Solid-waste-based high-durability radiation-proof concrete and preparation method thereof

Abstract

The invention relates to solid-waste-based high-durability radiation-proof concrete and a preparation method thereof.The solid-waste-based high-durability radiation-proof concrete is prepared from, by weight, 300-400 parts of Portland cement, 50-150 parts of composite mineral ultrafine powder, 700-800 parts of gold tailing sand fine aggregate, 1200-1400 parts of iron tailing ore coarse aggregate, 170-190 parts of water and 4-6 parts of admixture. The added composite mineral ultrafine powder is formed by compounding natural zeolite, fly ash, slag, metakaolin and other materials, the working performance of the concrete is improved, the density and impermeability of the concrete are improved, the durability of the concrete is greatly improved, and the prepared concrete has a good anti-radiation effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of construction engineering, and particularly relates to a radiation-proof and highly durable concrete and a preparation method thereof. Background Art

[0002] Nuclear energy and nuclear technology have been widely applied in many fields such as industry, agriculture, nuclear power, military, national defense, education, scientific research and medical treatment, and have played an important role in optimizing the energy structure, ensuring energy security, promoting pollution reduction and coping with climate change. While bringing huge economic and social benefits to mankind, nuclear energy also poses a great threat to human health and environmental safety. Its nuclear radiation pollution has always been the key to restricting the further development of nuclear technology. Therefore, certain protective measures are needed to eliminate this hidden danger.

[0003] Radiation-proof concrete is the most widely used ray protection material at present, mainly used for making the inner and outer shells of nuclear reactors and the solidification treatment of nuclear waste, and can effectively shield nuclear radiation. However, due to its large volume and large shrinkage deformation, radiation-proof concrete is prone to increase the restraint internal force of the structure, resulting in concrete cracking. Therefore, the radiation-proof concrete structure used for the protection of the inner and outer shells of nuclear reactors, scientific research and medical institutions, etc. needs to have good long-term and durable performance. Most radiation-proof concretes are prone to problems such as segregation, cracking and poor workability due to the use of high-density materials as aggregates. Therefore, the development and research of new, economical, safe and reasonable high-durability cement-based radiation-proof materials based on solid waste materials have great strategic significance and social benefits. Summary of the Invention

[0004] To solve the above problems, the present invention uses composite mineral ultrafine powder and high-efficiency water reducer as admixtures to improve the filling property of cement particles and the fluidity of concrete mixtures, increase the density and impermeability of cement paste, greatly enhance the strength of concrete, and reduce the heat of hydration of concrete, thereby greatly improving the durability of radiation-proof concrete.

[0005] The present invention solves the above technical problems through the following technical solutions: A solid waste-based high-durability radiation-proof concrete, by weight, comprises the following raw material components in parts by weight: 300-400 parts of Portland cement, 50-150 parts of composite mineral ultrafine powder, 700-800 parts of fine aggregate of gold tailings sand, 1000-1200 parts of coarse aggregate of iron tailings ore, 170-190 parts of water, and 4-6 parts of admixture.

[0006] In the above solution, the cement is P.O 42.5 type Portland cement, with a specific surface area of 335m 2 / kg and a median particle size of 17.34μm.

[0007] In the above solution, the particle size range of the gold tailings sand is 0 - 5 mm, the fineness modulus is 2.8 - 3.0, and the apparent density is 2600 kg / m 3 .

[0008] In the above solution, the particle size of the iron tail ore is 5 - 20 mm, and the apparent density is 4250 kg / m 3 .

[0009] In the above solution, the composite mineral ultrafine powder is obtained by uniformly mixing one or several materials of natural zeolite, fly ash, slag and metakaolin in a certain mass ratio and co-grinding through a 500-mesh sieve.

[0010] In the above solution, the fly ash is the coal ash waste discharged from the coal-fired boiler of a thermal power plant. The main chemical components are SiO2, Al2O3, CaO and Fe2O3, and the median particle size is 5.66 μm.

[0011] In the above solution, the slag is basic slag, and the main minerals are dicalcium silicate (C2S) and calcium yellow feldspar (C2AS), among which the content of the vitreous phase is higher than 80%, and the median particle size is 9.31 μm.

[0012] In the above solution, the natural zeolite is an aluminosilicate mineral with a porous structure. The main mineral is clinoptilolite, and there are also some quartz and clay minerals. The specific surface area is 335 m 2 / kg, and the median particle size is 5.45 μm.

[0013] In the above solution, the metakaolin is the product obtained by heating kaolin at 700 °C for 1 hour, and the median particle size is 5.30 μm.

[0014] In the above solution, the admixture is a polycarboxylate-based high-range water reducer, the water reduction rate is 26% - 30%, and the density is 1.05 g / cm 3 .

[0015] A preparation process of a solid waste-based high-durability radiation-proof concrete provided by the present invention includes the following operation steps: S1: Weigh raw materials such as portland cement, composite mineral ultrafine powder, fine aggregate, water, admixture, etc. according to the designed mix ratio, and add the raw materials into a mixer for mixing (about 1 minute) to obtain a premixed material; S2: Then add the coarse aggregate into the premixed material in S1 and stir evenly (about 2 minutes) to obtain the radiation-proof concrete with excellent durability performance.

[0016] The raw materials used in the present invention have different structures and compositions, which can achieve the effect of complementary advantages to optimize the composition of cement and concrete and improve their durability. Among them, natural zeolite has a high ion exchange capacity and can effectively adsorb alkali metal ions in the cement paste, thereby inhibiting the alkali-aggregate reaction; the quality coefficient of slag is as high as 1.94 and has high activity. The mass median diameter of fly ash is 4.06 μm. Fly ash can significantly reduce the conductivity and alkalinity of concrete and can play the effects of ultra-fine filling and micro-aggregate; slag and metakaolin can solidify chloride ions, effectively reduce the penetration and diffusion of free chloride ions into concrete, and can also prevent the bleeding and segregation of concrete, contributing to the formation of non-connected closed pores and improving the impermeability of concrete.

[0017] As described above, compared with the prior art, the present invention has the following advantages: The composite mineral ultra-fine powder added in the present invention can optimize the particle gradation of the cementitious material, improve the filling property of cement particles, and enhance the density and impermeability of the cement stone. The composite mineral ultra-fine powder contains highly active amorphous silica, which can undergo a secondary reaction with the cement hydration products - calcium hydroxide and highly alkaline calcium silicate hydrate to generate lower-alkali calcium silicate hydrate that is more stable and has higher strength, thereby effectively reducing the free calcium oxide in the cement paste, continuously increasing the amount of cementitious matter, improving the interfacial structure between the cement stone and the aggregate, and greatly enhancing the strength of the concrete.

[0018] The high-range water reducer added in the present invention can extend the initial and final setting times of the concrete, reduce the unit water consumption of the concrete, improve the workability of the concrete, increase the compactness of the concrete, reduce the hydration heat, significantly slow down the hydration heat release rate, delay the appearance of the concrete temperature peak, facilitate the internal temperature control of the mass radiation-proof concrete, effectively reduce the generation of concrete temperature cracks, and thus improve the durability of the concrete. Specific embodiments

[0019] The present invention will be further described in detail below in conjunction with specific embodiments and attached tables, but the implementation manners of the present invention are not limited thereto. For the process parameters not specifically noted, conventional techniques can be referred to. Example 1

[0020] A solid waste-based high-durability radiation-proof concrete provided in this example includes the following components by weight: 315 parts of portland cement, 135 parts of composite mineral ultra-fine powder, 780 parts of gold tailing sand, 1280 parts of iron tailing ore, 180 parts of water, and 5 parts of admixture.

[0021] Among them, the composite mineral ultrafine powder is obtained by mixing natural zeolite, fly ash, and metakaolin in a mass ratio of 3:4:3, and co-grinding and passing through a 500-mesh sieve. The raw materials of each component are stirred according to the preparation steps of S1 and S2 until evenly mixed to obtain the high-durability radiation-proof concrete. Example 2

[0022] A solid waste-based high-durability radiation-proof concrete provided in this example, each component by weight includes: 315 parts of portland cement, 135 parts of composite mineral ultrafine powder, 780 parts of gold tailings sand, 1280 parts of iron tailings ore, 180 parts of water, and 5 parts of admixture.

[0023] Among them, the composite mineral ultrafine powder is obtained by mixing metakaolin, slag, and fly ash in a mass ratio of 3:3:4, and co-grinding and passing through a 500-mesh sieve. The raw materials of each component are stirred according to the preparation steps of S1 and S2 until evenly mixed to obtain the high-durability radiation-proof concrete. Example 3

[0024] A solid waste-based high-durability radiation-proof concrete provided in this example, each component by weight includes: 315 parts of portland cement, 135 parts of composite mineral ultrafine powder, 780 parts of gold tailings sand, 1280 parts of iron tailings ore, 180 parts of water, and 5 parts of admixture.

[0025] Among them, the composite mineral ultrafine powder is obtained by mixing natural zeolite, slag, and metakaolin in a mass ratio of 3:4:3, and co-grinding and passing through a 500-mesh sieve. The raw materials of each component are stirred according to the preparation steps of S1 and S2 until evenly mixed to obtain the high-durability radiation-proof concrete. Example 4

[0026] A solid waste-based high-durability radiation-proof concrete provided in this example, each component by weight includes: 315 parts of portland cement, 135 parts of composite mineral ultrafine powder, 780 parts of gold tailings sand, 1280 parts of iron tailings ore, 180 parts of water, and 5 parts of admixture.

[0027] Among them, the composite mineral ultrafine powder is obtained by mixing fly ash and slag in a mass ratio of 1:1, and co-grinding and passing through a 500-mesh sieve. The raw materials of each component are stirred according to the preparation steps of S1 and S2 until evenly mixed to obtain the high-durability radiation-proof concrete. Example 5

[0028] A solid waste-based high-durability radiation-proof concrete provided in this example, each component by weight includes: 400 parts of portland cement, 50 parts of composite mineral ultrafine powder, 780 parts of gold tailings sand, 1280 parts of iron tailings ore, 180 parts of water, and 4.5 parts of admixture.

[0029] Among them, the composite mineral ultrafine powder is obtained by mixing natural zeolite, fly ash and metakaolin according to a mass ratio of 3:4:3, and co-grinding and passing through a 500-mesh sieve. The raw materials of each component are stirred according to the preparation steps of S1 and S2 until evenly mixed to obtain the high-durability radiation-proof concrete. Example 6

[0030] A solid waste-based high-durability radiation-proof concrete provided in this example includes, by weight: 360 parts of portland cement, 90 parts of composite mineral ultrafine powder, 780 parts of gold tailings sand, 1280 parts of iron tailings ore, 180 parts of water, and 4.8 parts of admixture.

[0031] Among them, the composite mineral ultrafine powder is obtained by mixing natural zeolite, fly ash and metakaolin according to a mass ratio of 3:4:3, and co-grinding and passing through a 500-mesh sieve. The raw materials of each component are stirred according to the preparation steps of S1 and S2 until evenly mixed to obtain the high-durability radiation-proof concrete. Example 7

[0032] A solid waste-based high-durability radiation-proof concrete provided in this example includes, by weight: 300 parts of portland cement, 150 parts of composite mineral ultrafine powder, 780 parts of gold tailings sand, 1280 parts of iron tailings ore, 180 parts of water, and 5 parts of admixture.

[0033] Among them, the composite mineral ultrafine powder is obtained by mixing natural zeolite, fly ash and metakaolin according to a mass ratio of 3:4:3, and co-grinding and passing through a 500-mesh sieve. The raw materials of each component are stirred according to the preparation steps of S1 and S2 until evenly mixed to obtain the high-durability radiation-proof concrete.

[0034] The mechanical properties of the high-durability radiation-proof concrete of Examples 1-7 were tested. The results are as follows: Table 1 Test results of the mechanical properties of the concrete of Examples 1-7 Number Slump flow / mm Slump / mm <![CDATA[Apparent density / kg / m 3 > 28-day compressive strength / MPa 360-day compressive strength / MPa Example 1 452 195 3190 46.8 73.5 Example 2 463 190 3210 45.2 72.8 Example 3 440 192 3195 46.1 71.6 Example 4 530 202 3180 47.3 72.5 Example 5 495 230 3256 46.0 75.2 Example 6 472 205 3200 46.2 74.8 Example 7 435 192 3182 45.8 73.5

[0035] The radiation-proof performance of the high-durability radiation-proof concrete of Examples 1-7 was tested. The results are as follows: Table 2 Test results of the radiation-proof performance of the concrete of Examples 1-7 Number <![CDATA[γ-ray absorption coefficient / cm -1 > Half-value layer thickness (HVL) / cm Tenth-value layer thickness (TVL) / cm Example 1 0.32 3.20 9.25 Example 2 0.28 3.22 10.10 Example 3 0.31 3.18 9.63 Example 4 0.30 3.20 9.90 Example 5 0.18 4.42 12.15 Example 6 0.25 4.08 10.63 Example 7 0.34 3.17 9.12

[0036] The above are only the preferred embodiments of the present invention and do not impose any form of limitation on the present invention. Although the present invention has been shown above in the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments of equivalent changes within the scope of the technical solution of the present invention by using the technical content shown above. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A solid waste-based highly durable radiation-proof concrete, by weight, comprises the following raw material components in parts by weight: 300-400 parts of portland cement, 50-150 parts of composite mineral ultrafine powder, 700-800 parts of fine aggregate of gold tailing sand, 1000-1200 parts of coarse aggregate of iron tailing ore, 170-190 parts of water, and 4-6 parts of admixture.

2. A highly durable radiation-proof concrete according to claim 1, characterized in that, The particle size range of the gold tailings sand is 0 - 5 mm, the fineness modulus is 2.8 - 3.0, and the apparent density is 2600 kg / m 3 .

3. A solid waste-based highly durable radiation-proof concrete according to claim 1, characterized in that, The particle size of the iron tail ore is 5 - 20 mm, and the apparent density is 4250 kg / m 3 .

4. A solid waste-based highly durable radiation shielding concrete according to claim 1, wherein The composite mineral ultrafine powder is obtained by uniformly mixing one or several materials from natural zeolite, fly ash, slag and metakaolin in a certain mass ratio and co-grinding through a 500-mesh sieve.

5. A solid waste-based highly durable radiation-proof concrete according to claim 1 or 4, characterized in that The fly ash is coal ash waste discharged from the coal-fired boiler of a thermal power plant, and the median particle size is 5.66 μm.

6. A solid waste-based highly durable radiation-proof concrete according to claim 1 or 4, characterized in that, The slag is basic slag, and the main minerals are dicalcium silicate (C2S) and calcium aluminosilicate (C2AS), and the content of the vitreous phase is higher than 80%.

7. A solid waste-based highly durable radiation shielding concrete according to claim 1 or 4, characterized in that, The natural zeolite is an aluminosilicate mineral with a porous structure. The main minerals are clinoptilolite, quartz, and clay minerals, and the specific surface area is 335 m 2 / kg.

8. A solid waste-based highly durable radiation-proof concrete according to claim 1 or 4, characterized in that, The metakaolin is a product obtained by heating kaolin at 700 °C for 1 hour, and the median particle size is 5.30 μm.

9. A solid waste-based highly durable radiation-proof concrete according to claim 1, characterized in that, The admixture is a polycarboxylate-based superplasticizer, and the water reduction rate is 26% - 30%.

10. The preparation method of a solid waste-based highly durable radiation-proof concrete according to claims 1-9, characterized in that, It includes the following steps: S1: Weigh raw materials such as portland cement, composite mineral ultrafine powder, fine aggregate, water, and admixture according to the designed mix ratio, add the raw materials into a mixer for mixing (about 1 minute) to obtain a premixed material. S2: Then add the coarse aggregate into the premixed material in S1 and stir evenly (about 2 minutes) to obtain the radiation-proof concrete with excellent durability.