CN101921092B - Concrete for profiled steel concrete composite structure with C110 in strength grade - Google Patents
Concrete for profiled steel concrete composite structure with C110 in strength grade Download PDFInfo
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Abstract
The invention discloses a concrete for a profiled steel concrete composite structure with C110 in strength grade and is characterized in that the concrete mix ratio to fine aggregate to coarse aggregate to water to water reducer to siliceous dust to coal ash (kg/m<3>) is 450:496:1276:138:9:60:90. A preparation method of the concrete comprises the following steps: adding the fine aggregate and the water to a forced mixer in proportion by weight, wherein the water accounts for 50% of the total water consumption; evenly stirring the mixture for 1-2min, adding the coarse aggregate for evenly stirring for 2-4min, adding the concrete, the siliceous dust and the coal ash for stirring for 2-3min, and adding the water reducer and the rest of the water; and finally evenly stirring the mixture for 2-3min and discharging to obtain the concrete mixture. The concrete can obviously improve the adhesive property between the profiled steel and the concrete under the natural condition and effectively exert individual capacity and cooperative work performance of the two materials, thereby greatly improving bearing capacity and performance of construction members and enhancing durability, high-volume stability and economy thereof.
Description
Technical field
The invention belongs to building material technical field, relating to a kind of is the super high strength high performance concrete of C110 for the reinforced concrete composite structure strength grade.
Background technology
After portland cement in 1824 invention, make concrete technology obtain rapidly development, its consumption is big, the scope of application extensively may occupy the first in the world.Although this artificial material of concrete is a kind of traditional material of construction, but because this material has the superiority do not replaced and the continuous progress of concrete material science and technology, concrete has become civil engineering work with the main body of material, also will be one of indispensable main material in the civil engineering work in future and nation-building.Continuous expansion along with city size, being on the increase of population, the continuous rising of land price, continuous progress and the rapid development of economy of Building technology, buildings is more and more to aerial extension, namely building (surpass) heightization, (surpassing) large striding, reach the development of heavy type structure, especially steel reinforced concrete structure is in the greatly widespread use of striding building etc. of (surpassing) heightization, (surpassing), and is also more and more higher to the requirement of this material of construction of concrete.Therefore, concrete high reinforcement, superelevation are strengthened, and guarantee that simultaneously the research and practice of its durableization, super durableization will become the development trend in this field.
Shaped steel super high strength high performance concrete combined structure is the application of novel High Technique Concrete in reinforced concrete composite structure (being called for short the SRC structure).Wherein, the SRC structure is a kind of principal mode of steel-concrete combined structure, because its supporting capacity is high, the series of advantages such as rigidity is large, ductility good, anti-seismic performance is superior, fire retardant anticorrosion, constructability, be applied to more and more widely stride greatly, high level and the high-rise building of heavy type structure and earthquake/typhoon zone.Compare with steel construction, the SRC structure can be saved great deal of steel, strengthens section rigidity, overcomes the shortcomings such as steel structure fire-resistant and poor durability and easy flexing unstability, and the ability of steel is fully played; Compare with ordinary reinforced concrete structure (abbreviation reinforced concrete structure), steel reinforced concrete structure can reduce the sectional dimension of member, reduces shared space, thereby increases the building usage space; In construction, the Steel Skeleton of steel reinforced concrete structure itself can be used as the skeleton that concrete is hung mould, sliding formwork, has not only greatly simplified the formwork engineering, still bears whole construction loads supporting system of (comprising extension, sliding formwork and institute's pouring concrete); In addition since the SRC structure to have globality strong, the advantages such as good working ductility can be improved the brittleness of Steel Concrete sheared destruction greatly, and the anti-seismic performance of structure is significantly improved, supporting capacity and ductility all are greatly improved than reinforced concrete structure.Therefore, in Japan and the developed country such as American-European, the SRC structure with good anti-seismic performance has become a kind of generally acknowledged novel earthquake-proof structural system, and with steel construction, timber structure, skeleton construction and be called four macrostructures.China also is earthquake more than country, and most areas be the seismic region, and part is positioned at the highly seismic region, so in China, and is particularly underdeveloped and be subjected to the larger west area popularization SRC structure of earthquake effect just to have very important realistic meaning.Therefore, the SRC structure has boundless application prospect in China, especially along with the successful development of the continuous enhancing of China's economic strength and high-strength steel and high-strength/super high strength high performance concrete (they be putative 21 century material) with use, will promote applying and progress of this structural system.
In the steel reinforced concrete structure, good cohesive action is the basis that guarantees the medium-sized Steel concrete co-ordination of Steel Reinforced Concrete Members between shaped steel and the concrete, shaped steel, reinforcing bar and three kinds of material elements collaborative works of concrete, to resist various external action effects, can give full play to the advantage of reinforced concrete composite structure.But one of remarkable difference of steel reinforced concrete structure and skeleton construction is the cohesive force between shaped steel and the concrete and is far smaller than the cohesive force between reinforcing bar and the concrete that the cohesive force of shaped steel and normal concrete approximately only is equivalent to 45% of plain bar cohesive force.Domestic and international many experimental studies show, exist the bond-slip phenomenon between shaped steel and the concrete, and stress performance and even the supporting capacity of SRC member had remarkably influenced.Therefore, how to guarantee shaped steel and concrete effectively collaborative work become one of emphasis of reinforced concrete composite structure research.At present one has two kinds to the treatment process of bond-slip problem between shaped steel and the concrete in the engineering design: the first is by calculating the shearing connecting piece that adds some amount in component surface, certainly will cause like this inconvenience in the construction and improve cost, and easily cause the defective such as the congenital microfracture of inside concrete; It two is not if a small amount of shearing connecting piece only is set, and considers the impact of bond-slip in supporting capacity is calculated, and the supporting capacity of corresponding reduction member certainly exists uneconomic factor like this.On the other hand, ubiquity is focused on intensity and the phenomenon of light weather resistance in Structural Design, has occurred the security in use of many concrete structures and the problem of weather resistance aspect both at home and abroad.Half is former owing to alkali-aggregate reaction, Chloride Attack etc. thereby completely loses use function and even supporting capacity some concrete structure engineerings using not enough design period, indivedual engineerings even partial collapse occurs or Total Collapse cause casualties or Architectural Equipment is destroyed.Therefore, improve the natural adhesive property between shaped steel and the super high strength high performance concrete, on the shaped steel surface not if only by construct requirement arrange a small amount of shearing connecting piece just can guarantee shaped steel and concrete effectively the research of collaborative work be significant; Simultaneously, the weather resistance of concrete structure engineering also causes people's close attention and great attention day by day.
The technology of preparing that it is the high-strength high-performance concrete of C60, C70, C80, C90 and C100 that prior art is used for the concrete strength grade classification of reinforced concrete composite structure, above-mentioned each strength grade concrete has significantly improved the adhesive property between shaped steel and the high-strength concrete, and has improved the weather resistance of structure; But, also exist and to extend to thus the super high strength high performance concrete, be that concrete superelevation is strengthened, super durableization, and can not solve the poor problem of natural adhesive property between shaped steel and the super high strength high performance concrete when using it for reinforced concrete composite structure, so can not satisfy civil engineering work to aerial extension, i.e. the greatly requirement of these trend of development such as striding, (surpassing) durableization and heavy type structure of building (surpassing) heightization, (surpassing).In addition, also exist in the prior art part with the concrete superelevation strengthen, the technology of preparing of super durableization, but they all do not relate to or the unresolved poor problem of natural adhesive property between shaped steel and the super high strength high performance concrete during for reinforced concrete composite structure.
Summary of the invention
The purpose of this invention is to provide a kind of is the super high strength high performance concrete of C110 for the reinforced concrete composite structure strength grade, this concrete is applied in the reinforced concrete composite structure, can be at the adhesive property between the remarkable modified version Steel concrete under the state of nature (that is the shaped steel surface is not if only arrange a small amount of shearing connecting piece by the structure requirement), effectively bring into play Steel concrete bi-material ability and cooperative work performance separately, thus supporting capacity and the performance of significant lift structure member; In addition, this concrete can improve the weather resistance of structure, and has good serviceability, high volume stability and economy.
For solving the problems of the technologies described above, it is the concrete of C110 for the reinforced concrete composite structure strength grade that the present invention is achieved in that a kind of, it is characterized in that, this mix proportion is (unit: kg/m
3):
Cement: fine aggregate: coarse aggregate: water: water reducer: silicon ash: flyash
＝450∶496∶1276∶138∶9∶60∶90。
It is the concrete preparation method of C110 for the reinforced concrete composite structure strength grade that the present invention gives this, and the method adopts cement to wrap up in sand method concrete secondary mixing methods, and the concrete technology step is as follows:
1/2 the water 69kg that adds the fine aggregate of 496kg and water total amount according to weight proportion every cubic meter of concrete in forced mixer, behind the uniform stirring 1～2 minute, the coarse aggregate (particle diameter is Φ 5～Φ 10mm simple grain level rubble) that adds 446.6kg, uniform stirring adds the coarse aggregate (particle diameter is Φ 10～Φ 20mm simple grain level rubble) of 829.4kg after 1～2 minute, behind the uniform stirring 2 minutes, the cement that adds again whole consolidating materials: 450kg, the silicon ash of 60kg and the flyash of 90kg, behind the uniform stirring 2～3 minutes, the polycarboxylic acid series high efficiency water reducing agent and the residue water 69kg that add 9kg, last uniform stirring is after 2～3 minutes, discharging namely gets prepared concrete mix.
Described cement is selected the 525R ordinary Portland cement of steady quality, better performances, need and high efficiency water reducing agent carry out compatibility test between the two before the use, test method adopts the method among existing building material industry standard " cement and water reducer compatibility test method " the JC/T 1083-2008, and the good cement type of selection and high efficiency water reducing agent consistency.Selected cement performance index (comprises fineness, SO
3Content, MgO content, presetting period, final setting time, 3 days intensity, 28 days intensity) should be not less than the requirement of national existing relevant criterion, and select that alkali content is few, hydration heat is low, need also low cement type of water-based.
Partially thick river sand during described fine aggregate employing particle is round and smooth, quality is hard, grating is good, the quality of sand should be not less than the high-quality sand standard of stipulating among existing building material industry standard " regular concrete sand, stone quality and test method standard " JC/T 52-2006 and national standard " building sand " the GB/T 14684-2001.Its fineness modulus is that silt content is controlled at below 1.0% between 2.4～3.2.
The artificial rubbles such as described coarse aggregate adopts that the quality densification is hard, intensity is high, surface irregularity, particle shape is almost spherical, elongated particles is little, grating is good limestone, grouan, diabase, the quality of rubble should be not less than the specified requirement of the relevant criterion such as existing building material industry standard " regular concrete sand, stone quality and test method standard " JC/T 52-2006.The cubic compressive strength of aggregate parent rock should be not lower than the concrete strength of preparing.Maximum particle diameter should be controlled at 20mm, and silt content is controlled at below 0.5%, and faller gill shape granule content should not be greater than 5%, and must not sneak into the weathering particle.When carrying out this Concrete, employing simple grain level ballast grain sizes is that two gratings of Φ 5～Φ 10mm and Φ 10～Φ 20mm feed intake, and ingredient proportion is 3.5: 6.5.
The special fine powdered coal of the high-quality I level that described flyash adopts coal-fired technique advanced person's power plant to produce.Its quality should be not less than the specified requirement of the relevant criterion such as national standard " flyash that is used for cement and concrete " GB/T 1596-2005, and its loss on ignition should be not more than 4%, SO
3Content should be not more than 3%, and water demand ratio should be not more than 95%, and specific surface area should be greater than 700m
2/ kg.
Described silicon ash should adopt ultra-fine silicon ash, its quality should be not less than the specified requirement of the relevant criterion such as national standard " mineral admixture for high-strength high-performance concrete " GB/T 18736-2002, dioxide-containing silica in the silicon ash should be not less than 90%, water ratio should be less than 3%, loss on ignition should be less than 6%, pozzolanic activity index should be greater than 90%, and specific surface area should be not less than 20000m
2/ kg.
Reach and the cement compatibility test through a large amount of tentative simultaneous tests, the selected water reducer of this invention is polycarboxylic acid series high efficiency water reducing agent, its quality should be not less than the specified requirement of the relevant criterion such as existing national standard " concrete admixture " GB 8076-2008, and the water-reducing rate of selected high efficiency water reducing agent should be greater than 30%.The maximum doping quantity of selected high efficiency water reducing agent is not less than 2% of whole binder total amounts, adopts the method for mixing together, and needs before using carry out compatibility test with selected cement type.
Described mixing water is selected tap water, and its quality should be not less than the specified requirement of the relevant criterion such as Minstry of Housing and Urban-Rural Development of People Republic of China's ministerial standard " concrete mixing water supply standard " JGJ 63-89, and requires the alkali content of selected tap water few.
The invention has the beneficial effects as follows:
1. the concrete of the present invention's production is a kind of super high strength high performance concrete that the reinforced concrete composite structure strength grade is C110 that is applicable to.This concrete can guarantee that its mechanical property that should possess (is the C110 strength grade, plasticity etc.) and have a high-durability, high workability, on the basis of high volume stability and economy, improve significantly the natural adhesive property between this concrete and the shaped steel, it is applied in the steel reinforced concrete structure design need not (or only needing by a little ground of structure requirement) and adds shearing connecting piece on the shaped steel surface, can guarantee shaped steel and this concrete effective collaborative work, thereby reduced working procedure, steel have been saved, improved operating efficiency, and avoided arranging in a large number on the shaped steel surface shearing connecting piece and easily caused the defectives such as the congenital microfracture of this inside concrete, have significant economic benefit and construction quality improvement effect, its mechanical property comparative test result sees Table 2.
2. the high efficiency water reducing agent that uses among the present invention is selected polycarboxylic acid series high efficiency water reducing agent (water-reducing rate should greater than 30%), compares the water reducer of other type, and good with the consistency of ordinary Portland cement, it does not contain Na
2SO
4, can further improve this concrete weather resistance.
3. the present invention produces, and to be used for the reinforced concrete composite structure strength grade be that the super high strength high performance concrete of C110 is under the normal concrete manufacturing condition, and adopt and to reduce cement that cement granules and superfine active mineral grain fly upward as far as possible everywhere wrap up in that the feeding method of sand stirring technique realizes when concrete-agitating, preparation technology is simple and be easy to realize, be suitable for through engineering approaches, be convenient to large-scale promotion application, have preferably social benefit.
4. the present invention produces, and to be used for the reinforced concrete composite structure strength grade be that the concrete starting material of super high strength high performance of C110 contain a large amount of flyash, silicon ash, they are industrial waste and waste, for mass-produced market circulation, buy and sell product, starting material are easy to get; It is dissolved and can make huge contribution to environment protection, meets the requirement of Sustainable development, is a kind of green concrete, a kind of environment-friendly material.
5. the present invention produces, and to be used for the reinforced concrete composite structure strength grade be that to adopt simple grain level ballast grain sizes be that two gratings of Φ 5～Φ 10mm and Φ 10～Φ 20mm feed intake for the concrete starting material of super high strength high performance of C110, ingredient proportion is 3.5: 6.5, not only can avoid or reduce the unstable impact on preparation super high strength high performance concrete strength and performance of coarse aggregate quality, the grain composition of coarse aggregate is better optimized, and make in the coarse aggregate between the different-grain diameter particle and and the fine aggregate particle between good filling is arranged, reduced the voidage of aggregate.
6. the present invention produces, and to be used for the reinforced concrete composite structure strength grade be that the super high strength high performance concrete of C110 is disastrously to expect (flyash and silicon ash) by adding the superfine active mineral, utilize the pozzolanic reaction of active mineral admixture, reinforcing effect, filling effect, weather resistance is improved the warm peak subtractive effect of effect and super high strength high performance hydration heat of concrete, and take full advantage of that active mineral admixture is compound to be mixed and super synergistic effect that the composite blend of active mineral admixture and high efficiency water reducing agent produces, do not optimizing gelling material grain composition partly in the super high strength high performance concrete material with the characteristics of one-level according to them and cement granules particle diameter, not only make gather materials in the super high strength high performance concrete and Behavior of Hardened Cement Paste between interface structure and the pore structure of Behavior of Hardened Cement Paste all obtained significantly improving, improved the density of Behavior of Hardened Cement Paste, impervious, simultaneously typical dense structure can expand to aggregate surface, thereby make the super high strength high performance concrete more closely knit hard, the concrete mechanical property of super high strength high performance (especially and the adhesive property between the shaped steel), endurance quality and serviceability all improve a lot.
Embodiment
The present invention is with the adhesive property between the lower remarkable modified version Steel concrete of state of nature (that is the shaped steel surface is not if only arrange a small amount of shearing connecting piece by the structure requirement), effectively bring into play Steel concrete bi-material ability and cooperative work performance separately, thereby supporting capacity and the performance of significant lift structure member, and the weather resistance that improves structure is aim, and studying for the reinforced concrete composite structure strength grade is the concrete technology of preparing of super high strength high performance of C110.At present, quality and the intensity of making the used ordinary Portland cement of super high strength high performance concrete both at home and abroad are more and more higher, processing technology and the quality of used active mineral admixture (silicon ash, flyash etc.) are updated, the research of the concrete admixture such as high efficiency water reducing agent, superplasticizer has all obtained larger progress with using in addition, thereby has identified the basis for the realization of above-mentioned study tenet.Simultaneously, the cement consumption of the concrete requirement of super high strength high performance is relatively less, means a large amount of dischargings of carbonic acid gas and produce cement, so alleviated to a certain extent the Greenhouse effect that the earth is caused; Its requirement has sufficient amount and accounts for the active mineral spike of the high-qualitys such as the larger flyash of consolidating material proportion, silicon ash; mean the reasonable disposal utilization of industrial waste; to be conducive to form good production cycle and environment protection, and that the active mineral spike of these high-qualitys improves the concrete material self performance just is needed.In a word, use the super high strength high performance concrete can save cement, with industrial waste turn waste into wealth, extending structure engineering working life, and finally preserve the ecological environment and natural resources.In sum, the concrete research and development of super high strength high performance that are used for reinforced concrete composite structure will have been walked out the road of a Sustainable development for using better concrete, it is with integration capability and the performance of lift structure engineering, promote steel-concrete combined structure in China, especially the high level of the low developed area such as Midwest, high-rise building, large-span structure and heavy duty industrial are (such as electric power plant, Large Steel ironworks etc.) apply in the factory building, improve the scientific and technological content of building structure among Infrastructure and the human settlement, and bring into play it and have larger supporting capacity and rigidity, good anti-seismic performance, construction speed is fast, durable and resistivity against fire reaches well the unique advantages such as significant society and economic benefit.
What the present invention developed is the super high strength high performance concrete of C110 for the reinforced concrete composite structure strength grade, except adopting similar material-cement, sand, rubble, the water with normal concrete, also added its indispensable component: high efficiency water reducing agent and active mineral admixture.The super high strength high performance concrete is different from normal concrete, and its intensity and performance all are greatly improved than normal concrete, and than high-strength concrete further raising is arranged also.The concrete water cement ratio of super high strength high performance one all less than 0.24, and the water cement ratio of normal concrete one more than 0.45, the water cement ratio of high-strength concrete one about 0.3, the concrete maximum size of coarse aggregate of super high strength high performance is also less than the maximum particle diameter of normal concrete, even less than the maximum particle diameter of high-strength concrete.Above-mentioned every difference has caused super high strength high performance concrete and normal concrete in performance very large difference to be arranged, with high-strength concrete larger difference is arranged also on performance, disastrously expect by adding the superfine active mineral, utilize the pozzolanic reaction of superfine active mineral spike, filling effect and plasticization effect, optimize the grain composition of gelling material part in the super high strength high performance concrete material, not only make gather materials in the super high strength high performance concrete and Behavior of Hardened Cement Paste between interface structure and the pore structure of Behavior of Hardened Cement Paste all obtained significantly improving, improved the density of Behavior of Hardened Cement Paste, impervious, simultaneously typical dense structure can expand to aggregate surface, thereby make the super high strength high performance concrete more closely knit hard, the concrete mechanical property of super high strength high performance (especially and the adhesive property between the shaped steel) and endurance quality all improve a lot.
And the Binder Phase between plain bar and the concrete seemingly, and the cohesive force between shaped steel and the concrete also mainly is comprised of chemical bond power, friction resistance and mechanical snap power three parts.Each integral part of cohesive force between shaped steel and the concrete is all closely related with concrete performance.
Chemical bond power is chemical clinging power or the adsorptive power that the cement gel body in the concrete produces on the shaped steel surface, and its (shearing resistance) ultimate value depends on the character of cement and the degree of roughness on shaped steel surface.During casting concrete, cement slurry produces surface tension at steel surface, and under capillary effect, the cement slurry on the steel surface will form self-equilibrating; One will vibrate deposit concrete, and cement slurry can be strengthened and accelerate to the power of vibrating (disturbance) to the infiltration of steel surface zone of oxidation; Cement slurry crystallization in maintenance processes, the cement crystal forms chemical bond power.Chemical bond power only exists under the original formation state of Steel Reinforced Concrete Members, in case (part) bond-slip on the joint face occurs, the cement crystal will be cut off and attrition crushing, and chemical bond power is then lost.The principal element that affects chemical bond power has concrete strength, shaped steel steel surface degree of roughness, test specimen to build mode and the maintenance in vibrate degree and later stage and concrete contraction situation etc.
After the forfeiture of chemical bond power, coarse injustice and the caused steel surface changed condition of other reason (steel surface is uneven) owing to steel surface, concrete crystal grain on itself and the contact surface is interlocked, has so just formed mechanical snap power.For the shaped steel such as rolled steel joist of processing plant produced and postmenstruation, in case the crushed integration of concrete crystal on shaped steel and the concrete surface, at this moment also substantial loss of mechanical snap power are accelerated in the bond-slip development.The principal element that affects mechanical snap power is the degree of roughness of shaped steel steel surface and the force way of surface appearance (corrosion degree etc.), aggregate grating, concrete strength and Steel Reinforced Concrete Members etc.
The shaped steel surrounding concrete also is to form behind the bond failure between shaped steel and the concrete to the friction resistance of shaped steel, and mainly is just to play a role after mechanical snap power is lost substantially.When chemical bond power; especially after the forfeiture of mechanical snap power; owing to cut off, crushed and expanded with the concrete crystal on the shaped steel contact surface; the in addition lateral confinement such as protective layer and stirrup; to produce positive pressure at shaped steel and concrete joint face; add that frictional coefficient is larger on the joint face, thereby formed friction resistance.Friction resistance all exists after the forfeiture of chemical bond power always, is the major portion of later stage cohesive force between shaped steel and the concrete.The factor that affects friction resistance has the size of joining adhesive surface between steel form and surface characteristic, shaped steel and the concrete, member stress mode, the aggregate grating of shaped steel and affects factor (thickness of concrete cover of shaped steel, stirrup ratio, concrete shrinkage) of lateral confinement etc.
Key technical problem to be solved by this invention is, guarantee the mechanical property that the super high strength high performance concrete should possess (being intensity and plasticity) and having high-durability, high workability, on the basis of high volume stability and economy, improve significantly (nature) adhesive property between concrete and the shaped steel, make in steel reinforced concrete structure design and need not (or only needing by a little ground of structure requirement) and add shearing connecting piece on the shaped steel surface, can guarantee has reliable bonding and anchoring between shaped steel and the concrete, make both energy under loading action harmonious, common work.
The present invention from theory and design in principle, break the restriction of " full sieve rice " formula, by orthogonal experiment and contrast experiment's method, consider the consistency of high efficiency water reducing agent and cement, maximum size of coarse aggregate, between the coarse aggregate different-grain diameter and and the fine aggregate particle diameter between level pairing concrete strength and the impact of performance and the performance factors such as pozzolanic activity of active mineral spike, select the high-quality coarse-fine aggregate and control particle diameter and grating, in super high strength high performance concrete matched prepared material, mix an amount of high efficiency water reducing agent and high-quality composite active mineral ultrafine powder, reduce water cement ratio, be based on the local existing material that is easy to get, do not change conventional production process, fly upward everywhere when the concrete-agitating and adopt cement to wrap up in the feeding method of sand stirring technique for reduce cement granules and superfine active mineral grain as far as possible, utilize the pozzolanic reaction of active mineral admixture, reinforcing effect, filling effect, weather resistance is improved the warm peak subtractive effect of effect and super high strength high performance hydration heat of concrete, and take full advantage of that active mineral admixture is compound to be mixed and super synergistic effect that the composite blend of active mineral admixture and high efficiency water reducing agent produces, it is good to make mechanical property (especially and the adhesive property between the shaped steel), serviceability is excellent, excellent in durability, the relatively low strength grade that is applicable to widely apply in steel reinforced concrete structure of cost is the super high strength high performance concrete of C110.The mechanical property comparative test result of the present invention and normal concrete (strength grade is the concrete of C30～C50), one high-strength concrete (strength grade is the concrete of C60～C100) and one super high strength concrete (strength grade is the concrete of C110) is as shown in table 2.
When the present invention selected starting material, not only requiring starting material was high-quality, and also requiring the used starting material of preparation super high strength high performance concrete is that the locality is easy to get.In addition, consider that the intensity of institute's concrete batching is very high, be optimized according to the grain composition of maximum density theory to coarse-fine aggregate in the concrete material, make large or fine granule that good filling be arranged mutually, to reduce the voidage of aggregate; Simultaneously, the median size of one cement is 20～30 μ m, particle less than 10 μ m is also few, and the grain diameter of active mineral admixture is tiny more than the cement granules particle diameter, the median size of superfined flyash is 3～6 μ m, space between the energy filling concrete particle, the median size of silicon ash is less, be 0.10～0.26 μ m, between energy filling concrete particle and the superfined flyash particle and the space between the superfined flyash particle is so the grain composition to the gelling material part is optimized also most important in the super high strength high performance concrete material of preparing.And the outside deteriorated factor (such as factors such as vitriol) depends on concrete pore structure to a great extent to concrete aggressiveness, and this causes the major cause of Durability of Concrete just.Mixing of active mineral admixture, reduced between the cement granules and the voidage at interface, make water mudrock structure and interface structure more fine and close, blocked the infiltration path that may form, thereby the concrete impermeability of the super high strength high performance of preparing is increased substantially, water and other various etching medium (CL
-, SO
4 2-, CO
2Deng) all be difficult to enter inside concrete, and can reduce the occurrence probability of alkali-pasc reaction and the generation probability of Losantin, its intensity and endurance quality are greatly improved.Namely when low greater than the macropore content of 0.1 μ m in water mudrock structure and the interface structure, to be conducive to the improvement of the concrete properties of super high strength high performance of preparing, otherwise, all unfavorable to the concrete intensity of preparation super high strength high performance, anti-permeability performance and endurance quality.
Behind active mineral admixture replacement part of cement, mineral admixture that the portion of water in the cement granules space is filled in it cements out, and the degree of mobilization of cement paste is increased.But also not all mineral admixture all has this significant plasticization effect, mainly be because the specific surface area of part active mineral admixture is too large or itself have vesicular structure, although can displace the part moisture in the cement paste behind its replacement cement, but since itself the suction or wetted surface need more free water, cause the flowability of cement paste not increase.Develop the concrete high workload performance of super high strength high performance in order to guarantee, the present invention adopts high efficiency water reducing agent and the compound method of mixing of active mineral admixture, under both collaborative works, the subparticle of active mineral spike has not only been given full play to their filling effect, and the moisture that will be filled among the space cements out, make between the particle between the water-resisting layer thickening; In addition, the subparticle of active mineral admixture has adsorbed the high efficiency water reducing agent molecule, the electrostatic repulsion that the electrostatic double layer current potential that its surface forms produces is greater than the universal gravitation between the powder particle, impel powder granule to disperse, and further aggravate the dispersion of cement granules, the flowability of cement paste is increased, thereby effectively improved the flowability of compound; Simultaneously, compound the mixing of super fine active mineral admixture reduced hydration heat, can improve concrete volume stability.
In addition, for normal concrete, usually contain a large amount of alkali in the grout body opening liquid, its pH value can reach 13, and aggregate also has alkaline matter, therefore when this concrete is in the wet environment, the hydroxide ion in its hole liquid will with aggregate in activated silica generation alkali-aggregate reaction, thereby cause concrete expanding and cracking.In addition, villaumite is the most harmful a kind of aggressiveness compound, when Chloride Attack in microstructure of concrete, will be to the hydrated cementitious phase shift of separating out, and finally cause concrete to be etched damage.Therefore, improving concrete pore structure and anti-permeability performance is to improve it to resist the effective way of alkali-aggregate reaction and Chloride Attack ability.The present invention adopts low alkali cement, aggregate that activated silica content is little, and compoundly mixes the measures such as active mineral spike and suppress alkali-aggregate reaction and Chloride Attack.Test-results shows, behind a part of cement of silicon ash replacement that mixes, can effectively alleviate even eliminate fully the self-expanding that alkali-aggregate reaction causes.Its mechanism of action is: before the concrete strength development, the silicon ash can consume rapidly potash and the soda in the liquid of hole, so that hydroxide ion concentration reaches lower level; The silicon ash also can consume the calcium hydroxide that is discharged by hydrated cementitious, and is remarkable to improving concrete weather resistance effect.After adding the active mineral ultrafine powder in the super high strength high performance concrete of the present invention, concrete electric conduction quantity also obviously descends, the penetrating power of chlorion is controlled at very low level, can reduce the occurrence probability of alkali-pasc reaction and the generation probability of Losantin, thereby improve concrete weather resistance.
The aggregate that is used for the concrete starting material of preparation super high strength high performance should have higher inherent strength, toughness and stability, can resisting various Static and dynamic stress, impact and abrasive action, and can not cause the decline of institute's concrete batching performance.Because the condition of surface of different aggregates is different, cause cement slurry also not identical with cohesive strength between the aggregate, generally rubble has higher cohesive strength than cobble; On the other hand, the asynchronous cohesive strength of silicon ash content ratio differs also very large in the cement slurry, mixes silicon when ash, and the cohesive strength between cement slurry and the aggregate is much higher when not mixing.Normal concrete is when destroying, the bonding interface of cement slurry and aggregate is weak link, the crack is to occur along the interface of cement slurry and aggregate, one can not destroy aggregate, and extraneous often corrode also from then on that the interface begins development, and the bonding interface of the cement slurry in the super high strength high performance concrete and aggregate no longer is weak link, its destruction also no longer occurs along the interface, but owing to the destruction of aggregate causes, so the performance of aggregate has larger impact to the concrete performance of super high strength high performance.The coarse aggregate of selecting in the research of the present invention is surface irregularity, fine quality, rubble that grating is good.Thick river sand during fine aggregate employing particle is round and smooth, quality is hard, grating is good, silt content is little.Simultaneously, the continuous size fraction ballast grain sizes is that the quality of Φ 5～Φ 20mm is very different on the market, even it is high-quality and the quality stability of Φ 5～Φ 20mm that same producer can not guarantee the continuous size fraction ballast grain sizes, for fear of or reduce the unstable impact on preparation super high strength high performance concrete strength and performance of coarse aggregate quality, and in the acquisition coarse aggregate between the different-grain diameter particle and and the fine aggregate particle between etc. the filling optimization, the present invention is optimized according to the grain composition of maximum density theory to coarse aggregate in the concrete material, employing simple grain level ballast grain sizes is that two gratings of Φ 5～Φ 10mm and Φ 10～Φ 20mm feed intake, ingredient proportion is 3.5: 6.5, make in the concrete material thick, good filling is arranged mutually, to reduce the voidage of aggregate in the fine aggregate between the large or fine granule.
When the present invention is used in the preparation of cement sand leggings (also known as SEC method) secondary concrete mixing process, in a forced mixer with stirring, the feeding order of: adding fine aggregate, and 1/2 of the total water → stir (1 to 2 minutes) → adding coarse aggregate (particle size Φ5 ~ Φ10mm single-sized gravel) → stir (1 to 2 minutes) → adding coarse aggregate (particle size of Φ10 ~ Φ20mm single-sized gravel ) → stir (1 to 2 minutes) → Add → stir all the cementing material (2 to 3 minutes) → polycarboxylate superplasticizer added and residual water → stir (2 to 3 minutes) → the material.This technique can reduce cement granules as far as possible and the superfine active mineral grain flies upward when concrete-agitating everywhere, and can improve prepared concrete intensity, and prepared concrete should not form segregation phenomenon, and bleeding is few, and serviceability is relatively better.
Embodiment:
(1) starting material
1. cement
Select the Qinling Mountains board PO 52.5R cement of steady quality, better performances, carry out between the two compatibility test with high efficiency water reducing agent before using, test method adopts the method among existing building material industry standard " cement and the water reducer compatibility test method " JC/T1083-2008, and is good with the high efficiency water reducing agent consistency.Selected cement performance index meets the requirement of national existing relevant criterion, and its alkali content is few, hydration heat is low, need water-based also low.
2. aggregate
Partially thick, Ba river sand during fine aggregate employing particle is round and smooth, quality is hard, grating is good, the quality of sand meets the high-quality sand standard of stipulating among existing building material industry standard " regular concrete sand, stone quality and test method standard " JC/T 52-2006 and national standard " building sand " the GB/T 14684-2001.Its fineness modulus is 2.5, and silt content is controlled at below 1.0%.
The artificial rubbles such as coarse aggregate adopts that the quality densification is hard, intensity is high, surface irregularity, particle shape is almost spherical, elongated particles is little, grating is good limestone, grouan, diabase, the quality of rubble meet the specified requirement of the relevant criterion such as existing building material industry standard " regular concrete sand, stone quality and test method standard " JC/T 52-2006.The cubic compressive strength of aggregate parent rock is 120～250MPa.Maximum particle diameter is controlled at 20mm, and silt content is controlled at below 0.5%, and faller gill shape granule content is controlled at below 5%, and must not sneak into the weathering particle.Employing simple grain level ballast grain sizes is that two gratings of Φ 5～Φ 10mm and Φ 10～Φ 20mm feed intake, and ingredient proportion is 3.5: 6.5.
3. flyash
Adopt the special fine powdered coal of high-quality I level of power plant's production of coal-fired technique advanced person.Its quality meets the specified requirement of the relevant criterion such as national standard " flyash that is used for cement and concrete " GB/T 1596-2005, and its loss on ignition is 3.5%, SO
3Content is 1.9%, and water demand ratio is 95%, and specific surface area is 750m
2/ kg.
4. silicon is grey
The quality of the silicon ash of selecting meets the specified requirement of the relevant criterion such as national standard " mineral admixture for high-strength high-performance concrete " GB/T 18736-2002, dioxide-containing silica in the silicon ash is 92%, water ratio is 2.8%, loss on ignition is 3.8%, pozzolanic activity index is 95%, and specific surface area is 21000m
2/ kg.
5. high efficiency water reducing agent
Reach and the cement compatibility test through a large amount of tentative simultaneous tests, the selected high efficiency water reducing agent of this invention is polycarboxylic acid series high efficiency water reducing agent, its quality meets the specified requirement of the relevant criterion such as existing national standard " concrete admixture " GB 8076-2008, and the water-reducing rate of selected high efficiency water reducing agent is greater than 30%.The maximum doping quantity of selected high efficiency water reducing agent is 2.5% of whole binder total amounts, adopts with mixing method, and use is front and selected cement type carries out compatibility test and consistency is good.
6. mixing water
Selecting tap water is mixing water, and its quality meets the specified requirement of the relevant criterion such as Minstry of Housing and Urban-Rural Development of People Republic of China's ministerial standard " concrete mixing water supply standard " JGJ 63-89, and alkali content is few.
(2) proportioning
The present invention is as shown in table 1 for the proportioning that the super high strength high performance concrete of C110 provides for the strength grade that will widely apply in steel reinforced concrete structure.
Table 1 is used for the super high strength high performance concrete mix (unit: kg/m of reinforced concrete composite structure
3)
(3) stirring technique
The method adopts cement to wrap up in sand method concrete secondary mixing methods, and the concrete technology step is as follows:
1/2 the water 69kg that adds the fine aggregate of 496kg and water total amount according to weight proportion every cubic meter of concrete in forced mixer, behind the uniform stirring 1～2 minute, the coarse aggregate (particle diameter is Φ 5～Φ 10mm simple grain level rubble) that adds 446.6kg, uniform stirring adds the coarse aggregate (particle diameter is Φ 10～Φ 20mm simple grain level rubble) of 829.4kg after 1～2 minute, behind the uniform stirring 2 minutes, the cement that adds again whole consolidating materials: 450kg, the silicon ash of 60kg and the flyash of 90kg, behind the uniform stirring 2～3 minutes, the polycarboxylic acid series high efficiency water reducing agent and the residue water 69kg that add 9kg, last uniform stirring is after 2～3 minutes, discharging namely gets prepared concrete mix.
This technique can reduce cement granules as far as possible and the superfine active mineral grain flies upward when concrete-agitating everywhere, and can improve prepared concrete intensity, and prepared concrete should not form segregation phenomenon, and bleeding is few, and serviceability is relatively better.
(4) mechanical property test result contrast
The strength grade that is applicable to reinforced concrete composite structure of preparing according to above-mentioned proportioning is that the mechanical property comparative test result of the super high strength high performance concrete of C110 and normal concrete (strength grade is the concrete of C30～C50), one high-strength concrete (strength grade is the concrete of C60～C100) and one super high strength concrete (strength grade is the concrete of C110) is as shown in table 2.
Table 2 mechanical performance of concrete comparative test result
As can be seen from Table 2, strength grade by this technology preparation is the super high strength high performance concrete of C110, realized to guarantee that its mechanical property that should possess (is the C110 strength grade, plasticity etc.) and have a high-durability, high workability, on the basis of high volume stability and economy, improve significantly (nature) adhesive property between concrete and the shaped steel, make in steel reinforced concrete structure design and need not (or only needing by a little ground of structure requirement) and add shearing connecting piece on the shaped steel surface, can guarantee shaped steel and concrete effective collaborative work, thereby reduced working procedure, steel have been saved, improved operating efficiency, and avoided arranging in a large number on the shaped steel surface shearing connecting piece and easily caused the defectives such as the congenital microfracture of inside concrete, have significant economic benefit and construction quality improvement effect.
Claims (2)
1. one kind is the concrete of C110 for the reinforced concrete composite structure strength grade, it is characterized in that this concrete is according to kg/m
3Proportioning be:
Cement: fine aggregate: coarse aggregate: water: water reducer: silicon ash: flyash
=450∶496∶1276∶138∶9∶60∶90；
It is that Φ 5～Φ 10mm and Φ 10～Φ 20mm two gratings feed intake that described coarse aggregate adopts simple grain level ballast grain sizes, and ingredient proportion is 3.5:6.5;
Described water reducer is selected polycarboxylic acid series high efficiency water reducing agent, and water-reducing rate is greater than 30%.
2. being used for the reinforced concrete composite structure strength grade is the concrete preparation method of C110, it is characterized in that, the method adopts cement to wrap up in sand method concrete secondary mixing methods, and the concrete technology step is as follows:
1/2 the water 69kg that adds the fine aggregate of 496kg and water total amount according to weight proportion every cubic meter of concrete in forced mixer, behind the uniform stirring 1～2 minute, adding the 446.6kg particle diameter is the coarse aggregate of Φ 5～Φ 10mm simple grain level rubble, uniform stirring adds the coarse aggregate that the 829.4kg particle diameter is Φ 10～Φ 20mm simple grain level rubble after 1～2 minute, behind the uniform stirring 2 minutes, the cement that adds again whole consolidating materials: 450kg, the silicon ash of 60kg and the flyash of 90kg, behind the uniform stirring 2～3 minutes, the polycarboxylic acid series high efficiency water reducing agent and the residue water 69kg that add 9kg, last uniform stirring is after 2～3 minutes, discharging namely gets prepared concrete mix.
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| CN1451626A (en) * | 2002-04-17 | 2003-10-29 | 杨果林 | High strength steel fibre concrete and making method thereof |
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| CN1451626A (en) * | 2002-04-17 | 2003-10-29 | 杨果林 | High strength steel fibre concrete and making method thereof |
| CN101250040A (en) * | 2006-03-22 | 2008-08-27 | 西安建筑科技大学 | Concrete with strength grade of C100 used for steel reinforced concrete combined structure |
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| Title |
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| 李磊 等.型钢与高强高性能混凝土界面强化机理研究.《哈尔滨工业大学学报》.2007,第39卷142-145. * |
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