WO2013064849A2

WO2013064849A2 - Glass fiber reinforced thermoset plastic waste doped concrete composition and process for preparation the same

Info

Publication number: WO2013064849A2
Application number: PCT/HU2012/000118
Authority: WO
Inventors: László CSATÁRI
Original assignee: Jager Invest Kereskedelmi Szolgaltato Es Ingatlanhasznosito Kft
Current assignee: Jager Invest Kereskedelmi Szolgaltato Es Ingatlanhasznosito Kft
Priority date: 2011-11-02
Filing date: 2012-10-31
Publication date: 2013-05-10
Anticipated expiration: 2014-05-02
Also published as: HUP1100606A2; WO2013064849A3; EP2773597A2; WO2013064849A4

Abstract

The invention relates to concrete doped with glass fiber reinforced thermoset plastic waste, process for preparing the same and a lightweight dry concrete premix usable in said process.

Description

GLASS FIBER REINFORCED THERMOSET PLASTIC WASTE DOPED CONCRETE COMPOSITION AND PROCESS FOR PREPARING THE SAME

TECHNICAL FIELD

TECHNICAL BACKGROUND

Glass fiber reinforced plastic composites have specific role among thermoset plastics.

Thermoset SMC products (Sheet molding Compound) comprising glass fiber, in particular SMC products based on unsaturated polyester, further BMC products (Bulk molding Compound) and FRP products (Fiber-Reinforced Plastic) are widely used both outdoor and in-door, since they keep their excellent features for a long time. According to literature data their large scale use increases exponentially. On the other hand, this increase has its significant disadvantages. Like all plastics, they degrade and become aesthetically obsolete and finally waste. Their decomposition lasts for many generations, their quick eradication is almost impossible, further their cost-effective recycling is unsolved. During burning a number of harmful substances are released. The high amount of glass fiber fragments further worsens the damaging effect of such type of plastic waste on health and the environment.

Environmental protection increasingly requires the life cycle follow-up of plastic waste classified as hazardous. The efforts required to destroy hazardous waste often exceed the efforts necessary to manufacture them. This refers both to technology and the expenses. In extremis, manufacturers may be required to repurchase waste.

As is known, concreting can be carried out in summer, in winter, under water and under other conditions, with surprisingly high setting hardening rate using special additives of today. Precast concrete elements have a wide range of applications, too.

Among documents belonging to the prior art Patent Document HU222303 (B l) proposes the use of fibrous aggregates or fibrous fillers. In this document additives are added to ground concreting mixture to improve its static and dynamic parameters, wherein as additives, mineral fibers, glass fibers, cellulose fibers, steel fibers, carbon fibers, plastic fibers and in particular coated glass fibers are mentioned. Glass fiber is used as a separate material, i.e. its embedding into any other material is not mentioned. Furthermore the treatment of the fibrous material with a surface-active agent is not disclosed. In International Publication Document WO2004039746 (Al) glass fiber aggregate is used for fabricating footpath coverings. Finely ground powder of fiberglass and a component consisting of flexible glass wool are used in separate steps of the process. The cement concrete product to be prepared this way is formed layer by layer in a mold made of low density polyethylene. The end product practically has two layers. The glass fiber and the glass wool are present as separate components in the layers. The glass fibers are not combined with other materials, like a thermoset.

International Publication Document WO2007046681 (Al) discloses the composition of a fiber reinforced concrete product having high strength and low bulk density. In the matrix glass fiber waste is preferably used. The origin of the glass fiber component or its connection with the rest of the materials or preliminary uncovering of its surface is not mentioned.

In Application JP 06-191917 (A) the preparation of a laminated cement product is disclosed, wherein fiber reinforced non-thermoplastic waste is mixed with a cement-based inorganic material. After adding water the mixture is combined with a carbon fiber sheet to form a new laminated product. The technology disclosed in this document prescribes a complex forming and treating process.

In another Application, i.e. in JP 07-081992 (A) authors proceed as disclosed in the application above. By grinding glass fiber reinforced non-thermoplastic FRP (Fiber- Reinforced Plastic), fibers shorter than 5 mm are uncovered. They are mixed into concrete mortar or other architectural mortars, and from the materials prepared this way multilayer sandwich structure coats are formed.

Application JP 10-053451 (A) provides technical solution for the use of industrial waste dusts of any origin, containing glass fiber, by adding them to cement and water. In particular this application refers to recycling of synthetic wood i.e. expanded urethane. The end product includes industrial dust, glass fiber, cement, water and ground synthetic wood, which mixture has a porous structure after setting and thus it is useful for draining groundwater. A special field of use is water drainage of golf-courses.

Firstly, the documents belonging to the prior art do not disclose products comprising glass fiber and plastic waste where the glass fiber was originally included in the plastic as a result of a previous preparation process. Other documents do not deal with the influence of the size of the ground particles comprising glass fiber fragments on the strength of the concrete product. Accordingly, the relationship between the main binding component, i.e. cement powder, and the particle size of the ground material was not examined, furthermore no reference to this relationship can be found in these documents. In summary, these documents do not provide exact technical solution for the environmentally friendly recycling of SMC, BMC and FRP thermoset products comprising glass fiber.

Another object of the present invention was to provide solution for the safe disposal of the increasingly accumulating amounts of non environmentally friendly thermoset plastic waste. With the present invention we surpassed this aim and created the hydraulic mixture of materials compounded as proposed, which shows improved features, i.e. higher tensile strength and compressive strength, bending strength and impact strength, further higher abrasive hardness and freezing resistance, and does not crack while setting. Over and above the foregoing the process according to the present invention fits well to the otherwise known concrete preparing processes and mechanical bulk production technologies as well as instruments used for concrete mixing.

SHORT DESCRIPTION OF THE INVENTION

The present invention relates to a process for preparing doped concrete by embedding glass fiber reinforced ground thermoset plastic waste in hydraulic concrete mortar prepared with cement. In this process the glass fiber reinforced thermoset plastic waste is separated from foreign materials, then ground optionally in several steps to form ground plastic waste having particle size one order of magnitude larger than the particle size of the cement, then a) cement, graded gravel, sand, water, said glass fiber reinforced ground thermoset plastic waste and optionally other additives commonly used in the preparation of concrete mortar are mixed applying wet technology, or

b) cement, gravel and sand, said glass fiber reinforced ground thermoset plastic waste and optionally other dry additives commonly used in the preparation of concrete mortar are mixed and homogenized applying dry technology to form a dry premix, to which water and optionally other dry and/or wet additives commonly used in the preparation of concrete mortar are added with continuous agitating, before use, and after carrying out process step a) or b) the final consistency of the concrete mortar is optionally adjusted with continuous agitating and the resultant concrete mortar is poured and allowed to set.

The invention further relates to a lightweight dry concrete premix containing glass fiber reinforced ground thermoset plastic waste, cement and optionally other dry additives commonly used in the preparation of concrete, wherein the particle size of the ground plastic waste is one order of magnitude higher than the particle size of the Portland cement. In one embodiment of the invention the lightweight dry concrete premix is packed in unit portions.

The invention further relates to a process for preparing doped concrete by embedding glass fiber reinforced ground thermoset plastic waste in hydraulic concrete mortar prepared with cement, where in the process said lightweight dry concrete premix is mixed with graded gravel, sand, water and optionally other dry additives commonly used in the preparation of concrete mortar, then the final consistency of the concrete mortar is adjusted with continuous agitating and the resultant concrete mortar is poured and allowed to set.

In one embodiment of the invention the concrete mortar prepared by any of the above processes is placed with pouring, self-spreading technology or with framework technology, in step-by-step or continuous process or by preparing discrete elements.

The invention further relates to a concrete product prepared by any of the above processes, containing the following components expressed in % by volume of the concrete:

1 1 to 16 % (v/v) cement,

1 to 16 % (v/v) glass fiber reinforced ground thermoset plastic waste,

0 to 2 % (v/v) other additives,

3 to 10 % (v/v) filtered purified water,

the rest are graded river gravel and pit sand in 1 : 1 ratio by volume.

In one embodiment of the concrete product according to the invention the average particle size of the glass fiber reinforced ground thermoset plastic waste is 300 μη or more.

In a preferred embodiment of the concrete product · according to the invention the , average particle size of the glass fiber reinforced ground thermoset plastic waste is between 500 μηι and 3 mm.

In one embodiment of the concrete product according to the invention, as glass fiber reinforced thermoset waste, glass fiber reinforced thermoset SMC and/or BMC and/or FRP waste comprising more than 10 % by volume glass fiber is used.

In one embodiment of the concrete product according to the invention the other additives are materials advantageously influencing the preparation process or the features of the end product. Preferably they are colorants, materials influencing the setting rate, antimolding agents, freezing point lowering agents and the like.

In one embodiment of the invention the concrete product is a concrete building element or a discrete element, which is preferably a pre-product, a cover element or a mobil element. DETAILED DESCRIPTION OF THE INVENTION

During elaborating the technical solution according to the invention we found that, when glass fiber reinforced thermoset plastic is ground to one order of magnitude larger than the average particle size of the incorporated cement, and this ground plastic is embedded in commonly used hydraulic concrete, a concrete product showing outstanding strength is obtained.

The cement is preferably Portland cement.

Building elements prepared from this high-strength concrete can advantageously be used in building construction and civil engineering and also for preparing discrete elements, for example structures. Moreover large amounts of high-strength concrete products are consumed by road and railway construction. Concrete can be prepared in small amounts or in large scale, further it can be job-mixed or machine-made and produced by an automated process. Concrete transporting is technically solved, concrete placing technologies are available.

Accordingly, the present invention relates to the preparation of concrete doped with glass fiber reinforced thermoset waste which is prepared by combining hydraulic concrete with glass fiber reinforced ground thermoset plastic waste. The process according to the invention is disclosed below in detail.

In a first step of the process glass fiber reinforced thermoset plastic is prepared for grinding, foreign materials, such as metals are separated, then it is ground expediently in multiple steps, that is, coarse grinding and fine grinding is carried out. The average particle size of the ground material is adjusted to one order of magnitude larger than the average particle size of the cement to be incorporated. In view of the fact that the average particle size of the Portland cement is about 30 μπι, grinding of the plastic waste is continued until its particles reach a size equal to or larger than 300 μπι.

In a second step the concrete mortar taking up the ground plastic is prepared and homogenized, where the components of the concrete mortar are: Portland cement, filtered purified water, river gravel and sand.

In a third step the ground component prepared in the first step is added to the concrete mortar obtained above. Finally, the other additives are added, then a final homogenization is carried out and the required consistence is adjusted, then the concrete is poured and allowed to set.

The composition of the concrete prepared according to the foregoing is preferably as follows: 1 1 to 16 % by volume cement, 1 to 16 % by volume ground thermoset plastic, 0 to 2 % by volume other additives, 3 to 10 % by volume purified filtered water and the rest are gravel and sand in ratio 1 :1.

In a preferred embodiment a premix is prepared from all of the dry components, i.e. from cement powder, dry gravel, dry sand, ground thermoset plastic, expediently by machinery, in an automatic mixing plant with proportionate dosing control, and the wet components are added with continuous agitating, during or after transporting to the place of concreting.

The invention can be implemented by dry premixing the ground thermoset, the cement powder and optionally the other additives in suitable ratio to obtain lightweight dry concrete premix, which is then portioned out and packed in the form of unit portions, i.e. pre-packed.

In any embodiment of the invention the concrete mortar can be placed by pouring, self- spreading or cradling technology, in step-by-step or continuous process or by preparing discrete elements, for example pre-products, cover elements or mobil elements.

By keeping the granulometric rule according to the present invention a hydraulic concrete structure is created which incorporates wide range of glass fiber reinforced thermoset plastics otherwise harmful to the environment. Having embedded into concrete commonly used in building industry they do not exert harmful effect on the environment. On the effect of pressure and heat used in the preparation of thermoset the structure of the glass fiber surface decomposes. Activation of the surface is also promoted by the chemical milieu inside the resin. During grinding this surface considerably increases. Glass fibers take part in the hydraulic bonding with relative large activated surface. This explains the outstanding mechanical properties of the doped concrete prepared by the process according to the present invention.

The process according to the invention is disclosed in detail in the following application examples.

EXAMPLES

Example 1

Preparation of reinforced concrete basement subbase

Reinforced concrete basement subbase is prepared via large scale continuous concrete production. The concrete is transported to the place of use in transit mixer with pear-shaped drum, incorporated using mechanical pump on 25°C, then compacted with vibrator rod and the surface is spaded using a finishing disc. Thus concrete subbase having structural thickness 55 cm (without blanket insulation) is formed.

The composition of concrete is as follows:

- Portland cement 12 % by volume

- purified filtered pH neutral water 5 % by volume

- ground thermoset (glass fiber content : at least 17%) 7 % by volume

- accelerating agent 1.5 % by volume and the rest are

- graded river gravel having medium bulk density and

particle size 32 mm 50 % by volume of the rest and

- earth-moist pit sand 50% by volume of the rest

The above composition is cast in place. According to our experience the glass fiber reinforced ground thermoset used is fully covered by the spaded finish of concrete. The embedded glass fibers take a substantial part in the hydraulic bond. The hardened surface is event, crack-free and can be coated without a leveling course. Hygroscopicity of the final concrete subbase was not experienced. Mechanical properties of standard cast-in-place cubes were examined in mechanical test laboratory, where all the received data surpassed the data measured for the references (see Table after the Examples).

Example 2

Preparation of public road bed

Public road bed is prepared by continuous spreading in standard breadth and average depth of 50 cm. The conditions of preparation and pouring were identical with those described in Example 1.

The composition of concrete is as follows:

- Portland cement 13 % by volume

- tested local well water 6 % by volume

- ground thermoset (containing mixed glass fiber) 9 % by volume

- fluxing agent 1 % by volume and the rest are

- mixed size river gravel with mixed bulk density,

one half is from 24 to 30 mm and the other half is kule gravel with sizes up to 63 mm 50 % by volume of the rest and

- earth-moist pit sand 50% by volume of the rest

The concrete bed prepared this way takes up the glass fiber reinforced plastic waste otherwise qualified as harmful to the environment. After hardening the concrete has a closed surface, the embedded ground plastic is not released. Owing to its physical properties, i.e. good waterproofhess, no dissolution was experienced. The glass fiber takes an active part in hydraulic bond and shows characteristics of pure silicate. The mechanical strength of the concrete prepared according to this process is better than those of the concrete bed materials of control compositions (see in the Table).

Example 3

Preparation of fencepost elements

Fencepost elements are prepared from pre-packed dry lightweight concrete premix. The size of the post at base is 20 x 20 cm and at cap is 10 x 10 cm, its length is 3 m. The fence element is equipped with four reinforcing iron accessories of 10 cm having extending galvanized lugs for fixing wire mesh. The concrete is mixed in place and a gauge is used for pouring. The concrete may be agitated manually or mobil concrete mixer can be used.

The proposed composition is as follows:

- pre-packed lightweight dry concrete premix containing

Portland cement and glass fiber reinforced ground

thermoset, and sand 50 % by volume

- pea gravel, 8 to 12 mm, with mixed bulk density 45 % by volume

- tap-water 5 % by volume The elements prepared this way form compact, weatherproof fence posts with high load bearing capacity and need no subsequent attention. A particular advantage is that the grounded part needs no pre-treatment or impregnation.

Example 4

Preparation of colored outdoor going elements, flags

Colored outdoor going elements, flags are prepared in size 40 x 40 x 8 cm using gauges, by the home-made process outlined above.

The proposed composition is as follows: ^■ pre-packed lightweight dry concrete premix containing

Portland cement and glass fiber reinforced ground

thermoset, and sand 45 % by volume

^■ washed mixed gravel with particle size up to 16 mm 45 % by volume

• tap-water 7 % by volume

• antifreeze agent with colorant 2 % by volume

• pea gravel for additional gritting the footpath surface 1 % by volume

The two latter examples can be carried out on large scale as well. In any technology version automatic batcher and dosing devices can be applied setting proper mixing time and using good quality materials with constant composition.

Examination of characteristics

The characteristics of the products of the invention were examined according to MSZ EN 206-1 : 2002 (internationally extended Hungarian Standard) and MSZ 4798-1 : 2004 (Hungarian Application Standard).

In accordance with these standards compressive strength is examined on a 28-day-old sample cube with lateral edge of 150 mm using hydraulic compression press. Force vs. dislocation curves are recorded and the pressure value at which the cube collapses corresponds to the strength value in question. The actual loads of structures are designed with this knowledge and the construction is carried out accordingly. During the construction process concrete sample cubes are put down and the occupancy permission is issued after examination of these samples.

The table below shows the characteristic data of the samples prepared from the concrete products of the present invention, which were determined by the standard methods described above, as compared to data determined under similar conditions, of concrete products comprising glass fiber reinforced plastic waste representing the closest prior art.

CONCLUSION

As it appears from the above data that the compressive strength of the fully hardened concrete product according to the present invention considerably improved in the examined broad bulk density range.

A great advantage of the present invention is that it contributes to the removal of plastic waste by using it in concrete prepared for the building industry, thereby decreasing harmful effect of said waste on the environment.

A further unexpected effect of the present invention is that the characteristics of the concrete products, such as tensile strength, bending strength, impact strength, abrasive hardness, compressive strength and resistance to shear and extreme conditions, like fire- resistance and frost-resistance, and crack resistance are highly improved.

Claims

Claims:

1. Process for preparing doped concrete by embedding glass fiber reinforced ground thermoset plastic waste in hydraulic concrete mortar prepared with cement, characterized in that the glass fiber reinforced thermoset plastic waste is separated from foreign materials, then ground optionally in multiple steps to form ground plastic waste having particle size one order of magnitude larger than the particle size of the cement, then

a) cement, graded gravel, sand, water, said glass fiber reinforced ground thermoset plastic waste and optionally other additives commonly used in the preparation of concrete mortar are mixed applying wet technology, or

2. Lightweight dry concrete premix containing glass fiber reinforced ground thermoset plastic waste, cement and optionally other dry additives commonly used in the preparation of concrete, wherein the particle size of the ground plastic waste is one order of magnitude larger than the particle size of the Portland cement.

3. The lightweight dry concrete premix according to claim 2, which is in the form of unit portions.

4. Process for preparing doped concrete by embedding glass fiber reinforced ground thermoset plastic waste in hydraulic concrete mortar prepared with cement, characterized in that the lightweight dry concrete premix according to claim 2 or 3 is mixed with graded gravel, sand, water and optionally other additives commonly used in the preparation of concrete mortar, the final consistency of the concrete mortar is adjusted and the resultant concrete mortar is poured and allowed to set.

5. The process according to claim 1 or 4 characterized in that the concrete mortar is placed with pouring, self-spreading technology or with framework technology, in batch type process or continuous process, or discrete elements are prepared.

6. Concrete product prepared by the process according to any of claims 1, 4 or 5, which contains the following components expressed in % by volume of the concrete:

11 to 16 % (v/v) cement,

1 to 16 % (v/v) glass fiber reinforced ground thermoset plastic waste,

0 to 2 % (v/v) other additives,

3 to 10 % (v/v) filtered purified water,

the rest are graded river gravel and pit sand in 1 : 1 ratio by volume.

7. The process according to claim 1, the concrete premix of lightweight structure according to claim 2 or the concrete product according to claim 6, wherein the average particle size of the glass fiber reinforced ground thermoset plastic waste is 300 μιη or larger.

8. The process according to claim 1, the concrete premix of lightweight structure according to claim 2 or the concrete product according to claim 6 or claim 7, which contains, as glass fiber reinforced thermoset plastic waste, glass fiber reinforced thermoset SMC and/or BMC waste comprising more than 10 % by volume glass fiber.

9. The process according to claim 1, the concrete premix of lightweight structure according to claim 2, the process according to claim 4 or the concrete product according to claim 6, wherein the other additives are preferably colorants, materials influencing the setting rate, antimolding agents, freezing point lowering agents.

10. The concrete product according to any of claims 6 to 9, which is a concrete building element or a discrete element, which is preferably a pre-product, a cover element or a mobil element.