper surface is floated or screed. Where aggregate has not been integrally mixed into the concrete mixture, the aggregate is surface seeded by broadcasting the aggregate upon the ASR resistant concrete surface. Thereafter, the concrete surface is troweled to embed the aggregate in the upper surface and provide a homogenous uniform surface. The aggregate is then exposed utilizing chemical retardants or mechanical apparatus.

Description

BACKGROUND OF THE INVENTION

The present invention relates to concrete construction and to methods for producing concrete constructions. Even more particularly, the present invention relates to aesthetic aggregate concrete constructions which are resistant to alkali silica reactivity (ASR).

Concrete is a well known building material for commercial and residential applications. Concrete is durable and has good weight resistance and excellent cost economy. More recently, concrete has become used more and more for horizontal surface applications, but also for other structural applications which are highly visible to the public. Because of its widespread use, it is desirable to provide the concrete with both color and surface enhancement. For example, it is well known to improve the aesthetics of concrete by providing a decorative aggregate finish.

A first method of preparing a decorative aggregate finish produces “integrally mixed decorative aggregate concrete”. The integrally mixed aggregate concrete is prepared by mixing, in other words, integrating, aggregate throughout the concrete slab. Thereafter, surface cement and fines are washed or removed from the concrete while the concrete surface is still in a plastic state so that the aggregate (such as stone, gravel or glass) is left exposed on the surface of the concrete. Alternatively, a topical surface retardant is applied so as to allow the top layer of the concrete to be removed. The normal size of the aggregate is typically less than 1.5 inches in mean diameter.

More recently, a surface seeded exposed aggregate method has been introduced. In this particular method, subsequent to pouring of the concrete, an aggregate is broadcast (also referred to as “seeded”) over the top surface of the concrete. Thereafter, the aggregate is troweled into the concrete so as to form a planar concrete upper surface. With the curing of the concrete, the previously broadcast aggregate is affixed in place but otherwise exposed. Preferably, the aggregate is nominally about 0.5 inch in diameter or less mean size such that the aggregate can be worked into the top surface and adequately affixed in place.

Several patents have been filed to surface seeded exposed aggregate concrete. U.S. Pat. No. 4,748,788 describes a method of creating a surface seeded aggregate concrete wherein aggregate is broadcast into a concrete surface. A surface retardant vapor barrier is applied and a surface retardant is sprayed upon and washed from the surface. U.S. Pat. Nos. 7,322,772 and 7,607,859 describe methods for producing a surface seeded aggregate concrete which is intended to simulate quarried stone. Allegedly, the methods described in these patents provide improved aesthetics. Still additional U.S. Pat. No. 7,614,820 describes a method for producing a non-slick surface seeded aggregate concrete. Thus, numerous attempts have been made to create surface seeded aggregate concrete with a variety of characteristics including improved aesthetics.

A problem with surface seeded exposed aggregate concrete has been the non-compatibility of placing certain materials in the concrete mixture as chemical reactions can occur which will degrade the surface. For example, silicious materials found in aggregates are well known to react with alkalis in Portland cement to create silicious gels which lead to expansion, cracking and exudations upon exposed surfaces. The reactivity of particulates in concrete is recognized as complex. For example, expansion resulting from reaction between aggregates and cement alkalis is believed increased with increases in cement content due to the greater abundance of available alkalis. For reactive aggregates, maximum expansion of concrete tends to increase as the particulate size of the reactive material decreases. It is thought that the expansion of aggregate and high-alkali cement may be lower if the aggregate is porous. In addition, some materials may be harmful for reasons other than reactivity with alkalis released during hydration of cement; for example, sulphates have been known to react with silicates of cement.

Traditionally, and currently, as a way to combat ASR, concrete mix designs utilize fly-ash or other natural Pozzolans in specific ratios/dosages to minimize the concrete destroying effects of ASR. Unfortunately, fly-ash or other natural Pozzolans also has its limitations. It can only reduce ASR to a limited extent and has limited applications. This is of particular importance when introducing, broadcasting or integrally combining potentially reactive elements, such as surface seeded aggregates (i.e. glass chips, shells, stone chips, etc.). Fly-ash and other natural Pozzolans are traditionally used as a cement substitute in a concrete mix. Fly-ash and other natural Pozzolans are a manufacturing by-product and as such is viewed by some as inferior to the use of real cement. For this reason, there are specific projects with state, city and local agencies that do not allow the use of fly-ash or other natural Pozzolans in any concrete mix designs on their projects or inside their respective jurisdictions as fly-ash is not true cement and they require 100% cement and no fly-ash or other natural Pozzolans substitutions in their concrete mixes.

Additional attempts have been made to overcome the harmful effects of the chemical reactions between the concrete and aggregates. For example, U.S. Pat. No. 6,033,146 describes methods of reducing the harmful reaction between the concrete and aggregates by applying a surface sealant of a hydrolyzed alkali silica solution, preferably hydrolyzed lithium quartz, as a surface sealant. The methodology allegedly provides proper adherence of small particulates on the surface of the concrete, and reduces ASR effects in the surface of the placed concrete structure.

Unfortunately, the methods described in U.S. Pat. No. 6,033,146 suffer from significant problems. Perhaps foremost is that the method described in U.S. Pat. No. 6,033,146 is completely inoperable. Specifically, the described method requires that a hydrolyzed alkali silica solution be applied so as to penetrate only to the depth of the surface concentrated particulate and cement/fines concrete paste. Unfortunately, it is presently impossible to apply a hydrolyzed alkali silica solution to concrete and determine the depth that the solution has penetrated. Thus, one cannot tell if the applied solution has penetrated insufficiently or excessively.

Moreover, application of the hydrolyzed alkali silica solution is accomplished using a brush or sprayer, but it is very difficult, if not impossible, to apply a hydrolyzed alkali silica solution to concrete in a perfectly uniform manner. This leads to the concrete surface having uneven treatment and a resulting uneven reduction of the harmful reaction between the concrete and aggregates. This topical application of a hydrolyzed lithium quartz solution is further flawed in that it only minimizes ASR effects in the surface of the concrete structure to an unknown depth and ASR is known to occur throughout an entire concrete structure. There are also other ways for the topically applied lithium quartz solution to be defeated such as cracking of concrete and chipping of concrete from incidental damages allowing a portion of the surface to be unprotected and allow an ASR condition to form and spread.

Thus, there is a significant need for a process for uniformly reducing the harmful reaction between concrete and aggregates throughout the concrete structure.

SUMMARY OF THE INVENTION

The present invention addresses the aforementioned disadvantages by providing an improved method of producing alkali silica reactivity (ASR) resistant seeded concrete. The first step of the present method comprises preparing a subgrade formwork for concrete placement. The term subgrade is to be interpreted broadly to include the preparation of the ground, introduction of a steel pan for placement of concrete, or the construction of any other type of formwork for receipt of a concrete mixture. Preferably, though not necessary, the subgrade is covered with a layer of fill sand and reinforcement members, such as rebar, are introduced into the subgrade to provide additional structural stability and strength.

An ASR resistant concrete mixture is prepared by mixing a lithium solution (preferably 5-50% lithium nitrate solution) with concrete. The preferred lithium solution is 30% lithium nitrate solution wherein at least two gallons of the 30% lithium nitrate solution are mixed with each cubic yard of concrete. Even more preferably, three to five gallons of 30% lithium nitrate solution is introduced for each cubic yard of concrete mix. Preferred lithium nitrate solutions include Rasir from Grace Constructions, Control ASR from Fica, and Eukon Integral ARC from Euclid Concrete Admixtures.

In a first preferred embodiment of the invention, the ASR resistant concrete mixture, preferably consisting of at least 5.5 sacks of cement content per cubic yard, is poured over the subgrade to a desired concrete slab thickness. After pouring the ASR resistant concrete, but while the ASR resistant concrete is in a plastic state, the surface of the concrete is “floated” utilizing steel, aluminum, wood, fiberglass and magnesium bull-float tools. Preferably, the ASR resistant concrete surface is reviewed and confirmed to comply with Americans with Disabilities Act (ADA) compliance. Where the ASR resistant concrete pour results in a surface having a large square footage, preferably various screeds such as laser screeds, roller screeds, Texas screeds, laboratory floats, or troweling machines are utilized to modify the ASR resistant concrete surface.

After the ASR resistant concrete surface has been floated or screed to a desired uniform and consolidated condition, but while the ASR resistant concrete surface is still in a plastic state, selected aggregates are then broadcast onto the surface of the ASR resistant concrete. The aggregates may be any type as can be selected by those skilled in the art such as glass, seashells, stone materials, metals, etc. As understood by those skilled in the art, each of these materials have varying degrees of reactivity to the alkalis typically found in concrete. The aggregate may be broadcast utilizing a variety of broadcasting methods including hand broadcasting, mechanical broadcasting or pneumatically distributing the aggregate to a desired concentration per square footage.

Once the aggregate has been broadcast to a desired coverage into the ASR resistant concrete, the concrete surface is again re-troweled to fully work the aggregate into the concrete slab to ensure full embedment of the aggregate. Alternatively, float tools may be employed to work the aggregate into the concrete slab for proper embedment.

Thereafter, the aggregate is exposed so as to be visible upon the concrete upper surface. Exposure of the aggregate can be accomplished by a variety of processes known to those skilled in the art such as utilizing a concrete surface retardant in accordance with manufacturer's recommendations and instructions. Alternatively, the aggregate can be exposed within the concrete upper surface by utilizing abrasive mechanical apparatus such as brushes, sponges, rotaries, abrasive machines or media blasting (such as sand blasting) to remove the upper layer of the concrete upper surface. Furthermore, when employing mechanical apparatus to expose the aggregate, an acid solution may be employed to remove the upper portion of the concrete to expose the seeded aggregate. Once the aggregate has been exposed, preferably the upper ASR resistant surface is washed to remove any surface contaminants and the concrete surface is allowed to dry.

In still an additional embodiment of the present invention, the ASR resistant aggregate seeded concrete is prepared as described above; however instead of surface seeding the aggregate upon the concrete's upper surface after the ASR concrete mixture has been poured, the aggregate is mixed with the concrete and lithium solution prior to the ASR resistant concrete being poured over the subgrade or formwork. Thus, instead of simply pouring a concrete lithium solution admixture upon a subgrade or formwork, an ASR resistant aggregate concrete mixture is poured upon the subgrade or formwork. Once poured, this embodiment still includes the steps of troweling or floating the aggregate into the concrete's upper surface and exposing the aggregate within the concrete's upper surface. Preferably, the upper surface is sealed with a concrete sealant.

Advantageously, the ASR resistant aggregate concrete does not suffer the disadvantages of topical treated concrete. For example, any surface damage, such as a chipped surface, will not expose an underlying untreated potentially ASR eroding subsurface. Moreover, the practice of the present invention does not require application of a topical solution to a depth which can not be applied uniformly or measured for compliance. Instead, the integral lithium concrete admixture provides a homogenous structure for protection against ASR eroding effects.

The use and other features and advantages of the present invention will be appreciated by those skilled in the art from the following detailed description taken in conjunction with the drawings.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is schematic flow chart of a first embodiment of the method of producing an alkali silica reactivity (ASR) resistant aggregate seeded concrete of the present invention;

FIG. 2 is a schematic flow chart of the second embodiment of the method of producing an alkali silica (ASR) resistant integral aggregate concrete of the present invention; and

FIG. 3 is a cross-sectional view of the various layers of an alkali silica reactivity (ASR) resistant seeded concrete.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1 and 3, a first method of producing an exposed aggregate concrete resistant to alkali silica reactivity 1 comprises the initial step 10 of preparing a subgrade or formwork for concrete placement. It is envisioned that the present invention will most often require the preparation of the subgrade for creating substantially horizontal surfaces such as for walkways, driveways and the like. However, the present invention has application for producing partially vertical or substantially vertical concrete surfaces such as walls, signs, seat-walls, water fixtures, etc. Where a vertical concrete construction is required, a traditional formwork utilizing wood, steel or other materials is assembled to create an envelope for the receipt of a concrete mixture. The term formwork, also commonly referred to as a framework, is intended to be interpreted broadly to also include steel pans and the like. A typical subgrade 2 is prepared to desired elevation and grade. Preferably, the subgrade is compacted to a desired compaction, such as a 90%. Thereafter, the subgrade is preferably, though not necessarily, covered with a layer of fill sand 3. It is also preferred, though not necessary, that reinforcement members 5 be introduced into and/or upon the subgrade 2 and fill sand 3. The reinforcement members 5 may include wire mesh, rebar, integral fibermesh or the like so as to increase the resulting strength of the concrete slab. As illustrated in FIG. 1, the addition of fill sand 20 and the introduction of reinforcement members 30 are considered optional steps in the process of creating the alkali silica reactivity resistant concrete of the present invention.

As reflected in step 40 shown in FIG. 1, the present invention requires the preparation of an ASR resistant concrete mixture. The ASR resistant concrete mixture is prepared by mixing a liquid lithium solution with concrete. Preferably, the concrete consists of at least 5.5 standard sacks of cement content per cubic yard. Preferably, the lithium solution is a 5-50% lithium nitrate solution wherein two to eight gallons of such lithium nitrate solution are all mixed within each cubic yard of concrete. As understood by those skilled in the art, wherein the lithium nitrate solution is of a greater concentration, less volume is required for mixing with the concrete. For example, two gallons of a 30-50% lithium nitrate solution is likely sufficient for each cubic yard of concrete. However, eight or more gallons of a 5% lithium nitrate solution would be required for each cubic yard of concrete to adequately resist alkali silica reactivity, depending on the reactivity of the concrete material and aggregates to be employed. In a preferred embodiment, two to five gallons of about 30% lithium nitrate solution are mixed within each cubic yard of concrete. Even more preferably, about three gallons of 30% lithium nitrate solution are mixed within each cubic yard of concrete.

Once the reinforcement members have been positioned in place, the ASR resistant concrete mixture 4 is poured 40 over the prepared subgrade 2 or within the constructed formwork to a desired concrete slab thickness. Still with reference to FIG. 1, after the concrete mixture has been poured, preferably the concrete surface is “floated” or “screed” 50 to a desired level plane or grade. Preferably, the surface of the concrete is floated utilizing steel, aluminum, wood, fiberglass or magnesium concrete bull-float tools. Where the concrete slab has a large square footage, the use of hand floats may be abandoned and instead more efficient screeds including laser screeds, roller screeds, Texas screeds, floats, or manually pushed or motorized finishing machines may be utilized depending on the concrete surface.

Preferably, though not necessarily, the concrete upper surface is troweled 70. The troweling 70 of the concrete is intended to create a substantially homogenous concrete surface having a substantially uniform finish. Once troweled, it is preferred that the concrete surface 7 be checked for ADA code compliance. While the ASR resistant concrete is still in a plastic state, a quantity of aggregate is broadcast 80 onto the concrete surface until the coverage of aggregate is uniform to a desired ratio of aggregate to concrete. Various aggregates may be utilized such as coarse sand, glass chips, organic material such as seashells, metals or composite materials. It is preferred that the aggregate have a mean diameter of 0.5 inch or less. Importantly, each of the identified aggregate materials is reactive to some extent to traditional concrete. However, as a result of the introduction of the lithium nitrate solution into the concrete, the reactivity is greatly reduced or eliminated.

After the aggregate has been broadcast upon the ASR resistant concrete surface 80, the surface is again re-troweled 90 to fully seed and work the aggregate 6 into the concrete slab to create a uniform and homogenized surface with embedment of the aggregate into the concrete to form a substantially planer concrete surface. As an alternative to traditional troweling, float tools may be utilized to float the aggregate into the concrete upper surface to provide a homogenous and planer concrete surface.

As illustrated in step 100 of FIG. 1, once the introduction of aggregate has been completed and the concrete's surface has been troweled or floated, the aggregate 6 is exposed. Exposure of the aggregate may be accomplished utilizing any of numerous methods known to those skilled in the art such as the utilization of either surface retardant or chemical exposure methods. When utilizing a concrete surface retardant, a preferred surface retardant such as Grace Constructions Top-Cast™ is applied in accordance with the manufacturer's specifications to the ASR resistant concrete surface 7. Once the retardant has dried, which typically requires one to two hours, the retardant is removed utilizing water such as by using a pressure washer. As the surface retardant is removed, the retardant removes the upper layer of the concrete slab to expose the seeded ASR resistant concrete upper surface.

As an alternative to utilizing a concrete surface retardant to expose the aggregate 100, mechanical exposure may be accomplished utilizing brushes, sponges, rotary flooring machine with abrasive pads, and handheld power tools with abrasive pads, or media blasting such as sand blasting. Mechanical exposure may include application of an acid solution to remove the upper portion of the concrete to expose the seeded aggregate. Like the method of utilizing a concrete surface retardant, mechanical exposure methods remove an upper layer of the concrete slab. Advantageously, mechanical exposure methods can be utilized both the same day of concrete placement or in subsequent days after the concrete has hardened.

After exposure of the aggregates within the ASR resistant concrete surface, surface contaminants are removed by washing the concrete surface 110 utilizing a pressure washer, hose, scrub brushes, or cleaning machines, etc. Preferably, the surface is then allowed to dry overnight and a seal is applied 120 to the concrete surface. Various concrete sealants can be selected and utilized as can be determined by those skilled in the art so as to protect the ASR resistant concrete surface from the elements such as weather and traffic. A preferred sealant includes Floric Polytech-101 which is a single component solvent acrylic based sealant. Water based sealants can also be utilized in environmentally sensitive areas. It is preferred that the sealant be applied 120 utilizing sprayers in accordance with manufacturer's recommendations. Typically, a sealant is applied utilizing an airless high volume low pressure (ACLP) sprayer or roller or the like. It is preferred that adjacent surfaces be protected against over spray and that the sealant be applied at a rate of approximately 250 square feet per gallon. Anti-slip additives may be added to the sealant mixture if an increase in the coefficient of friction is desired or required for ADA code compliance.

Various modifications may be made within the scope of this invention. For example, with reference to FIGS. 2 and 3, in an alternative embodiment of the invention, the aggregate is mixed integrally with the lithium nitrate solution and concrete prior to the ASR resistant concrete being poured upon the subgrade and formwork. Of course for this embodiment, the aggregate is not broadcast upon the concrete upper surface. In this embodiment illustrated in FIG. 2, the method of creating an integrally mixed exposed aggregate concrete resistant to alkali silica reactivity includes the same initial step 10 of preparing a subgrade or formwork for concrete placement. The subgrade 2 is preferably covered with a layer of fill sand 3 in step 220. Thereafter, reinforcement members 5 such as wire mesh, rebar, integral fibermesh or the like, are introduced 230 into or upon the subgrade and fill sand.

As illustrated in step 240 in FIG. 2, for this embodiment the ASR resistant concrete mixture is prepared by mixing concrete, aggregate and a liquid lithium solution. As described above, the lithium solution is preferably lithium nitrate wherein two to eight gallons of 5-50% lithium nitrate liquid solution are mixed within each cubic yard of concrete. Even more preferably, the integrally mixed ASR resistant concrete mixture includes two to five gallons of about 30% lithium nitrate solution within each cubic yard of concrete.

Prior to pouring the concrete, the aggregate is mixed within the concrete and lithium nitrate solution in an amount to provide the desired aesthetics, as can be determined by one skilled in the art. Though this method requires substantially more aggregate than simple surface seeding of aggregate upon an upper surface of the concrete surface, the additional cost of mixing the aggregate throughout the entire concrete slab may be minimal where the concrete slab is not particularly thick. Still with reference to FIG. 2, once the ASR resistant aggregate concrete mixture has been prepared, it is poured 250 so as to create a concrete slab of desired thickness. Preferably, the ASR resistant integrally mixed aggregate concrete surface is “floated” or “screed” 260 to a desired level plane or grade. Thereafter, the upper surface is troweled or floated to create a uniform and homogenized surface 290.

Once in a uniform state, in step 300, the aggregate is exposed by utilizing concrete surface retardants or abrasive mechanical apparatus. Once the aggregate has been exposed 300, the ASR resistant surface is washed 310 to remove any surface contaminant. Once dry, the surface may be sealed by applying a sealant 320.

The present invention provides for both a method of creating a surface seeded exposed aggregate concrete resistant to ASR as well as a method of creating an integrally mixed exposed aggregate concrete resistant to ASR. While several particular forms of the invention have been illustrated and described, it will be apparent that various modifications can be made without departing from the spirit and scope of the invention. Therefore, it is not intended that the invention be limited except by the following claims. Having described my invention in such terms as to enable a person skilled in the art to understand the invention, create the invention, and practice it, and having presently identified the presently preferred embodiments thereof, I claim:

Claims

1. A method of creating a surface seeded exposed aggregate concrete resistant to alkali silica reactivity, the method comprising: (a) preparing a subgrade or formwork for concrete placement;(b) preparing an integral alkali silica reactivity resistant concrete mixture by mixing a lithium nitrate solution with concrete in a ratio of two (2)-eight (8) gallons of 5-50% lithium nitrate solution with each cubic yard of concrete;(c) pouring the alkali silica reactivity resistant concrete mixture upon the subgrade or within the formwork to create an exposed concrete surface;(d) floating, screeding or troweling the concrete surface utilizing bull floats, screeds or trowels so that the concrete surface is consolidated and uniform, while in a plastic state;(e) broadcasting an aggregate reactive to concrete upon the concrete surface;(f) mixing the aggregate into the concrete surface by troweling or floating the aggregate into the concrete surface; and(h) exposing the aggregate within the concrete surface by either (1) applying a concrete surface retardant, allowing the retardant to retard hardening of a layer of the concrete, and washing away the surface retardant with water, or (2) mechanically exposing the aggregates utilizing abrasive mechanical apparatus to remove a surface layer of the concrete surface.

2. A method of creating a surface seeded exposed aggregate concrete resistant to alkali silica reactivity of claim 1 wherein the step of preparing an integral alkali silica reactivity resistant concrete mixture includes mixing a ratio of two (2)-five (5) gallons of about 30% lithium nitrate solution with each cubic yard of concrete.

3. A method of creating a surface seeded exposed aggregate concrete resistant to alkali silica reactivity of claim 1 wherein the step of preparing an integral alkali silica reactivity resistant concrete mixture includes mixing more than three (3) gallons of about 30% lithium nitrate solution with each cubic yard of concrete.

4. A method of creating a surface seeded exposed aggregate concrete resistant to alkali silica reactivity of claim 1 wherein the aggregate includes seashells, stone, or glass.

5. A method of creating a surface seeded exposed aggregate concrete resistant to alkali silica reactivity of claim 3 wherein the aggregate includes seashells, stone, or glass.

6. A method of creating an integrally mixed exposed aggregate concrete resistant to alkali silica reactivity, the method comprising: (a) preparing a subgrade or formwork for concrete placement;(b) preparing an integral alkali silica reactivity resistant aggregate seeded concrete mixture by mixing: 1) a lithium nitrate solution, 2) an aggregate reactive to concrete, and 3) concrete, and wherein the ratio of lithium nitrate solution to concrete is two (2)-eight (8) gallons of 5-50% lithium nitrate solution with each cubic yard of concrete;(c) pouring the concrete mixture upon the subgrade or within the formwork to create a concrete surface;(d) floating, screeding or troweling the concrete surface utilizing bull floats, screeds or trowels so that the concrete surface is consolidated and uniform, while in a plastic state; and(e) exposing the aggregate within the concrete surface by either (1) applying a concrete surface retardant to the concrete surface, allowing the retardant to retard hardening of the layer of the concrete, and washing away the surface retardant with water, or (2) mechanically exposing the aggregates utilizing abrasive mechanical apparatus to remove a surface layer of the concrete surface.

7. A method of creating an integrally mixed exposed aggregate concrete resistant to alkali silica reactivity of claim 6 wherein the step of preparing an integral alkali silica reactivity resistant concrete mixture includes mixing a ratio of two (2)-five (5) gallons of about 30% lithium nitrate solution with each cubic yard of concrete.

8. A method of creating an integrally mixed exposed aggregate concrete resistant to alkali silica reactivity of claim 6 wherein the step of preparing an integral alkali silica reactivity resistant concrete mixture includes mixing more than three (3) gallons of about 30% lithium nitrate solution with each cubic yard of concrete.

9. A method of creating an integrally mixed exposed aggregate concrete resistant to alkali silica reactivity of claim 6 wherein the aggregate includes seashells, stone, or glass.

10. A method of creating an integrally mixed exposed aggregate concrete resistant to alkali silica reactivity of claim 8 wherein the aggregate includes seashells, stone, or glass.