CN114163195A - Bare concrete and concrete construction method - Google Patents
Bare concrete and concrete construction method Download PDFInfo
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- CN114163195A CN114163195A CN202111599643.9A CN202111599643A CN114163195A CN 114163195 A CN114163195 A CN 114163195A CN 202111599643 A CN202111599643 A CN 202111599643A CN 114163195 A CN114163195 A CN 114163195A
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- 238000010276 construction Methods 0.000 title claims abstract description 39
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 77
- 239000010881 fly ash Substances 0.000 claims abstract description 48
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 36
- 239000004568 cement Substances 0.000 claims abstract description 27
- 238000000034 method Methods 0.000 claims abstract description 18
- 230000008569 process Effects 0.000 claims abstract description 16
- 238000012423 maintenance Methods 0.000 claims abstract description 8
- 239000004576 sand Substances 0.000 claims description 39
- 239000004575 stone Substances 0.000 claims description 33
- 238000002156 mixing Methods 0.000 claims description 28
- 239000002245 particle Substances 0.000 claims description 22
- 239000010410 layer Substances 0.000 claims description 20
- 239000000843 powder Substances 0.000 claims description 13
- 239000000463 material Substances 0.000 claims description 12
- 239000002253 acid Substances 0.000 claims description 11
- 230000000979 retarding effect Effects 0.000 claims description 10
- 239000011248 coating agent Substances 0.000 claims description 9
- 238000000576 coating method Methods 0.000 claims description 9
- 239000003513 alkali Substances 0.000 claims description 8
- 239000003223 protective agent Substances 0.000 claims description 8
- 229910000831 Steel Inorganic materials 0.000 claims description 7
- 239000010959 steel Substances 0.000 claims description 7
- 239000003795 chemical substances by application Substances 0.000 claims description 6
- 230000007547 defect Effects 0.000 claims description 6
- 239000011241 protective layer Substances 0.000 claims description 5
- 239000010754 BS 2869 Class F Substances 0.000 claims description 4
- 239000002283 diesel fuel Substances 0.000 claims description 3
- NBVXSUQYWXRMNV-UHFFFAOYSA-N fluoromethane Chemical compound FC NBVXSUQYWXRMNV-UHFFFAOYSA-N 0.000 claims description 3
- 238000003780 insertion Methods 0.000 claims description 3
- 230000037431 insertion Effects 0.000 claims description 3
- 239000010721 machine oil Substances 0.000 claims description 3
- 230000035515 penetration Effects 0.000 claims description 3
- 230000000694 effects Effects 0.000 abstract description 18
- 230000004075 alteration Effects 0.000 abstract description 2
- 238000012360 testing method Methods 0.000 description 22
- 239000000203 mixture Substances 0.000 description 15
- 239000000126 substance Substances 0.000 description 6
- 238000013461 design Methods 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 238000009415 formwork Methods 0.000 description 4
- 230000000740 bleeding effect Effects 0.000 description 3
- HOOWDPSAHIOHCC-UHFFFAOYSA-N dialuminum tricalcium oxygen(2-) Chemical compound [O--].[O--].[O--].[O--].[O--].[O--].[Al+3].[Al+3].[Ca++].[Ca++].[Ca++] HOOWDPSAHIOHCC-UHFFFAOYSA-N 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 239000003292 glue Substances 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- 238000010998 test method Methods 0.000 description 3
- 238000005266 casting Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000008399 tap water Substances 0.000 description 2
- 235000020679 tap water Nutrition 0.000 description 2
- 241000124879 Grus leucogeranus Species 0.000 description 1
- 241001374849 Liparis atlanticus Species 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000008030 superplasticizer Substances 0.000 description 1
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- 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
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- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G21/00—Preparing, conveying, or working-up building materials or building elements in situ; Other devices or measures for constructional work
- E04G21/02—Conveying or working-up concrete or similar masses able to be heaped or cast
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04G—SCAFFOLDING; FORMS; SHUTTERING; BUILDING IMPLEMENTS OR AIDS, OR THEIR USE; HANDLING BUILDING MATERIALS ON THE SITE; REPAIRING, BREAKING-UP OR OTHER WORK ON EXISTING BUILDINGS
- E04G21/00—Preparing, conveying, or working-up building materials or building elements in situ; Other devices or measures for constructional work
- E04G21/02—Conveying or working-up concrete or similar masses able to be heaped or cast
- E04G21/06—Solidifying concrete, e.g. by application of vacuum before hardening
- E04G21/08—Internal vibrators, e.g. needle vibrators
-
- 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
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
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- Architecture (AREA)
- Structural Engineering (AREA)
- Ceramic Engineering (AREA)
- Mechanical Engineering (AREA)
- Civil Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
The invention relates to the technical field of concrete construction, in particular to fair-faced concrete and a concrete construction method, wherein the fair-faced concrete adopts components such as cement, fly ash, fine aggregate, coarse aggregate, a water reducing agent and the like, and limits the characteristics and the using amount of each component; the concrete construction process also adjusts the concrete pouring sequence, vibration and maintenance process, so that the strength and surface effect of the finally formed concrete structure can meet the requirements. The component proportion of the fair-faced concrete provided by the invention can be used for preparing the fair-faced concrete with higher overall strength, less surface forming chromatic aberration and less bubbles; after the construction is carried out according to the method disclosed by the invention, the surface forming effect of the concrete structural member is good, the strength is sufficient, the color is consistent, and a better state can be kept after the construction for a long time.
Description
Technical Field
The invention relates to the technical field of concrete construction, in particular to fair-faced concrete and a concrete construction method.
Background
The color of the surface of the fair-faced concrete needs to be uniform without obvious color difference; meanwhile, the surface of the concrete has no obvious bubbles, and the concrete is called as decorative concrete in the field of buildings because of good appearance effect. The above effects that the fair-faced concrete can achieve are based on the dense and inseparable relations such as stable raw material quality, stable mix proportion, stable construction process and the like, so that the component proportion of the fair-faced concrete needs to be strictly screened and determined before the construction of the fair-faced concrete.
Meanwhile, the construction process of the fair-faced concrete also has direct influence on the forming effect, the difference of the front and rear processes directly influences the stability and the surface effect of the forming structure, and the service life of the structural surface used for a long time is obviously different.
Therefore, on the premise of ensuring the working performance, the mechanical property, the durability and the like, the components and the construction process of the fair-faced concrete need to be strictly controlled, so that the final forming structure quality and the appearance forming effect of the fair-faced concrete are improved. In order to improve the construction quality of the fair-faced concrete, a more reasonable technical scheme needs to be provided, and the defects in the prior art are overcome.
Disclosure of Invention
In order to solve the defects of the prior art mentioned in the content, the invention provides the fair-faced concrete and the concrete construction method, the selection of the components of the fair-faced concrete is limited, and the construction mode of the fair-faced concrete adopting the components in proportion is optimized and improved, so that the quality of the structural member after the construction of the fair-faced concrete is integrally improved, the internal stability of the structural member is kept, the surface is smooth and free of bubbles, color difference and the like.
In order to achieve the purpose, the invention specifically adopts the technical scheme that:
the fair-faced concrete comprises the following components in parts by mass:
376-411 parts of cement, 68-94 parts of fly ash, 691-716 parts of fine aggregate, 427-432 parts of coarse aggregate of the component A, 641-648 parts of coarse aggregate of the component B, 150-155 parts of water and 5.02-5.32 parts of water reducing agent;
wherein the fine aggregate comprises medium sand with fineness modulus of 3.0, stone powder content is 8.4%, and mud block content is 0.2%; the component A coarse aggregate comprises crushed stone with the particle size of 5-10mm, the component B coarse aggregate comprises crushed stone with the particle size of 10-25mm, the component A coarse aggregate accounts for 10-50% of the total weight of the coarse aggregate, the average mud content of the coarse aggregate is 0.4%, the mud block content is 0.1%, and the needle sheet content is 2%; the fly ash comprises class F class 2 fly ash; the water reducing agent is a polycarboxylic acid high-performance retarding water reducing agent, and the water reducing rate is 30%.
In the bare concrete disclosed above, the fine aggregate is machine-made sand.
The invention also discloses fair-faced concrete which is different from the above components and materials in components and specifically comprises the following components in parts by mass:
368 parts of cement, 92 parts of fly ash, 766-785 parts of fine aggregate, 200-204 parts of A-component coarse aggregate, 799-815 parts of B-component coarse aggregate, 148-153 parts of water and 5.06 parts of a water reducing agent;
wherein, the cement alkali content is 0.59 percent, the fine aggregate comprises coarse sand with fineness modulus of 3.3 and stone powder content is 5.6 percent, and the medium sand with fineness modulus of 2.8 and mud content is 0.8 percent; the component A coarse aggregate comprises crushed stone with the particle size of 5-10mm, the component B coarse aggregate comprises crushed stone with the particle size of 10-25mm, and the component A coarse aggregate accounts for 10-50% of the total weight of the coarse aggregate; the fly ash comprises class F1 grade fly ash with the loss on ignition of 1.08 percent and class F2 grade fly ash with the loss on ignition of 1.25 percent; the water reducing agent is a polycarboxylic acid high-performance retarding water reducing agent, and the water reducing rate is 26%.
The cement of the bare concrete disclosed above has higher tricalcium aluminate content and lower harmful substance content than the previous cement. The adopted fly ash has small fineness, high activity index, lower content of harmful substances and better performance index than the adopted fly ash.
The invention also discloses the fair-faced concrete, which is optimized again and comprises the following components in parts by mass:
368-388 parts of cement, 68-92 parts of fly ash, 716-785 parts of fine aggregate, 200-430 parts of coarse aggregate of the component A, 645-814 parts of coarse aggregate of the component B, 151-155 parts of water and 5.02-5.06 parts of a water reducing agent;
wherein, the cement alkali content is 0.59 percent, the fine aggregate comprises coarse sand with fineness modulus of 3.3 and stone powder content is 5.6 percent, and the medium sand with fineness modulus of 2.8 and mud content is 0.8 percent; the component A coarse aggregate comprises crushed stone with the particle size of 5-10mm, the component B coarse aggregate comprises crushed stone with the particle size of 10-25mm, and the component A coarse aggregate accounts for 10-50% of the total weight of the coarse aggregate; the fly ash comprises class F1 grade fly ash with the loss on ignition of 1.08 percent and class F2 grade fly ash with the loss on ignition of 1.25 percent; the water reducing agent is a polycarboxylic acid high-performance retarding water reducing agent, and the water reducing rate is 26%.
The bare concrete disclosed above adjusts the components aiming at the steel mould, can effectively reduce the condition of adhesion when the mould is removed, and the appearance quality is easy to control.
The invention also discloses a concrete construction method, which adopts the bare concrete disclosed in the above content and comprises the following processes:
preparing concrete according to the component proportion of the concrete, and performing layered pouring after treating a pouring construction foundation surface;
in the pouring process, vibrating points are uniformly arranged at intervals, and an insertion type vibrating rod is vertically inserted into each vibrating point below a pouring surface for pouring; the vibrating points are arranged at intervals and are divided into a plurality of vibrating ring layers from inside to outside, the vibrating points vibrate ring by ring from inside to outside, and all the vibrating points on a single vibrating ring layer vibrate simultaneously;
watering the pouring surface for curing in the concrete hardening and strength increasing period;
after the concrete template is removed, carrying out tight covering maintenance through a film;
and after the concrete is hardened, coating a transparent protective agent on the surface of the concrete.
Further, the construction method is optimized and improved, and the following feasible options are given: when the concrete is poured in layers, the height of each layer is less than or equal to 500 mm. By adopting the scheme, the overall strength of the structural body with a certain thickness or height can be improved by layering and constructing for multiple times; and for the structural surface with larger span, the color difference of the surface can keep higher consistency through layered construction.
Furthermore, when vibration is carried out, the vibration points are uniformly distributed, so that the vibration effect can be improved, bubbles, hollows and the like are reduced, and the compactness of concrete is improved; here, optimization is performed and one possible option is presented as follows: the vibrating points on the adjacent vibrating ring layers are arranged at intervals in a staggered mode, and the vibrating time is kept between 40s and 60s when the vibrating points on each vibrating ring layer are vibrated.
Still further, when the transparent protective agent is coated, the following processes are included:
repairing the pouring surface of the concrete to restore the part with the local defect to be consistent with the whole body;
adjusting the adjusting material to locally adjust the existing color difference, water flowing trace and local repairing trace, so as to achieve uniform color on the whole concrete surface without obvious repairing and adjusting trace;
and forming a transparent protective layer by adopting water-based penetration primary coating and water-based fluorocarbon transparent surface coating.
The transparent protective agent on the surface is coated through the steps to form a protective layer on the surface of the fair-faced concrete, so that the surface protection of the fair-faced concrete is improved.
Further, in order to facilitate the removal of the formwork and reduce the damage of the surface structure caused by the adhesion of the formwork and the concrete, the following feasible options are provided and optimized: adding a release agent during concrete pouring, wherein the release agent adopts machine oil and diesel oil according to the mass ratio of 7: 3 blending to prepare the product.
Furthermore, the curing time after concrete pouring is more than or equal to 14 days.
And further, the template adopted by concrete pouring is a steel template.
Compared with the prior art, the invention has the beneficial effects that:
the component proportion of the fair-faced concrete provided by the invention can be used for preparing the fair-faced concrete with higher overall strength, less surface forming chromatic aberration and less bubbles; after the construction is carried out according to the method disclosed by the invention, the surface forming effect of the concrete structural member is good, the strength is sufficient, the color is consistent, and a better state can be kept after the construction for a long time.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a schematic diagram of arrangement of vibration points.
Fig. 2 is a schematic view of a layered casting.
Fig. 3 is a process diagram of a concrete construction process.
Fig. 4 is a schematic view of a process of applying a transparent protection.
Detailed Description
The invention is further explained below with reference to the drawings and the specific embodiments.
It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. Specific structural and functional details disclosed herein are merely illustrative of example embodiments of the invention. This invention may, however, be embodied in many alternate forms and should not be construed as limited to the embodiments set forth herein.
Aiming at the defects of the fair-faced concrete in the prior art, the embodiment is optimized to solve the problems in the prior art.
Example 1
The embodiment discloses fair-faced concrete which comprises the following components in parts by mass:
376-411 parts of cement, 68-94 parts of fly ash, 691-716 parts of fine aggregate, 427-432 parts of coarse aggregate of the component A, 641-648 parts of coarse aggregate of the component B, 150-155 parts of water and 5.02-5.32 parts of water reducing agent;
wherein the fine aggregate comprises medium sand with fineness modulus of 3.0, stone powder content is 8.4%, and mud block content is 0.2%; the component A coarse aggregate comprises crushed stone with the particle size of 5-10mm, the component B coarse aggregate comprises crushed stone with the particle size of 10-25mm, the component A coarse aggregate accounts for 10-50% of the total weight of the coarse aggregate, the average mud content of the coarse aggregate is 0.4%, the mud block content is 0.1%, and the needle sheet content is 2%; the fly ash comprises class F class 2 fly ash; the water reducing agent is a polycarboxylic acid high-performance retarding water reducing agent, and the water reducing rate is 30%.
In the bare concrete disclosed above, the fine aggregate is machine-made sand.
Preferably, in this embodiment, three schemes are specifically adopted to perform the test to obtain the actual effect, and a control experiment is set at the same time. The details are as follows.
The design of the mix proportion of the comparison experiment adopts the following materials:
cement: china new cement (Ziguo) limited (P.O42.5).
Fly ash: class F and class II fly ash of Chongqing Fengjie power plants.
Coarse aggregate: the gravel with good grain size grading of 5-25mm contains 0.4% of mud, 0.1% of mud blocks and 2% of needle-shaped pieces, and is produced in the following places: wuxi.
Fine aggregate: machine-made sand, medium sand with fineness modulus of 3.0, stone powder content of 8.4%, mud block content of 0.2%, production area: wuxi; river sand with fineness modulus of 1.1 ultrafine sand, mud content of 4.6%, mud block content of 0.8%, production area: wuxi;
water reducing agent: the Fengjie Boronglong superplasticizer has the water reduction rate of 23 percent.
Mixing water: tap water.
According to the design scheme of the mixing ratio, the using amount of various materials is calculated, the materials are shown in table 1, a 60L forced stirrer is adopted for mixing, the materials are filled into a standard test mould (the size is 100mm multiplied by 100mm) for forming after mixing, a test piece after pouring forming is maintained by a standard maintenance system, the maintenance temperature is 20 +/-1 ℃, the humidity is more than 95%, the cubic compressive strength is respectively tested when the test piece is maintained to the age of 3d, 7d and 28d, the test is carried out according to the standard of a concrete physical and mechanical property test method (GBT50081-2019), and the test result is shown in table 2.
TABLE 1 comparison experiment bare concrete mix proportion table
TABLE 2 first concrete Strength and appearance
The results show that the wuxi river sand is extra fine sand, the mud content is large, the appearance quality of the concrete is yellow no matter the sand is singly adopted or the sand is mixed with machine-made sand, and the sand content of the sand is serious, so that certain adhesion effect is realized, the air bubbles in the sand are not easy to discharge, and the air holes on the surface of the concrete are obvious. Due to the adoption of the high-efficiency water reducing agent, the water reducing rate is low, the water consumption is relatively large under the condition of slump meeting the construction requirement, and in addition, due to the large slump loss of the additive, bleeding is easy to occur, the appearance of concrete is bleeding, and the color is not uniform. Under the conditions of fineness deviation and low activity index of the II-grade fly ash, the strength values of the three mixing ratios do not reach the requirement of 48.2MPa from the 28-day strength.
After the proportioning is adjusted and the scheme disclosed in the embodiment is adopted, the concrete conditions are as follows:
fine aggregate: only machine-made sand is used, the fineness modulus is 3.0, the stone powder content is 8.4%, the mud block content is 0.2%, the production area: wuxi;
water reducing agent: the polycarboxylic acid high-performance retarding water reducer produced by Shanxi Orrunt Limited liability company has the mixing amount of 1.1% and the water reduction rate of 30%;
according to the design scheme of the mixing proportion, the using amount of various materials is recalculated, see table 3, a 60L forced stirrer is adopted for mixing, the mixed materials are filled into a standard test mould (the size is 100mm multiplied by 100mm) for forming, a test piece after pouring forming is maintained by a standard maintenance system, the maintenance temperature is 20 +/-1 ℃, the humidity is more than 95%, the cube compressive strength is respectively tested when the test piece is maintained to the age of 3d, 7d and 28d, the test is carried out according to the standard of a concrete physical and mechanical property test method (GBT50081-2019), and the test result is seen in table 4.
Table 3 clear water concrete mix proportion table of this embodiment
TABLE 4 Strength and appearance of bare concrete according to this example
Through test comparison, the selected three groups of fair-faced concrete mixing proportion have ideal apparent color under the condition that the bubble control meets the requirement, and under the conditions of fineness deviation and low activity index of the II-grade fly ash, the 28-day concrete compressive strength is not high, so that the requirements of strength, workability and facing of the fair-faced concrete can be basically met.
Example 2
The embodiment discloses fair-faced concrete which is different from the embodiment 1 in components and materials and specifically comprises the following components in parts by mass:
368 parts of cement, 92 parts of fly ash, 766-785 parts of fine aggregate, 200-204 parts of A-component coarse aggregate, 799-815 parts of B-component coarse aggregate, 148-153 parts of water and 5.06 parts of a water reducing agent;
wherein, the cement alkali content is 0.59 percent, the fine aggregate comprises coarse sand with fineness modulus of 3.3 and stone powder content is 5.6 percent, and the medium sand with fineness modulus of 2.8 and mud content is 0.8 percent; the component A coarse aggregate comprises crushed stone with the particle size of 5-10mm, the component B coarse aggregate comprises crushed stone with the particle size of 10-25mm, and the component A coarse aggregate accounts for 10-50% of the total weight of the coarse aggregate; the fly ash comprises class F1 grade fly ash with the loss on ignition of 1.08 percent and class F2 grade fly ash with the loss on ignition of 1.25 percent; the water reducing agent is a polycarboxylic acid high-performance retarding water reducing agent, and the water reducing rate is 26%.
Several groups of detailed proportioning schemes are specifically mentioned here:
cement: chongqing sea snail cement (P.O42.5) has alkali content of 0.59%, tricalcium aluminate content higher, and harmful substance content lower than that of the former Huaxin cement.
Fly ash: the class-I and class-II fly ashes of the white crane in Chongqing Kexian county have the ignition loss of 1.08 percent and 1.25 percent respectively, small fineness, high activity index, lower content of harmful substances and better performance indexes than those of the fly ashes of Chongqing Fengjie power plants.
Coarse aggregate: in order to make the aggregate reach the most compact state, the second-level graded broken stones are adopted at this time, and the corresponding broken stones of 5-10mm and 10-25mm are optimally designed, which is shown in Table 5.
TABLE 5 test results of coarse aggregate blending ratio
Through five different blending ratios of 50 percent to 50 percent, 40 percent to 60 percent, 30 percent to 70 percent, 20 percent to 80 percent and 10 percent to 90 percent according to the proportion of 5-10mm to 10-25mm, particle grading analysis and bulk density test are respectively carried out, wherein the blending ratio is 50 percent: the 50 percent and 10 percent to 90 percent coarse aggregate particle grading does not meet the technical requirement of construction pebbles and gravels GB/T14685-2011, the other three kinds of blending proportion particle grading can meet the requirement, the comparative bulk density test shows that the bulk density is maximal at 1680kg/m3 under the condition of 20 percent to 80 percent, and meanwhile, the particle grading also meets the requirement of continuous grading. Finally, 5-25mm continuous graded broken stone is prepared by compounding 5-10mm and 10-25mm according to the proportion of 20% to 80%.
Fine aggregate: coarse sand with a mechanical sand fineness modulus of 3.3, stone powder content of 5.6%, production area: volvin county Bright ; medium sand with river sand fineness modulus of 2.8, mud content of 0.8%, production area: "Lixin Longan" for ever.
Water reducing agent: the Shanghai Hongyun high-performance water reducing agent, namely the polycarboxylic acid high-performance water reducing agent, has the water reducing rate of 26 percent, the mixing amount of 1.1 percent, low bleeding rate and alkali content and good collapse protection effect, and each performance index is superior to that of the Boronglong water reducing agent.
Mixing water: tap water.
For contrast river sand, mechanism sand, I level, II level fly ashes to the concrete influence condition, in this embodiment design fair-faced concrete mix proportion, designed four kinds of benchmark mix proportions, every benchmark cooperation increases and decreases corresponding glue and water ratio again and form 12 different mix proportions of group: HP2101001 baseline cement ratio of 0.33, two of 0.28, 0.37; HP2101002 benchmark glue-water ratio was 0.32, the other two were 0.31, 0.37; HP2101003 benchmark water-to-glue ratio was 0.33, two of the others were 0.31, 0.35; HP2101004 standard water-to-glue ratio was 0.33, two others were 0.315, 0.342. According to the design scheme of the mixing proportion, the using amounts of various materials are calculated, and the mixture and the mechanical property detection are respectively carried out on 12 groups of different mixing proportions. Mixing by a 60L forced mixer, filling into a standard test mold (the size is 100mm multiplied by 100mm) for molding after mixing, curing the cast test piece by a standard curing system, wherein the curing temperature is 20 +/-1 ℃, the humidity is more than 95%, and when the test piece is cured to the age of 3d, 7d and 28d, the cube compressive strength is respectively tested, and the test is carried out according to the test method standard of concrete physical and mechanical properties (GBT 50081-2019). The performance, mechanical property and appearance quality of the screened mixture from the 4 reference mixture ratios are summarized in table 6, and the test results are shown in table 7.
TABLE 6 clear water concrete mix proportion table for the third time
TABLE 7 third bare concrete Strength and appearance
In the four standard soil-water-cement ratios, the mixing amount of the fly ash is increased from 15% to 20%, the slump is controlled within 200mm, after the water reducing rate is increased, the water consumption is reduced, the precipitation of redundant water is reduced, the number of air holes is reduced, the air holes are shallow, the apparent color is ideal, the 28-day compressive strength is far higher than the configured strength, and the overall quality basically meets the technical requirements of the fair-faced concrete.
The cement of the bare concrete disclosed above has higher tricalcium aluminate content and lower harmful substance content than the previous cement. The adopted fly ash has small fineness, high activity index, lower content of harmful substances and better performance index than the adopted fly ash.
Example 3
The embodiment also discloses the fair-faced concrete, which is optimized again in components and comprises the following components in parts by mass:
368-388 parts of cement, 68-92 parts of fly ash, 716-785 parts of fine aggregate, 200-430 parts of coarse aggregate of the component A, 645-814 parts of coarse aggregate of the component B, 151-155 parts of water and 5.02-5.06 parts of a water reducing agent;
wherein, the cement alkali content is 0.59 percent, the fine aggregate comprises coarse sand with fineness modulus of 3.3 and stone powder content is 5.6 percent, and the medium sand with fineness modulus of 2.8 and mud content is 0.8 percent; the component A coarse aggregate comprises crushed stone with the particle size of 5-10mm, the component B coarse aggregate comprises crushed stone with the particle size of 10-25mm, and the component A coarse aggregate accounts for 10-50% of the total weight of the coarse aggregate; the fly ash comprises class F1 grade fly ash with the loss on ignition of 1.08 percent and class F2 grade fly ash with the loss on ignition of 1.25 percent; the water reducing agent is a polycarboxylic acid high-performance retarding water reducing agent, and the water reducing rate is 26%.
The bare concrete disclosed above adjusts the components aiming at the steel mould, can effectively reduce the condition of adhesion when the mould is removed, and the appearance quality is easy to control.
In this example, a steel die is used for molding, and a test scheme of several specific data is illustrated in table 8 below:
TABLE 8 fourth bare concrete mix proportion table
The test results of mixing, pouring and molding the 3 mixing ratios are as follows:
1) this adopts the steel form, and three short columns appearance quality is smooth level and smooth, does not have the sticking phenomenon, and the appearance quality is better than former plank sheathing.
2) No. 04 columns, namely HP2101004 are mixed according to a mixing ratio, and are poured by river sand, the color of the columns is naturally dull, and the main reason is caused by the fact that the river sand is yellow.
3) The commercial mixing station No. 03, namely HP2012001 mixing proportion, has the advantages that the content of the used machine-made sand powder is high, the loss on ignition of the class II fly ash is large, the fineness is large, obvious pores exist on the surface, and the color is dark.
4) The No. 03 column, namely HP2101003 has the advantages of consistent appearance quality and color, grey color, no large air holes, good performance of the mixture and easy pouring. Determining the mix proportion as a selected mix proportion for on-site construction
Example 4
As shown in fig. 3, the embodiment discloses a concrete construction method, which adopts the bare concrete disclosed in the above, and includes the following processes:
s1: preparing concrete according to the component proportion of the concrete, and performing layered pouring after treating a pouring construction foundation surface;
s2: in the pouring process, vibrating points are uniformly arranged at intervals, and an insertion type vibrating rod is vertically inserted into each vibrating point below a pouring surface for pouring; the vibrating points are arranged at intervals and are divided into a plurality of vibrating ring layers from inside to outside, the vibrating points vibrate ring by ring from inside to outside, and all the vibrating points on a single vibrating ring layer vibrate simultaneously; as shown in fig. 1, four points 2, 4, 5 and 7 are four vibration points of the inner vibrating ring layer, and four points 1, 3, 6 and 8 are four vibration points of the outer vibrating ring layer.
S3: watering the pouring surface for curing in the concrete hardening and strength increasing period;
s4: after the concrete template is removed, carrying out tight covering maintenance through a film;
s5: and after the concrete is hardened, coating a transparent protective agent on the surface of the concrete.
Specifically, the construction method is optimized and improved, and the following feasible options are provided: as shown in FIG. 2, when the concrete is poured in layers, the height of each layer is less than or equal to 500 mm. By adopting the scheme, the overall strength of the structural body with a certain thickness or height can be improved by layering and constructing for multiple times; and for the structural surface with larger span, the color difference of the surface can keep higher consistency through layered construction.
In the embodiment, when vibration is carried out, the vibration points are uniformly distributed, so that the vibration effect can be improved, bubbles, hollows and the like are reduced, and the compactness of concrete is improved; here, optimization is performed and one possible option is presented as follows: the vibrating points on the adjacent vibrating ring layers are arranged at intervals in a staggered mode, and the vibrating time is kept between 40s and 60s when the vibrating points on each vibrating ring layer are vibrated.
As shown in fig. 4, when the transparent protective agent is coated, the following process is included:
s1: repairing the pouring surface of the concrete to restore the part with the local defect to be consistent with the whole body;
s2: adjusting the adjusting material to locally adjust the existing color difference, water flowing trace and local repairing trace, so as to achieve uniform color on the whole concrete surface without obvious repairing and adjusting trace;
s3: and forming a transparent protective layer by adopting water-based penetration primary coating and water-based fluorocarbon transparent surface coating.
The transparent protective agent on the surface is coated through the steps to form a protective layer on the surface of the fair-faced concrete, so that the surface protection of the fair-faced concrete is improved.
In order to make the form removal easier and reduce the surface structure damage caused by the adhesion of the form and the concrete, the optimal arrangement is made here and one feasible choice is shown as follows: adding a release agent during concrete pouring, wherein the release agent adopts machine oil and diesel oil according to the mass ratio of 7: 3 blending to prepare the product.
Preferably, the curing time after the concrete pouring is 14 days or more.
Preferably, the formwork used for concrete casting is a steel formwork.
The above embodiments are just exemplified in the present embodiment, but the present embodiment is not limited to the above alternative embodiments, and those skilled in the art can obtain other various embodiments by arbitrarily combining with each other according to the above embodiments, and any other various embodiments can be obtained by anyone in light of the present embodiment. The above detailed description should not be construed as limiting the scope of the present embodiments, which should be defined in the claims, and the description should be used for interpreting the claims.
Claims (10)
1. The fair-faced concrete is characterized by comprising the following components in parts by mass:
376-411 parts of cement, 68-94 parts of fly ash, 691-716 parts of fine aggregate, 427-432 parts of coarse aggregate of the component A, 641-648 parts of coarse aggregate of the component B, 150-155 parts of water and 5.02-5.32 parts of water reducing agent;
wherein the fine aggregate comprises medium sand with fineness modulus of 3.0, stone powder content is 8.4%, and mud block content is 0.2%; the component A coarse aggregate comprises crushed stone with the particle size of 5-10mm, the component B coarse aggregate comprises crushed stone with the particle size of 10-25mm, the component A coarse aggregate accounts for 10-50% of the total weight of the coarse aggregate, the average mud content of the coarse aggregate is 0.4%, the mud block content is 0.1%, and the needle sheet content is 2%; the fly ash comprises class F class 2 fly ash; the water reducing agent is a polycarboxylic acid high-performance retarding water reducing agent, and the water reducing rate is 30%.
2. The fair-faced concrete is characterized by comprising the following components in parts by mass:
368 parts of cement, 92 parts of fly ash, 766-785 parts of fine aggregate, 200-204 parts of A-component coarse aggregate, 799-815 parts of B-component coarse aggregate, 148-153 parts of water and 5.06 parts of a water reducing agent;
wherein, the cement alkali content is 0.59 percent, the fine aggregate comprises coarse sand with fineness modulus of 3.3 and stone powder content is 5.6 percent, and the medium sand with fineness modulus of 2.8 and mud content is 0.8 percent; the component A coarse aggregate comprises crushed stone with the particle size of 5-10mm, the component B coarse aggregate comprises crushed stone with the particle size of 10-25mm, and the component A coarse aggregate accounts for 10-50% of the total weight of the coarse aggregate; the fly ash comprises class F1 grade fly ash with the loss on ignition of 1.08 percent and class F2 grade fly ash with the loss on ignition of 1.25 percent; the water reducing agent is a polycarboxylic acid high-performance retarding water reducing agent, and the water reducing rate is 26%.
3. The fair-faced concrete is characterized by comprising the following components in parts by mass:
368-388 parts of cement, 68-92 parts of fly ash, 716-785 parts of fine aggregate, 200-430 parts of coarse aggregate of the component A, 645-814 parts of coarse aggregate of the component B, 151-155 parts of water and 5.02-5.06 parts of a water reducing agent;
wherein, the cement alkali content is 0.59 percent, the fine aggregate comprises coarse sand with fineness modulus of 3.3 and stone powder content is 5.6 percent, and the medium sand with fineness modulus of 2.8 and mud content is 0.8 percent; the component A coarse aggregate comprises crushed stone with the particle size of 5-10mm, the component B coarse aggregate comprises crushed stone with the particle size of 10-25mm, and the component A coarse aggregate accounts for 10-50% of the total weight of the coarse aggregate; the fly ash comprises class F1 grade fly ash with the loss on ignition of 1.08 percent and class F2 grade fly ash with the loss on ignition of 1.25 percent; the water reducing agent is a polycarboxylic acid high-performance retarding water reducing agent, and the water reducing rate is 26%.
4. A concrete construction method using the bare concrete according to any one of claims 1 to 3, characterized by comprising the following steps:
preparing concrete according to the component proportion of the concrete, and performing layered pouring after treating a pouring construction foundation surface;
in the pouring process, vibrating points are uniformly arranged at intervals, and an insertion type vibrating rod is vertically inserted into each vibrating point below a pouring surface for pouring; the vibrating points are arranged at intervals and are divided into a plurality of vibrating ring layers from inside to outside, the vibrating points vibrate ring by ring from inside to outside, and all the vibrating points on a single vibrating ring layer vibrate simultaneously;
watering the pouring surface for curing in the concrete hardening and strength increasing period;
after the concrete template is removed, carrying out tight covering maintenance through a film;
and after the concrete is hardened, coating a transparent protective agent on the surface of the concrete.
5. The concrete construction method according to claim 4, wherein: when the concrete is poured in layers, the height of each layer is less than or equal to 500 mm.
6. The concrete construction method according to claim 4, wherein: the vibrating points on the adjacent vibrating ring layers are arranged at intervals in a staggered mode, and the vibrating time is kept between 40s and 60s when the vibrating points on each vibrating ring layer are vibrated.
7. The concrete construction method according to claim 4, wherein the application of the transparent protective agent comprises the following steps:
repairing the pouring surface of the concrete to restore the part with the local defect to be consistent with the whole body;
adjusting the adjusting material to locally adjust the existing color difference, water flowing trace and local repairing trace, so as to achieve uniform color on the whole concrete surface without obvious repairing and adjusting trace;
and forming a transparent protective layer by adopting water-based penetration primary coating and water-based fluorocarbon transparent surface coating.
8. The concrete construction method according to claim 4, wherein: adding a release agent during concrete pouring, wherein the release agent adopts machine oil and diesel oil according to the mass ratio of 7: 3 blending to prepare the product.
9. The concrete construction method according to claim 4, wherein: and the curing time after the concrete pouring is finished is more than or equal to 14 days.
10. The concrete construction method according to claim 4, wherein: the template used for concrete pouring is a steel template.
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