Claims:We Claim:
1. A seismic resistant composite concrete having high ductility, high energy absorbency and high damage tolerance, wherein the seismic resistant composite concrete comprises recyclate material 101, cement 102a, sand/gravel 102b, water 102c, additives 103 and coating material (101g), wherein the coating material 101g is selected from the group comprises of mineral silicate paints, hydrophobic silane monolayers and plasma coating.
2. The seismic resistant composite concrete of claim 1, wherein the recyclate material 101 is obtained by recycling thermoset composite wastes using a mechanical method that allows the extraction of all the constituents of the original composite comprises of matrix 101a, fillers 101b and fibers 101c.
3. The seismic resistant composite concrete of claim 1, wherein the fibers used in thermoset composite, which also appear in the extracted recyclate material 101, comprises at least any one of the fiber that includes of aramid fibers 101d, glass fibers 101e and carbon fibers 101f.
4. The seismic resistant composite concrete of claim 1, wherein the fibers in the recyclate material is coated with coating material 101g.
5. A method of producing seismic resistant composite concrete having high strength, high energy absorbency and high damage tolerance, wherein the method comprising the step of:
providing seismic resistant composite concrete comprises recyclate material 101, cement 102a, sand/gravel 102b, water 102c, additives 103,
coating the recylate material 101 with a coating material 101g, wherein the coating material 101g is selected from the group comprises of mineral silicate paints, hydrophobic silane monolayers and plasma coating.
6. The method of claim 5, wherein the recyclate material 101 is obtained by recycling thermoset composite wastes using a mechanical method that allows the extraction of all the constituents of the original composite comprises of matrix 101a, fillers 101b and fibers 101c.
7. The method of claim 5, wherein the fibers appear in the extracted recyclate material 101, comprises at least any one of the fiber that includes of aramid fibers 101d, glass fibers 101e and carbon fibers 101f, wherein the fibers in the recyclate material is coated with coating material 101g.
, Description:SEISMIC RESISTANT COMPOSITE CONCRETE WITH HIGHER DUCTILITY
FIELD OF INVENTION
[0001] The embodiment herein generally relates to the field of seismic resistant composite concrete. More specifically, the embodiment provides a method for protective coating of fibers thermoset composite recyclate material in order to prevent the degradation of the fibers in the concrete mix thereby producing seismic resistant composite concrete with higher ductility.
BACKGROUND AND PRIOR ART
[0002] Thermoset composites (TC) are increasingly used in aerospace, automotive, marine, construction, electrical, domestic appliances, furniture, wind turbine blades and sports equipment due to their light weight and high mechanical strength. A tremendous amount of end-of-life TC wastes are being generated globally that need to be recycled.
[0003] A project has been undertaken to recycle TC Wastes from Indian Aerospace Industries using a mechanical method to produce recyclate and allow extraction of all the constituents of the original composite consisting of fibers, matrix and fillers. The fibers used in TCs, which also appear in the extracted recyclate, consist of any or all of the following: carbon fibers, glass fibers and aramid fibers.
[0004] The recyclate components are further transformed into a Seismic Resistant Composite Concrete. For this purpose, the recyclate components are mixed with concrete and some selected additives to form a concrete composite blend. Upon investigation, the inventor has observed that the seismic resistant composite concrete in the prior art does not possess high-energy absorption. The most important characteristic of seismic resistant composite concrete is its high ductility. Without this the purpose of seismic resistant concrete is negated.
[0005] The inventor has further observed that another a major concern in the prior arts is the possibility of degradation of fibers in the concrete mix. The inventor has further observed that this is particularly true for recyclates containing glass fibers. It is feared that the high alkali content of the cement based matrix (pH > 12.5) will react with glass fiber thereby reducing its strength. From the point of developing a seismic resistant concrete composite, the blend should have high-energy absorbency and high damage tolerance. While concrete and recyclate fibers are high strength materials, they are brittle in nature. In the course of the development, the inventor has observed that reaction of the cement based matrix with the fibers in the recyclate material causes degradation of the fibers and this is what reduces the strength and energy absorption of the seismic resistant composite concrete.
[0006] Therefore, there exists an immediate need to prevent the degradation of fibers in the recyclate material and to increase the overall strength of the seismic resistant composite concrete. There is a need for a method of making a seismic resistant composite concrete with high ductility, energy absorbency and high damage tolerance. More specifically, there is a need for developing a method whereby the fibers in the recyclate material do not react with the cement based matrix, reducing the strength of the concrete.
OBJECTS OF THE INVENTION
[0007] Some of the objects of the present disclosure are described herein below:
[0008] A main object of the present invention is to make seismic resistant composite concrete with higher energy absorption capacity.
[0009] Another object of the invention is to provide methods of coating the fibers in thermoset composite recyclate material used in seismic resistant composite concrete, to prevent the degradation of fibers in the concrete due to the high alkali content of the cement based matrix.
[00010] Yet another object of the present invention is to prevent the high alkali content of the cement based matrix from reacting with the glass fibers in the recyclate material that causes its degradation.
[00011] Another object of the invention is to improve the overall strength, energy absorbency and damage tolerance of seismic resistant composite concrete.
[00012] Still another object of the present invention is to coat the glass fibers with mineral silicate paint to enable the creation of a good bond between glass fibers and the cement.
[00013] Yet another object of the present invention is to apply hydrophobic silane monolayers to glass or carbon fibers by immersion or spraying on the surface.
[00014] Yet another object of the present invention is to protect the fibers in the recyclate material by plasma coating, which involves the process of plasma nitriding and plasma fluorination.
[00015] The other objects and advantages of the present invention will be apparent from the following description when read in conjunction with the accompanying drawings, which are incorporated for illustration of preferred embodiments of the present invention and are not intended to limit the scope thereof.
SUMMARY OF THE INVENTION
[00016] In view of the foregoing, an embodiment herein relates to the coating of fibers in thermoset composite recyclate material used in making seismic resistant composite concrete in order to increase the ductility of the concrete. The invention relates to producing seismic resistant composite concrete of higher energy absorption using one or more methods of coating the fibers in recyclate material, to prevent the fiber from degrading and thereby improving strength.
[00017] According to an embodiment, in order to improve the strength of the seismic resistant composite concrete, the fibers in the recyclate material are coated with a coating material selected from the group comprises of mineral silicate paints, hydrophobic silane monolayers and plasma coating,
[00018] According to preferred embodiment, the glass fibers in the recyclate material may be coated with mineral silicate paints before they are used in the concrete mix to prevent the fibers from reacting with the concrete matrix, thereby improving the strength and ductility of the seismic resistant composite concrete. It is observed by the inventor that even though polymer paints may be used for the same purpose, the tenacious nature of the silicate paints makes them more preferable. Silicates react with calcium salts found in concrete and also with silica in the glass fiber thus not only protecting the glass fiber but also creating a good bond between the cement and glass fiber.
[00019] According to another embodiment, the glass or carbon fibers in the recyclate material may be coated through the application of hydrophobic silane monolayers before mixing with the concrete. Silane coatings can be applied at room temperature by one or more methods, including but not limited to immersion and spraying the surface to be treated, wherein the time taken for curing during immersion is less than the other methods.
[00020] According to another embodiment, the fibers in the recyclate material may be protected through plasma coating process, wherein the process can include but not limited to plasma nitriding and plasma fluorination. The plasma nitriding process can protect the fiber against acid and alkaline environments. The plasma fluorination process can help in increasing the hydro-phobicity. These two coating treatments are applicable to all types of fibers.
[00021] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.
BRIEF DESCRIPTION OF DRAWINGS
[00022] The detailed description is set forth with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The use of the same reference numbers in different figures indicates similar or identical items.
[00023] Fig. 1 illustrates the composition of seismic resistant composite concrete with higher ductility (or energy absorption) that is made by mixing thermoset composite recyclate material, concrete and additives.
[00024] Fig. 2 illustrates methods of coatings that may be applied to the surface of the fibers in recyclate material before it is mixed with the concrete.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[00025] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[00026] Seismic resistant composite concrete is made by mixing plurality of materials, wherein the material comprises thermoset composite recyclate material, concrete and additives. As such, there is a need for a method of making a seismic resistant composite concrete with high strength, high energy absorbency and high damage tolerance. More specifically, there is a need for developing a method whereby the fibers in the recyclate material do not react with the cement based matrix thereby improving the energy absorption of the concrete.
[00027] According to an embodiment, providing an adherent polymeric coating on the fiber surface can protect the fiber from getting degraded in an alkaline environment encountered in concrete mixtures. The seismic resistant composite concrete is made by mixing plurality of materials, wherein the material comprises thermoset composite recyclate material, concrete and additives, wherein the recyclate material comprises at least any one of the material includes of fillers, matrix and fibers, wherein the fibers may include carbon fibers, glass fibers and aramid fibers. The concrete comprises cement, sand/ gravel and water. The additives comprises, at least any one of the material includes of polyurethane, silicone, or polyvinyl chloride.
[00028] According to an embodiment, in order to improve the ductility of the seismic resistant composite concrete, the fibers in the recyclate material are coated with a coating material selected from the group comprises of mineral silicate paints, hydrophobic silane monolayers and plasma coating.
[00029] According to preferred embodiment, the glass fibers in the recyclate material may be coated with mineral silicate paints before they are used in the concrete mix to prevent the fibers from reacting with the concrete matrix, thereby improving the ductility of the seismic resistant composite concrete. In another embodiment, the polymer paints may be used for the same purpose. The mineral silicate binder carries inorganic mineral pigments into the surface of a mineral-based substrate (concrete) where it chemically reacts with the substrate. Silicates react with calcium salts found in concrete and also with silica in the glass fiber thus not only protecting the glass fiber but also creating a good bond between the cement and glass fiber.
[00030] According to another embodiment, the glass or carbon fibers in the recyclate material may be coated through the application of hydrophobic silane monolayers before mixing with the concrete, wherein hydrophobic silane monolayers may be applied to glass fibers to prevent degradation of the glass fiber or to carbon fibers that are prone to galvanic corrosion. The monolayers consist of an inorganic head group that binds covalently to the silaceous surface and an organic tail that self-organizes to form a dense network of carbon chains. The fiber surface is thus protected from degradation in any aggressive environment. The silane coatings can be applied at room temperature by one or more methods including but not limited to immersion or spraying the surface to be treated, wherein the time taken for curing during immersion is less than the other methods.
[00031] According to preferred embodiment, the fibers in the recyclate material may be protected through plasma coating process, wherein the process can include but not limited to plasma nitriding and plasma fluorination. Plasma nitriding process can protect the fiber against acid and alkaline environments. Plasma fluorination process can help in increasing the hydro-phobicity. These two coating treatments are applicable to all types of fibers and can ensure protection from environmental conditions while providing enhanced adhesion to concrete mixture.
[00032] Fig.1 illustrates the composition of seismic resistant composite concrete, which has high strength, high energy absorbency and high damage tolerance. The seismic resistant composite concrete comprises recyclate material 101, cement 102a, sand/gravel 102b, water 102c, additives 103 and coating material (101g). The recyclate material 101 is obtained by recycling thermoset composite wastes using a mechanical method that allows the extraction of all the constituents of the original composite comprises matrix 101a, fillers 101b and fibers 101c. The fibers used in thermoset composite, which also appear in the extracted recyclate, comprises at least any one of the fiber that includes of aramid fibers 101d, glass fibers 101e and carbon fibers 101f. The fibers in the recyclate material is coated in order to enhance the ductility of the seismic resistant composite concrete, wherein the coating material (101g) is selected from the group comprises of mineral silicate paints, hydrophobic silane monolayers and plasma coating.
[00033] According to an embodiment, for the recyclate material to be transformed into seismic resistant composite concrete, the recyclate material is mixed with concrete 102 and additives 103, wherein concrete comprises cement 102a, sand/gravel 102b and water 102c, wherein the additives may either be polyurethane 103a or silicone 103b or polyvinyl chloride 103c.
[00034] Fig. 2 illustrates the methods of coating 101g the fibers in the recyclate material, before it is mixed with the concrete in order to improve the ductility of the seismic resistant composite concrete, wherein the method of coating the glass fibers with mineral silicate paints 201 allows the silicates to react with calcium salts found in concrete and also with silica in the glass fiber thus not only protecting the glass fiber but also creating a good bond between cement and glass fiber. In another embodiment, the hydrophobic silane monolayers 202 may be applied to glass or carbon fibers. The silane coatings (202) can be applied at room temperature by one or more methods including immersion or spraying the surface to be treated, wherein the time required for curing during immersion is less than the other methods. In another embodiment, the method involves protecting the fibers by plasma coating process 203, wherein the process can include but limited to plasma nitriding 203a and plasma fluorination 203b.
[00035] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.