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Title:
METHOD FOR PRODUCING CONCRETE USING RECYCLED PLASTIC
Document Type and Number:
WIPO Patent Application WO/2020/000106
Kind Code:
A1
Abstract:
A method for producing thermally insulated concrete by making use of treated, and preferably recycled, plastic as an aggregate ingredient. In particular, plastic elements are coated with cement and/or sand to render the surfaces of the plastic elements rough in order to better bond and mix more uniformly in a concrete mixture in forming concrete.

Inventors:
PICCONE FRANCESCO (CA)
Application Number:
PCT/CA2019/050898
Publication Date:
January 02, 2020
Filing Date:
June 27, 2019
Export Citation:
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Assignee:
PICCONE HOLDINGS LTD (CA)
International Classes:
B28C5/00; C04B18/20; C04B28/00; C08J5/12
Foreign References:
US20020050233A12002-05-02
US20020018895A12002-02-14
DE19744967A11999-04-15
Attorney, Agent or Firm:
SMITHS IP (CA)
Download PDF:
Claims:
CLAIMS

1. A method for producing concrete, comprising the steps of:

coating a plurality of plastic elements with at least one of cement and sand by:

applying glue to the plastic elements; and, adhering said at least one of cement and sand to the plastic elements; and

mixing the coated plastic elements with cement, an aggregate and water to form a concrete mix. 2. The method of claim 1 wherein said step of adhering comprises:

mixing the plastic elements in a tumbler along with said at least one of cement and sand, and drying.

3. The method in claim 1 , wherein the glue is vinyl glue diluted with water and said step of applying comprises spraying said glue onto said plastic elements.

4. The method of claim 1 wherein said step of adhering comprises blowing said at least one of cement and sand onto said plastic elements.

5. The method in claim 1 wherein said plurality of plastic elements comprise pieces of comminuted recycled plastic. 6. The method of claim 5 wherein said pieces have an average footprint of less than 2 square centimeters.

7. The method in claim 1 wherein the plastic elements comprise plastic elements formed in coiled filaments having a diameter of 2 to 4 millimeters and a coil length of 2 to 4 centimeters.

8. The method in claim 1 wherein the plastic elements are formed in at least one of elongated rigid straight spaghetti-like filaments and rigid curved spaghetti-like filaments having a diameter of 3 to 19 millimeters and a length of 3 to 7 centimeters. 9. The method in claim 1 wherein the plastic elements are formed in at least one of lumps, spheres or quasi-spherical shapes having a diameter of 3 to 19 millimeters.

10. The method in claim 1 wherein the concrete mix further comprises pulverized plastic.

Description:
TITLE OF INVENTION

METHOD FOR PRODUCING CONCRETE USING RECYCLED PLASTIC

FIELD OF THE INVENTION This invention relates to aggregates for concrete. In particular, this invention relates to making use of treated, and preferably recycled, plastic as an aggregate ingredient to produce structural concrete that is thermally insulated.

BACKGROUND OF THE INVENTION

Concrete is one of the most widely used building materials in the world. In its simplest form, concrete is made up of three basic ingredients: cement (typically, Portland cement), aggregate (typically, a fine and coarse aggregate - i.e. sand and gravel), and water. When mixed together in appropriate proportions, the cement and water form a paste that coats the surface of the aggregates, and through the chemical reaction of hydration, the paste hardens over time binding the aggregates to form the rock-like material that we know as concrete.

Concrete is an ideal building material because it is durable, low maintenance, and resistant to wind, water and fire. The ingredients are easily available in most places, and due to its ability to retain heat, it may also increase the efficiency of buildings. However, the concrete industry has often been criticized as being unsustainable because of the massive carbon footprint of cement - the key ingredient in concrete. Cement production is one of the world’s biggest greenhouse gas emissions accounting for approximately 5% of annual anthropogenic global C0 2 production. Since the 1950s, 8.3 billion metric tons of plastic have been generated across the world - 6.3 billion metric tons of which have become plastic waste. Of that, 12% has been incinerated and only 9% has been recycled. The vast majority (79%) has ended up in landfills or the natural environment. Incinerating plastic releases harmful chemicals into the environment, creating a public health risk. Disposing plastics in landfills, on the other hand, is also problematic because it takes thousands of years to biodegrade. There have been attempts to integrate plastic into concrete. One example is shown in U.S. Patent No. 10,294,155 to Alqahtani, which discloses a synthetic recycled plastic aggregate for use in concrete. The method of making the plastic aggregates includes shredding and grinding recycled plastic, mixing the ground plastic with a filler to form a homogenized mixture, compressing the homogenized mixture in a mold, melting the plastic in the homogenized mixture to form a composite sheet or slab, and shredding the composite sheet or slab to form either coarse or fine aggregates for use in making concrete. The filler may include a granular waste, such as dune sand, fly ash, and/or quarry fines. Another example is U.S. Patent Nos. 6,844,065 to Reddy et al. and 7,025,85 to Pyzik et al., which disclose the use of plastic fibers for reinforcing concrete. The plastic fibers are comprised of at least two filaments bonded together such that upon mixing in a concrete mix, the filaments may fray at the ends of the fibers to allow for more surface area of the fiber to bond with the concrete mix and anchor to the resulting concrete.

One disadvantage of integrating plastic into concrete is that generally the plastic pieces tend to slip out of the resulting concrete due to the smooth and slippery surfaces of the plastic pieces.

There is therefore a need to provide more eco-friendly concrete, as well as more ways to recycle plastic waste and redirect it from ending up in landfills and the natural environment. Furthermore, when integrating plastic into concrete, there is a need to prevent the plastic pieces from slipping out of the resulting concrete. SUMMARY OF THE INVENTION

It is an object of the invention to provide structural concrete that is thermally insulated, by making use of treated, and preferably recycled, plastic as an aggregate ingredient. As polyvinyl chloride (PVC) and other plastics are known to have excellent insulating values and strengths, their use in concrete may improve the thermal efficiency and strength of concrete.

Plastic waste is capable of being sorted into different types of plastic such as polyvinyl chloride (PVC) and polystyrene (PS), shredded or comminuted into smaller pieces, and extruded, molded, injection formed or compressed under heat and high pressure into various shapes and sizes, by plastic sorting, recycling and processing facilities.

The processed plastic elements, which may include a mixture of different types of plastic of various shapes and sizes, are further treated before being used in appropriate proportions with other aggregates in forming concrete.

In one aspect of the invention, the plastic elements are coated with cement and/or sand to render the surfaces of the plastic elements rough in order to better bond and mix more uniformly with other ingredients in a concrete mix. In another aspect, vinyl glue is applied onto the plastic elements, followed by cement and/or sand. In another aspect, the plastic elements are run through a tumbler along with cement and/or sand. Other means of coating the plastic elements with cement and/or sand may be used.

After further treating the processed plastic elements, they are mixed with more cement and a fine aggregate in appropriate proportions to form a concrete mix to form concrete.

The potential advantages of the invention include the elimination of reinforcing bars in single family constructions, the elimination of the need for standard insulation in walls, the reduction of sound transmission, and putting to good use plastic waste.

In another aspect, the invention is a method for producing concrete, comprising the steps of: coating a plurality of plastic elements with at least one of cement and sand by applying glue to the plastic elements and adhering the cement and/or sand to the plastic elements, and mixing the coated plastic elements with cement, an aggregate and water to form a concrete mix.

In a further aspect, the plastic elements are coated by mixing and drying them in a tumbler along with the cement and/or sand. In another aspect, the glue is vinyl glue diluted with water and the glue is sprayed onto the plastic elements.

In yet another aspect, the cement and/or sand is blown onto the plastic elements.

In yet a further aspect, the plurality of plastic elements comprises pieces of comminuted recycled plastic. In another aspect, the pieces have an average footprint of less than 2 square centimeters.

In yet another aspect, the plastic elements comprise plastic elements formed in coiled filaments having a diameter of 2 to 4 millimeters and a coil length of 2 to 4 centimeters. In a further aspect, the plastic elements are formed in at least one of elongated rigid straight spaghetti-like filaments and rigid curved spaghetti-like filaments having a diameter of 3 to 19 millimeters and a length of 3 to 7 centimeters. In yet a further aspect, the plastic elements are formed in at least one of lumps, spheres or quasi-spherical shapes having a diameter of 3 to 19 millimeters. In another aspect, the concrete mix further comprises pulverized plastic.

The foregoing may cover only some of the aspects of the invention. Other and sometimes more particular aspects of the invention will be appreciated by reference to the following description of at least one preferred mode for carrying out the invention in terms of one or more examples. The following modes for carrying out the invention are not a definition of the invention itself, but are only examples that embody the inventive features of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

At least one mode for carrying out the invention in terms of one or more examples will be described by reference to the drawings thereof in which:

Fig. 1 illustrates the various shapes and sizes of the plastic elements which may be used in the concrete mix;

Fig. 2 illustrates coating a plurality of plastic elements with cement and/or sand using vinyl glue and a tumbler in accordance with one embodiment of the invention;

Fig. 3 illustrates mixing the coated plastic elements with a fine standard concrete aggregate, pulverized plastic powder, cement powder and water to form a concrete mix in accordance with one embodiment of the invention; and

Fig. 4 is a cross-sectional view of a concrete column with a plurality of coated plastic elements embedded within in accordance with one embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This invention is particularly suited for the use of recycled plastic as an aggregate in concrete, but the plastic aggregate need not necessarily be recycled. Such plastic generally includes synthetic materials made from a range of organic polymers such as polyvinyl chloride (PVC), polystyrene (PS) and polyethylene (PE), that can typically be molded into various shapes and sizes while soft and set into more rigid or slightly elastic forms. The plastic should be comminuted into small plastic elements 100 suitable for integration into the concrete.

Referring to Fig. 1 , the plastic elements 100 may take the form of various shapes and sizes. The plastic elements 100 may be in the form of small fragments 102 having an average footprint of less than 2 square centimeters. The plastic elements 100 may be in the form of 2- to 4-millimeter diameter filaments formed in coils 108, with the coil being approximately 2 to 4 centimeters in length. The plastic elements 100 may also be in the form of elongated straight or curved spaghetti-like rigid filaments 110 and 11 1 , for example having diameters of about 3 to 19 millimeters and lengths in the range of 3 to 7 centimeters. Furthermore, the plastic elements 100 may be in the form of lumps, spheres or quasi-spherical shapes 106 having a diameter of 3 to 19 millimeters to mimic the shape and size of aggregate typically used in the production of concrete. Other shapes and sizes of the plastic elements 100 may also be suitable for use in the invention.

In cases where plastic waste is received in forms that are not immediately suitable by reasons of their size or shape, they may be processed to produce plastic elements 100 of the desired dimensions.

A mix of various types and forms of plastic elements 100 may be used in a concrete mix to form concrete. Moreover, the type and form of the plastic elements 100 may be selected to achieve certain desired characteristics, as well more consistent characteristics of the resulting concrete. For example, plastic elements 100 made from polystyrene may be chosen to provide useful thermal and sound insulation to the resulting concrete. Plastic elements 100 in the form of rigid spaghetti-like filaments 110 and 11 1 , and in the form of lumps, spheres or quasi-spherical shapes 106 that mimic aggregate typically used in concrete may be chosen to enhance the structural integrity of the resulting concrete. The plastic elements 100 may also optionally be exposed to gamma radiation before mixing in a concrete mix to increase the structural strength of the resulting concrete.

The plastic elements 100 are treated before being used in appropriate proportions in a concrete mix. In particular, a plurality of plastic elements 100 are coated with cement powder 112 and/or sand 114 to render the surfaces of the plastic elements 100 rough in order to better bond and mix more uniformly in the concrete mix.

In one embodiment of the invention shown in Fig. 2, adhesion of the cement powder 112 and/or sand 1 14 to the plastic elements may be accomplished by applying glue 124 onto the plastic elements 100, and running the plastic elements 100 through a mechanical tumbler 1 16 along with cement powder 1 12 and/or sand 1 14 for drying and mixing purposes. Heat may also be applied for drying purposes. As a result of the heat and/or tumbling in the presence of the cement powder 112 and/or sand 114, the plastic elements 100 are dried and become coated with adhered cement powder 1 12 and/or sand 114 to form coated plastic elements 120.

The glue 124 is preferably vinyl glue diluted with water. Application of the glue 124 may be accomplished by spraying the glue 124 onto the plastic elements 100. Adhesion of the cement powder 112 and/or sand 1 14 may also be accomplished by blowing the cement powder 112 and/or sand 114 onto the plastic elements 100.

The purpose of the vinyl glue coating is for the cement powder 1 12 and/or sand 114 to better adhere to the plastic elements 100 prior to the mixing of the concrete. The inventor has found the vinyl glue approach to be effective, resulting in adhesion of the cement powder to the plastic and subsequent adherent integration of the plastic elements 100 into the set concrete as illustrated in Fig. 4. Other means of coating the plastic elements 100 with cement powder 112 and/or sand 114 may be used. The purpose of the cement and/or sand coating is to render the smooth and slippery surfaces of the plastic elements 100 rough, so that the coated plastic elements 120 bond and mix uniformly in the concrete mix. The coating provides improved tensile strength of the concrete. The coating also allows a more consistent and uniform mixture of the plastic aggregate in the concrete mix than would be the case without the prior application of the coating.

After the plastic elements 100 are treated to form coated plastic elements 120, the coated plastic elements 120 are ready to be mixed with other ingredients in the concrete mix (as shown in Fig. 3). These other ingredients include more cement powder 112, a fine standard concrete aggregate 128, and water 130. Pulverized plastic 126 may also be added to the concrete mix.

The percentage by volume of the plastic elements as compared to the other aggregates and in comparison to the overall weight of the concrete varies according to the insulation value or structural strength of the concrete that is desired. The percentages to be used may depend on local building requirements and regulations.

The following percentages by volume have been found to be suitable for use in the invention:

1 ) Portland cement 7% to 20%

2) Fine standard concrete aggregate 15 to 25%

3) Pulverized plastic powder 10 to 15%

4) Flard plastic elements 25% to 35%

5) Water 12 to 18%

6) Vinyl glue 3 to 4% (optional)

7) Soft plastic elements: balance of the mix. As polyvinyl chloride (PVC) or other plastics are known to have excellent insulating values and strength, its use in the concrete can not only replace and/or supplement structural steel, but can render the completed wall highly thermally efficient. A value exceeding R2 per 1” of wall thickness should be expected using the percentages indicated above.

When used in conjunction with PVC stay-in-place concrete forms such as are disclosed in U.S. Patent Nos. 5,740,648 and US 6,219,984 to Piccone, the resulting R value of the wall substantially increases, due to the presence of air filaments between the panels and the concrete as well as due to the panels themselves.

It will be appreciated that the usual reinforcing bars found in concrete may also be used as appropriate for a given application and when superior structural strength is desired.

In the foregoing description, exemplary modes for carrying out the invention in terms of examples have been described. However, the scope of the claims should not be limited by those examples, but should be given the broadest interpretation consistent with the description as a whole. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.