CN115504751B

CN115504751B - Concrete and preparation method thereof

Info

Publication number: CN115504751B
Application number: CN202110698317.7A
Authority: CN
Inventors: 柳祚龙; 施文照; 韦景然; 金伟; 胡广君
Original assignee: CR Chemical Materials Technology Inc
Current assignee: CR Chemical Materials Technology Inc
Priority date: 2021-06-23
Filing date: 2021-06-23
Publication date: 2023-07-04
Anticipated expiration: 2041-06-23
Also published as: CN115504751A

Abstract

The invention discloses a concrete and a preparation method thereof, wherein the concrete comprises the following components: cement, polyester foaming beads, fly ash, quicklime, sand stone, fine slag, a compatilizer and a set retarder. The concrete has excellent tensile strength and buffering performance, greatly reduces the cracking probability in use, can be easily cast and molded, has good stability, impermeability and heat preservation performance, and shows good temperature resistance and chemical, oil and frost attack resistance. Meanwhile, the concrete has lighter weight, better strength-to-weight ratio and positive influence on the cost of transportation and composite structures. In addition, the concrete helps reduce the carbon footprint, improving the concrete sustainability, so that the concrete can be used to build stronger, more flexible, lighter and more sustainable concrete structures, such as from sidewalks and street guardrails, to precast concrete exterior wall cladding and manhole covers, and the like.

Description

Concrete and preparation method thereof

Technical Field

The invention relates to the field of building materials, in particular to concrete and a preparation method thereof.

Background

Concrete, abbreviated as "concrete", is usually obtained by mixing cement as a cementing material, sand and stone as an aggregate, and water in a certain proportion, and stirring. The concrete has the characteristics of rich raw materials, low price and simple production process, so that the application range of the concrete is very wide, the concrete is not only used in various civil engineering, but also used in shipbuilding industry, mechanical industry, ocean development, geothermal engineering and the like, and the concrete is also an important material. The concrete has the advantages of high compressive strength, easy material acquisition, easy molding, low price, and capability of being combined with steel to form various bearing members, but the fatal weaknesses of the concrete are low tensile strength, large brittleness and easy cracking, thereby reducing the bearing capacity of the concrete structure, shortening the service life and becoming the hidden trouble of various disaster accidents.

Disclosure of Invention

The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, an object of the present invention is to provide a concrete having excellent tensile strength and buffering properties, greatly reducing the probability of cracking in use, being easily castable and formable, and having good stability, impermeability and thermal insulation properties, exhibiting good temperature and chemical, oil and frost attack resistance. Meanwhile, the concrete has lighter weight, better strength-to-weight ratio and positive influence on the cost of transportation and composite structures. In addition, the concrete helps reduce the carbon footprint, improving the concrete sustainability, so that the concrete can be used to build stronger, more flexible, lighter and more sustainable concrete structures, such as from sidewalks and street guardrails, to precast concrete exterior wall cladding and manhole covers, and the like.

In one aspect of the invention, the invention provides a concrete. According to an embodiment of the present invention, the concrete includes: cement, polyester foaming beads, fly ash, quicklime, sand stone, fine slag, a compatilizer and a set retarder.

According to the concrete provided by the embodiment of the invention, the cement, the polyester foaming beads, the fly ash, the quicklime, the sand stone, the fine slag, the compatilizer and the retarder are mixed, namely, the polyester foaming beads are filled in the concrete, so that the tensile strength and the buffering performance of the concrete can be remarkably improved, the cracking probability of the concrete in use is greatly reduced, and the casting and the forming are easily realized; meanwhile, the concrete has good stability, impermeability and heat preservation performance, and shows good temperature resistance, chemical resistance, oil resistance and frost aggressivity. Meanwhile, the weight of the concrete can be greatly reduced by adding polyester foaming beads as a filler, so that a better strength-weight ratio is generated, and the cost of transportation and a composite structure is positively influenced. In addition, the polyester foaming beads are added as the filler, so that the carbon footprint of the concrete is reduced, and the sustainability of the concrete is improved. And the problem of poor compatibility of the concrete and the polyester foaming beads can be effectively solved by adding the compatilizer, so that the mixing uniformity of the concrete raw material and the polyester foaming beads is greatly improved. The addition of the retarding water reducer can lead the molecules of the water reducer to be directionally adsorbed on the surfaces of cement particles, so that the surfaces of the cement particles have the same charge (usually negative charge), thereby forming electrostatic repulsion, promoting the mutual dispersion of the cement particles, the disintegration of a flocculation structure, releasing the water of the wrapped part and participating in flowing, and further effectively increasing the fluidity of the concrete mixture. In addition, the retarding water reducer structure has hydrophilic branched chains which extend into the aqueous solution, so that a hydrophilic three-dimensional adsorption layer with a certain thickness is formed on the surface of the adsorbed cement particles. When the cement particles are close, the adsorption layers start to overlap, namely, the more the adsorption layers overlap, the larger the steric hindrance repulsive force is, the larger the obstruction to the agglomeration among the cement particles is, so that the slump of the concrete is kept good. Thus, the concrete of the present application composition can be used to construct stronger, more flexible, lighter and more sustainable concrete structures, from sidewalks and street guardrails, to precast concrete exterior wall cladding and manholes, and the like.

In addition, the concrete according to the above embodiment of the present invention may have the following additional technical features:

in some embodiments of the present invention, the mass ratio of the cement, the polyester-based expanded beads, the fly ash, the quicklime, the sand, the fine slag, the compatilizer and the retarder/water reducer is (40-60): (20-30): (5-10): (5-10): (5-10): (5-10): (2-5): (1-5). Therefore, the tensile strength and the buffer performance of the concrete are obviously improved, and the cracking probability of the concrete in use is greatly reduced, so that the casting and the forming are easily realized.

In some embodiments of the invention, the compatibilizing agent is selected from at least one of polyether modified polysiloxanes and silicone oils, preferably polyether modified polysiloxanes. Therefore, the mixing uniformity of the concrete raw material and the polyester foaming beads can be greatly improved.

In some embodiments of the invention, the set-retarding water reducing agent comprises at least one of sodium gluconate and sodium salt of a beta-naphthalenesulfonic acid formaldehyde high condensate.

In some embodiments of the invention, the polyester-based expanded beads have a density of 100kg/m ³ ~250kg/m ³ . Thus, the weight of the concrete can be greatly reduced, a better strength-to-weight ratio is produced, and the cost of transportation and composite structures is positively influenced.

In some embodiments of the invention, the polyester-based expanded beads include polyesters, chain extenders, nucleating agents, anti-hydrolysis agents, stabilizers, high temperature lubricants, and physical blowing agents. Therefore, the polyester foaming beads with environmental friendliness, high foaming multiplying power, small volume weight and high compression resilience can be obtained, and the polyester foaming beads can be used as fillers in concrete to remarkably improve the performances of tensile strength, buffering and the like of the concrete.

In some embodiments of the invention, the mass ratio of the polyester, the chain extender, the nucleating agent, the anti-hydrolysis agent, the stabilizer, the high temperature resistant lubricant, and the physical blowing agent is 100: (0.5-2): (0.5-2): (0.5-1): (0.5-1): (0.2 to 0.5): (1.5-3). Thus, the tensile strength, the buffering performance and the like of the concrete can be remarkably improved.

In some embodiments of the invention, the polyester comprises at least one of PET, PETG, PBT, PLA, PC, TPEE and rPET.

In some embodiments of the invention, the chain extender comprises at least one of pyromellitic anhydride (PMDA), 2' bis (2-oxazoline), and triglycidyl isocyanurate (TGIC). Therefore, the melt strength of the polyester is effectively improved, the foamability of the polyester is improved, no obvious weakening phenomenon exists along with the processing time, and the phenomena of foam collapse, foam cell breakage and foam cell merging in the foaming process are effectively prevented.

In some embodiments of the invention, the nucleating agent comprises at least one of silica, talc, montmorillonite.

In some embodiments of the invention, the hydrolysis inhibitor is a sterically hindered aromatic carbodiimide-based hydrolysis inhibitor. Therefore, a large number of low potential energy points are formed at the interface between melts in the foaming process, and a large number of uniform nucleation hot spots are formed, so that the subsequent obtaining of the polyester foaming beads with higher multiplying power is facilitated.

In some embodiments of the invention, the stabilizer comprises at least one of trimethyl phosphate (TMP) and triphenyl phosphate (TPP).

In some embodiments of the invention, the high temperature resistant lubricant comprises at least one of polyethylene wax, EBS, and PETs, preferably PETs.

In some embodiments of the invention, the physical blowing agent comprises at least one of carbon dioxide, nitrogen, alkanes, and fluorides.

In a further aspect of the invention, the invention provides a method of preparing the concrete described above. According to an embodiment of the invention, the method comprises: cement, fly ash, quicklime, sand stone, fine slag, a compatilizer and a retarding and water reducing agent are mixed with polyester foaming beads so as to obtain concrete.

According to the method for preparing concrete, disclosed by the embodiment of the invention, cement, polyester foaming beads, fly ash, quicklime, sand stone, fine slag, a compatilizer and a retarder are mixed, namely, the polyester foaming beads are filled in the concrete, so that the tensile strength and the buffering performance of the concrete can be remarkably improved, the cracking probability of the concrete in use is greatly reduced, and casting and forming are easily realized; meanwhile, the concrete has good stability, impermeability and heat preservation performance, and shows good temperature resistance, chemical resistance, oil resistance and frost aggressivity. Meanwhile, the weight of the concrete can be greatly reduced by adding polyester foaming beads as a filler, so that a better strength-weight ratio is generated, and the cost of transportation and a composite structure is positively influenced. In addition, the polyester foaming beads are added as the filler, so that the carbon footprint of the concrete is reduced, and the sustainability of the concrete is improved. And the problem of poor compatibility of the concrete and the polyester foaming beads can be effectively solved by adding the compatilizer, so that the mixing uniformity of the concrete raw material and the polyester foaming beads is greatly improved. The addition of the retarding water reducer can lead the molecules of the water reducer to be directionally adsorbed on the surfaces of cement particles, so that the surfaces of the cement particles have the same charge (usually negative charge), thereby forming electrostatic repulsion, promoting the mutual dispersion of the cement particles, the disintegration of a flocculation structure, releasing the water of the wrapped part and participating in flowing, and further effectively increasing the fluidity of the concrete mixture. In addition, the retarding water reducer structure has hydrophilic branched chains which extend into the aqueous solution, so that a hydrophilic three-dimensional adsorption layer with a certain thickness is formed on the surface of the adsorbed cement particles. When the cement particles are close, the adsorption layers start to overlap, namely, the more the adsorption layers overlap, the larger the steric hindrance repulsive force is, the larger the obstruction to the agglomeration among the cement particles is, so that the slump of the concrete is kept good. Thus, the concrete obtained by the method can be used for building stronger, more flexible, lighter and more sustainable concrete structures, such as sidewalks and street guardrails, precast concrete outer wall cladding, manhole and the like.

In addition, the method of preparing concrete according to the above embodiment of the present invention may have the following additional technical features:

in some embodiments of the invention, the polyester-based expanded beads comprise polyester-based expanded beads prepared by: (1) Mixing polyester, a chain extender, a nucleating agent, an anti-hydrolysis agent, a stabilizer and a high-temperature resistant lubricant, and then carrying out melt blending extrusion for granulation to obtain polyester modified particles; (2) Adding the polyester modified particles into a dry high-pressure reaction kettle, injecting a physical foaming agent into the dry high-pressure reaction kettle through high pressure, and soaking the polyester modified particles by the physical foaming agent under the conditions of 160-260 ℃ and 5-10 MPa of vapor pressure to form a polyester modified particle/foaming agent homogeneous saturated system; (3) Opening a discharging valve at the bottom of the dry high-pressure reaction kettle in the step (2) to release pressure, forming internal and external pressure drops, enabling the homogeneous system to be in a thermodynamically unstable state, driving cells to grow up, and then cooling, cleaning and drying to obtain polyester foaming beads. Therefore, the polyester foaming beads with environmental friendliness, high foaming multiplying power, small volume weight and high compression resilience can be obtained, and the polyester foaming beads can be used as fillers in concrete to remarkably improve the performances of tensile strength, buffering and the like of the concrete.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Drawings

The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:

FIG. 1 is a photograph of polyester-based expanded beads obtained in example 1;

FIG. 2 is a cross-sectional view of the concrete obtained in example 2;

FIG. 3 is a photograph of example 3 after concreting.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.

In one aspect of the invention, the invention provides a concrete. According to an embodiment of the present invention, the concrete includes cement, polyester-based expanded beads, fly ash, quicklime, sand, fine slag, a compatibilizer, and a set retarder.

The inventor finds that by mixing cement, polyester foaming beads, fly ash, quicklime, sand stone, fine slag, a compatilizer and a retarder, namely filling the polyester foaming beads in concrete, the tensile strength and the buffering performance of the concrete can be remarkably improved, the cracking probability of the concrete in use is greatly reduced, and thus the casting and the forming can be easily realized; meanwhile, the concrete has good stability, impermeability and heat preservation performance, and shows good temperature resistance, chemical resistance, oil resistance and frost aggressivity. Meanwhile, the weight of the concrete can be greatly reduced by adding polyester foaming beads as a filler, so that a better strength-weight ratio is generated, and the cost of transportation and a composite structure is positively influenced. In addition, the polyester foaming beads are added as the filler, so that the carbon footprint of the concrete is reduced, and the sustainability of the concrete is improved. And the problem of poor compatibility of the concrete and the polyester foaming beads can be effectively solved by adding the compatilizer, so that the mixing uniformity of the concrete raw material and the polyester foaming beads is greatly improved. And adding the polyester modified particles into a dry high-pressure reaction kettle, injecting a physical foaming agent into the dry high-pressure reaction kettle through high pressure, and soaking the polyester modified particles by the physical foaming agent under the conditions of 160-260 ℃ and 5-10 MPa of vapor pressure to form a homogeneous saturated system of the polyester modified particles/foaming agent. Thus, the concrete of the present application composition can be used to construct stronger, more flexible, lighter and more sustainable concrete structures, from sidewalks and street guardrails, to precast concrete exterior wall cladding and manholes, and the like.

Further, in the concrete composition, the mass ratio of cement, polyester foaming beads, fly ash, quicklime, sand stone, fine slag, compatilizer and retarder to water reducer is (40-60): (20-30): (5-10): (5-10): (5-10): (5-10): (2-5): (1-5). The inventors found that if the polyester-based expanded beads were excessively added, the bonding force with the concrete would be poor and the beads would be easily peeled off; if the polyester foaming beads are added too little, the weight reduction is not obvious, the carbon footprint is not obviously reduced, and the performances of tensile strength, buffering and the like of the concrete cannot be obviously improved; meanwhile, the compatilizer and the retarder are added into the concrete according to the mass ratio, the concrete and the polyester foaming beads have good compatibility and bonding property, and the dispersion, lubrication, fluidity and slump resistance of the concrete/polyester foaming bead system are the most excellent. Specifically, the above-mentioned compatibilizing agent includes, but is not limited to, at least one of polyether-modified polysiloxane and silicone oil. The inventor discovers that on one hand, the siloxane chain segment in the compatilizer has lipophilicity, has good compatibility with silicate part in concrete, and meanwhile, the polyether chain segment has hydrophilicity, has good compatibility with polyester foaming beads, and solves the problem of poor compatibility between the concrete and the polyester foaming beads; on the other hand, the compatilizer has lower surface tension, heat resistance and excellent acid and alkali resistance, and can reduce the friction between the polyester foaming beads and the concrete when being added into a polyester foaming bead/concrete system, thereby reducing the damage of the polyester foaming beads in the stirring process and improving the leveling property and the durability of the concrete; on the other hand, the existence of hydrophilic groups enables the adhesion between the polyester foaming beads and the concrete to be tighter, the polyester foaming beads are not easy to peel off, the dispersibility of the polyester foaming beads in the concrete is improved, the stress of the concrete is better dispersed on the polyester foaming beads, and the tensile strength, the buffering performance and the heat preservation performance of the concrete are greatly improved.

Further, in the concrete composition, the retarding water reducing agent comprises at least one of sodium gluconate and beta-naphthalene sulfonic acid formaldehyde high condensate sodium salt, and the fine slag can be derived from industrial waste residues, so that waste recycling is facilitated, and the maximum particle size of the fine slag is not higher than 3cm.

Further, the polyester-based expanded beads include polyester-based expanded beads, and the density of the polyester-based expanded beads is 100kg/m ³ ~250kg/m ³ The foaming ratio is 5-20 times, and the cell size is 50-300 um. According to GBT10799-2008 standard, the closed porosity of the polyester expanded beads is above 96%; the polyester-based expanded beads have a tensile strength of greater than 1.0MPa according to ASTM C297 standard. According to one embodiment of the invention, the polyester-based expanded beads include polyesters, chain extenders, nucleating agents, anti-hydrolysis agents, stabilizers, high temperature lubricants, and physical blowing agents. The inventor finds that the addition of the chain extender can effectively improve the melt strength of the polyester and improve the foamability of the polyester, does not have obvious weakening phenomenon along with the processing time, and effectively prevents the occurrence of foam collapse, foam cell breakage and foam cell merging phenomenon in the foaming process; the nucleating agent forms a large number of low potential energy points at the interface between melts in the foaming process to form a large number of uniform nucleation hot spots, thereby being beneficial to obtaining higher-magnification polyester foaming beads subsequently; the hydrolysis resistance agent is added, so that the hydrolysis generated in the processing process of the polyester is effectively reduced, and the stability of the strength of the polyester foaming melt is ensured. The high-temperature resistant lubricant can improve the phenomena of thermal degradation, melt fracture and surface roughness of the melt caused by over-high temperature and shearing, improve the fluidity of the melt, and enable the surface of the extruded material to be smoother, thereby being beneficial to the molding of foaming materials and forming uniform and stable foam cells with controllable size. The physical foaming agent impregnates polyester modified particles of polyester at a certain temperature and vapor pressure (supercritical fluid) to form a polymer/foaming agent homogeneous saturated system, finally, a discharging valve at the bottom of the dry high-pressure reaction kettle is opened to release pressure, internal and external pressure drop and thermodynamic instability are formed, and finally, the foam cells are driven to grow up to obtain polyester foaming beads with excellent characteristics of environmental friendliness, high foaming multiplying power, small volume weight, high compression resilience and the like, so that the polyester foaming beads can be used as fillers in concrete, the stress of the concrete can be better dispersed on the polyester foaming beads, and the performances of tensile strength, buffering and the like of the concrete can be remarkably improved.

Further, in the polyester-based expanded beads, the mass ratio of the polyester, the chain extender, the nucleating agent, the anti-hydrolysis agent, the stabilizer, the high-temperature resistant lubricant and the physical expanding agent is 100: (0.5-2): (0.5-2): (0.5-1): (0.5-1): (0.2 to 0.5): (1.5-3). The inventor finds that if the chain extender is added too high, the melt is gel-like, similar to rubber, and the color is also deep, which is not beneficial to extrusion; if the chain extender is added too low, the growth of foam cannot be supported, so that the foam collapse phenomenon is caused; meanwhile, if the nucleating agent is excessively added, agglomeration is formed, and the formation of uniform cell structures is not facilitated; if the addition of the nucleating agent is too low, the ideal nucleating effect cannot be obtained, heterogeneous nucleation points are few, and a compact foam structure cannot be formed; if the addition amount of the stabilizer exceeds 2 parts by weight, the thermal degradation inhibition effect and the side reaction effect are not increased any more, and precipitation phenomenon exists; if the stabilizer is added too low, the stability of melt processing and the generated thermal degradation cannot be effectively reduced, so that the material changes color; in addition, the hydrolysis inhibitor with the addition amount can reduce the hydrolysis of the polyester in the processing process and ensure the stability of the strength of the polyester foaming melt; if the addition amount of the high-temperature resistant lubricant is too low, the lubricant cannot play a role in lubrication, and the melt is rough at a high temperature; if the addition amount of the high-temperature-resistant lubricant is too high, the melt strength of the melt is reduced, and the support of the foam cells on the gas is not facilitated; meanwhile, if the addition amount of the physical foaming agent is too high, the solubility of the foaming agent is limited under certain temperature and pressure conditions, and the excessive foaming agent does not participate in the growth process of the foam holes, so that the phenomenon of hole crossing exists; if the addition amount of the physical foaming agent is too low, the foaming ratio is low, and the weight reduction is not obvious.

Specifically, the polyester comprises at least one of PET, PETG, PBT, PLA, PC, TPEE, rPET, wherein the base material of the rPET polyester foaming beads can adopt recycled PET bottle flakes, so that the recycling of waste resources is realized, and the problem of environmental protection is solved. In addition, the concrete manufacturing process generates a large amount of CO ₂ The addition of the polyester foaming beads helps to reduce the carbon footprint of the concrete and improve the sustainability of the concrete. Chain extenders include, but are not limited to, pyromellitic anhydride (PMDA), 2' bis (2-oxazoline), and isocyanuric acid trishortAt least one of the water glycerides (TGIC); nucleating agents include, but are not limited to, at least one of silica, talc, montmorillonite; anti-hydrolysis agents include, but are not limited to, hindered aromatic carbodiimide-based anti-hydrolysis agents; stabilizers include, but are not limited to, at least one of trimethyl phosphate (TMP) and triphenyl phosphate (TPP); high temperature resistant lubricants include, but are not limited to, at least one of polyethylene waxes, EBS and PETs, preferably PETs; physical blowing agents include, but are not limited to, at least one of carbon dioxide, nitrogen, alkanes.

Further, the polyester-based foaming beads include at least one of PET foaming beads, TPEE foaming beads, PLA foaming beads, PETG foaming beads, PBT foaming beads and rPET foaming beads, PC foaming beads (including at least one of bisphenol a polycarbonate and carbon dioxide based polycarbonate PPC), that is, the polyester-based foaming beads of the present application are bead combinations composed of at least one of PET foaming beads, TPEE foaming beads, PLA foaming beads, PETG foaming beads, PBT foaming beads, rPET foaming beads and rPETG foaming beads, PC foaming beads, and peak angles are reached from carbon neutralization, preferably rPET foaming beads, PLA foaming beads, PPC foaming beads, which are helpful for reducing carbon footprint of concrete and improving concrete sustainability. The inventor also found that rPET expanded beads have excellent strength, and can produce better strength-to-weight ratio when combined with PETG expanded beads as a filler to be added into concrete, so that the porosity of the foamed concrete is improved, and the tensile strength, the buffering performance and the heat preservation performance are greatly improved. Meanwhile, the polyester foaming beads are filled into the water seepage channels in the concrete system, so that the water seepage resistance of the concrete can be improved; meanwhile, the PETG foaming beads with excellent toughness are added into a concrete/rPET foaming bead system, so that the problem of high brittleness of concrete can be solved, the stress of the rPET foaming beads and slurry in the stirring process is buffered, the foam walls of the polyester foaming beads are not easy to break, and the stability of a foam structure is maintained.

In a further aspect of the invention, the invention provides a method of preparing the concrete described above. According to an embodiment of the invention, the method comprises: cement, fly ash, quicklime, sand stone, fine slag, a compatilizer and a retarding and water reducing agent are mixed with polyester foaming beads so as to obtain concrete. The inventor finds that by mixing cement, polyester foaming beads, fly ash, quicklime, sand stone, fine slag, a compatilizer and a retarder, namely filling the polyester foaming beads in concrete, the tensile strength and the buffering performance of the concrete can be remarkably improved, the cracking probability of the concrete in use is greatly reduced, and thus the casting and the forming can be easily realized; meanwhile, the concrete has good stability, impermeability and heat preservation performance, and shows good temperature resistance, chemical resistance, oil resistance and frost aggressivity. Meanwhile, the weight of the concrete can be greatly reduced by adding polyester foaming beads as a filler, so that a better strength-weight ratio is generated, and the cost of transportation and a composite structure is positively influenced. In addition, the polyester foaming beads are added as the filler, so that the carbon footprint of the concrete is reduced, and the sustainability of the concrete is improved. And the problem of poor compatibility of the concrete and the polyester foaming beads can be effectively solved by adding the compatilizer, so that the mixing uniformity of the concrete raw material and the polyester foaming beads is greatly improved. The addition of the retarding water reducer has the advantages of improving the dispersion, lubrication, fluidity and slump of the concrete, and the existence of hydrophilic groups plays a role in synergistically improving the compatibility of polyester foaming beads and the concrete. Thus, the concrete of the present application composition can be used to construct stronger, more flexible, lighter and more sustainable concrete structures, from sidewalks and street guardrails, to precast concrete exterior wall cladding and manholes, and the like.

Further, the mixing of cement, fly ash, quicklime, sand, fine slag, compatilizer, retarding water reducer and polyester foaming beads can be performed by the following steps: firstly, mixing cement, fly ash, quicklime, water and a retarding water reducer uniformly to obtain a mixture A; adding sand and fine slag into the mixture A, and uniformly stirring to obtain a mixture B; and finally, adding the polyester foaming beads and the compatilizer into the mixture B, and uniformly stirring to obtain the concrete C. Therefore, the mixing efficiency and uniformity of the components can be greatly improved. Preferably, the stirring speed of the mixing process of the cement, the fly ash, the quicklime, the water and the retarding water reducer is 200-300r/min, and the stirring time is 15-20 minutes; the stirring speed of adding the sand stone and the fine slag into the mixture A is 100-200r/min, and the stirring time is 10-15 minutes; the polyester foaming beads and the compatilizer are added into the mixture B, the stirring speed is 50-80r/min, and the stirring time is 10-15 minutes.

Further, the above polyester-based expanded beads include polyester-based expanded beads, which according to one embodiment of the present invention can be prepared by the following steps:

S100: mixing polyester, chain extender, nucleating agent, anti-hydrolysis agent, stabilizer and high-temperature resistant lubricant, and granulating by melt blending extrusion

In the step, polyester, a chain extender, a nucleating agent, an anti-hydrolysis agent, a stabilizer and a high-temperature resistant lubricant are mixed and then are subjected to melt blending extrusion for granulation, so that polyester modified particles with the particle size of 0.5-1mm are obtained. The inventor finds that the addition of the chain extender can effectively improve the melt strength of the polyester and improve the foamability of the polyester, does not have obvious weakening phenomenon along with the processing time, and effectively prevents the occurrence of foam collapse, foam cell breakage and foam cell merging phenomenon in the foaming process; the nucleating agent forms a large number of low potential energy points at the interface between melts in the foaming process to form a large number of uniform nucleation hot spots, thereby being beneficial to obtaining higher-magnification polyester foaming beads subsequently; the hydrolysis resistance agent is added, so that the hydrolysis generated in the processing process of the polyester is effectively reduced, and the stability of the strength of the polyester foaming melt is ensured; the high-temperature resistant lubricant can improve the phenomena of thermal degradation, melt fracture and surface roughness of the melt caused by over-high temperature and shearing, improve the fluidity of the melt, and enable the surface of the extruded material to be smoother, thereby being beneficial to the molding of foaming materials, and being beneficial to forming uniform and stable foam cells with controllable size, and further being beneficial to obtaining the polyester foaming beads with higher multiplying power subsequently.

S200: adding the polyester modified particles and water into a dry high-pressure reaction kettle for mixing, and then injecting a physical foaming agent into the dry high-pressure reaction kettle

In the step, the polyester modified particles obtained by granulation are added into a dry high-pressure reaction kettle, then a physical foaming agent is injected into the dry high-pressure reaction kettle through high pressure, and the physical foaming agent and the polyester modified particles are well soaked under the conditions that the temperature is 160-260 ℃ and the vapor pressure is 5-10 MPa, so that a homogeneous phase saturated system of the polyester modified particles/foaming agent is formed.

S300: opening a discharging valve at the bottom of the dry high-pressure reaction kettle in the step S200 to release pressure to form internal and external pressure drops

In the step, a discharging valve at the bottom of the dry high-pressure reaction kettle in the step S200 is opened to release pressure, so that internal and external pressure drops are formed, the polyester modified particle/foaming agent homogeneous system is in a thermodynamically unstable state, the growth of cells is driven, and then the polyester foaming beads are obtained after cooling, cleaning and drying. Preferably, the change of the internal and external pressure drop is maintained at-0.1 mpa to 0.1mpa. Specifically, compared with the prior art that the pressure in the dry high-pressure reaction kettle is always reduced in the whole discharging process from the beginning of pressure relief discharging to the end of discharging, namely, the pressure drop of polyester beads discharged in the later stage is smaller than that of polyester beads discharged in the earlier stage, so that the problem of uneven density and cell size among polyester foaming beads is caused. Specifically, the polyester foaming beads are filled in concrete, the weight is reduced by more than 30%, the surface of the concrete is free from cracking, the polyester foaming beads are well combined with the concrete, and the tensile strength, the water seepage resistance and the heat insulation performance are improved.

It should be noted that the features and advantages described above for concrete are equally applicable to the method for preparing concrete, and are not described here again.

The following detailed description of embodiments of the invention is provided for the purpose of illustration only and is not to be construed as limiting the invention. In addition, all reagents employed in the examples below are commercially available or may be synthesized according to methods herein or known, and are readily available to those skilled in the art for reaction conditions not listed, if not explicitly stated.

Example 1

Method for preparing expanded beads a:

(1) 100 parts by weight of rPET (from a recovery bottle flake), 0.5 part by weight of pyromellitic anhydride (PMDA), 0.5 part by weight of 2,2' -bis (2-oxazoline) (BO), 1 part by weight of talcum powder (Talc), 1 part by weight of trimethyl phosphate (TMP), 0.5 part by weight of hydrolysis inhibitor TNK-01 (hindered aromatic carbodiimide) and 0.5 part by weight of PETs are uniformly mixed in proportion, and melt extrusion granulation is carried out at 260 ℃ by a double screw extruder (Keplong STS-50MC 11) to obtain modified particles with the diameter of 1 mm;

(2) Adding the modified particles into a dry high-pressure reaction kettle, and then adding a physical foaming agent CO ₂ (the addition amount accounts for 2wt% of the final polyester foaming beads) is injected into a dry high-pressure reaction kettle, and the foaming agent is made to impregnate the rPET modified microparticle homogeneous phase saturated system under the conditions of 10MPa of vapor pressure and 250 ℃;

(3) Releasing pressure and discharging at a discharging valve at the bottom of the reaction kettle, cooling, cleaning with clear water and drying to obtain rPET expanded beads A (density of 200 kg/m) ³ ）。

The method for preparing concrete comprises the following steps:

(a) 11000g of cement, 1150g of fly ash, 1080g of quicklime, 5000g of water and 250g of sodium gluconate are stirred for 15 minutes at a stirring speed of 250r/min to obtain a mixture A;

(b) Then 1080g of sand and 1150g of fine slag are added into the mixture A and stirred for 12 minutes under the condition of the stirring speed of 130r/min, so as to obtain a mixture B;

(c) 4500g of the above-mentioned expanded beads A and 400g of polyether-modified polysiloxane were added to the mixture B and stirred at a stirring speed of 70r/min for 12 minutes to obtain concrete.

Example 2

Method for preparing expanded beads C:

(1) 100 parts by weight of PETG, 0.5 part by weight of 2,2' -bis (2-oxazoline) (BO), 0.5 part by weight of triglycidyl isocyanurate (TGIC), 1 part by weight of talcum powder (Talc), 0.8 part by weight of trimethyl phosphate (TMP), 0.5 part by weight of hydrolysis inhibitor TNK-01 (hindered aromatic carbodiimide) and 0.5 part by weight of PETs are uniformly mixed according to a proportion, and the mixture is subjected to melt extrusion granulation at 220 ℃ by a double screw extruder (Keplong STS-50 MC 11) to obtain modified particles with the diameter of 1 mm;

(2) Adding the modified particles into a dry high-pressure reaction kettle, and then respectively adding physical foaming agents CO ₂ (the addition amount accounts for 2wt% of the final polyester foam beads) and cyclopentane serving as a material foaming agent (the addition amount accounts for 1wt% of the final polyester foam beads) are injected into a dry high-pressure reaction kettle, and under the conditions of 6MPa of vapor pressure and 220 ℃, PETG modified particles are soaked by the foaming agent to form a homogeneous saturated system;

(3) Releasing pressure and discharging at a discharging valve at the bottom of the reaction kettle, cooling, cleaning with clear water, and drying to obtain PETG foam beads C (with density of 150 kg/m) ³ ）。

The method for preparing concrete comprises the following steps:

(a) 10000g of cement, 1280g of fly ash, 1150g of quicklime, 5000g of water and 250g of sodium gluconate are stirred for 15 minutes at a stirring speed of 220r/min to obtain a mixture A;

(b) Then 1080g of sand and 1250g of fine slag are added into the mixture A and stirred for 12 minutes under the condition of the stirring speed of 120r/min, so as to obtain a mixture B;

(c) 4500g of the expanded beads A of example 1, 500g of the expanded beads C of example 1 and 520g of polyether-modified polysiloxane were added to the mixture B and stirred at a stirring speed of 60r/min for 13 minutes to obtain concrete.

Example 3

Method for preparing expanded beads B:

(1) 100 parts by weight of rPET (from recycled bottle flakes), 0.5 part by weight of pyromellitic anhydride (PMDA), 0.5 part by weight of 2,2' -bis (2-oxazoline) (BO), 1 part by weight of silica (SiO ₂ ) Mixing trimethyl phosphate (TMP) 0.5 weight parts, hydrolysis inhibitor TNK-01 (hindered aromatic carbodiimide) 0.5 weight parts, and PETs 0.5 weight partsUniformly, and carrying out melt extrusion granulation at 260 ℃ by a double-screw extruder (Keplong STS-50MC 11) to obtain modified particles with the diameter of 1 mm;

(2) Adding the modified particles into a dry high-pressure reaction kettle, and then adding a physical foaming agent CO ₂ (the addition amount accounts for 2wt% of the final polyester foaming beads) is injected into a dry high-pressure reaction kettle, and the foaming agent is used for impregnating rPET modified particles to form a homogeneous saturated system under the conditions of 10MPa of vapor pressure and 260 ℃;

(3) Releasing pressure and discharging at a discharging valve at the bottom of the reaction kettle, cooling, cleaning with clear water and drying to obtain rPET expanded beads B (density of 150 kg/m) ³ ）。

The method for preparing concrete comprises the following steps:

(c) 4500g of the above-mentioned expanded beads B and 400g of silicone oil were added to the mixture B and stirred at a stirring speed of 70r/min for 12 minutes to obtain concrete.

Example 4

The method for preparing concrete comprises the following steps:

(c) 4500g of the expanded beads B of example 3, 500g of the expanded beads C obtained in example 2 and 520g of polyether-modified polysiloxane were added to the mixture B and stirred at a stirring speed of 60r/min for 13 minutes to obtain concrete.

Example 5

Method for preparing expanded beads D:

(1) 100 parts by weight of PLA, 0.5 part by weight of pyromellitic anhydride (PMDA), 1 part by weight of talcum powder (Talc), 0.5 part by weight of triphenyl phosphate (TPP), 0.5 part by weight of hydrolysis inhibitor TNK-01 (hindered aromatic carbodiimide) and 0.3 part by weight of PETs are uniformly mixed according to a proportion, and melted, extruded and granulated at 190 ℃ by a double screw extruder (Keplong STS-50 MC 11) to obtain modified particles with the diameter of 1 mm;

(2) Adding the modified particles into a dry high-pressure reaction kettle, and then adding a physical foaming agent N ₂ (the addition amount accounts for 3wt% of the final polyester foaming beads) is injected into a dry high-pressure reaction kettle, and the PLA modified particles are soaked by the foaming agent to form a homogeneous saturated system under the conditions of 5MPa of vapor pressure and 190 ℃;

(3) Releasing pressure and discharging at a discharging valve at the bottom of the reaction kettle, cooling, cleaning with clear water and drying to obtain PLA foaming beads D (with density of 180 kg/m) ³ ）。

The method for preparing concrete comprises the following steps:

(a) 11200g of cement, 1100g of fly ash, 1180g of quicklime, 5000g of water and 250g of sodium gluconate are stirred for 15 minutes at a stirring speed of 250r/min to obtain a mixture A;

(b) Then adding 500g of sand and 200g of fine slag into the mixture A, and stirring for 12 minutes at the stirring speed of 130r/min to obtain a mixture B;

(c) 4000g of the above-mentioned expanded beads D and 480g of polyether-modified polysiloxane were added to the mixture B and stirred at a stirring speed of 70r/min for 12 minutes to obtain concrete.

Example 6

Method for preparing expanded beads E:

(1) 100 parts by weight of rPBT, 0.5 part by weight of 2,2' -bis (2-oxazoline) (BO), 1 part by weight of talcum powder (Talc), 0.5 part by weight of triphenyl phosphate (TPP), 0.5 part by weight of hydrolysis inhibitor TNK-01 (hindered aromatic carbodiimide) and 0.3 part by weight of PETs are uniformly mixed according to a proportion, and melted, extruded and granulated at 220 ℃ by a double screw extruder (Keplong STS-50MC 11) to obtain modified particles with the diameter of 1 mm;

(2) Adding the modified particles into a dry high-pressure reaction kettle, and then adding a physical foaming agent CO ₂ (the addition amount accounts for 1.5 weight percent of the final polyester foaming beads) is injected into a dry high-pressure reaction kettle, and the PBT modified particles are soaked by the foaming agent to form a homogeneous saturated system under the conditions of 7MPa of vapor pressure and 220 ℃;

(3) Releasing pressure and discharging at a discharging valve at the bottom of the reaction kettle, cooling, cleaning with clear water and drying to obtain PBT foaming beads E (with density of 180 kg/m) ³ ）。

The method for preparing concrete comprises the following steps:

(a) 10500g of cement, 1350g of fly ash, 1280g of quicklime, 5000g of water and 250g of sodium salt of beta-naphthalenesulfonate formaldehyde high condensate are stirred for 15 minutes at a stirring speed of 250r/min to obtain a mixture A;

(b) Then 1250g of sand and 1280g of fine slag are added into the mixture A and stirred for 12 minutes under the condition of the stirring speed of 120r/min, thus obtaining a mixture B;

(c) 4200g of the above-mentioned expanded beads E and 480g of polyether-modified polysiloxane were added to the mixture B and stirred at a stirring speed of 70r/min for 12 minutes to obtain concrete.

Example 7

Method for preparing expanded beads F:

(1) 100 parts by weight of TPEE, 1 part by weight of triglycidyl isocyanurate (TGIC), 1 part by weight of silicon dioxide (SiO ₂ ) Mixing 0.5 weight part of triphenyl phosphate (TPP), 0.5 weight part of hydrolysis inhibitor TNK-01 (hindered aromatic carbodiimide) and 0.2 weight part of polyethylene wax uniformly in proportion, and carrying out melt extrusion granulation at 220 ℃ by a double screw extruder (Keplong STS-50M 11) to obtain modified particles with the diameter of 1 mm;

(2) Adding the modified particles into a dry high-pressure reaction kettle, and then adding a physical foaming agent CO ₂ (the addition amount accounts for 2wt% of the final polyester foaming beads) is injected into a dry high-pressure reaction kettle, and the foaming agent is made to impregnate TPEE modified particles to form a homogeneous saturated system under the conditions of the vapor pressure of 6MPa and 220 ℃;

(3) Releasing pressure and discharging at a discharging valve at the bottom of the reaction kettle, cooling, cleaning with clear water, and drying to obtain TPEE foaming beads F (density 160 kg/m) ³ ）。

The method for preparing concrete comprises the following steps:

(a) 10200g of cement, 1280g of fly ash, 1280g of quicklime, 5000g of water and 250g of beta-naphthalenesulfonic acid formaldehyde high condensate sodium salt are stirred for 15 minutes at a stirring speed of 250r/min to obtain a mixture A;

(b) Then 1250g of sand and 1250g of fine slag are added into the mixture A and stirred for 12 minutes under the condition of the stirring speed of 130r/min to obtain a mixture B;

(c) 4600g of the above-mentioned expanded beads F and 480g of polyether-modified polysiloxane were added to the mixture B and stirred at a stirring speed of 70r/min for 12 minutes to obtain concrete.

Example 8

Method for preparing expanded beads G:

(1) 100 parts by weight of PET, 0.5 part by weight of pyromellitic anhydride (PMDA), 0.5 part by weight of 2,2' -bis (2-oxazoline) (BO), 2 parts by weight of montmorillonite (MMT), 1 part by weight of trimethyl phosphate (TMP), 0.5 part by weight of hydrolysis inhibitor TNK-01 (hindered aromatic carbodiimide) and 0.5 part by weight of EBS are uniformly mixed in proportion, and are subjected to melt extrusion granulation at 260 ℃ by a double screw extruder (Keplong STS-50MC 11) to obtain modified particles with the diameter of 1 mm;

(2) Adding the modified particles into a dry high-pressure reaction kettle, and then adding a physical foaming agent CO ₂ (the addition amount accounts for 2wt% of the final polyester foaming beads) is injected into a dry high-pressure reaction kettle, and the foaming agent is used for impregnating PET modified particles to form a homogeneous saturated system under the conditions of 10MPa of vapor pressure and 260 ℃;

(3) Releasing pressure and discharging at a discharging valve at the bottom of the reaction kettle, cooling, cleaning with clear water and drying to obtain PET foaming beads G (density of 150 kg/m) ³ ）。

The method for preparing concrete comprises the following steps:

(a) 10800g of cement, 1180g of fly ash, 1120g of quicklime, 5000g of water and 250g of sodium gluconate are stirred for 15 minutes at a stirring speed of 250r/min to obtain a mixture A;

(b) Then 1080g of sand and 1150g of fine slag are added into the mixture A and stirred for 15 minutes under the condition of the stirring speed of 120r/min, so as to obtain a mixture B;

(c) 4500G of the above-mentioned expanded beads G and 450G of polyether-modified polysiloxane were added to the mixture B and stirred at a stirring speed of 70r/min for 12 minutes to obtain concrete.

Example 9

Method for preparing expanded beads H:

(1) 100 parts by weight of PPC, 1 part by weight of 2,2' -bis (2-oxazoline) (BO), 2 parts by weight of montmorillonite (MMT), 1 part by weight of trimethyl phosphate (TMP), 0.5 part by weight of hydrolysis inhibitor TNK-01 (hindered aromatic carbodiimide) and 0.5 part by weight of EBS are uniformly mixed according to a proportion, and melted, extruded and granulated at 160 ℃ by a double screw extruder (Keplong STS-50MC 11) to obtain modified particles with the diameter of 1 mm;

(2) Adding the modified particles into a dry high-pressure reaction kettle, and then adding a physical foaming agent CO ₂ (the addition amount accounts for 2wt% of the final polyester foaming beads) is injected into a dry high-pressure reaction kettle, and the PPC modified particles are impregnated with a foaming agent to form a homogeneous saturated system under the conditions of 10MPa of vapor pressure and 160 ℃;

(3) Releasing pressure at the discharge valve at the bottom of the reaction kettle, discharging, cooling, cleaning with clear water, and drying to obtain PPC foaming beads H (density of 150 kg/m) ³ ）。

The method for preparing concrete comprises the following steps:

(c) 4500g of the above-mentioned expanded beads H and 450g of polyether-modified polysiloxane were added to the mixture B and stirred at a stirring speed of 70r/min for 12 minutes to obtain concrete.

Example 10

The method for preparing concrete comprises the following steps:

(a) 10400g of cement, 1000g of fly ash, 1280g of quicklime, 5000g of water and 250g of sodium gluconate are stirred for 15 minutes at a stirring speed of 250r/min to obtain a mixture A;

(b) Then 1250g of sand and 1380g of fine slag are added into the mixture A and stirred for 15 minutes under the condition of the stirring speed of 130r/min to obtain a mixture B;

(c) 3500G of the above-mentioned expanded beads G, 1000G of the above-mentioned expanded beads F, 520G of polyether-modified polysiloxane were added to the mixture B and stirred at a stirring speed of 70r/min for 12 minutes to obtain concrete.

Example 11

The method for preparing concrete comprises the following steps:

(a) 10100g of cement, 1240g of fly ash, 1200g of quicklime, 5000g of water and 250g of sodium gluconate are stirred for 15 minutes at a stirring speed of 250r/min to obtain a mixture A;

(b) Then 1250g of sand and 1280g of fine slag are added into the mixture A and stirred for 15 minutes under the condition of the stirring speed of 130r/min, thus obtaining a mixture B;

(c) 900g of the above-mentioned expanded beads C, 3800g of the above-mentioned expanded beads D, 520g of polyether-modified polysiloxane were added to the mixture B and stirred at a stirring speed of 70r/min for 12 minutes to obtain concrete.

Example 12

The method for preparing concrete comprises the following steps:

(a) 10500g of cement, 1100g of fly ash, 1180g of quicklime, 5000g of water and 250g of sodium gluconate are stirred for 15 minutes at a stirring speed of 250r/min to obtain a mixture A;

(b) Then 1150g of sand and 1150g of fine slag are added into the mixture A and stirred for 15 minutes under the condition of the stirring speed of 130r/min, thus obtaining a mixture B;

(c) 4100g of the above-mentioned expanded beads A, 600g of the above-mentioned expanded beads F, 520g of polyether-modified polysiloxane were added to the mixture B and stirred at a stirring speed of 70r/min for 12 minutes to obtain a concrete.

Example 13

The method for preparing concrete comprises the following steps:

(a) 10600g of cement, 1280g of fly ash, 1120g of quicklime, 5000g of water and 250g of sodium gluconate are stirred for 15 minutes at a stirring speed of 250r/min to obtain a mixture A;

(c) 1000g of the above-mentioned expanded beads E, 3500g of the above-mentioned expanded beads F, 520g of polyether-modified polysiloxane were added to the mixture B and stirred at a stirring speed of 70r/min for 12 minutes to obtain concrete.

Example 14

The method for preparing concrete comprises the following steps:

(a) 10400g of cement, 1170g of fly ash, 1240g of quicklime, 500g of water and 250g of sodium gluconate are stirred for 15 minutes at a stirring speed of 250r/min to obtain a mixture A;

(b) Then 1250g of sand and 1150g of fine slag are added into the mixture A and stirred for 15 minutes under the condition of the stirring speed of 120r/min, thus obtaining a mixture B;

(c) 1000G of the above-mentioned expanded beads E, 3600G of the above-mentioned expanded beads G, 520G of polyether-modified polysiloxane were added to the mixture B and stirred at a stirring speed of 70r/min for 12 minutes to obtain concrete.

Example 15

The method for preparing concrete comprises the following steps:

(a) 11000g of cement, 1020g of fly ash, 1080g of quicklime, 5000g of water and 250g of sodium gluconate are stirred for 15 minutes at a stirring speed of 250r/min to obtain a mixture A;

(b) Then 1050g of sand and 1150g of fine slag are added into the mixture A and stirred for 15 minutes under the condition of the stirring speed of 120r/min, so as to obtain a mixture B;

(c) 3500g of the above-mentioned expanded beads B, 1000g of the above-mentioned expanded beads F, 520g of polyether-modified polysiloxane were added to the mixture B and stirred at a stirring speed of 70r/min for 12 minutes to obtain concrete.

Example 16

The method for preparing concrete comprises the following steps:

(c) 3500g of the above-mentioned expanded beads A, 1000g of the above-mentioned expanded beads H, 520g of polyether-modified polysiloxane were added to the mixture B and stirred at a stirring speed of 70r/min for 12 minutes to obtain concrete.

Comparative example

The method for preparing concrete comprises the following steps:

(a) 15000g of cement, 1200g of fly ash, 1080g of quicklime, 5000g of water and 250g of sodium gluconate are stirred for 15 minutes at a stirring speed of 250r/min to obtain a mixture A;

(b) Then adding 1280g of sand and 1350g of fine slag into the mixture A, and stirring for 12 minutes at the stirring speed of 130r/min to obtain a mixture B;

(c) 400g of polyether-modified polysiloxane was added to the mixture B and stirred at a stirring speed of 70r/min for 12 minutes to obtain concrete.

Evaluation:

1. the foam density, the foaming multiplying power, the cell size, the difference between the maximum size and the minimum size of the cells and the bending strength and the dimensional heat stability of the foaming beads A-H obtained in the embodiment are evaluated;

2. method for evaluating performance of expanded beads:

foam density: according to GB/T6343-86

Foaming ratio: ratio of density of material after foaming to density before foaming

Cell size: scanning Electron Microscope (SEM) sizing

Difference between maximum size and minimum size of cells: scanning Electron Microscope (SEM) sizing

Compressive strength: according to ISO 844

The test results of the expanded beads A to H obtained in the above examples are shown in Table 1.

TABLE 1 polyester-based expanded beads A-H Performance data

	Density (Kg/m 3)	Foaming multiplying power (times)	Cell size (μm)	Difference between maximum size and minimum size (μm) of cells	Compressive Strength (MPa)
						Expanded beads A	200	7	210	40	2.42
Expanded beads B	150	9	150	45	1.95
						Expanded beads C	150	9	160	30	1.65
Expanded beads D	180	8	180	45	1.74
						Expanded beads E	180	8	200	40	1.96
Expanded beads F	160	9	180	35	1.64
						Expanded beads G	150	9	160	35	2.10
Expanded beads H	150	9	190	40	1.89

3. The concrete obtained in examples 1-16 and comparative examples were characterized by evaluating volume weight, 3d flexural strength, thermal conductivity, surface cracking condition and water absorption;

4. A method for evaluating concrete;

weight by volume: GB/T1966-1996

Thermal conductivity coefficient: GB/T10294

Surface cracking conditions: JC/T984

Water absorption rate: GB/T5486

3d flexural strength: GB/T17671

The results of characterization of the properties of the concretes obtained in examples 1 to 16 are shown in Table 2.

Table 2 data for testing the performance of concrete

	Bulk density (g/cm 3)	3d flexural Strength (MPa)	Coefficient of thermal conductivity (W/m.K)	Surface cracking conditions	Water absorption (V%/V%) for 2h
						Example 1	2010	5.6	0.054	No cracking	7.4
Example 2	1845	5.8	0.051	No cracking	7.1
						Example 3	1960	5.5	0.055	No cracking	7.6
Example 4	1775	5.7	0.050	No cracking	7.3
						Example 5	1945	5.4	0.054	No cracking	7.4
Example 6	1950	5.3	0.054	No cracking	7.6
						Example 7	2020	5.5	0.055	No cracking	7.6
Example 8	2010	5.4	0.056	No cracking	7.8
						Example 9	1940	5.5	0.055	No cracking	7.5
Example 10	1980	5.4	0.054	No cracking	7.4
						Example 11	1860	5.6	0.055	No cracking	7.7
Example 12	1920	5.5	0.055	No cracking	7.6
						Example 13	1820	5.4	0.054	No cracking	7.9
Example 14	1910	5.5	0.055	No cracking	7.6
						Example 15	1985	5.5	0.056	No cracking	7.7
Example 16	1930	5.5	0.056	No cracking	7.8
						Comparative example	2450	5.4	0.058	With cracking of	8.7

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims

1. The concrete is characterized by comprising the following components: cement, polyester foaming beads, fly ash, quicklime, sand stone, fine slag, a compatilizer and a set retarder; the mass ratio of the cement to the polyester foaming beads to the fly ash to the quicklime to the sand and the fine slag to the compatilizer to the retarder water reducer is (40-60): (20-30): (5-10): (5-10): (5-10): (5-10): (2-10): (1-5);

the compatilizer is at least one selected from polyether modified polysiloxane and silicone oil;

the polyester foaming beads comprise polyester, a chain extender, a nucleating agent, an anti-hydrolysis agent, a stabilizer, a high-temperature resistant lubricant and a physical foaming agent; the mass ratio of the polyester, the chain extender, the nucleating agent, the anti-hydrolysis agent, the stabilizer, the high-temperature resistant lubricant and the physical foaming agent is 100: (0.5-2): (0.5-2): (0.5-1): (0.5-1): (0.2 to 0.5): (1.5-3);

The polyester foaming beads are prepared by the following steps:

(1) Mixing polyester, a chain extender, a nucleating agent, an anti-hydrolysis agent, a stabilizer and a high-temperature resistant lubricant, and then carrying out melt blending extrusion for granulation to obtain polyester modified particles;

(2) Adding the polyester modified particles into a dry high-pressure reaction kettle, injecting a physical foaming agent into the dry high-pressure reaction kettle through high pressure, and soaking the polyester modified particles by the physical foaming agent under the conditions of 160-260 ℃ and 5-10 MPa of vapor pressure to form a polyester modified particle/foaming agent homogeneous saturated system;

(3) Opening a discharging valve at the bottom of the dry high-pressure reaction kettle in the step (2) to release pressure, forming internal and external pressure drop, enabling the polyester modified particle/foaming agent homogeneous system to be in a thermodynamically unstable state, driving cells to grow up, and then cooling, cleaning and drying to obtain polyester foaming beads.

2. The concrete of claim 1, wherein the set retarder water reducer comprises at least one of sodium gluconate and sodium salt of a beta-naphthalene sulfonic acid formaldehyde high condensate.

3. The concrete according to claim 1, wherein the density of the polyester-based expanded beads is 100kg/m ³ ~250kg/m ³ 。

4. The concrete of claim 1, wherein the polyesters comprise at least one of PET, PETG, PBT, PLA, PC, TPEE and rPET.

5. The concrete of claim 1, wherein the chain extender comprises at least one of pyromellitic anhydride, 2' bis (2-oxazoline), and triglycidyl isocyanurate.

6. The concrete of claim 1, wherein the nucleating agent comprises at least one of silica, talc, and montmorillonite.

7. The concrete according to claim 1, wherein the hydrolysis inhibitor is a sterically hindered aromatic carbodiimide-based hydrolysis inhibitor.

8. The concrete of claim 5, wherein the stabilizer comprises at least one of trimethyl phosphate and triphenyl phosphate.

9. The concrete of claim 1, wherein the high temperature resistant lubricant comprises at least one of polyethylene waxes, EBS, and PETs.

10. The concrete of claim 9, wherein the high temperature resistant lubricants are PETs.

11. The concrete of claim 1, wherein the physical blowing agent comprises at least one of carbon dioxide, nitrogen, alkanes, and fluorides.

12. A method of preparing concrete according to any one of claims 1 to 11, comprising the steps of: cement, fly ash, quicklime, sand stone, fine slag, a compatilizer and a retarding and water reducing agent are mixed with polyester foaming beads so as to obtain concrete.