CN109626916A - The dedicated self-compacting concrete of subway unballasted track bed course and its preparation and application - Google Patents
The dedicated self-compacting concrete of subway unballasted track bed course and its preparation and application Download PDFInfo
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- CN109626916A CN109626916A CN201910113830.8A CN201910113830A CN109626916A CN 109626916 A CN109626916 A CN 109626916A CN 201910113830 A CN201910113830 A CN 201910113830A CN 109626916 A CN109626916 A CN 109626916A
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- 239000011376 self-consolidating concrete Substances 0.000 title claims abstract description 88
- 238000002360 preparation method Methods 0.000 title claims abstract description 15
- 238000010276 construction Methods 0.000 claims abstract description 31
- 239000000203 mixture Substances 0.000 claims abstract description 30
- 238000002156 mixing Methods 0.000 claims abstract description 28
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 31
- 239000000843 powder Substances 0.000 claims description 28
- 239000000463 material Substances 0.000 claims description 21
- 239000003638 chemical reducing agent Substances 0.000 claims description 20
- 238000003756 stirring Methods 0.000 claims description 20
- 238000000034 method Methods 0.000 claims description 19
- 239000003795 chemical substances by application Substances 0.000 claims description 13
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 11
- 239000002518 antifoaming agent Substances 0.000 claims description 11
- 239000004576 sand Substances 0.000 claims description 11
- 239000000654 additive Substances 0.000 claims description 10
- 230000000996 additive effect Effects 0.000 claims description 10
- 239000012744 reinforcing agent Substances 0.000 claims description 10
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 claims description 8
- 239000004568 cement Substances 0.000 claims description 8
- 235000019738 Limestone Nutrition 0.000 claims description 7
- 239000006028 limestone Substances 0.000 claims description 7
- 239000004575 stone Substances 0.000 claims description 7
- 239000001913 cellulose Substances 0.000 claims description 6
- 229920002678 cellulose Polymers 0.000 claims description 6
- 239000010881 fly ash Substances 0.000 claims description 6
- 239000004816 latex Substances 0.000 claims description 6
- 229920000126 latex Polymers 0.000 claims description 6
- 229910021487 silica fume Inorganic materials 0.000 claims description 6
- 239000002893 slag Substances 0.000 claims description 6
- -1 alkyl aromatic hydrocarbon sulfonic acids Chemical class 0.000 claims description 5
- 210000000988 bone and bone Anatomy 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 4
- 229920002503 polyoxyethylene-polyoxypropylene Polymers 0.000 claims description 4
- 238000010521 absorption reaction Methods 0.000 claims description 3
- 239000002253 acid Substances 0.000 claims description 3
- 238000013329 compounding Methods 0.000 claims description 3
- RSWGJHLUYNHPMX-UHFFFAOYSA-N Abietic-Saeure Natural products C12CCC(C(C)C)=CC2=CCC2C1(C)CCCC2(C)C(O)=O RSWGJHLUYNHPMX-UHFFFAOYSA-N 0.000 claims description 2
- KHPCPRHQVVSZAH-HUOMCSJISA-N Rosin Natural products O(C/C=C/c1ccccc1)[C@H]1[C@H](O)[C@@H](O)[C@@H](O)[C@@H](CO)O1 KHPCPRHQVVSZAH-HUOMCSJISA-N 0.000 claims description 2
- 125000001931 aliphatic group Chemical group 0.000 claims description 2
- 125000000217 alkyl group Chemical group 0.000 claims description 2
- 150000001412 amines Chemical class 0.000 claims description 2
- 235000014113 dietary fatty acids Nutrition 0.000 claims description 2
- 239000000194 fatty acid Substances 0.000 claims description 2
- 229930195729 fatty acid Natural products 0.000 claims description 2
- DGVVJWXRCWCCOD-UHFFFAOYSA-N naphthalene;hydrate Chemical compound O.C1=CC=CC2=CC=CC=C21 DGVVJWXRCWCCOD-UHFFFAOYSA-N 0.000 claims description 2
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 claims description 2
- 229920005989 resin Polymers 0.000 claims description 2
- 239000011347 resin Substances 0.000 claims description 2
- 229920002545 silicone oil Polymers 0.000 claims description 2
- 238000003860 storage Methods 0.000 claims description 2
- KHPCPRHQVVSZAH-UHFFFAOYSA-N trans-cinnamyl beta-D-glucopyranoside Natural products OC1C(O)C(O)C(CO)OC1OCC=CC1=CC=CC=C1 KHPCPRHQVVSZAH-UHFFFAOYSA-N 0.000 claims description 2
- 229910052799 carbon Inorganic materials 0.000 claims 1
- 239000004567 concrete Substances 0.000 description 18
- 238000005516 engineering process Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 5
- 238000011049 filling Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 230000007547 defect Effects 0.000 description 4
- 229910000831 Steel Inorganic materials 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000010959 steel Substances 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 238000004581 coalescence Methods 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000002708 enhancing effect Effects 0.000 description 2
- 230000005012 migration Effects 0.000 description 2
- 238000013508 migration Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 241000264877 Hippospongia communis Species 0.000 description 1
- 239000011398 Portland cement Substances 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000015271 coagulation Effects 0.000 description 1
- 238000005345 coagulation Methods 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 239000003623 enhancer Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 239000011150 reinforced concrete Substances 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 230000000979 retarding effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/04—Portland cements
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00034—Physico-chemical characteristics of the mixtures
- C04B2111/00146—Sprayable or pumpable mixtures
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
- C04B2111/0075—Uses not provided for elsewhere in C04B2111/00 for road construction
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/20—Resistance against chemical, physical or biological attack
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
The present invention is aiming at the problem that mixing plant system supplied on a large scale in the prior art can not adapt to subway unballasted track self-compacting concrete this special operation condition of cushion construction, by changing product formula and producing, transport, pour the mode of smashing, a kind of dedicated self-compacting concrete of subway unballasted track bed course and its preparation and application are developed, solves the problems, such as that fragment-free track slab self-compacting concrete bed course pouring quality is unqualified in the prior art, mixture performance loss, durability are underproof.
Description
Technical Field
The invention belongs to the field of building materials, and particularly relates to a self-compacting concrete special for a subway ballastless track cushion layer and a preparation and use method thereof.
Background
With the rapid development of economy and cities in China, urban rail transit enters a large development period, and rail transit projects are rapidly increased. The existing subway integral ballast bed construction adopts a concrete on-site pouring mode, and has the defects of slow construction progress, difficult control of concrete cast-in-place quality, high labor intensity, bad operation environment and the like. And later maintenance is difficult due to the integral casting. In addition, with the application of the vibration and noise reduction technology with complex structural design in the rail engineering, the traditional cast-in-place concrete road bed construction mode also has the problems of low construction efficiency, difficult quality control and influence on the vibration reduction effect.
The slab ballastless track comprises a steel rail, a fastener, a track slab, a self-compacting concrete filling layer, an isolation layer, a reinforced concrete base and the like. As the filler between the track slab and the base plate, the self-compacting concrete filling layer has the functions of supporting, limiting, adjusting elevation and the like, and the construction quality of the self-compacting concrete filling layer determines the safety and durability of the whole ballastless track structure in operation. The self-compacting concrete does not need to be vibrated, so that the self-compacting concrete is widely applied to new buildings with dense steel bars and special-shaped members, steel pipe concrete and structural repair and reinforcement. In the prior art, the construction of the self-compacting concrete cushion layer is carried out by pre-mixing the self-compacting concrete by a mixing plant, transporting the self-compacting concrete to a project site by a tank truck, and pouring the self-compacting concrete cushion layer by secondary transshipment.
Although the ballastless track is widely applied to domestic high-speed railways, the related technologies are relatively mature, but the difference of subway working conditions is large compared with the high-speed railways, the environment is worse, so that the related technologies of high-speed railway plate track construction cannot be directly used, and particularly, the ballastless track system most critical self-compacting cushion layer material and construction technology need to be specially designed in combination with the subway working conditions.
In the prior art, the self-compacting concrete of the ballastless track of the subway is supplied by a mixing plant, is transported to a site by a mixing truck through a long distance, is transported to an underground track through secondary refutation, is transported to a track slab construction site by the underground track, and is poured. This leads to at least the following problems:
firstly, the performance of the mixture is lost with time and the problem is solved.
1. The time interval from the leaving of the factory to the entering of the mold of the self-compacting concrete is inconsistent.
In recent years, due to environmental protection reasons, each city moves a mixing plant in a city center to the periphery of the city, the mixing plant is not basically arranged in the city center, and the subway construction needs to transport self-compacting concrete from the mixing plant to a construction site through a long distance. For urban subway construction, a subway line construction site is usually in the city center, a mixing plant is usually at the periphery of a city, and the self-compacting concrete transportation time is uncertain due to traffic jam. And the construction site of each platform is greatly different from the mixing plant, so that the road transportation time is inconsistent.
In addition, the concrete is transported to a construction site and needs to be transported to an underground track construction site through secondary transshipment, and the distances from the gallery wells to pouring points are inconsistent, so that the actual time from the secondary transshipment to the final pouring is inconsistent. Therefore, after the self-compacting concrete leaves the factory from the mixing plant, the self-compacting concrete is poured into the mould at last, and the interval time is inconsistent, so that the performance of the self-compacting concrete mixture is changed too much, and the construction quality is unqualified. The surface has the defects of floating pulp, cavities, honeycombs and the like, and the durability index also does not meet the requirement.
2. The duration from the beginning of pouring the self-compacting concrete to the end of pouring is too long.
The volume of a common concrete tank car is about 10 square, the maximum size of a subway slag-free track bed slab is 4.8m multiplied by 2.4m multiplied by 0.08m, the volume is less than 1 square, and the pouring time is 10-15 minutes. The self-compacting concrete delivered to the site needs at least one half hour after pouring by each vehicle, and the performance of the mixture of the self-compacting concrete is changed too much in the pouring process, so that the pouring quality is unstable, and the construction quality is unqualified.
Therefore, the original mixing station system is only suitable for fixing construction sites, common concrete with little performance loss change along with time, and special self-compacting concrete which is not suitable for subways.
Secondly, the performance loss compensation scheme of the mixture in the prior art cannot solve essential problems.
The existing concrete retarding technology can only delay the setting time and cannot solve the problem of the performance loss of the mixture. The subway self-compacting concrete is a concrete with high requirements on various performances of a mixture, and although the conventional concrete technology additive technology delays the setting time by adding a retarder, the problem that the performances of the mixture of the concrete are lost along with time cannot be solved. Actual measurements show that the loss of mixing performance of self-compacting concrete provided by a typical mixing plant over time is as follows:
| item | Initial value | After 1h | After 2h | After 3 hours |
| Slump spread, mm | 660 | 528 | 409 | 290 |
| Content of gas, content of | 5.8 | 4.9 | 4.2 | 3.1 |
And thirdly, the durability of the self-compacting concrete in the prior art does not reach the standard.
According to national durability regulations on urban rail facilities, the urban rail facilities are required to reach a one-hundred-year-durable standard. The experimental section of the twelve-line of the subway in Shanghai city adopts the self-compacting concrete supplied by a mixing plant to pour, and the actually measured durability index of the self-compacting concrete basically does not meet the requirement, and is shown in the following table:
disclosure of Invention
In view of the defects in the prior art, the invention aims to provide the self-compacting concrete special for the ballastless track cushion of the subway and the preparation and use methods thereof, and solve the problems of unqualified pouring quality, loss of performance of the mixture and unqualified durability of the self-compacting concrete cushion of the ballastless track slab in the prior art.
In the percentage contents mentioned in the description of the present invention, the other percentages refer to weight percentages except for the gas content which refers to volume percentages. The cement as referred to in the present specification means the sum of the concrete components excluding the aggregate, i.e., cement, fly ash, durability enhancing agent and admixture. In the technical field, the additive refers to a chemical substance which is added into concrete in a small amount and can obviously improve the performance of the concrete, such as a water reducing agent, an air entraining agent, an antifoaming agent, a retarder, cellulose, latex powder and the like mentioned in the specification of the invention, and as for the additive not mentioned in the specification of the invention, a person skilled in the art can completely apply the additive by means of knowledge and experience mastered by the person skilled in the art, and in principle, the implementation effect of the invention is not influenced as long as the action of the additive does not conflict with the additive used in the invention.
In a first aspect of the invention, the invention provides a self-compacting concrete special for a subway ballastless track cushion layer, which comprises coarse aggregate and fine aggregate. Wherein the coarse aggregate is basalt broken stone, and the content is 25-42%; the fine aggregate is dry sand with the content of 23-35%.
Furthermore, the particle diameter of the basalt broken stone is 5-16mm, continuous gradation is adopted, the needle-shaped content in the basalt broken stone is less than or equal to 1%, the mud content is less than or equal to 0.5%, the mud block content is less than or equal to 0.1%, and the water absorption rate is less than or equal to 0.5%. In the prior art, common limestone macadam with the thickness of 5-16mm or 5-20mm is usually selected as the coarse aggregate of the self-compacting concrete. In contrast, the invention adopts the basalt roundstone with less flaky particles, smooth and uniform particles, lower water absorption, mud content and mud block content, and more stable performance, so that the mixture of the self-compacting concrete has more stable performance and little time variation.
Furthermore, the dry sand is medium sand with 35-60 meshes (0.5-0.25mm), the water content is less than or equal to 2 percent, the mud content is less than or equal to 0.5 percent, the mud block content is less than or equal to 0.1 percent, and the dry sand is preferred. In the prior art, common river sand is mostly selected as fine aggregate for the self-compacting concrete, and the self-compacting concrete has high water content and mud content. In contrast, the self-compacting concrete disclosed by the invention adopts the dried sand with low water content, mud content and mud block content, so that the self-compacting concrete disclosed by the invention is more stable in property.
Further, the self-compacting concrete special for the ballastless track cushion layer of the subway further comprises a water reducing agent, a defoaming agent and an air entraining agent. Wherein, the content of the water reducing agent is 0.5-2% of the content of the cementing material, preferably 1%, and the water reducing agent is selected from one or more of a naphthalene water reducing agent, an aliphatic water reducing agent, an amino water reducing agent and a polycarboxylic acid water reducing agent; the content of the defoaming agent is 0.5-1.5% of that of the water reducing agent, preferably 1%, and the defoaming agent is selected from one or more of emulsified silicone oil, a higher alcohol fatty acid ester compound, polyoxyethylene polyoxypropylene pentaerythritol ether and polyoxyethylene polyoxypropylene amine ether; the content of the air entraining agent is 0.5-2% of that of the water reducing agent, preferably 1.2%, and the air entraining agent is selected from one or more of rosin resins, alkyl and alkyl aromatic hydrocarbon sulfonic acids and fatty alcohol sulfonates. According to the regulations of technical conditions for self-compacting concrete filling layers of rail transit in Shanghai city, the gas content of the self-compacting concrete is required to be 3.0-6.0% in order to ensure the filling performance and the mixture performance of the self-compacting concrete. In the prior art, in order to make up for slump loss in the transportation and pouring processes, a mixing plant is doped with a retarder to slow down the concrete setting time. However, for self-compacting concrete with high fluidity, the slump expansion index parameter needs to be maintained, the effect of the doped retarder on the slump expansion index is small, and the air content cannot be ensured. On the other hand, the invention adopts a field stirring mode to fundamentally solve the problem of slump expansion loss; on the other hand, the defoaming agent and the air entraining agent are adopted simultaneously, so that not only can overlarge and undersize uneven bubbles generated in the stirring process be eliminated, but also bubbles which are uniformly distributed (20-1000 mu m), are closed stably, have low migration speed and have small possibility of mutual coalescence are introduced, so that the stability of the performance of the mixture before entering the mold and the meeting of the air content requirement are ensured, and the problem of performance loss compensation is solved; meanwhile, the water-cement ratio is reduced, so that a compact and uniform structure is formed, and the durability is obviously enhanced.
Further, the self-compacting concrete special for the ballastless track cushion layer of the subway further comprises cellulose and latex powder; wherein, the content of the cellulose is 0.05 to 0.2 percent of the content of the cementing material; the content of the latex powder is 0.5-2% of the content of the cementing material.
Further, the self-compacting concrete special for the subway ballastless track cushion layer further comprises a durability reinforcing agent, the content of the durability reinforcing agent is 1-5%, the preferable content is 3%, the durability reinforcing agent is prepared by compounding slag powder, superfine limestone and superfine silica fume, and the proportion of the three components is 2-4: 1-3: 1, preferably 3: 2: 1. wherein the fineness of the slag powder is 300-500 meshes, preferably 500 meshes; the fineness of the superfine limestone is 500-800 meshes, preferably 800 meshes; the fineness of the ultrafine silica fume is 1500-2000 meshes, and the preferable fineness is 2000 meshes. The durability reinforcing agent can enable the hardened concrete to be more densely filled in gaps, and the durability is obviously improved.
In a second aspect of the invention, the invention provides a preparation method of the self-compacting concrete special for the subway ballastless track cushion layer, which comprises the following steps:
(1) the additive, the cement, the fine aggregate, the fly ash and the durability reinforcing agent are metered from respective storage containers according to the proportion and are introduced into a stirring device for mixing and stirring to form powder.
(2) And (3) metering and bagging the powder and the coarse aggregate to form a bagged finished product material.
Further, the stirring device in the step (1) is a powder mixer.
Further, the bagging in the step (2) has two forms: one is to separately pack powder and coarse aggregate to form a powder bag and an aggregate bag respectively; alternatively, the powder and coarse bone are mixed and bagged together.
In a third aspect of the invention, the invention further provides a use method of the self-compacting concrete special for the subway ballastless track cushion layer, which comprises the following steps:
(a) transporting the bagged finished product material to a construction site of a subway ballastless track cushion layer;
(b) taking finished product materials which are approximately equal to or slightly larger than the finished product materials required for pouring a cushion plate, for example, about 1 square, adding water, uniformly stirring to form a mixture, immediately introducing the mixture into a mold, and pouring the mixture into a cushion plate;
(c) and (c) repeating the step (b) to finish the pouring of the next cushion plate.
Further, the stirring in step (b) is accomplished by a mini-stirrer.
The invention solves the problems of unqualified pouring quality, mixture performance loss and unqualified durability of the self-compacting concrete cushion layer of the ballastless track slab in the prior art by the following means:
1. problem of loss of blend Properties
(1) In the aspect of aggregate selection, the invention selects an innovative coarse and fine aggregate formula with more stable performance, so that the prepared self-compacting concrete mixture has more stable performance and less change along with time.
(2) In the mixing method, premixing is innovatively changed from premixing in a mixing station in a factory, then the mixed finished material is transported to a construction site in a bag form, water is added into the site for mixing, and pouring is carried out immediately. Thus, the problem that the performance of the mixture of the self-compacting concrete is lost along with the transportation time in the transportation process due to a material supply system of a mixing plant is thoroughly avoided; the problem that the self-compacting concrete admixture loses efficacy along with the prolonging of the stirring time is avoided; and the problem that other physical properties and durability are changed due to the coagulation reaction of the self-compacting concrete along with the time extension is also avoided.
(3) In the pouring method, according to the actual pouring requirement of the subway self-compacting concrete cushion layer, the construction of one cushion layer plate is just finished when the stirring amount is about one side each time, the consistency of the performance of the self-compacting concrete before the concrete is poured into a mould each time is ensured, and the defects that the pouring time is too long when the self-compacting concrete is sent by a stirring station tank are avoided.
(4) On the aspect of the external additive, on one hand, the invention adopts a field stirring mode, does not need to add a retarder as in the prior art, and fundamentally solves the problem of slump expansion loss in the prior art; on the other hand, the defoaming agent and the air entraining agent are added in the formula, so that overlarge and undersize uneven bubbles generated in the stirring process are eliminated, and bubbles which are uniform in distribution, stable in closing, low in migration speed and low in possibility of mutual coalescence are introduced, so that the stability of the performance of the mixture before entering the mold is ensured, and the air content meets the requirements.
2. Durability problem
(1) According to the invention, the defoaming agent and the air entraining agent are added in the formula, and the uniformly distributed closed bubbles are introduced into the self-compacting concrete, so that the effect of ensuring the performance of the concrete mixture is achieved, and the water cement ratio is reduced, thereby forming a compact and uniform structure, and the durability is obviously enhanced.
(2) The invention innovatively provides a concept of a durability reinforcing agent, and the durability of the self-compacting concrete can be obviously improved by compounding and blending the slag powder, the limestone and the silica fume with different fineness moduli.
Compared with the prior art, the beneficial technical effects of the invention are at least reflected in the following aspects:
(1) for the construction of the ballastless track cushion layer of the urban subway, the transportation time of a material supply system of a traditional mixing plant is uncertain, so that the performance of a mixture before the mixture is fed into a mold is unstable, and the pouring quality is in a problem. The invention adopts factory premixing and field stirring for pouring, thereby fundamentally avoiding the quality problem caused by uncertain transportation time of the traditional system.
(2) The construction space of the urban subway is narrow and small, and the construction speed is low. The traditional large-scale supply of mixing plant system is not suitable for the small-scale construction condition of the self-compacting concrete of the subway. The invention can be stirred by adding water on site, and a small-sized stirrer and a small-sized pumping device can be adopted, so that the operation is simple and convenient; construction can be carried out according to the using amount, and the construction is flexible and convenient.
(3) Self-compacting concrete supplied by a traditional mixing plant is not subjected to targeted formula design in the aspect of durability, and the performance of a mixture is unstable, so that a poured self-compacting concrete cushion layer is not consistent with the requirement on the durability of urban rail transit. The invention can obviously improve the durability of the self-compacting concrete by improving the formula and adding the durability reinforcing agent.
Drawings
Fig. 1 is a schematic diagram of a preparation and use method of the self-compacting concrete special for the subway ballastless track cushion layer according to a preferred embodiment of the invention.
Detailed Description
The following examples are given to illustrate the present invention in detail, and the following examples are given to illustrate the detailed embodiments and specific procedures of the present invention, but the scope of the present invention is not limited to the following examples.
Example 1
In a preferred embodiment, the self-compacting concrete special for the ballastless track cushion layer of the subway disclosed by the invention adopts the following formula (by weight):
additive: 3 parts of a polycarboxylic acid water reducing agent, 0.03 part of a defoaming agent, 0.045 part of an air entraining agent, 0.3 part of cellulose and 4 parts of latex powder;
fine aggregate: drying 600 parts of sand;
fly ash: 100 parts of type II fly ash;
durability enhancing agent: 30 parts in total; wherein, 15 parts of 500-mesh slag powder, 10 parts of 800-mesh superfine limestone and 5 parts of 2000-mesh superfine silica fume;
coarse aggregate: 750 parts of basalt broken stone;
cement: 425 parts of ordinary portland cement.
As shown in fig. 1, the preparation method of the self-compacting concrete special for the subway ballastless track cushion layer in embodiment 1 is as follows:
(1) the admixture, the cement, the fine aggregate, the fly ash and the durability enhancer are metered according to the mixture ratio and are introduced into a powder mixer for mixing and stirring to form powder;
(2) and (3) metering the powder and the coarse aggregate according to the proportion, and respectively packaging to form a powder bag and a bone material bag.
The use method of the self-compacting concrete special for the subway ballastless track cushion layer in the embodiment 1 is as follows:
(a) transporting the bagged finished product material to a construction site of a subway ballastless track cushion layer;
(b) taking finished products required for pouring the cushion plate with the size of about 1 square, adding water, uniformly stirring by using a small stirrer to form a mixture, immediately introducing the mixture into a die, and pouring the cushion plate with the size of 4.8m multiplied by 2.4m multiplied by 0.08 m;
(c) and (c) repeating the step (b) to finish the pouring of the next cushion plate.
Examples 2 to 10
The preparation method and the using method of the self-compacting concrete special for the ballastless track cushion of the subway of the embodiment 2-10 are the same as the embodiment 1, the difference is only the formula, and the formula of the embodiment 2-10 is shown in the following table (by weight):
compared with the prior art, the durability of the cushion plate poured by the self-compacting concrete special for the subway ballastless track cushion is obviously improved, the durability can completely meet the requirements of various existing technical specifications on the durability, and the actually measured related indexes are shown in the following table:
the foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.
Claims (13)
1. The self-compacting concrete special for the subway ballastless track cushion layer is characterized by comprising coarse aggregate and fine aggregate; wherein the coarse aggregate is basalt macadam, and the content of the basalt macadam is 25-42%; the fine aggregate is dry sand, and the content of the fine aggregate is 23-35%.
2. The self-compacting concrete special for the ballastless track cushion of the subway as claimed in claim 1, wherein the particle diameter of the basalt broken stone is 5-16mm, and the basalt broken stone adopts continuous gradation, the needle-shaped content in the basalt broken stone is less than or equal to 1%, the mud content is less than or equal to 0.5%, the mud block content is less than or equal to 0.1%, and the water absorption rate is less than or equal to 0.5%.
3. The self-compacting concrete special for the bed course of the ballastless track of the subway as claimed in claim 2, wherein said dry sand is dried sand of 35-60 meshes, the water content of said dried sand is less than or equal to 2%, the mud content is less than or equal to 0.5%, and the mud block content is less than or equal to 0.1%.
4. The self-compacting concrete special for the ballastless track cushion layer of the subway of claim 3, wherein the self-compacting concrete further comprises a water reducing agent, a defoaming agent and an air entraining agent; wherein,
the content of the water reducing agent is 0.5-2% of the content of the cementing material in the self-compacting concrete, and the water reducing agent is selected from one or more of a naphthalene water reducing agent, an aliphatic water reducing agent, an amino water reducing agent and a polycarboxylic acid water reducing agent;
the content of the defoaming agent is 0.5-1.5% of that of the water reducing agent, and the defoaming agent is selected from one or more of emulsified silicone oil, a high-carbon alcohol fatty acid ester compound, polyoxyethylene polyoxypropylene pentaerythritol ether and polyoxyethylene polyoxypropylene amine ether;
the content of the air entraining agent is 0.5-2% of that of the water reducing agent, and the air entraining agent is selected from one or more of rosin resins, alkyl and alkyl aromatic hydrocarbon sulfonic acids and fatty alcohol sulfonates.
5. The self-compacting concrete special for the ballastless track cushion of the subway of claim 4, wherein the self-compacting concrete further comprises cellulose and latex powder; wherein the content of the cellulose is 0.05-0.2% of the content of the cementing material; the content of the latex powder is 0.5-2% of the content of the cementing material.
6. The self-compacting concrete special for the subway ballastless track cushion layer according to claim 4 or 5, wherein the self-compacting concrete further comprises a durability reinforcing agent with a content of 1-5%, the durability reinforcing agent is prepared by compounding slag powder, ultrafine limestone and ultrafine silica fume, and the weight ratio of the three components is 2-4: 1-3: 1.
7. the self-compacting concrete special for the ballastless track cushion layer of the subway as claimed in claim 6, wherein the fineness of the slag powder is 300-500 meshes; the fineness of the superfine limestone is 500-800 meshes; the fineness of the superfine silica fume is 1500-2000 meshes.
8. The preparation method of the special self-compacting concrete for the ballastless track cushion of the subway as claimed in claim 7, wherein the preparation method comprises the following steps:
(1) the additive, the cement, the fine aggregate, the fly ash and the durability reinforcing agent are metered from respective storage containers according to the proportion and are introduced into a stirring device for mixing and stirring to form powder;
(2) and metering and bagging the powder and the coarse aggregate according to the proportion to form a bagged finished product material.
9. The preparation method of the self-compacting concrete special for the ballastless track cushion of the subway as claimed in claim 8, wherein said stirring device in step (1) is a powder mixer.
10. The preparation method of the self-compacting concrete special for the ballastless track cushion of the subway as claimed in claim 8, wherein said bagging in step (2) is separately bagging said powder and said coarse aggregate, thereby forming a powder bag and a bone bag respectively.
11. The preparation method of the self-compacting concrete special for the ballastless track cushion of the subway as claimed in claim 8, wherein said bagging in step (2) is mixing said powder material and said coarse bone and bagging together.
12. The use method of the self-compacting concrete prepared by the preparation method of the self-compacting concrete special for the ballastless track cushion layer of the subway according to claim 8, wherein the use method comprises the following steps:
(a) transporting the bagged finished product material to a construction site of a subway ballastless track cushion layer;
(b) taking the finished product material which is approximately equal to or slightly larger than the finished product material required for pouring a cushion plate, adding water, uniformly stirring to form a mixture, immediately introducing the mixture into a mold, and pouring the mixture into a cushion plate;
(c) and (c) repeating the step (b) to finish the pouring of the next cushion plate.
13. The method for using the self-compacting concrete prepared by the method for preparing the self-compacting concrete special for the ballastless track cushion of the subway according to claim 12, wherein the stirring in the step (b) is completed by a small mixer.
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| CN108101427A (en) * | 2017-11-24 | 2018-06-01 | 中国铁道科学研究院铁道建筑研究所 | A kind of high polymer for steel truss girder non-fragment orbit filling layer fills concrete certainly |
| CN111807771A (en) * | 2020-07-14 | 2020-10-23 | 四川华西绿舍建材有限公司 | Self-compacting fair-faced concrete for special-shaped column structure and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108101427A (en) * | 2017-11-24 | 2018-06-01 | 中国铁道科学研究院铁道建筑研究所 | A kind of high polymer for steel truss girder non-fragment orbit filling layer fills concrete certainly |
| CN111807771A (en) * | 2020-07-14 | 2020-10-23 | 四川华西绿舍建材有限公司 | Self-compacting fair-faced concrete for special-shaped column structure and preparation method thereof |
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