Radiation-proof ultra-high performance concrete with carbonized steel slag and phosphogypsum lightweight aggregate and preparation method thereof

Abstract

The present application relates to cement-based building material technical field, especially to a kind of carbonized steel slag phosphogypsum light aggregate anti-radiation super high performance concrete and preparation method thereof, the present application uses cement as main cementitious material, adds composite admixture, utilizes steel slag and phosphogypsum to prepare light aggregate with core-shell structure, and cooperates with copper-plated steel fiber, and the anti-radiation super high performance concrete with good fluidity, high mechanical property, low shrinkage, strong neutron radiation resistance is prepared.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cement-based building materials, in particular to a carbonized steel slag phosphogypsum light aggregate anti-radiation ultra-high performance concrete and a preparation method thereof. BACKGROUND

[0002] With the development and utilization of nuclear energy technology, more attention is paid to the prevention of radiation damage. Anti-radiation concrete has good shielding ability to rays and neutrons. Heavy metals or high-density aggregates are often added during the preparation process. The addition of natural anti-radiation materials not only increases the production cost of concrete, but also often causes the aggregates to sink in the concrete slurry, resulting in concrete segregation.

[0003] Industrial production is accompanied by the generation of a large amount of industrial solid waste. Steel slag, fly ash, silica fume, mineral powder, and phosphogypsum have certain activity and can be used as concrete admixtures. However, there is little research on using them to prepare anti-radiation concrete.

[0004] Ultra-high performance concrete has the advantages of high mechanical properties and good construction performance, and is often used for special engineering structures. The strength grade of ordinary anti-radiation concrete is usually not higher than C70, and its high performance needs to be developed. SUMMARY

[0005] To solve the problems in the prior art, the present application provides a carbonized steel slag phosphogypsum light aggregate anti-radiation ultra-high performance concrete. Specifically, the present application uses cement as the main cementitious material and adds composite admixtures. The light aggregate with a core-shell structure is prepared using steel slag and phosphogypsum, and is combined with copper-plated steel fibers to prepare an anti-radiation ultra-high performance concrete with good fluidity, high mechanical properties, low shrinkage, and strong neutron radiation resistance.

[0006] Specifically, the carbonized steel slag phosphogypsum light aggregate anti-radiation ultra-high performance concrete of the present application is composed of the following raw materials in parts by weight: cement 400-500 parts, metakaolin 10-50 parts, silica fume 50-100 parts, fly ash 50-100 parts, copper slag powder 5-50 parts, carbonized steel slag phosphogypsum light aggregate 400-450 parts, copper-plated steel fiber 180-250 parts, coarse sand 300-700 parts, medium sand 260-400 parts, water reducing agent 20-35 parts, and water 160-180 parts.

[0007] The application adds metakaolin and copper residue powder, metakaolin is rich in amorphous SiO2 and Al2O3, and is a kind of admixture with high pozzolanic property, the amorphous molecules can effectively fill the internal pores of the mortar and promote subsequent hydration, thereby improving the strength, metakaolin as an auxiliary additive can also improve the rheological property, mechanics and durability of the concrete; the copper residue contains a large amount of calcium oxide, which generates calcium hydroxide when meeting water, and can generate more ettringite with metakaolin, the ettringite contains 32 crystal waters, and the metakaolin can also bond the crystal water to make it more stable, thereby being beneficial to the prevention of neutron radiation.

[0008] Preferably, the preparation process of the carbonized steel slag phosphogypsum light aggregate is as follows:

[0009] a. uniformly mix 40-70 parts of phosphogypsum, 8-12 parts of cement, 2-5 parts of mineral powder, 1-2 parts of aluminum ash and 0.1-0.2 parts of calcium borate to obtain a core mixture, and mix 35-45 parts of steel slag powder, 2-5 parts of silica fume, 8-10 parts of cement and 3-5 parts of sodium silicate to obtain a shell mixture,

[0010] b. add the core mixture into a disc granulator, and spray water for granulation at a water-binder ratio of 0.2-0.25 to obtain 1-2.36 mm cores, and then add the shell mixture and continue to spray water for granulation at a water-binder ratio of 0.25-0.27 to obtain 2.5-4.75 mm green bodies,

[0011] c. naturally, carbonize and standardize the maintenance of the green bodies, and the carbonized steel slag phosphogypsum light aggregate is obtained.

[0012] The application uses phosphogypsum, cement, mineral powder, aluminum ash and calcium borate as the core raw materials, and uses steel slag powder, silica fume, cement and sodium silicate as the shell raw materials, a large amount of industrial waste is used, the phosphogypsum and sodium silicate also have excitation characteristics, the light aggregate has improved mechanical properties, the carbonization curing can eliminate the instability of the steel slag and optimize the pore structure of the light aggregate; in addition, the phosphogypsum has a high content of crystal water and contains a small amount of heavy metal elements, which has a shielding effect on neutron rays, the addition of aluminum ash and calcium borate can adjust the hydration products of the shell raw materials, which is helpful to improve the mechanical properties and radiation resistance of the core by the phosphogypsum, cement and mineral powder, the light aggregate has a water storage and release effect, and has a spherical shape, which can effectively improve the fluidity of the slurry, play the internal curing performance, and be beneficial to the improvement of the radiation resistance.

[0013] Preferably, the cement is ordinary Portland cement with a strength grade of 52.5 or above.

[0014] Preferably, the specific surface area of the metakaolin is not less than 600 m 2 / kg.

[0015] Preferably, the content of SiO2 in the silica fume is 90 wt% or above.

[0016] Preferably, the 28-day activity index of the fly ash is ≥100%.

[0017] Preferably, the copper slag powder has a specific surface area of ​​650-800 m². 2 Between / kg.

[0018] Preferably, the coarse sand has a particle size of 1.18-2.36 mm.

[0019] Preferably, the particle size of the medium sand is 0.6-1.18 mm.

[0020] Preferably, the water-reducing agent is a polycarboxylate high-performance water-reducing agent with a water reduction rate of ≥35%.

[0021] Preferably, the phosphogypsum contains ≥80% CaSO4·2H2O and ≥15% SiO2.

[0022] Preferably, the steel slag powder has a γ-C2S content ≥82%, a loss on ignition ≤2.2%, and a particle size of 50-200μm.

[0023] Preferably, the natural curing time in step c is 24-48 hours.

[0024] Preferably, during step c, the CO2 pressure is ≥0.4MPa and the curing time is 15-20h.

[0025] Preferably, step c involves standard curing for 28 days.

[0026] Preferably, the saturated water absorption rate of carbonized steel slag phosphogypsum lightweight aggregate is ≤9%.

[0027] This invention also relates to a method for preparing the above-mentioned carbonized steel slag phosphogypsum lightweight aggregate radiation-resistant ultra-high performance concrete, specifically including the following steps:

[0028] 1) Weigh each raw material according to its weight.

[0029] 2) Add the carbonized steel slag phosphogypsum lightweight aggregate and an appropriate amount of water to the mixer for pre-wetting.

[0030] 3) Add cement, metakaolin, silica fume, fly ash, and copper slag powder to the mixer, mix thoroughly, then add coarse sand, medium sand, and copper-plated steel fibers, and mix thoroughly.

[0031] 4) Add the water-reducing agent to the remaining water and mix well to obtain the admixture solution.

[0032] 5) Add the additive solution to the mixer and mix thoroughly to obtain a slurry.

[0033] 6) Vibrate the slurry to form a mold, cure it, remove the mold, and cure it to the specified age to obtain the final product.

[0034] Preferably, the mold is removed after curing for 1 day in step 6).

[0035] Preferably, the age specified in step 6) is 28 days.

[0036] This invention has the following technical advantages:

[0037] 1. This invention utilizes a large amount of industrial solid waste as raw material for preparing cementitious materials and lightweight aggregates, achieving cost reduction and waste utilization.

[0038] 2. The carbonized steel slag phosphogypsum lightweight aggregate of the present invention has good internal curing and radiation protection enhancement effects.

[0039] 3. The concrete of this invention has the advantages of good fluidity, high mechanical properties, low shrinkage rate, and strong neutron radiation protection capability, and belongs to ultra-high performance concrete. Detailed Implementation

[0040] To characterize the technical effects of this invention, concrete was prepared and its performance was tested. During the experiment, P·O52.5 cement was used, the coarse sand particle size was 1.18-2.36 mm, the medium sand particle size was 0.6-1.18 mm, the water-reducing agent was polycarboxylate high-performance water-reducing agent with a water reduction rate of 36%, the phosphogypsum had a CaSO4·2H2O content of 80.6% and a SiO2 content of ≥16.3%, the steel slag powder had a γ-C2S content of 84.6%, a loss on ignition of 2.1%, and a particle size of 50-200 μm.

[0041] Example 1

[0042] Concrete is composed of the following raw materials in parts by weight: 460 parts cement, 20 parts metakaolin, 50 parts silica fume, 60 parts fly ash, 50 parts copper slag powder, 420 parts carbonized steel slag phosphogypsum lightweight aggregate, 200 parts copper-plated steel fiber, 600 parts coarse sand, 400 parts medium sand, 33 parts water-reducing agent, and 170 parts water.

[0043] The preparation process of lightweight aggregate made from carbide steel slag phosphogypsum is as follows:

[0044] a. Mix 60 parts phosphogypsum, 12 parts cement, 2 parts mineral powder, 2 parts aluminum ash, and 0.1 parts calcium borate evenly to obtain the core mixture. Mix 40 parts steel slag powder, 2 parts silica fume, 8 parts cement, and 4 parts sodium silicate to obtain the shell mixture.

[0045] b. Add the core mixture to a disc granulator and granulate by spraying water at a water-to-binder ratio of 0.22 to obtain cores of 1-2.36 mm. Add the shell mixture and continue granulating by spraying water at a water-to-binder ratio of 0.25 to obtain preforms of 2.5-4.75 mm.

[0046] c. Naturally cure the billet for 24 hours, carbonize it under CO2 partial pressure of 0.4 MPa for 18 hours, and then standard cure it for 28 days to obtain the final product.

[0047] Tests showed that the initial spread of the concrete was 670 mm, the 28-day compressive strength was 128 MPa, the flexural strength was 17.3 MPa, and the drying shrinkage rate was 300 × 10⁻⁶ mm. -6 The chloride ion diffusion coefficient is 0.03 × 10⁻⁶. -12 m 2 / s, when the neutron radiation energy is 14 MeV, ∑R ≥ 0.095cm -1 , HVT / cm≤5.3, TVT / cm≤18.0.

[0048] Example 2

[0049] Concrete is composed of the following raw materials by weight: 400 parts cement, 50 parts metakaolin, 70 parts silica fume, 100 parts fly ash, 30 parts copper slag powder, 420 parts carbonized steel slag phosphogypsum lightweight aggregate, 210 parts copper-plated steel fiber, 600 parts coarse sand, 380 parts medium sand, 32 parts water-reducing agent, and 170 parts water.

[0050] The preparation process of lightweight aggregate made from carbide steel slag phosphogypsum is as follows:

[0051] a. Mix 50 parts phosphogypsum, 8 parts cement, 3 parts mineral powder, 1.5 parts aluminum ash, and 0.2 parts calcium borate evenly to obtain the core mixture. Mix 40 parts steel slag powder, 4 parts silica fume, 9 parts cement, and 5 parts sodium silicate to obtain the shell mixture.

[0052] b. Add the core mixture to a disc granulator and granulate by spraying water at a water-to-binder ratio of 0.22 to obtain cores of 1-2.36 mm. Add the shell mixture and continue granulating by spraying water at a water-to-binder ratio of 0.26 to obtain preforms of 2.5-4.75 mm.

[0053] c. Naturally cure the billet for 24 hours, carbonize it under CO2 partial pressure of 0.4 MPa for 18 hours, and then standard cure it for 28 days to obtain the final product.

[0054] Tests showed that the initial spread of the concrete was 660 mm, the 28-day compressive strength was 123 MPa, the flexural strength was 16.0 MPa, and the drying shrinkage rate was 325 × 10⁻⁶ mm. -6 The chloride ion diffusion coefficient is 0.04 × 10⁻⁶. -12 m 2 / s, when the neutron radiation energy is 14 MeV, ∑R ≥ 0.100cm -1 , HVT / cm≤5.5, TVT / cm≤17.5.

[0055] Comparative Example 1

[0056] Concrete is composed of the following raw materials by weight: 480 parts cement, 50 parts silica fume, 110 parts fly ash, 420 parts carbonized steel slag phosphogypsum lightweight aggregate, 200 parts copper-plated steel fiber, 600 parts coarse sand, 400 parts medium sand, 33 parts water-reducing agent, and 170 parts water.

[0057] The preparation process of lightweight aggregate made from carbide steel slag phosphogypsum is as follows:

[0058] a. Mix 60 parts phosphogypsum, 12 parts cement, 2 parts mineral powder, 2 parts aluminum ash, and 0.1 parts calcium borate evenly to obtain the core mixture. Mix 40 parts steel slag powder, 2 parts silica fume, 8 parts cement, and 4 parts sodium silicate to obtain the shell mixture.

[0059] b. Add the core mixture to a disc granulator and granulate by spraying water at a water-to-binder ratio of 0.22 to obtain cores of 1-2.36 mm. Add the shell mixture and continue granulating by spraying water at a water-to-binder ratio of 0.25 to obtain preforms of 2.5-4.75 mm.

[0060] c. Naturally cure the billet for 24 hours, carbonize it under CO2 partial pressure of 0.4 MPa for 18 hours, and then standard cure it for 28 days to obtain the final product.

[0061] Tests showed that the initial spread of the concrete was 630 mm, the 28-day compressive strength was 96 MPa, the flexural strength was 13.1 MPa, and the drying shrinkage rate was 465 × 10⁻⁶ mm. -6 The chloride ion diffusion coefficient is 0.11 × 10⁻⁶. -12 m 2 / s, when the neutron radiation energy is 14 MeV, ∑R ≥ 0.075cm -1 , HVT / cm≤6.5, TVT / cm≤19.0.

[0062] Comparative Example 2

[0063] Concrete is composed of the following raw materials in parts by weight: 460 parts cement, 20 parts metakaolin, 50 parts silica fume, 60 parts fly ash, 50 parts copper slag powder, 420 parts 2.5-4.75mm fly ash ceramsite, 200 parts copper-plated steel fiber, 600 parts coarse sand, 400 parts medium sand, 33 parts water-reducing agent, and 170 parts water.

[0064] Tests showed that the initial spread of the concrete was 600 mm, the 28-day compressive strength was 79 MPa, the flexural strength was 8.5 MPa, and the drying shrinkage rate was 570 × 10⁻⁶ mm. -6 The chloride ion diffusion coefficient is 0.16 × 10⁻⁶. -12 m 2 / s, when the neutron radiation energy is 14 MeV, ∑R ≥ 0.080cm -1 , HVT / cm≤7.4, TVT / cm≤20.0.

[0065] Comparative Example 3

[0066] Concrete is composed of the following raw materials in parts by weight: 460 parts cement, 20 parts metakaolin, 50 parts silica fume, 60 parts fly ash, 50 parts copper slag powder, 420 parts carbonized steel slag phosphogypsum lightweight aggregate, 200 parts copper-plated steel fiber, 600 parts coarse sand, 400 parts medium sand, 33 parts water-reducing agent, and 170 parts water.

[0067] The preparation process of lightweight aggregate made from carbide steel slag phosphogypsum is as follows:

[0068] a. Mix 60 parts phosphogypsum, 20 parts cement, 2 parts mineral powder, 2 parts aluminum ash, 40 parts steel slag powder, 2 parts silica fume, and 4 parts sodium silicate to obtain a mixture.

[0069] b. Add the mixture to a disc granulator, spray water to granulate at a water-to-binder ratio of 0.24, and obtain 2.5-4.75mm spherical preforms.

[0070] c. Naturally cure the billet for 24 hours, carbonize it under CO2 partial pressure of 0.4 MPa for 18 hours, and then standard cure it for 28 days to obtain the final product.

[0071] Tests showed that the initial spread of the concrete was 620 mm, the 28-day compressive strength was 83 MPa, the flexural strength was 8.9 MPa, and the drying shrinkage rate was 490 × 10⁻⁶. -6 The chloride ion diffusion coefficient is 0.18 × 10⁻⁶. -12 m 2 / s, when the neutron radiation energy is 14 MeV, ∑R ≥ 0.080cm -1 , HVT / cm≤7.2, TVT / cm≤19.5.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A radiation-resistant ultra-high performance concrete using carbonized steel slag phosphogypsum lightweight aggregate, characterized in that, Composed of the following raw materials in parts by weight: The composition includes: 400-500 parts cement, 10-50 parts metakaolin, 50-100 parts silica fume, 50-100 parts fly ash, 5-50 parts copper slag powder, 400-450 parts carbonized steel slag phosphogypsum lightweight aggregate, 180-250 parts copper-plated steel fiber, 300-700 parts coarse sand, 260-400 parts medium sand, 20-35 parts water-reducing agent, and 160-180 parts water. The copper slag powder has a specific surface area of ​​650-800 m². 2 Between / kg The preparation process of the carbonized steel slag phosphogypsum lightweight aggregate is as follows: a. Mix 40-70 parts phosphogypsum, 8-12 parts cement, 2-5 parts mineral powder, 1-2 parts aluminum ash, and 0.1-0.2 parts calcium borate evenly to obtain the core mixture. Mix 35-45 parts steel slag powder, 2-5 parts silica fume, 8-10 parts cement, and 3-5 parts sodium silicate to obtain the shell mixture. b. Add the core mixture to a disc granulator and granulate by spraying water at a water-to-binder ratio of 0.2-0.25 to obtain cores of 1-2.36 mm. Add the shell mixture and continue granulating by spraying water at a water-to-binder ratio of 0.25-0.27 to obtain preforms of 2.5-4.75 mm. c. The slab is cured naturally, then carbonized, and then cured according to standard methods.

2. The ultra-high performance radiation-resistant concrete using carbonized steel slag phosphogypsum lightweight aggregate according to claim 1, characterized in that, The cement is ordinary Portland cement with a strength grade of 52.5 or higher.

3. The ultra-high performance radiation-resistant concrete using carbonized steel slag phosphogypsum lightweight aggregate according to claim 1, characterized in that, The specific surface area of ​​the metakaolin is not less than 600 m². 2 / kg, the SiO2 content in the silica fume is above 90wt%, and the 28d activity index of the fly ash is ≥100%.

4. The ultra-high performance radiation-resistant concrete using carbonized steel slag phosphogypsum lightweight aggregate according to claim 1, characterized in that, The coarse sand has a particle size of 1.18-2.36 mm, and the medium sand has a particle size of 0.6-1.18 mm.

5. The ultra-high performance radiation-resistant concrete using carbonized steel slag phosphogypsum lightweight aggregate according to claim 1, characterized in that, The water-reducing agent is a high-performance polycarboxylate water-reducing agent with a water reduction rate of ≥35%.

6. The ultra-high performance radiation-resistant concrete using carbonized steel slag phosphogypsum lightweight aggregate according to claim 1, characterized in that, The phosphogypsum contains ≥80% CaSO4·2H2O and ≥15% SiO2.

7. The ultra-high performance radiation-resistant concrete using carbonized steel slag phosphogypsum lightweight aggregate according to claim 1, characterized in that, The steel slag powder has a γ-C2S content ≥82%, a loss on ignition ≤2.2%, and a particle size of 50-200μm.

8. The ultra-high performance radiation-resistant concrete using carbonized steel slag phosphogypsum lightweight aggregate according to claim 1, characterized in that, In step c, the natural curing time is 24-48 hours, the CO2 pressure during carbonization curing is ≥0.4MPa, the curing time is 15-20 hours, and the standard curing is up to 28 days.

9. The ultra-high performance radiation-resistant concrete using carbonized steel slag phosphogypsum lightweight aggregate according to claim 1, characterized in that, The saturated water absorption rate of carbonized steel slag phosphogypsum lightweight aggregate is ≤9%.

10. The method for preparing radiation-resistant ultra-high performance concrete using carbonized steel slag phosphogypsum lightweight aggregate according to any one of claims 1-9, characterized in that, Includes the following steps: 1) Weigh each raw material according to its weight. 2) Add the carbonized steel slag phosphogypsum lightweight aggregate and an appropriate amount of water to the mixer for pre-wetting. 3) Add cement, metakaolin, silica fume, fly ash, and copper slag powder to the mixer, mix thoroughly, then add coarse sand, medium sand, and copper-plated steel fibers, and mix thoroughly. 4) Add the water-reducing agent to the remaining water and mix well to obtain the admixture solution. 5) Add the additive solution to the mixer and mix thoroughly to obtain a slurry. 6) Vibrate the slurry to form a mold, cure it, remove the mold, and cure it to the specified age to obtain the final product.