CN114573299A - Anti-cracking and anti-impact ultrahigh-performance radiation-proof concrete and preparation method thereof - Google Patents

Abstract

The invention provides crack-resistant and impact-resistant ultrahigh-performance radiation-proof concrete and a preparation method thereof₂Calcium carbonate crystal whiskers, an expanding agent, heavy metal sludge regeneration aggregate, a water reducing agent and super absorbent resin. The ultra-high performance radiation-proof concrete is prepared by doping nano TiO₂The calcium carbonate whiskers and the hybrid fibers toughen the concrete material from different scales and are distributed in the concrete in a disorderly manner, and the calcium carbonate whiskers and the hybrid fibers have ultrahigh tensile strength and complementary size ranges, can bridge cracks in the concrete from different scales, absorb impact energy when the concrete is subjected to impact load, and effectively improve the impact toughness of the radiation-proof ultrahigh-performance concrete. Micro-nano scale material TiO₂The filling effect of the calcium carbonate crystal whisker can improve the compactness of the ultra-high performance concrete, and the TiO crystal whisker₂The material has a strong ray shielding effect, and can enhance the radiation protection performance of the ultra-high performance concrete.

Description

Anti-cracking and anti-impact ultrahigh-performance radiation-proof concrete and preparation method thereof

Technical Field

The invention relates to the field of radiation shielding building materials, in particular to anti-cracking and anti-impact ultrahigh-performance radiation-proof concrete and a preparation method thereof.

Background

With the increasing maturity and widespread use of nuclear technology, the protection against its associated gamma and neutron rays is also of increasing importance. The radiation-proof concrete is the most widely and economically used nuclear radiation protection material at present, and compared with metal and organic polymer protection materials, the radiation-proof concrete has the advantages of wide raw material source, convenience in construction, low manufacturing cost and the like. Nuclear engineering facilities, which are critical to national security and development, are destroyed and destroyed (possibly by high-tech weapon attacks, explosion attacks, earthquakes, etc.) causing enormous national property losses and environmental security damages. The radiation-proof concrete is used as a main structural material of nuclear engineering (nuclear power station) and nuclear medicine (hospital radiology department) buildings, and not only plays a role in shielding rays, but also is an important safety guarantee of nuclear facilities. Therefore, the design strength and the impact resistance of the radiation-proof concrete need to be improved, and the radiation-proof and impact-resistant high-strength concrete is prepared to resist the damage of explosion impact load or high-strength dynamic load caused by major geological disasters to buildings, so that the important strategic requirements of national defense and civil nuclear engineering safety protection in China are met.

The ultra-high performance concrete has the characteristics of high compactness, ultra-high strength and high toughness, and is an ideal material for building ultra-high strength and impact-resistant ray shielding buildings. At present, the measure for preparing the radiation-proof concrete at home and abroad is mainly to enhance the ray absorption capacity of the concrete by adding minerals containing heavy metal elements, such as aggregates of serpentine, magnetite, limonite, barite and the like, so as to improve the gamma ray and neutron ray absorption capacity of the concrete. For example, the prior art discloses radiation-proof ultra-high performance concrete and a preparation method thereof, which comprises hematite, steel fiber and other raw materials.

Although the prior art adopts the aggregate containing the heavy metal mineral to prepare the ultra-high performance concrete and increases the ray shielding capability of the concrete, the prepared concrete has two problems: (1) natural mineral with high density (barite 4.3X 10)³kg/m³4.0 to 5.0 x 10 of iron ore³kg/m³) The high-density aggregate is also easy to settle and separate when used for preparing concrete, so that the uniformity and the quality of the concrete are poor, and the mechanical property of the concrete is influenced; (2) the ultra-high performance concrete cementing material has high dosage and overlarge shrinkage (up to 8.0 multiplied by 10)^-4). If shrinkage cracks occur so that the radiation is transmitted along the cracks, the radiation shielding ability of the concrete is greatly compromised. And the steam curing is adopted to improve the volume stability and the crack resistance of the component, thereby limitingThe application of the concrete in cast-in-place concrete building cannot give full play to the advantage of convenience in construction of concrete materials; (3) only steel fibers are mixed in the ultra-high performance concrete, so that the expansion of micro cracks cannot be inhibited, and the impact resistance is designed in a targeted manner; therefore, the improvement of the crack resistance and the impact resistance of the concrete and the improvement of the homogeneity of the concrete are the key points for preparing the radiation-proof ultrahigh-performance concrete.

Disclosure of Invention

In view of this, the invention provides an anti-cracking and anti-impact ultrahigh-performance radiation-proof concrete and a preparation method thereof, so as to solve or partially solve the problems in the prior art.

In a first aspect, the invention provides crack-resistant and impact-resistant ultrahigh-performance radiation-proof concrete, which comprises the following raw materials in parts by weight: 690-740 kg/m cement³230-280 kg/m of mineral admixture³Nano TiO 2₂ 20～40kg/m³10-30 kg/m of calcium carbonate crystal whisker³1400-1800 kg/m of heavy metal sludge regenerated aggregate³2-6 kg of super absorbent resin and 40-70 kg/m of expanding agent³10-30 kg/m of water reducing agent³160-260 kg/m of hybrid fiber³180 to 200kg/m of water³。

Preferably, the mineral admixture is a mixture of fly ash microbeads and silica fume, wherein the proportion of the silica fume is 100-140 kg/m³The rest is fly ash micro-beads; wherein the specific surface area of the silica fume is more than or equal to 15000m²Per kg, active index not less than 105%, SiO₂The mass content is more than or equal to 95 percent, and the ignition loss is less than or equal to 4 percent; the specific surface area of the fly ash micro-beads is more than or equal to 1300m²/kg, activity index is more than or equal to 90 percent.

Preferably, the anti-cracking and anti-impact ultrahigh-performance radiation-proof concrete is prepared by mixing steel fibers and basalt fibers; the steel fiber is a flat steel fiber with copper plated on the surface, the length of the steel fiber is 10-16 mm, the diameter of the steel fiber is 0.18-0.2 mm, the tensile strength is not less than 2850MPa, and the density is 8.0g/cm³(ii) a The basalt fiber has the length of 5-20 mm, the diameter of 5-40 mu M and the tensile strength of more than or equal to 1000MPa; the volume percentage of basalt fibers in the hybrid fiber is 5-20%.

Preferably, the anti-cracking and anti-impact ultrahigh-performance radiation-proof concrete contains 10-30% by mass of heavy metal oxide, 20-30% by mass of aluminum oxide and 14-19% by mass of silicon oxide in the heavy metal sludge regenerated aggregate.

Preferably, the apparent density of the heavy metal sludge regenerated aggregate is 2.8-3.2 kg/m³The grain diameter is less than or equal to 2.36mm, the fineness modulus is 2.2-3.2, and the crushing value is less than or equal to 15%.

Preferably, the crack-resistant and impact-resistant ultrahigh-performance radiation-proof concrete is prepared from the nano TiO₂The specific surface area of (a) is 35-95 m²/g。

Preferably, the high water absorption resin is polyacrylic resin, and the particle size of the high water absorption resin is 30-250 μm.

Preferably, the expansion agent is calcium sulphoaluminate-calcium oxide type or compound expansion agent.

Preferably, the water reducing agent is a polycarboxylic acid high-efficiency water reducing agent, and the cement is P.O 52.5 portland cement.

In a second aspect, the invention also provides a preparation method of the crack-resistant impact-resistant ultrahigh-performance radiation-proof concrete, which comprises the following steps:

mixing cement, mineral admixture and nano TiO₂Adding the calcium carbonate crystal whisker, the expanding agent and the heavy metal sludge regenerated aggregate into a concrete mixer, uniformly stirring, and then adding water, a water reducing agent and super absorbent resin; after the components are uniformly stirred, adding the hybrid fibers, uniformly stirring, and carrying out die filling, vibrating and forming to obtain a concrete mixture;

and covering the surface of the concrete mixture with a waterproof film, and then placing the concrete mixture into a curing room for curing to obtain the cracking-resistant and impact-resistant ultrahigh-performance radiation-proof concrete.

Compared with the prior art, the crack-resistant and impact-resistant ultrahigh-performance radiation-proof concrete and the method have the following beneficial effects:

1. the crack-resistant and impact-resistant ultrahigh-performance radiation-proof concrete is prepared by doping nano TiO₂The concrete material toughening is carried out on the calcium carbonate whiskers and the hybrid fibers (specifically comprising basalt fibers and steel fibers) from different scales, the calcium carbonate whiskers and the hybrid fibers are distributed in the concrete disorderly, the calcium carbonate whiskers and the hybrid fibers have ultrahigh tensile strength, the size ranges of the calcium carbonate whiskers and the hybrid fibers are mutually complemented (ranging from nanometer to millimeter), cracks in the concrete from different scales can be bridged, impact energy is absorbed when the concrete is subjected to impact load, and the impact toughness of the radiation-proof ultrahigh-performance concrete is effectively improved. Micro-nano scale material TiO₂The filling effect of the calcium carbonate crystal whisker can improve the compactness of the ultra-high performance concrete, and the TiO crystal whisker₂The material has a strong ray shielding effect, and can enhance the radiation resistance of the ultra-high performance concrete;

2. according to the crack-resistant impact-resistant ultrahigh-performance radiation-proof concrete, the heavy metal sludge recycled aggregate is adopted to replace natural heavy aggregate, so that on one hand, industrial waste is eliminated, the advantages of low density and good ray shielding performance of the heavy metal sludge recycled aggregate are utilized, the segregation of concrete mixture prepared from the natural heavy aggregate is avoided, the concrete uniformity is improved, on the other hand, the surface of the recycled aggregate is rough and is tightly bonded with concrete slurry, and meanwhile, the recycled aggregate is close to the elastic modulus of the concrete slurry, and the stress concentration of an interface transition region can be reduced when the concrete is subjected to impact load;

3. according to the anti-cracking and anti-impact ultrahigh-performance radiation-proof concrete, the high water-absorbing resin capable of absorbing water in advance is doped, so that water is slowly released in the slurry hydration process to play an internal curing effect, and the early shrinkage of the ultrahigh-performance concrete is reduced; the expansion agent is hydrated to compensate shrinkage under the action of internal curing water, the shrinkage of the ultrahigh-performance concrete is reduced by combining the expansion agent and the curing water, the cracking risk of the radiation-proof ultrahigh-performance concrete is reduced, and the initial microcrack in the ultrahigh-performance concrete is inhibited from growing.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the embodiments of the present invention in conjunction with the technical solutions. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. The components of embodiments of the present invention that are generally shown herein may be arranged and designed in a wide variety of different configurations.

In the following, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

The embodiment of the application provides an anti-cracking and anti-impact ultrahigh-performance radiation-proof concrete which comprises the following raw materials in parts by weight: 690-740 kg/m cement³230-280 kg/m of mineral admixture³TiO 2 nanoparticles₂ 20～40 kg/m³10-30 kg/m of calcium carbonate crystal whisker³1400-1800 kg/m of heavy metal sludge regenerated aggregate³2-6 kg of super absorbent resin and 40-70 kg/m of swelling agent³10-30 kg/m of water reducing agent³160-260 kg/m of hybrid fiber³180 to 200kg/m of water³。

The anti-cracking and impact-resistant ultrahigh-performance radiation-proof concrete utilizes heavy metal sludge regenerated aggregate as aggregate, and is added with nano TiO₂Increase the compactness degree of the matrix and improve the ray shielding performance, and is based on the relative low density (2.8-3.2 multiplied by 10) of the aggregate³kg/m³) And in addition, the internal curing of the super absorbent resin SAP and the compensation of shrinkage by an expanding agent effectively reduce the early cracking risk of the ultrahigh-performance concrete, and the ultrahigh-performance anti-radiation concrete with crack resistance and impact resistance is prepared.

In some embodiments, the mineral admixture is a mixture of fly ash microbeads and silica fume, wherein the silica fume is proportioned100 to 140kg/m³The rest is fly ash micro-beads; wherein the specific surface area of the silica fume is more than or equal to 15000m²Per kg, active index not less than 105%, SiO₂The mass content is more than or equal to 95 percent, and the ignition loss is less than or equal to 4 percent; the specific surface area of the fly ash micro-beads is more than or equal to 1300m²The activity index is more than or equal to 90 percent and the water demand ratio is less than or equal to 95 percent.

In some embodiments, the hybrid fiber is a blend of steel fibers and basalt fibers; the steel fiber is a flat steel fiber with copper plated on the surface, the length of the steel fiber is 10-16 mm, the diameter of the steel fiber is 0.18-0.2 mm, the tensile strength is not less than 2850MPa, and the density is 8.0g/cm³(ii) a The length of the basalt fiber is 5-20 mm, the diameter is 5-40 mu m, and the tensile strength is more than or equal to 1000 MPa; the volume percentage of basalt fibers in the hybrid fiber is 5-20%.

In some embodiments, the heavy metal sludge regeneration aggregate contains 10-30% of heavy metal oxide, 20-30% of aluminum oxide and 14-19% of silicon oxide by mass.

Specifically, the heavy metal sludge regeneration aggregate is obtained by mixing heavy metal-containing sludge and a correction raw material and then carrying out stepped calcination. The preparation method of the heavy metal sludge regeneration aggregate comprises the following steps: mixing the heavy metal-containing sludge and a correction raw material, and granulating to obtain particles with the water content of 20-25%; then, preserving the heat of the granules obtained by granulation for 20-30 min at 105-110 ℃ in a high temperature furnace, preserving the heat for 20-50 min at 450-500 ℃, and finally calcining for 30-40 min at 1100-1200 ℃ to fully discharge the gas in the pores and densify the aggregate; finally, cooling along with the furnace to obtain the heavy metal sludge regeneration aggregate.

The sludge containing heavy metals is industrial waste residue sludge, wherein the heavy metals comprise Cr₂O₃ZnO, etc.; the correction raw materials comprise kaolin, shale, coal gangue and the like.

In some embodiments, the heavy metal oxide in the heavy metal sludge reclaimed aggregate comprises Cr₂O₃ZnO; cr in heavy metal sludge regeneration aggregate₂O₃10-15% of ZnO, 6-10% of aluminum oxide, 20-30% of silicon oxide19～14％。

In some embodiments, the apparent density of the heavy metal sludge reclaimed aggregate is 2.8-3.2 kg/m³The grain diameter is less than or equal to 2.36mm, the fineness modulus is 2.2-3.2, and the crushing value is less than or equal to 15%.

In some embodiments, the nano-TiO₂Has a specific surface area of 35 to 95m²Per g, nano TiO₂The purity of the product is more than or equal to 99 wt%.

In some embodiments, the super absorbent resin is a polyacrylic resin, the particle size of the super absorbent resin is 30 to 250 μm, and the internal curing water intake rate is 8 to 15.

In some embodiments, the expansion agent is a calcium sulfoaluminate-calcium oxide type or composite type expansion agent.

Specifically, the expanding agent is calcium sulphoaluminate-calcium oxide type (such as HCSA expanding agent) or compound expanding agent (such as HME expanding agent), or the specific surface area is more than or equal to 200m²Per kg, the content of chloride ions is less than 0.05 percent, the 7d limited expansion rate in water is more than 0.05, and the 21d limited expansion rate in air is > -0.01.

In some embodiments, the water reducing agent is a polycarboxylic acid high-efficiency water reducing agent, the solid content is 50%, and the effective water reducing rate is 40-50%.

In some embodiments, the cement is a P · O52.5 portland cement.

Based on the same inventive concept, the application also provides a preparation method of the crack-resistant impact-resistant ultrahigh-performance radiation-proof concrete, which comprises the following steps:

s1, mixing cement, mineral admixture and nano TiO₂Adding the calcium carbonate crystal whisker, the expanding agent and the heavy metal sludge regenerated aggregate into a concrete mixer, uniformly stirring, and then adding water, a water reducing agent and super absorbent resin; after the components are uniformly stirred, adding the hybrid fibers, uniformly stirring, and carrying out die filling, vibrating and forming to obtain a concrete mixture;

and S2, covering the surface of the concrete mixture with a waterproof film, and then putting the concrete mixture into a curing room for curing to obtain the anti-cracking and anti-impact ultrahigh-performance radiation-proof concrete.

The following further describes a preparation method of the crack-resistant impact-resistant ultra-high performance radiation-proof concrete according to the present application with specific examples.

Examples 1 to 3

The embodiment provides a preparation method of heavy metal sludge regeneration aggregate, which comprises the following steps:

s1, mixing the heavy metal sludge with the correction raw materials according to the proportion in the table 1 to obtain a mixture, and matching the components to ensure that Cr in the mixture₂O₃13% by mass, 8% by mass of ZnO, 26% by mass of alumina and 18% by mass of silicon oxide;

s2, uniformly mixing and grinding the mixture, and then granulating to obtain particles with the particle size of less than or equal to 4.75mm and the water content of 20-25%;

and S3, roasting the granules obtained by granulation in a high-temperature furnace according to the roasting system in the table 2 to obtain the heavy metal sludge regeneration aggregate.

TABLE 1 raw Material composition of heavy Metal sludge recycled aggregates

TABLE 2 roasting System of heavy metal sludge regenerated aggregates

In Table 2, the temperature rise rate was 5 ℃/min for each stage of calcination.

The properties of the heavy metal sludge reclaimed aggregate prepared according to the above method are shown in table 3 below.

TABLE 3 Properties of heavy Metal sludge recycled aggregates

Examples	Apparent density (kg/m)3)	Modulus of fineness	Crush value (%)	Porosity (%)
					1	3050	2.4	10.1	5.8
2	2970	2.7	13.2	9.3
					3	3150	2.6	9.9	3.9

From the above Table 3, it can be seen that the crushing value of the heavy metal sludge regeneration aggregate obtained in the examples 1 to 3 is not more than 15%, and the apparent density is 2800 to 3200kg/m³The fineness modulus is 2.2-3.2, and the physical properties are excellent.

Examples 4 to 9

The embodiment of the application provides anti-cracking and anti-impact ultrahigh-performance radiation-proof concrete which comprises the raw materials in the proportion shown in the table 4;

wherein the cement is Huaxin P.O 52.5 ordinary portland cement;

the used silica fume is produced by Shanghai happy silicon powder materials Co., Ltd, wherein SiO is₂The mass content is 95 percent, and the specific surface area is 17500m²Kg, 28d activity index 105%;

the fly ash micro-beads are produced by Technology limited company of building new materials by Tianjin, and the specific surface area of the fly ash micro-beads is 1300m²Perkg, activity coefficient 105%, water demand ratio 88%, apparent density 2520kg/m³；

The nano TiO is used₂Manufactured by chenchenchen Taixin Shield alloy Co., Ltd, and having a specific surface area of 35m²/g；

The heavy metal sludge regeneration aggregate is the heavy metal sludge regeneration aggregate prepared in the embodiment 3;

the super absorbent resin is polyacrylic resin with particle size of 75-125 μm and water-intake rate of 10;

the used expanding agent is a Tianjin leopard singing HCSA type expanding agent, and the specific surface area of the expanding agent is 247 m²The content of chloride ions is 0.03 percent, the 7d restricted expansion rate in water is 0.06, and the 21d restricted expansion rate in air is 0.01;

the calcium carbonate crystal whisker is produced by Dongguan Guangxi Gyuan company, and has a length of 20-30 mu m and a diameter of 1-1.2 mu m;

the water reducing agent is a Subot polycarboxylic acid high-efficiency water reducing agent, the solid content is 50 percent, and the effective water reducing rate is 52 percent;

the water used is tap water;

the hybrid fiber comprises a mixture of steel fiber and basalt fiber, wherein the steel fiber is surface copper-plated flat steel fiber produced by Wuhan New-technology engineering fiber Limited, the length of the steel fiber is 13mm, the diameter of the steel fiber is 0.18mm, and the tensile strength of the steel fiber is 3000 MPa; the basalt fiber is Taian hong concrete basalt fiber, the length is 10mm, and the diameter is 7 μm; the volume ratio of the steel fibers to the basalt fibers is 90: 10.

Table 4 shows the raw material ratio (kg/m) of the cracking and impact resistant ultra-high performance radiation-proof concrete in examples 4 to 9³)

Wherein 1260kg/m is added in addition to the above proportion in the control group³Quartz sand aggregate and 190kg/m³Steel fiber; in examples 4 and 5, 190kg/m was added in addition to the above mixture ratio³Steel fibers.

Specifically, the preparation method of the crack-resistant impact-resistant ultrahigh-performance radiation-proof concrete comprises the following steps:

s1, pre-absorbing water by the super absorbent resin according to the internal curing water introduction rate of 10;

s2, mixing cement, mineral admixture and nano TiO₂Adding the calcium carbonate crystal whisker, the expanding agent and the heavy metal sludge regeneration aggregate (if the control group is used, the heavy metal sludge regeneration aggregate is replaced by the quartz sand aggregate) into a concrete mixer and uniformly stirring; pre-dispersing a polycarboxylic acid high-efficiency water reducing agent by using water; adding the pre-dispersed polycarboxylic acid high-efficiency water reducing agent and the pre-absorbed super absorbent resin into a medium concrete mixer for continuous stirring;

s3, after the components are uniformly stirred, adding steel fibers and basalt fibers, uniformly stirring, filling a mold, vibrating and forming, and covering the surface of the concrete mixture with a waterproof film to prevent the concrete mixture from drying and dehydrating; and 1d, removing the mold, and placing the hardened test piece into a curing room for curing to a specific age to obtain the anti-cracking and anti-impact ultrahigh-performance radiation-proof concrete.

In step S1, the super absorbent resin was treated with water, and the water used in this step is not included in table 4. As described in example 4, the amount of water used in step S1 was 30kg/m³The water used in the whole process was 30kg/m³+180kg/m³。

The performances of the crack-resistant and impact-resistant ultrahigh-performance radiation-proof concrete prepared in examples 4 to 9 and the control group were tested, and the results are shown in table 5 below.

TABLE 5-Properties of crack-resistant impact-resistant ultrahigh-performance radiation-resistant concrete

The impact compression performance of the crack-resistant and impact-resistant ultrahigh-performance radiation-proof concrete prepared in examples 4 to 9 and the control group was tested, and the results are shown in table 6 below.

TABLE 6 impact compressibility of crack-resistant impact-resistant ultra-high Performance radiation protective concrete

The radiation absorption coefficients of the crack-resistant and impact-resistant ultrahigh-performance radiation-proof concrete prepared in examples 4 to 9 and the control group were measured, and the results are shown in table 7 below.

TABLE 7 radiation absorption coefficient of crack-resistant impact-resistant ultra-high performance radiation-resistant concrete

The HVL in table 7 refers to the thickness of the radiation shielding layer required to attenuate the intensity of the radiation rays to half of its initial value, and the HVL value in table 6 is Lambert's law I-I₀e^-μtcm^-1Thus, the compound was obtained.

The results in tables 5-6 show that the ultrahigh-performance radiation-proof concrete prepared by the invention has the characteristics of high strength, low shrinkage and high crack resistance, has the same or better impact resistance compared with the ultrahigh-performance concrete of a comparison group, and meets the performance requirements of the crack-resistant and impact-resistant concrete. The results in table 7 show that the ultra-high performance radiation-proof concrete of the present invention has a higher gamma ray absorption coefficient than the ultra-high performance concrete of the control group, and compared with the ultra-high performance concrete of the control group, the thickness of the concrete layer required for attenuating the gamma ray to half of the original strength value is reduced, and the excellent ray shielding capability is exhibited.

The invention is not to be considered as limited to the particular embodiments shown and described, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. The anti-cracking and anti-impact ultrahigh-performance radiation-proof concrete is characterized by comprising the following raw materials in parts by weight: 690-740 kg/m cement³230-280 kg/m of mineral admixture³TiO 2 nanoparticles₂ 20～40kg/m³10-30 kg/m of calcium carbonate crystal whisker³1400-1800 kg/m of heavy metal sludge regenerated aggregate³2-6 kg of super absorbent resin and 40-70 kg/m of swelling agent³10-30 kg/m of water reducing agent³160-260 kg/m of hybrid fiber³180 to 200kg/m of water³。

2. The anti-cracking and impact-resistant ultrahigh-performance radiation-proof concrete as claimed in claim 1, wherein the mineral admixture is a mixture of fly ash microbeads and silica fume, wherein the proportion of the silica fume is 100-140 kg/m³The rest is fly ash micro-beads; wherein the specific surface area of the silica fume is more than or equal to 15000m²/kg, activity index not less than 105%, SiO₂The mass content is more than or equal to 95 percent, and the ignition loss is less than or equal to 4 percent; the specific surface area of the fly ash micro-beads is more than or equal to 1300m²/kg, activity index is more than or equal to 90 percent.

3. The anti-crack anti-impact ultra-high performance radiation protection concrete according to claim 1, wherein the hybrid fiber is a mixture of steel fiber and basalt fiber; the steel fiber is a flat steel fiber with a copper plated surface, the length of the steel fiber is 10-16 mm, the diameter of the steel fiber is 0.18-0.2 mm, the tensile strength is not less than 2850MPa, and the density is 8.0g/cm³(ii) a The length of the basalt fiber is 5-20 mm,The diameter is 5-40 mu m, and the tensile strength is more than or equal to 1000 MPa; the volume of the basalt fiber in the hybrid fiber accounts for 5-20%.

4. The anti-cracking impact-resistant ultrahigh-performance radiation-proof concrete as claimed in claim 1, wherein the heavy metal sludge regenerated aggregate contains 10-30% by mass of heavy metal oxide, 20-30% by mass of alumina and 14-19% by mass of silica.

5. The anti-cracking impact-resistant ultrahigh-performance radiation-proof concrete as claimed in claim 1, wherein the apparent density of the heavy metal sludge recycled aggregate is 2800-3200 kg/m³The grain diameter is less than or equal to 2.36mm, the fineness modulus is 2.2-3.2, and the crushing value is less than or equal to 15%.

6. The crack-resistant impact-resistant ultra-high performance radiation protection concrete according to claim 1, wherein the nano TiO is₂The specific surface area of (a) is 35-95 m²/g。

7. The anti-crack impact-resistant ultrahigh-performance radiation-proof concrete as claimed in claim 1, wherein the super absorbent resin is polyacrylic resin, and the particle size of the super absorbent resin is 30-250 μm.

8. The anti-crack impact-resistant ultra-high performance radiation protection concrete according to claim 1, wherein the expanding agent is calcium sulphoaluminate-calcium oxide type or composite type expanding agent.

9. The anti-cracking impact-resistant ultrahigh-performance radiation-proof concrete as claimed in claim 1, wherein the water reducing agent is a polycarboxylic acid high-efficiency water reducing agent, and the cement is P.O 52.5 portland cement.

10. The preparation method of the crack-resistant impact-resistant ultrahigh-performance radiation-proof concrete as claimed in any one of claims 1 to 9, characterized by comprising the following steps:

mixing cement, mineral admixture and nano TiO₂Adding the calcium carbonate crystal whisker, the expanding agent and the heavy metal sludge regenerated aggregate into a concrete mixer, uniformly stirring, and then adding water, a water reducing agent and super absorbent resin; after the components are uniformly stirred, adding the hybrid fibers, uniformly stirring, and carrying out die filling, vibrating and forming to obtain a concrete mixture;

and covering the surface of the concrete mixture with a waterproof film, and then putting the concrete mixture into a curing room for curing to obtain the anti-cracking and anti-impact ultrahigh-performance radiation-proof concrete.