Carbon Capture System and Method for Synthetic Turf Fields

The application claims priority to and the benefit of U.S. Provisional Patent Application No. 63/638,100, filed on Apr. 24, 2024, entitled “Carbon Capture System and Method for Synthetic Turf Fields”, which we incorporate by reference in its entirety.

Synthetic or artificial turf fields are composed of three primary components—from bottom to top: Shock pad, carpet, and infill. These components are generally assembled on top of a base of compacted stone. The shock pad is optional and serves to convey much of the shock absorption performance of the turf field, required for the safety of those playing on the surface in the case of impact with the surface. The carpet serves to mimic the blades of grass and root zone, conveying the softness and traction of the surface as well as many of the ball interaction properties. The infill is generally constituted of at least two layers, the bottom layer of which serves to weight down and stabilize the carpets that it is laid onto, whereas the top layers serve as an additional interface layer to those playing on the field, conveying surface softness, friction, traction, and much of the mechanical properties of the field that are felt directly by the players.

When installation of a synthetic turf field occurs, generally speaking, a living, natural turf field is being replaced with an artificial one. In this process, a living organism, e.g., grass, plants, etc., which naturally removes carbon dioxide from the atmosphere is removed. Additionally, the construction associated with a synthetic turf field, as well as the actual manufacturing of the synthetic turf, result in additional carbon entering the atmosphere.

The following presents a simplified summary to provide a basic understanding of some aspects of the disclosed subject matter. This summary is not an extensive overview. It is not intended to identify key/critical elements or to delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description presented later.

There remains a need for environmentally friendly and ultimately carbon-neutral or carbon-offsetting materials that present good mechanical properties and mechanical resistance, while presenting high availability, easy transportation, and low cost.

In aspects, a rock dust-based layer may be positioned immediately below the installation of an synthetic turf system, e.g., below a shock pad, on a top substrate material, e.g., a rock layer. In such a position, the rock dust-based layer may have a thickness of ⅛″ to ¼″.

In still other aspects, rock dust-based particles may be blended into a 1″ to 2″ topping stone layer positioned immediately below the shock pad.

In yet another aspect, a layer of rock dust-based particles may be positioned on a geotextile or subgrade layer. In such a position, the rock dust-based layer may have a thickness of ¼″ to ½″.

In another aspect, a rock dust-based material may be positioned at a bottom of a subdrain trench, below a layer of geotextile fabric.

In a further aspect, rock dust-based particles may be tilled or blended into native subgrade material. In such a position, the rock dust-based particles may be blended within the subgrade, e.g., soil, as discussed below.

In another aspect, a synthetic turf system includes a backing, turf fibers extended upward from the backing, and one or more infill layers positioned above the backing, below a top portion of the turf fibers. The one or more infill layers includes rock dust, or the synthetic turf system further includes a layer of the rock dust disposed above or below the one or more infill layers. The rock dust is accessible to rainwater from the top portion of the turf fibers, where the rainwater and the rock dust chemically react with each other, forming a carbonate or a bicarbonate.

In another aspect, infill for a synthetic turf system includes rock dust. The rock dust includes silicate rock, igneous rock, or reactive rock that forms a carbonate or bicarbonate with rainwater. At least 90 percent of the rock dust has a particle size less than 250 micrometers. Organic particles, rubber particles, elastomer particles, coated particles, or thermoplastic particles blended or layered with the rock dust in one or more infill layers.

In another aspect, a method of preparing a synthetic turf system includes dispersing rock dust over a top portion of turf fibers. The rock dust includes silicate rock, igneous rock, or reactive rock that forms a carbonate or bicarbonate with rainwater traveling through one or more infill layers.

In each of the foregoing aspects, certain carbon sequestration processes can occur as rainwater interacts with the rock dust-based particles, regardless of the position in the synthetic turf system. Further discussion of the processes referenced above are included in the following description.

To the accomplishment of the foregoing and related ends, certain illustrative aspects of the claimed subject matter are described herein in connection with the following description and the annexed drawings. These aspects indicate various ways in which the subject matter may be practiced, all of which are intended to be within the scope of the disclosed subject matter. Other advantages and novel features may become apparent from the following detailed description when considered in conjunction with the drawings.

These and other systems, methods, objects, features, and advantages of the present disclosure will be apparent to those skilled in the art from the following detailed description of the preferred embodiment and the drawings.

All documents mentioned herein are hereby incorporated in their entirety by reference. References to items in the singular should be understood to include items in the plural, and vice versa, unless explicitly stated otherwise or clear from the text. Grammatical conjunctions are intended to express any and all disjunctive and conjunctive combinations of conjoined clauses, sentences, words, and the like, unless otherwise stated or clear from the context.

Various aspects of the subject disclosure are now described in more detail with reference to the annexed drawings, wherein like numerals generally refer to like or corresponding elements throughout. It should be understood, however, that the drawings and detailed description relating thereto are not intended to limit the claimed subject matter to the particular form disclosed. Instead, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the described and claimed subject matter.

The following disclosure provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.

Numerical values in the specification and claims of this application should be understood to include numerical values which are the same when reduced to the same number of significant figures and numerical values which differ from the stated value by less than the experimental error of conventional measurement technique of the type described in the present application to determine the value. All ranges disclosed herein are inclusive of the recited endpoint.

The term “about” can be used to include any numerical value that can vary without changing the basic function of that value. When used with a range, “about” also discloses the range defined by the absolute values of the two endpoints, e.g., “about 2 to about 4” also discloses the range “from 2 to 4.” For example, the term “about” may refer to plus or minus 10% of the indicated number.

In accordance with some aspects described herein, there is provided an synthetic turf system that utilizes a material derived from one or more types of rock dust, including, for example and without limitation, basalt rock dust, igneous rock dust (such as andesite, diorite, gabbro, or rhyolite), limestone-derived dust (such as calcium carbonate-based materials), dolomitic lime (CaO/MgO), ultramafic rock dust (such as peridotite or dunite), industrial byproducts containing reactive silicates or carbonates, a blend of various types of rock dust, combinations thereof, or other similar mineral-based particulate materials. In some embodiments, the rock dust may be used as an intervening layer of material between existing layers of the system, mixed within a particular layer, lining a subdrain trench, on or mixed within a substrate, or combinations thereof. It will further be appreciated that as the rock dust is a natural byproduct of the mining industry, there is no additional carbon footprint from mining.

In some embodiments contemplated herein, the rock dust material, when in contact with rainwater, causes a chemical reaction to occur between carbonic acid naturally present in the rainwater and the rock dust. The reaction weathers the rock dust and converts the carbonic acid into a carbonate or bicarbonate. By converting the carbon dioxide into other substances, the carbon dioxide can no longer be released into the atmosphere. Further, the conversion of the carbonic acid has a de-acidifying effect on soils, storm water, rivers, and oceans, simultaneously enriching them with mineral nutrients. These carbonate or bicarbonate substances are carried by rivers to the sea, where they are ultimately deposited as limestone and dolomites, e.g., carbonate sediments. These carbonate sediments form a sink for carbon dioxide.

Turning now to, there is shown a three-dimensional cross-sectional view of a portion of an synthetic turf systemutilizing rock dustfor carbon sequestration in accordance with an example implementation of the embodiment described above. As shown in, the synthetic turf systemincludes one or more infill layers, a backing, and a plurality of turf fibersthat emulate grass blades extending substantially perpendicularly upwards relative to the backing. As such, the infill layersare positioned above the backing, in between the turf fibers, and below a top portionof the turf fibers.

Infill, as shown in, is representative of material that is deposited directly on top of the backingand forms the infill layersaround the turf fibers. Infill is interspersed between the turf fibers, rising out of the backing. As depicted, the infill layershave a total depth that covers a portion of the turf fibers, leaving at least part of the top portionexposed and extending above the infill layers.

In accordance with some embodiments, the infill layersassist in supporting the turf fibersin an upright position from the backing, and provide traction and shock absorption. As a general matter, various types of infill arrangements are contemplated. In this regard, the one or more infill layersmay be a single homogeneous or graded layer, or a plurality of distinct layers. For example, two layer, three layer, or other further layered arrangements of the one or more infill layersare contemplated. For convenience, the present description primarily discusses two and three layer embodiments.

In some embodiments, a first layerof infill material may include, for example and without limitation, styrene-butadiene rubber (SBR) particles ethylene propylene diene monomer (EPDM) rubber, other thermoplastics such as polyvinyl chloride (PVC), composite materials can be used that combine thermoplastics, elastomers, reinforcements and/or fillers or other sufficient material, is incorporated. In accordance with some embodiments, a second layerof infill material depicted inmay include a mixture of materials, e.g., material of the first layerand a sand material. In such embodiments, a third layerof infill material may include the aforementioned sand material, which may be implemented as a ballast layer.

In accordance with some embodiments, a shock pad (not shown) may be employed to achieve a desired shock absorption in accordance with a particular installation/purpose. For example, a shock pad (not shown) may be positioned below the one or more infill layersshown in. As such, the material of the infill layersconveys many of the mechanical properties that may be desired for use as artificial turf infill. As shown in the depicted embodiment, the backingmay be positioned below the infill layersshown in. In such embodiments, the permeable backing may correspond to the material into which the turf fibersare woven, held, inserted, etc.

In an embodiment where the rock dustis incorporated in the synthetic turf systemas a top dressing, the rock dustis periodically dispersed over the top portionof the turf fiberswith an application systemdepicted in. With continued reference to, the application systemincludes a seed tenderand a tractorthat disperses the rock dustover the synthetic turf systemfrom a broadcaster tool. The seed tenderis employed in conjunction with a hydraulically-controlled conveyorand a hopper gate, which supply the tractorthe rock dust. As the tractormoves at a consistent speed across the synthetic turf systemfollowing a predetermined pattern, the hydraulically-controlled conveyorand the hopper gateprecisely control a flow rate of the rock dustto the tractor, ensuring uniform distribution across the synthetic turf system.

While, as depicted, the application systemincludes the broadcaster toolpulled by the tractor, and continuously fed the rock dustby the seed tenderalong or across the synthetic turf system, the application systemmay additionally or alternatively include a variety of components configured to spread granular material across a field, such as, for example, a self-propelled, manually powered, or power take-off (PTO) driven broadcast material spreader, a pneumatic spreader, an air boom spreader, a drop spreader, a handheld spreader, or an aerial spreader for dispersing the rock dustwithout departing from the scope of the present disclosure.

Once the rock dustis dispersed across the synthetic turf systemby the application system, the rock dustis brushed into the one or more infill layers, including the first layer, the second layer, and the third layer. In this regard, a brushdepicted ingrooms the rock dustinto the one or more infill layers. Rotary brush action on the synthetic turf systemfrom the top portionby the brusheffectively works the rock dustdownward between the turf fibers, ensuring proper placement within the infill material forming the one or more infill layers, while maintaining structural integrity and performance characteristics of the synthetic turf system, including at the top portionand the first layer.

While, as depicted, the brushis a motorized, walk-behind rotary brush apparatus, such as a Shindaiwa or Laymor brush system, the brushmay additionally or alternatively include various components for incorporating the rock dustinto the one or more infill layerssuch as, for example, a ride-on turf groomer, a tractor-mounted brush that is dragged or PTO driven, or manual turf brushing equipment. Furthermore, brushes employed in such configurations may embody various shapes, sizes, and types, such as, for example, straight brushes, triangular brushes, hydraulic brushes, oscillating brushes, rigid brushes, flexible brushes, or brush assemblies including at least one plurality of brushes. Furthermore, the brushmay additionally or alternatively include specialty turf equipment, such as a vacuum or other devices complementary to the brush, and utilized to integrate the rock dustinto the existing infill material of the one or more infill layerswithout departing from the scope of the present disclosure.

Turning now to, there is shown a more detailed three-dimensional cross-sectional view of a portion of the synthetic turf systemutilizing the rock dustas a ballast infill material in accordance with the embodiment set forth above in. It will be appreciated that while illustrated inas a multi-stone layered installation, the rock dustmay be used in other types of turf systems and in varying mesh sizes, and the illustrations inare intended solely as one non-limiting example of turf carpet systems in which the rock dustmay be utilized.

As shown in, the synthetic turf system, in addition to including the turf fibers, the rock dust, the infill layers, and the backing, further includes a first base stone layerdisposed below the backingand above a second base stone layer. The synthetic turf systemfurther includes a geotextile componentthat is a fabric disposed between the second base stone layerand a subgrade. The synthetic turf systemmay further include a subdrain trench componentformed in the subgrade and housing a drainage pipe.

The synthetic turf systemmay include the rock dustin the infill layers, or further include a layer of the rock dustdisposed above or below the one or more infill layers. In the embodiment of, the rock dustis applied to a top surface of the first base stone layer, below the backingand the shock pad. More specifically, the rock dustis layered directly on the top surface of the first base stone layer, and forms a continuous layer along the backing, where the layer of the rock dusthas a thickness of at least one eighth of an inch. Application may be made via a suitable top-dressing machine, as described above. In an embodiment, the rock dustmay be deposited with a thickness in the range of about ⅛″ to ¼″. In such an embodiment, rainwater would flow directly through the infill layers, the backing, and the rock dust, and flow into the first base stone layer.

The rock dustis accessible to rainwater from the top portionof the turf fibers, where the rainwater and the rock dustchemically react with each other, forming a carbonate or a bicarbonate. More specifically, in operation, as rainwater contacts the rock dust, a chemical reaction occurs between carbonic acid naturally present in the rainwater and the rock dust. The reaction weathers the rock dust, e.g., silicate rock, igneous rock, or other reactive rock, rock blends, combinations thereof, etc., and converts the carbonic acid into a carbonate or bicarbonate. In this regard, the rock dustmay include wollastonite, basalt, peridotite, dunite, dolomitic lime, dolostone, andesite, diorite, gabbro, rhyolite, olivine, quick lime, lime stone, and other minerals in varying proportions effective for reacting with carbonic acid in rainwater.

The weathering rate and shape of particles forming the rock dustare influenced by material selection and particle size distribution. In this regard, consistent particle sizing promotes uniform weathering rates across the one or more infill layers, maintaining overall field performance and carbon sequestration efficiency in the synthetic turf system. The rock dustis accessible to rainwater traveling downward by gravity from the top portionof the turf fiberstoward the backing. As the rock dustweathers through exposure to rainwater, its constituent particles may substantially change morphology, or alternatively may remain largely the same shape. In embodiments, the selected silicate rock, igneous rock, or reactive rock materials form weathered particles that maintain a sphericity of about 0.65 to about 0.85. This sphericity range supports stable packing within the synthetic turf system, reduces compaction variability, and ensures continued mechanical performance while facilitating consistent chemical reactions for carbon capture.

The rock dusthas a particle size distribution that optimizes contact surface area and reactivity with rainwater, without preventing drainage of the rainwater from the synthetic turf system. In this regard, a majority of the particles forming the rock dustmay be silt, very fine sand, or fine sand in accordance with the Wentworth aggregate classification scheme. In such an embodiment, for example, at least 90 percent of the rock dustby weight may have a particle size greater than 4 micrometers and less than 250 micrometers. In a further embodiment, at least 90 percent of the rock dustby weight may have a particle size less than 125 micrometers. In a further embodiment, at least 90 percent of the rock dustby weight may have a particle size less than 62 micrometers.

The infill material forming the infill layersmay also include additional materials such as organic particles, rubber particles, elastomer particles, coated particles, or thermoplastic particles blended or layered with the rock dust. In an embodiment, the rock dustforms less than 10 percent of the infill by weight, as compared to the additional materials. In such an embodiment, the additional materials may be sized and shaped to provide an engineered drainage surface in the synthetic turf system, where the rock dustreacts with rainwater without forming an impermeable barrier in the infill layersor otherwise effectively blocking, clogging, or pooling flow of rainwater through the synthetic turf system.

As stated above, the conversion of the carbon dioxide into other substances, such as carbonate and bicarbonate substances prevents the release of the carbon dioxide into the atmosphere. Further, the conversion of the carbonic acid has a de-acidifying effect on soils, storm water, rivers, and oceans, simultaneously enriching them with mineral nutrients. These carbonate or bicarbonate substances permeate the first base stone layerand the second base stone layer, through the geotextile componentand into the subdrain trench componentand drainage pipe. Thereafter, the carbonate or bicarbonate substances are carried by rivers to the sea, where they are ultimately deposited as carbonate sediments such as limestone and dolomites, forming a sink for carbon dioxide.

Turning now to, there is shown the synthetic turf systemutilizing the rock dustin accordance with another embodiment. In the embodiment depicted in, the rock dustis incorporated into the first base stone layer. In accordance with one non-limiting example, the first base stone layermay be implemented as layer of stone having a thickness in the range of about 1 inch to 4 inches, and in some particular embodiments, in the range of about 1 inch to about 2 inches. In such embodiments, the first base stone layermay include ASTM #89 stone or the like. The rock dustmay be suitably mixed with the stone to distribute the rock dustthroughout the first base stone layer. Mixing of the rock dustwith the first base stone layermay be accomplished on-site, remotely, e.g., quarry, mine, etc., or the like. As described in greater detail above, reaction of the rock dustwith rainwater would occur as described above with respect to.

Turning now to, there is shown another embodiment of the synthetic turf systemutilizing the rock dust. As illustrated in, the rock dustis disposed or layered on the geotextile component. In such a position, the layer of the rock dustdisposed on the geotextile componentmay have a thickness of ¼″ to ½″. Stated another way, the layer of the rock dustmay be applied at the bottom of the second base stone layer, as shown in. Application of the layer of the rock dustinmay be accomplished, for example and without limitation, via a suitable top-dressing machine.

In accordance with one non-limiting example, the second base stone layermay be implemented as layer of stone having a thickness in the range of about 2 inch to 6 inches, and in some particular embodiments, in the range of about 3 inches to about 4 inches. In such embodiments, the second base stone layermay include ASTM #57 stone or the like. In this manner, the first base stone layeris formed from stone having a first nominal size range, the second base stone layerdisposed below the first base stone layerhas a second nominal size range coarser than the first nominal size range, and the rock dustis layered above, layered below, or mixed the first base stone layeror the second base stone layer. Further, with this construction, the first base stone layerand the second base stone layerare water permeable, and the rock dustis accessible by rainwater traveling from the top portionof the turf fibers, through the one or more infill layersby gravity

Further, reaction of rock dustwith rainwater would occur as described above with respect to. It will be appreciated that placement of the rock dustas shown inmay provide additional time for weathering of the rock dust, as the incorporation of the rock dustinto the first base stone layerand the second base stone layermay hold water for extended periods of time.

Referring now to, there is shown another embodiment of the synthetic turf systemutilizing rock dustfor carbon sequestration. As illustrated in, a layer of the rock dustis positioned at a bottom of the subdrain trench component. In such an embodiment, the rock dustmay be placed at the lowest elevation within the systemto maximize the possibility of water coming into contact with the rock dust. In some embodiments, although not shown, the rock dustmay also be placed below the geotextile component, preventing the rock dustfrom clogging up the drainage system at or between the geotextile componentand the subdrain trench component, or from being washed down stream. Accordingly, the elevation of the drainage pipeas a storm drain outlet may be utilized to maximize the contact time with the storm water, effectively maximizing the weathering and carbon dioxide capture of the rock dust.

Although not shown, it is contemplated that the rock dustmay be blended with the stone of the second base stone layersimilar to the manner described above with respect to. Similarly, although not illustrated in the accompanying figures, it is further contemplated that the rock dustmay be blended with stone in the subdrain trench component. The above described positions of the rock dustwould also enable the carbon capture reaction described above with respect to.

Referring now to, there is shown the synthetic turf systemutilizing rock dustin accordance with another embodiment. As illustrated in, the rock dustmay be tilled and incorporated into the subgradeof the synthetic turf system, e.g., soil, sediment, etc. In such an implementation, the geotextile componentand the 6″ to 8″ combined thickness of the first base stone layerand the second base stone layermay be installed on the modified subgradehaving the rock dustdistributed therein. It will be appreciated that more rock dustmay be used with this embodiment than the embodiments described above, thereby providing additional carbon sequestration capability. Furthermore, it will be appreciated that by placing the rock dustinto the subgrade, additional opportunity to capture carbon is presented, as soil contains more carbon dioxide then air. That is, as organic matter breaks down it creates additional carbon dioxide. Furthermore, the addition of rock dustin the subgrade, in addition to carbon sequestration, may also provide firmer and more permeable subgrade, particularly if the subgradeis formed of soft, silty, or sandy soils. Having rock dustin the subgradewhere there is potential for more water availability increases the ability for the weathering reaction to occur, e.g., carbon sequestration. In addition, as described above with respect to, rainwater reaction with the rock dustprovides the aforementioned carbon capture benefits.

Referring to, a methodfor preparing a synthetic turf system will be described according to an exemplary embodiment.will be described with reference to. For simplicity, the methodwill be described as a sequence of blocks, but the elements of the methodcan be organized into different architectures, elements, stages, and/or processes.

At block, the methodincludes measuring an aspect of the synthetic turf system. More specifically, a user may measure a thickness of an infill layer, such as one of the infill layers, may measure an acidity of rainwater at the infill layer, and may measure a quantity of silicate rock, ultramafic rock, or reactive rock present in the infill layer.