Mix proportion design method for neutron shielding serpentine concrete in high-temperature environment

Abstract

The invention relates to a mix proportion design method for neutron shielding serpentine concrete in a high-temperature environment. The mix proportion design method comprises the following steps: 1, calculating a neutron shielding attenuation coefficient of the serpentine concrete; 2, calculating the relationship between the neutron shielding attenuation coefficient of the serpentine concrete and the bound water content through an experiment; 3, calculating the relation between the binding material and the aggregate mixing amount according to the content of bound water in the concrete; 4, calculating the relationship between the cementing material and the aggregate according to the compressive strength requirement of the concrete; and 5, obtaining a formula for calculating the mix proportion of the serpentine concrete in the high-temperature environment. Through the thickness requirement of the serpentine concrete in the aspect of structural design, the requirement of the serpentine concrete in the aspect of neutron shielding and the like, and in combination with related physical parameters, the mix proportion design method of the neutron radiation shielding serpentine concrete in the high-temperature environment is provided, and the method has important significance for development of nuclear engineering.

Description

Technical Field

[0001] The invention belongs to the technical field of building construction, and particularly relates to a mix ratio design method of neutron shielding serpentine concrete in a high-temperature environment. Background Art

[0002] Nowadays, the application of nuclear physics has involved many aspects such as energy and medicine, which is of great significance for achieving low-carbon development and protecting people's lives and health. However, the rise of new nuclear-related facilities has also brought about construction problems, such as how to shield the generated nuclear radiation (neutrons, gamma).

[0003] In the field of building materials, aggregates containing bound water are often used to prepare concrete for neutron protection. The most commonly used aggregates containing bound water are serpentine, magnetite, etc. At the same time, γ easily causes the temperature of concrete to rise, and the stability of bound water at high temperatures is also an issue that needs to be considered. Serpentine is widely used in the construction of nuclear-related facilities due to its unique advantages such as high bound water content (11-18%) and water loss rate within 1% within 600°C. In the existing technology, the problem of how to adapt concrete is mainly considered from the perspective of construction performance and mechanical properties.

[0004] Therefore, how to study a mix design method for neutron shielding serpentine concrete in a high-temperature environment is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] The present invention provides a mix ratio design method for neutron shielding serpentine concrete in a high temperature environment, and realizes precise control of the mix ratio of neutron radiation shielding concrete by calculating the content of bound water in serpentine and bound water formed by cement chemical reaction in hardened pure paste.

[0006] In order to solve the above technical problems, the present invention includes the following technical solutions:

[0007] A mix design method for neutron shielding serpentine concrete in a high temperature environment comprises the following steps:

[0008] Step S1, calculating the neutron shielding attenuation coefficient σ of serpentine concrete: Where σ is the attenuation coefficient, unit is cm -1 , L is the thickness of serpentine concrete, in cm, M1 is the neutron flux before concrete shielding, in n / cm 2 ·s, M2 is the neutron flux after concrete shielding, unit is n / cm 2 ·s;

[0009] Step S2: Calculate the relationship between the neutron shielding attenuation coefficient of serpentine concrete and the bound water content through experiments: σ = 0.038ln(W混 +1)+0.018, formula (2), where W 混 The content of bound water in concrete, expressed in wt.%, 10≤W 混 ≤20;

[0010] Step S3, the relationship between cementitious materials and aggregates is calculated by the bound water content in concrete: W = w(t), formula (3), where W is the water loss of the pure paste at t degrees, in units of wt.%, 50≤t≤650; the bound water content W in the pure paste 净 For: W 净 =w(650)-w(T), formula (4), the relationship between coarse and fine aggregates and the amount of cementitious materials is: Where X is the amount of cementitious material added, in kg / m 3 , Y is the dosage of coarse and fine aggregate, unit is kg / m 3 , Z is the water content, unit is kg / m 3 , A is the bound water content of serpentine coarse and fine aggregates measured by X-ray fluorescence spectroscopy, in wt.%;

[0011] Step S4: Calculate the relationship between cementitious materials and aggregates by the concrete compressive strength requirement: In the formula, ρ 胶 is the density of cementitious material, ρ 骨 is the density of aggregate, f cus,o is the 28d compressive strength of concrete required, f ce is the compressive strength grade of the concrete; and

[0012] Step S5, combine formulas (5) and (6) to obtain the mix ratio calculation formula of serpentine concrete in high temperature environment:

[0013]

[0014] Furthermore, step S2 comprises: preparing hardened paste test blocks with bound water contents of 11.25%, 11.70%, 12.15%, 12.60%, 13.05%, 13.50%, 13.95%, 14.40% and 14.85% respectively through theoretical calculation, determining the actual bound water contents of 9 hardened paste samples through thermogravimetric analysis, preparing 9 corresponding serpentine concretes, calculating the bound water contents of the concretes, conducting neutron radiation tests on the 9 concrete samples, and fitting formula (2) through a large number of tests.

[0015] Furthermore, the step S3 comprises: soaking the cured hardened slurry in alcohol for 48 hours, taking it out, volatilizing it at room temperature for 24 hours, and determining the bound water content in the concrete slurry by thermogravimetric analysis to obtain formula (3).

[0016] Further, step S4 includes: according to the sum of the volumes of the three raw materials X, Y and Z being 1m 3 At the same time, the ratio of water to cementitious materials can be designed according to the concrete strength requirements, and formula (6) is obtained.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0018] The present invention provides a mix ratio design method for neutron shielding serpentine concrete in a high temperature environment. The present invention proposes a mix ratio design method for neutron radiation shielding serpentine concrete in a high temperature environment by considering the requirements for thickness of serpentine concrete in structural design and the requirements for neutron shielding, etc., and combining relevant physical parameters, which is of great significance for the development of nuclear-related engineering. The calculated serpentine concrete mix ratio is used to prepare concrete, and the obtained serpentine concrete is subjected to a neutron radiation shielding test. The result shows that the 25 cm thick serpentine concrete can reduce the neutron flux shielding to the original 4.94%, which meets the needs of practical applications. DETAILED DESCRIPTION

[0019] The following is a further detailed description of a mix ratio design method of neutron shielding serpentine concrete under high temperature environment provided by the present invention in combination with specific embodiments. The advantages and features of the present invention will become more clear according to the following description.

[0020] Embodiment 1:

[0021] The mix design method of neutron shielding serpentine concrete under high temperature environment in this embodiment mainly includes the following steps:

[0022] First, the neutron shielding attenuation coefficient of serpentine concrete is calculated; secondly, the bound water content of concrete is calculated through the attenuation coefficient; then, the relationship between the cementitious material and the aggregate content is calculated according to the bound water content in concrete; then, the relationship between the cementitious material and the aggregate content is calculated according to the concrete compressive strength requirement;

[0023] Finally, the mix ratio calculation formula of neutron shielding serpentine concrete is obtained.

[0024] The thickness of serpentine concrete is 25 cm, and the neutron flux before concrete shielding is required to be 10 10 n / cm 2 ·s, the neutron flux after shielding is 5×10 8 n / cm 2 s, substitute into formula (1) The calculated neutron attenuation coefficient is 0.12, which is substituted into formula (2): The bound water requirement in concrete is obtained to be 13.64%.

[0025] Serpentine concrete is exposed to high temperature of 150℃ for a long time. Substituting into formula (4), we can get W 净 =w(650)-W(150)=90kg / m 3 .

[0026] The combined water content of serpentine coarse and fine aggregates was measured by X-ray fluorescence spectroscopy to be A=12.24wt.%, and the cementitious material density was 3000kg / m 3 , serpentine aggregate density is 2300kg / m 3 , the required 28d compressive strength of concrete is 22MPa, and the compressive strength grade of concrete is 20MPa;

[0027] Then by substituting formula (7) into the calculation, we can get:

[0028]

[0029] The calculated serpentine concrete mix ratio was used to prepare concrete, and the obtained serpentine concrete was subjected to a neutron radiation shielding test. The results showed that the 25 cm thick serpentine concrete could reduce the neutron flux shielding to 4.94% of the original value, which met the needs of practical applications.

[0030] The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. The above embodiments only express several embodiments of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A mix design method for neutron shielding serpentine concrete in a high temperature environment, characterized in that: The steps include: Step S1: Calculate the neutron shielding attenuation coefficient of serpentine concrete Formula (1), where σ is the attenuation coefficient, unit is cm -1 , L is the thickness of serpentine concrete, in cm, M1 is the neutron flux before concrete shielding, in n / cm 2 ·s, M2 is the neutron flux after concrete shielding, unit is n / cm 2 ·s; Step S2: Calculate the relationship between the neutron shielding attenuation coefficient of serpentine concrete and the bound water content through experiments: σ = 0.038ln(W 混 +1)+0.018, formula (2), where W 混 The content of bound water in concrete, expressed in wt.%, 10≤W 混 ≤20; Step S3, calculate the relationship between cementitious material and aggregate by the bound water content in concrete: W = w(t), formula (3), where W is the water loss of the pure paste at t degrees, in units of wt.%, 50≤t≤650; the bound water content W in the pure paste 净 W 净 =w(650)-w(T), formula (4), the relationship between coarse and fine aggregates and the amount of cementitious materials is: Formula (5), where X is the amount of cementitious material added, in kg / m 3 , Y is the dosage of coarse and fine aggregate, unit is kg / m 3 , Z is the water content, unit is kg / m 3 , A is the bound water content of serpentine coarse and fine aggregates measured by X-ray fluorescence spectroscopy, in wt.%; Step S4: Calculate the relationship between cementitious materials and aggregates by the concrete compressive strength requirement: Formula (6), where ρ 胶 is the density of cementitious material, ρ 骨 is the density of aggregate, f cus,o is the 28d compressive strength of concrete required, f ce is the compressive strength grade of concrete; Step S5, combine formulas (5) and (6) to obtain the mix ratio calculation formula of serpentine concrete in high temperature environment:

2. The method according to claim 1, characterized in that The step S2 comprises: preparing hardened pure paste test blocks with bound water contents of 11.25%, 11.70%, 12.15%, 12.60%, 13.05%, 13.50%, 13.95%, 14.40% and 14.85% respectively through theoretical calculation, then determining the actual bound water contents of 9 hardened pure paste samples through thermogravimetric analysis, preparing 9 corresponding serpentine concretes, calculating the bound water contents of the concretes, conducting neutron radiation tests on the 9 concrete samples, and fitting formula (2) through a large number of tests.

3. The method according to claim 1, characterized in that The step S3 comprises: soaking the cured hardened concrete paste in alcohol for 48 hours, taking it out, volatilizing it at room temperature for 24 hours, and determining the bound water content in the concrete paste by thermogravimetric analysis to obtain formula (3).

4. The method according to claim 1, characterized in that: The step S4 includes: according to X, Y The sum of the volumes of the three raw materials Z is 1m 3 At the same time, the ratio of water to cementitious materials can be designed according to the concrete strength requirements, and formula (6) is obtained.

Images