CN102344269B

CN102344269B - Silica sacrificing concrete

Info

Publication number: CN102344269B
Application number: CN2011101774275A
Authority: CN
Inventors: 王龙; 王存杰; 沈益军
Original assignee: China Nuclear Industry Huaxing Construction Co Ltd
Current assignee: Jiangsu Zhonghe Huaxing Engineering Testing Co., Ltd; China Nuclear Industry Huaxing Construction Co Ltd
Priority date: 2011-06-28
Filing date: 2011-06-28
Publication date: 2013-01-23
Anticipated expiration: 2031-06-28
Also published as: CN102344269A

Abstract

Belonging to the technical field of building construction, the invention relates to sacrificing concrete. The concrete is obtained by mixing the following components by mass: 10-18% of cement meeting stand requirements, 3-8% of fly ash, 1-3% of silicon powder, 65-80% of silica, 5-10% of water, and 0.1-0.5% of a water reducer. The sacrificing concrete is prepared mixed by mixing the components in certain proportion in the invention can, through organic combination of the primary characteristics of each component, satisfy all the requirements for a reactor core constructing material simultaneously, and has the effects of controlling molten oxide diffusion and molten material homogeneity during diffusion. The concrete of the invention can interact with other molten materials of the reactor core at high temperature and preliminarily change the characteristics of molten materials, so that high radioactive components of molten materials in the reactor core can be oxidized, the temperature of molten materials in the reactor core can be lowered, and pressure increase inside a containment shell can be reduced by reducing gases generated within the containment shell.

Description

A kind of silica sacrificing concrete

Technical field

The present invention relates to a kind of sacrificial concrete, especially a kind of silica sacrificing concrete belongs to technical field of building construction.

Background technology

Understand according to the applicant, the reactor core of third generation EPR Nuclear power plants is equipped with trap, its effect is that the reactor core melts in the major accident (although probability is very low) is diffused on the side large area region, thereby by obviously increasing the surface/volume of melts, but and with the reactor core transfer of melt to cooled region, avoid the reactor core melts that the base plate fusing is penetrated base plate and cause the environment nuclear pollution.

For surperficial overflow, and give full play to the effect of trap cooling structure, carry out quenching from top, bottom and the periphery of melts, take away the disintegration heat on surface, wish the at high temperature melting of construction material of reactor core, and satisfy following the requirement:

A., enough stability must be arranged to provide melts to assemble the required time;

B. the diffusion of degradation production reply molten oxide produces Beneficial Effect, and makes melts be in uniform state when beginning to spread;

C. the gas that produces has additionally increased quality and the energy that is discharged in the nuclear reactor safety shell because melts-concrete interacts, therefore the gas that the concrete decomposition produces must be the least possible;

D. mechanical property should be not less than the common building concrete.

Experimental molten oxide test demonstration, common building can only satisfy above-mentioned A and the requirement of D bar with concrete.Therefore existing concrete can't satisfy above-mentioned requirements, is difficult to make trap to play a role.

Summary of the invention

In a single day the object of the invention is to: a kind of at high temperature silica sacrificing concrete of abundant melting is provided, thereby makes its nuclear power station reactor core of constructing when major accident occuring, form the melts of good fluidity.With in reactor core transfer of melt to a cooling structure, increase considerably the surface/volume of melts by this mode.Cool off by washing from the melts top with rapid, thereby eliminate the disintegration heat of melts upper surface; And by cooling pile core melts trap elimination melts bottom and side disintegration heat, avoid the reactor core melts that the base plate fusing is penetrated base plate and cause the environment nuclear pollution.

In order to achieve the above object, silica sacrificing concrete of the present invention is mixed by the component of following mass percent and forms:

The best particle diameter 0-4 of above-mentioned silica as aggregate millimeter 50-60%, particle diameter 4-8 millimeter 15-25%.Water reducer should adopt water-reducing rate greater than 25% high efficiency water reducing agent, for example poly carboxylic acid series water reducer.

The function of sacrificial concrete is to interact with the reactor core melts, and changes the characteristic of mixture (reactor core melts+container+sacrificial concrete).When the purpose of silica sacrificing concrete is to limit the molten component range of scatter, by reach be conducive to melts diffusion performance with the control melts; Its Main Function is: reduce oxidation stage density, thereby transform oxide compound and the metal level that consists of the reactor core melts; Reduce melt temperature; By reducing gas (H ₂O and CO ₂) the generation increase of lowering the reactor housing internal pressure.

Theoretical investigation and experiment show, in the above-mentioned each component of the present invention:

Silica flour is again the silicon ash, and the flue dust of usually overflowing with waste gas in the process of industrial furnace high melt industrial silicon and ferrosilicon forms through capturing collection and treatment.Be mainly SiO ₂, particle is very tiny, and mean particle size almost is nano level, in concrete, play simultaneously packing material and pozzolanic material effect, can greatly reduce the pore dimension in the aquation slurry, improve void distribution, concrete strength is improved, and perviousness reduces, and helps to improve durability index.

Flyash mainly by vitreum, mullite, quartzy and a small amount of other mineral compositions, is the industrial residue that the fuel-burning power plant produces usually, can produce i.e. " active effect ", " ball effect " and " micro aggregate effect " three kinds of effects in concrete." active effect " refers to the Ca (OH) that activeconstituents aluminosilicate glass body in the flyash and hydrated cementitious produce ₂Secondary reaction occuring generate hydrated calcium silicate etc., has slackened Ca (OH) ₂In the crystallization of concrete interface transition layer, greatly reduce the inside concrete voidage, improved the concrete hole structure, improved concrete intensity and density." ball effect " refers to a large amount of sponge glass body and alumina silicate glass microballons in the flyash, and its smooth surface has the spot contact bearing effect in concrete, improve concrete workability." micro aggregate effect " refers to that the subparticle of coal ash is filled into the slit between the cement granules, improved concrete microtexture, increased concrete density.Simultaneously, the flyash subparticle is evenly distributed between the cement granules, has stoped the cement granules adhesive aggregation, is conducive to the aquation of mixture, has reduced water consumption, makes that concrete is not emanated, bleeding reduces, and improved concrete cohesiveness and pumpability.In a word, flyash can improve concrete workability and pump-conveying property, prolongs simultaneously concrete time of coagulation, reduces hydration heat, reduces and shrinks, and improves concrete anti-permeability performance and later stage anti-freezing property etc.

Water reducer (admixture) is the tensio-active agent that contains the carboxyl graft copolymer in the molecule, wherein poly carboxylic acid series water reducer is the naphthalene system that continues, melamine series, third generation high efficiency water reducing agent after fat family and the sulfamate based water reducer, its molecular structure is pectination, main chain is short, be polymerized by carboxylic reactive monomer, have higher space steric effect and low-dosage, high water reducing rate, early strength increases significantly, function of slump protection is good, slow setting not, less on concrete drying shrinkage impact, result of use is not subjected to the plurality of advantages such as admixture sequentially affects.

SiO as the siliceous aggregate main component ₂After mixing with melts, generate silicate, reduced the release of fission product in melts-concrete interaction pond, further reduce melts and keep with normal concrete the same physical strength and decomposability with the active and help that water carries out energy response.

The sacrificial concrete of the present invention of making after these components are mixed by a certain percentage can be by the combination of each component primary characteristic, satisfy simultaneously the requirements as the reactor core construction material, and the homogeneous effect of melts when having control molten oxide diffusion and diffusion, can at high temperature interact with other melts of reactor core, the preliminary characteristic that changes molten mixture, so that the high radioactivity composition of oxidation reactor core melts, reduce the temperature of reactor core melts, reduce the increase of reactor housing internal pressure by reducing the gas that produces in the reactor housing.

Embodiment

The silica sacrificing concrete component of implementation of the present invention sees the following form

Relevant technologies requires to see Table 1.

The technical requirements of table 1 starting material and silica sacrificing concrete

(1) starting material

Cement: PII 42.5 cement that Zhujiang River Cement Co., Ltd is produced, satisfy PII42.5 requirement among " general purpose portland cement " GB175-2007, its performance sees Table 2.

The performance of table 2 cement

Flyash: the I level F class high-quality fly ash that Ming Hui trade Co., Ltd in Zhuhai produces, its performance sees Table 3.

The performance of table 3 flyash

Silica flour: sky, the Shanghai happy silica flour 90U of Materials Co., Ltd type silica flour, its performance sees Table 4.

The performance of table 4 silica flour

Sequence number	Interventions Requested	Assay
			1	Loss on ignition	2.82％
2	Chlorion	0.003％
			3	Silicon-dioxide	95.02％
4	Specific surface area	20800m ²/kg
			5	Water ratio	0.9％
6	Water demand ratio	110％
			7	28 days activity indexs	106％
8	Sulphur trioxide	0.75％
			9	Total alkali content	0.50％
10	Free calcium oxide	0.00
			11	Sulfonium ion	0.005％

Silica: the chemical composition that Rongshui Guangxi produces silica sees Table 5.

The chemical composition of table 5 silica

The 0-4mm silica: the salient features that Rongshui Guangxi produces the 0-4mm silica sees Table 6.

The salient features of table 60-4mm silica

Silt content %	Clod content %	Apparent density kg/m ³	Tap density kg/m ³
				2.7	0.2	2600	1450

The 4-8mm silica: the salient features that Rongshui Guangxi produces the 4-8mm silica sees Table 7.

The salient features of table 74-8mm silica

Silt content %	Clod content %	Apparent density kg/m ³	Tap density kg/m ³
				0.4	0.2	2640	1520

Water reducer: the ADVA161C type water reducer that Grace China Ltd. produces, its performance sees Table 8.

The performance of table 8ADVA161C type water reducer

(3) silica sacrificing concrete siliceous aggregate grain composition is calculated and is seen Table 9.

Table 9 silica sacrificing concrete siliceous aggregate grain composition reckoner

(4) meet under the prerequisite of technical requirements at starting material, the silica sacrificing concrete proportioning is studied test, test situation sees Table 10, and silica is unlisted in the table.

Table 10 silica sacrificing concrete proportioning research trial situation

Through the silica sacrificing concrete research trial is calculated with the chemical composition of benchmark proportioning, its result meets design requirements, specifically sees Table 11.

The chemical composition of table 11 silica sacrificing concrete

Project

Alkali content

CaCO ₃

MgCO ₃

Carbon content

Conversion CO ₂

Fe ₂O ₃

SiO ₂

H ₂O

Cl ^-

S ^2-

Design requirements (%)

/

＜1.0

＜4.0

/

＜8.0

/

Actual value

0.133

0.040

0.156

0.000

0.099

0.765

72.508

7.322

0.008

0.014

(5) the benchmark proportioning of research trial being used has been carried out feasibility test at concrete mixing plant, and the silica sacrificing concrete mixture goes out the machine slump in design requirements (170 ± 30) mm scope, and its ultimate compression strength meets the demands.

Confirm through pumping test: silica sacrificing concrete is through the stirring of 300s, and the mixture pumpability can be good when 60min, 90min after going out machine; The mixture workability that goes out behind the pump is good.This proportioning can satisfy the pumping construction technical requirements.

Confirm through the quantum of output test: stirrer is produced 2.0m ³Concrete actual output amount is 1.99m ³, error is-0.5%, in 2% error allowed band.

Therefore, according to above-mentioned test-results, finally determined the silica sacrificing concrete proportioning, as shown in table 12 below mix practical:

Table 12 C30/37 silica sacrificing concrete proportioning

For guaranteeing construction quality and improving concrete construction performance and physicals, when producing, concrete mix adds mineral additive silica flour and flyash and the high-efficiency water-reducing agent of poly-carboxylic acid that uses high water reducing rate.

From test-results, the concrete decomposition temperature of the present embodiment is approximately 1180 ℃.Mix owing to generating the convection current of γ-ray emission, melts-concrete can interact, and makes melts collecting tank border form uniform heat distribution.Test is demonstration also, and melt temperature only has a little reduction (if existence) in process of the test, and this explanation melts-concrete interacts and has a lower melting rate, thereby possesses favourable melts condition of divergence.

In addition to the implementation, the present invention can also have other embodiments.For example water reducer also can adopt Sample A or Sample B, the JM-PCA (I) of Su Bote novel material company limited, the ASTP5800-1 of BASF chemical building material company limited production or ADVA160C or the ADVA162C type polycarboxylic acid series high efficiency water reducing agent that Grace China Ltd. produces that Shanghai Fu Sile produces.All employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop on the protection domain of requirement of the present invention.

Claims

1. sacrificial concrete is characterized in that component by following mass percent mixes to form:

Satisfy the cement 10-18% that GB requires

Flyash 3-8%

Silica flour 1-3%

Silica 65-80%

Water 5-10%

Water reducer 0.1-0.5%;

Described silica particle diameter 0-4 millimeter 50-60%, 4＜particle diameter≤8 millimeter 15-25%, the water-reducing rate of described water reducer is greater than 25%.

2. sacrificial concrete according to claim 1 is characterized in that: the loss on ignition of described flyash≤1.5%.

3. sacrificial concrete according to claim 2 is characterized in that: Si0 in the described silica flour ₂Content 〉=90%.

4. sacrificial concrete according to claim 3 is characterized in that: Si0 in the described silica ₂Content 〉=83%.