CN115140984A - Bare concrete suitable for special-shaped structure veneer - Google Patents
Bare concrete suitable for special-shaped structure veneer Download PDFInfo
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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
-
- 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
- C04B14/00—Use of inorganic materials as fillers, e.g. pigments, for mortars, concrete or artificial stone; Treatment of inorganic materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B14/02—Granular materials, e.g. microballoons
- C04B14/04—Silica-rich materials; Silicates
- C04B14/047—Zeolites
-
- 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
- C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B18/04—Waste materials; Refuse
- C04B18/14—Waste materials; Refuse from metallurgical processes
- C04B18/146—Silica fume
-
- 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
-
- 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
- C04B2111/2023—Resistance against alkali-aggregate reaction
-
- 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
- C04B2111/27—Water resistance, i.e. waterproof or water-repellent materials
-
- 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
- C04B2111/29—Frost-thaw resistance
-
- 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
- C04B2111/76—Use at unusual temperatures, e.g. sub-zero
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Abstract
The invention particularly relates to fair-faced concrete suitable for a special-shaped structure veneer, and solves the problems that the surface of the existing fair-faced concrete has chromatic aberration when the existing fair-faced concrete is used for a special-shaped structure, and the existing fair-faced concrete is insufficient in durability when used in a cold area. The fair-faced concrete suitable for the special-shaped structural veneer is composed of the following raw materials in parts by weight: 469 parts of cement, 3234 parts of sand 613.12 parts of stones 1151.988 parts of water 230 parts, 37.52-46.9 parts of silica fume and 56.28-84.42 parts of zeolite powder. The invention adds the silica fume, can improve the workability of concrete mixture, reduce the heat of hydration, improve the chemical erosion resistance, anti-freezing, impervious performance of concrete, inhibit alkali-aggregate reaction, added zeolite powder at the same time, the active substance in zeolite powder can react with cement hydration product calcium hydroxide to produce the gel, improve compactness and intensity of concrete, the invention is suitable for the cold northern area, has improved the durability, has realized the plain face-to-the-day decorative effect of the profiled structure fair-faced concrete, the color is uniform and unanimous, have frost-resistant, dense effects.
Description
Technical Field
The invention relates to the technical field of fair-faced concrete, in particular to fair-faced concrete suitable for a special-shaped structural veneer.
Background
The fair-faced concrete does not need additional modification, does not need to be painted on the surface, is displayed in a visual field in a natural form, has fine texture, heavy atmosphere and exquisite texture, reduces the consumption of wood, stone and glass, greatly reduces the generation of construction waste, and meets the requirements of environmental protection and energy conservation. The fair-faced concrete is required to have a beautiful surface without defects in use and a surface subjected to weather or chemical attack throughout the year, and has a higher requirement on durability than ordinary concrete. These characteristics are mainly determined by the selection of raw materials, preparation technology and construction process of the fair-faced concrete.
However, practice shows that the existing fair-faced concrete has the following problems in application: firstly, the durability is insufficient when the paint is used in cold regions; secondly, the coating cannot be completely uniform when applied to a special-shaped structure, so that certain color difference exists on the surface, the color and luster cannot be consistent, and the appearance quality of the fair-faced concrete is influenced. Therefore, the invention is needed to provide the fair-faced concrete suitable for the veneer of the special-shaped structure, which has good durability and high color uniformity, and further improves the appearance of the special-shaped structure.
Disclosure of Invention
The invention provides fair-faced concrete suitable for a special-shaped structure veneer, and aims to solve the problems that when the existing fair-faced concrete is used for a special-shaped structure, the surface has chromatic aberration and the durability is insufficient when the existing fair-faced concrete is used in cold regions.
The invention is realized by adopting the following technical scheme:
the fair-faced concrete suitable for the special-shaped structure veneer is composed of the following raw materials in parts by weight: 469 parts of cement, 6253 parts of sand 613.12 parts of stone 1151.988 parts of water, 37.52-46.9 parts of silica fume and 3238-3262 parts of zeolite powder 56.28-84.42 parts.
Further, the cement is P042.5 portland cement or ordinary portland cement.
Further, the water satisfies the following criteria: the PH value is more than or equal to 4.5; insoluble substances are less than or equal to 2000mg/L; soluble matter is less than or equal to 5000mg/L; chloride ions are less than or equal to 1000mg/L; sulfate ion is less than or equal to 2000mg/L; the alkali content is less than or equal to 1500mg/L.
Furthermore, the stones are formed by mixing 5mm-10mm graded aggregate and 10mm-20mm graded aggregate according to any proportion, and the apparent density of the stones is 2700kg/m 3 The water content was 1.2%.
Further, the sand is machine-made sand with fineness modulus of 2.3-3, and apparent density of 2650kg/m 3 The water content was 2%.
Further, the determination of the proportion of the bare concrete is realized by adopting the following steps:
s1: calculating the concrete configuration strength f by the formula (1) cu,o ：
f cu,o ＝f cu,k +1.645δ (1)
In the formula, the concrete arrangement strength f cu,o The unit of (A) is Mpa; f. of cu,k Is the designed strength grade of the concrete; delta is the standard deviation of concrete strength, when f cu,k When the temperature is less than or equal to C20, delta is 4.0Mpa; when C25 is less than or equal to f cu,k When the pressure is less than or equal to C45, delta is 5.0Mpa; when C50 is less than or equal to f cu,k When the pressure is less than or equal to C55, delta is 6.0Mpa;
s2: calculating the water-to-glue ratio by the formula (2)
In the formula, alpha a 、α b All the coefficients are regression coefficients, different values of the stone types are different, and the crushed stone is respectively 0.53 and 0.49; taking 0.20 and 0.13 of pebbles respectively; f. of ce Is cement strength grade; f. of cu,o Is counted by step S1Calculating to obtain;
s3: determining the water consumption m per unit according to the set value of the slump coefficient s, the type of the stones and the maximum particle size of the stones wo ；
S4: according to the water-to-glue ratio
And the water consumption m of the design unit determined in the step S3 wo Calculating the cement dosage m of the design unit co ；
S5: according to the water-to-glue ratio
The type of stone and the maximum particle size of the stone determine the sand ratio beta s ；
S6: calculating the stone dosage m of the design unit through a formula (3) and a formula (4) go Design unit sand dosage m so ：
m co +m go +m so +m wo ＝m cp (3)
In the formula, m cp For the weight of the design unit concrete;
s7: using formula (5) to design unit cement dosage m co Correcting to obtain the cement consumption m of a construction unit c '; using formula (6), the unit sand dosage m is designed so Correcting to obtain the sand consumption m of the construction unit s '; using formula (7) to design unit stone dosage m go Correcting to obtain the stone dosage m of a construction unit g '; the water consumption m of the design unit is calculated by the formula (8) wo Correcting to obtain the water consumption m of a construction unit w ′；
m c ′＝m co (5)
m s ′＝m so ×(1+W s ) (6)
m g ′＝m go ×(1+W g ) (7)
m w ′＝m wo -(m so ×W s +m go ×W g ) (8)
In the formula, W s Measuring the water content of the sand in the construction site; w is a group of g Measuring the water content of the stones for the construction site;
s8: according to the cement consumption m of a construction unit c ', determining the adding amount of the silica fume and the adding amount of the zeolite powder.
The fair-faced concrete suitable for the special-shaped structural veneer is added with the silica fume, so that the workability of concrete mixture can be improved, the hydration heat is reduced, the chemical erosion resistance, the freezing resistance and the permeability resistance of the concrete are improved, the alkali-aggregate reaction is inhibited, and the effect is much better than that of the fly ash. The silica fume has large specific surface area and large water quantity ratio, and when the silica fume is doped into concrete, a high-efficiency water reducing agent is generally required to be doped.
The zeolite powder is added into the fair-faced concrete suitable for the special-shaped structural veneer, and active substances in the zeolite powder can react with a cement hydration product calcium hydroxide to generate gel, so that the compactness and the strength of the concrete are improved. In addition, the zeolite powder is the same as other mineral admixtures, can improve the workability of concrete mixture, improve the impermeability and frost resistance of concrete, inhibit alkali-aggregate reaction, and is also suitable for preparing pumping concrete and high-fluidity concrete, thereby having good effect on pouring concrete special-shaped structures.
The fair-faced concrete disclosed by the invention optimizes the mix proportion of the fair-faced concrete, is suitable for cold northern areas, improves the durability of the concrete, realizes the plain and skyward decoration effect of the special-shaped structure fair-faced concrete, is uniform and consistent in color and luster, and has the frost-resistant and compact effects of the fair-faced concrete structure.
Detailed Description
Example 1
The fair-faced concrete suitable for the special-shaped structure veneer is composed of the following raw materials in parts by weight: 469 parts of cement, 5363 parts of sand 613.12 parts of stones 1151.988 parts of water 230 parts of silica fume 37.52 parts of zeolite powder 56.28 parts of the cement.
The cement is P042.5 portland cement.
The water index is as follows: the pH is 4.5; insoluble matter is 1000mg/L; the soluble substance is 4000mg/L; the chloride ion is 500mg/L; sulfate ion is 1200mg/L; the alkali content was 1000mg/L.
The stones are prepared from 5mm-10mm graded aggregate and 10mm-20mm graded aggregate according to the weight ratio of 3:1 and has an apparent density of 2700kg/m 3 The water content was 1.2%.
The sand is machine-made sand with fineness modulus of 2.3 and apparent density of 2650kg/m 3 And the water content was 2%.
Example 2
The fair-faced concrete suitable for the special-shaped structural veneer is composed of the following raw materials in parts by weight: 469 parts of cement, 5363 parts of sand 613.12 parts, 3242 parts of pebbles 1151.988 parts, 230 parts of water, 46.9 parts of silica fume and 4736 parts of zeolite powder 84.42 parts.
The cement is ordinary portland cement.
The water index is as follows: the pH was 5.0; insoluble matter is 2000mg/L; the soluble substance is 5000mg/L; the chloride ion is 1000mg/L; sulfate ion is 2000mg/L; the alkali content was 1500mg/L.
The stones are prepared from 5mm-10mm graded aggregate and 10mm-20mm graded aggregate according to the weight ratio of 1:4 in proportion and has an apparent density of 2700kg/m 3 The water content was 1.2%.
The sand is machine-made sand with fineness modulus of 3 and apparent density of 2650kg/m 3 The water content was 2%.
Example 3
The fair-faced concrete suitable for the special-shaped structure veneer is composed of the following raw materials in parts by weight: 469 parts of cement, 5363 parts of sand 613.12 parts, 3242 parts of pebbles 1151.988 parts, 230 parts of water, 41.0 parts of silica fume and 4736 parts of zeolite powder 62.30 parts.
The cement is P042.5 Portland cement.
The water index is as follows: the pH is 4.8; the insoluble matter is 1600mg/L; the soluble matter is 4200mg/L; the chloride ion is 850mg/L; the sulfate ion is 1700mg/L; the alkali content was 1200mg/L.
The stones are prepared from 5mm-10mm graded aggregate and 10mm-20mm graded aggregate according to the weight ratio of 1:1, and has an apparent density of 2700kg/m 3 The water content was 1.2%.
The sand is machine-made sand with fineness modulus of 2.6 and apparent density of 2650kg/m 3 And the water content was 2%.
Example 4
The determination of the proportion of the bare concrete is realized by adopting the following steps:
s1: calculating the concrete configuration strength f by the formula (1) cu,o ：
f cu,o ＝f cu,k +1.645δ (1)
In the formula, f cu,k Is the designed strength grade of concrete, in this embodiment, f cu,k = C30; delta is the standard difference of concrete strength, and delta is 5.0Mpa;
s2: calculating the water-to-glue ratio by the formula (2)
In the formula, alpha a 、α b All are regression coefficients, in this example, the stones are crushed stones, alpha a 、α b Respectively taking 0.53 and 0.49; f. of ce Is cement strength grade, f ce ＝42.5；f cu,o Is obtained by calculation in step S1
S3: determining the water consumption m per unit according to the set value of the slump coefficient s, the type of the stones and the maximum particle size of the stones wo ；
The water consumption requirements for plastic concrete are shown in table 1:
table 1: water consumption of plastic concrete
In this example, the maximum particle size of the crushed stone was 20mm, the slump constant s was 180. + -. 20mm, and the water consumption m per design unit was determined wo When the slump s is 90mm, the water consumption is increased by 5kg/m for every 20mm increase 3 ；
S4: according to the water-to-glue ratio
And step S3, determining the water consumption m of the design unit wo Calculating the cement dosage m of the design unit co ；
S5: according to the water-to-glue ratio
The type of stone and the maximum particle size of the stone determine the sand rate beta s ；
The sand ratio of the concrete is shown in table 2:
table 2: sand ratio of concrete
In this example, the maximum particle size of the crushed stone was 20mm,
determination of beta s ＝32％-34％；
S6: calculating the unit stone dosage m by the formula (3) and the formula (4) go Design unit sand dosage m so ：
m co +m go +m so +m wo ＝m cp (3)
In the formula, m cp The weight of concrete is designed;
s7: in steps S1-S6, all the numerical values in the calculation formulas and the relevant parameter tables are based on aggregates in a dry state, and the sandstone materials stored in the construction site contain certain moisture and have difference with the design of the mixing ratio, so the actual weighing of various materials on the construction site is corrected according to the actual moisture content of the sandstone materials on the construction site, and the corrected mixing ratio is called as the construction mixing ratio. The specific method comprises the following steps:
using formula (5) to design unit cement dosage m co Correcting to obtain the cement consumption m of construction unit c '; using formula (6), the unit sand dosage m is designed so Correcting to obtain the sand consumption m of the construction unit s '; using formula (7) to design unit stone dosage m go Correcting to obtain the stone dosage m of a construction unit g '; the water consumption m of the design unit is calculated by the formula (8) wo Corrected to obtain the water consumption m of a construction unit w ′；
m c ′＝m co (5)
m s ′＝m so ×(1+W s ) (6)
m g ′＝m go ×(1+W g ) (7)
m w ′＝m wo -(m so ×W s +m go ×W g ) (8)
In the formula, W s Measuring the water content of the sand in the construction site; w g Measuring the water content of the stones for the construction site;
calculated, m c ′＝469kg/m 3 ，m s ′＝613.12kg/m 3 ，m g ′＝1151.988kg/m 3 ，m w ′＝230kg/m 3 。
The maximum water cement ratio and the minimum cement dosage of the concrete are shown in table 3:
table 3: maximum water cement ratio and minimum cement dosage of concrete
The water-cement ratio calculated in the embodiment is 0.49, which is less than the maximum water-cement ratios of 0.65, 0.60, 0.55 and 0.50 of the reinforced concrete under different environmental conditions, and meets the construction requirements;
the cement dosage calculated in this example was 469kg/m 3 Is more than 260kg/m of the minimum cement dosage of the reinforced concrete under different environmental conditions 3 、280kg/m 3 、280kg/m 3 、300kg/m 3 And the construction requirement is met.
S8: according to the cement consumption m of a construction unit c ', determining the adding amount of the silica fume and the adding amount of the zeolite powder; the doping amount of the silica fume is 8 to 10 percent of that of the cement; the mixing amount of the silica fume is 12 to 18 percent of the cement.
Example 5
The bare concrete described in example 3 was tested for compressive strength testing:
1. test basis and general provisions:
the test is carried out according to the relevant provisions of 'Standard test method for Performance of common concrete mixture' and 'Standard test method for mechanical Performance of common concrete'.
(1) The maximum nominal particle size of the aggregate is in accordance with the regulations of the existing industry standard JGJ 52-2006 Standard for quality and inspection method of sand and stone for common concrete.
(2) The relative humidity of the test environment is not less than 50%, and the temperature is kept at (20 +/-5) DEG C; the temperature of the equipment, containers and ancillary equipment used is preferably kept consistent with that of the laboratory.
(3) During field test, the concrete mixture sample is prevented from being influenced by wind, rain, snow and direct sunlight.
(4) The test equipment should be calibrated before use.
2. Main instrument equipment
The test adopts cubic test pieces, the test uses the same age as one group, and each group comprises at least three concrete test pieces which are simultaneously manufactured and cured.
Testing a mold: the cubic test piece with the side length of 150mm is a standard test piece; the cube specimens 100mm and 200mm on a side are non-strength standard specimens.
The equipment comprises a vibrating table, a compression testing machine, a steel base plate, a tamping bar, a small iron shovel, a steel plate ruler, a caliper and a spatula.
3. Test piece manufacture
3.1 test piece preparation the following specifications were met:
a. before forming, the inner surface of the clean test mould is coated with a thin layer of mineral grease or other release agent which does not react with the concrete.
b. When the concrete is prepared in a laboratory, the material amount is measured by mass. The weighing precision is as follows: the cement, the admixture, the water and the additive are +/-0.5 percent; the aggregate is +/-1 percent.
c. The concrete to be sampled or mixed in a laboratory should be formed in as short a time as possible after mixing, and generally should not exceed 15min.
d. Determining a concrete forming method according to the consistency of the concrete mixture, wherein the concrete with the slump not greater than 70mm is preferably compacted by vibration; tamping larger than 70mm by hand; the test piece forming method is preferably the same as the actually adopted method for testing the cast-in-place concrete or the concrete of the prefabricated part.
e. The concrete mixture used for each test piece group should be taken out from the mixture prepared in the same time.
f. The number of the intensity test piece groups in calculation is not less than 50.
3.2 test piece preparation procedure
3.2.1 the concrete mixture sampled or mixed should be mixed back and forth at least three times with a shovel.
3.2.2 the test piece is prepared by mixing and compacting by a vibration table according to the following method:
3.2.2.1, loading the concrete mixture into the test molds at one time, and inserting and tamping the concrete mixture along the walls of each test mold by using a spatula during loading, wherein the concrete mixture is higher than the opening of each test mold;
3.2.2.2 the test mould is adhered or fixed on a vibration table, the test mould is not jumped during vibration, and the vibration is continued until the surface is discharged with pulp without excessive vibration.
3.2.3 the manual insertion and tamping for manufacturing the test piece is carried out according to the following method:
3.2.3.1 the concrete mixture should be loaded into the test mould in two layers, the loading thickness of each layer being approximately equal.
3.2.3.2 the tamping is done uniformly from the edge to the centre in a spiral direction. When the concrete at the bottom layer is inserted and tamped, the tamping rod reaches the bottom of the test mould, and when the upper layer is vibrated, the lower layer is inserted into the upper layer by 20-30mm after penetrating through the upper layer. And (3) keeping the inserting and tamping vertical without inclining, and then inserting and pulling the spatula along the inner wall of the test mould for a plurality of times.
3.2.3.3 the number of times of tamping for each layer is 10000mm 2 The number of times in the area should not be less than 12.
5363 and lightly knocking the periphery of the test mold by a rubber hammer after the inserting and tamping of the 3.2.3.4 until the cavity left by the inserting and tamping rod disappears.
3.2.4 the manufacture of the test piece by using the inserted tamping rod and the compaction is carried out according to the following method:
3.2.4.1 filling the concrete mixture into the test mould at one time, inserting and smashing along each test mould wall by using a spatula during filling, and enabling the concrete mixture to be higher than the test mould opening.
An insertion vibrator with a diameter of 25mm is preferably used at 3.2.4.2. When the test mold is inserted into the test mold for vibration, the vibrating rod is 10-20mg away from the bottom plate of the test mold and does not touch the bottom plate of the test mold, the vibration is continued until the surface is discharged with slurry, excessive vibration is avoided to prevent concrete from segregation, and the vibration time is generally 20s. The vibrating rod needs to be pulled out slowly, and holes cannot be left after the vibrating rod is pulled out.
3.2.5 scrapes off the excess concrete on the upper opening of the test mold, and when the concrete is close to initial setting, the concrete is trowelled.
3.3 curing of the test pieces
3.3.1 the test pieces should be covered immediately after shaping with a water-impermeable film.
3.3.2 the test piece cured by the standard method is allowed to stand for one day and night to two days and night in the environment of the temperature of (20 +/-5) DEG C, and then is numbered and demoulded. Immediately placing into a standard curing room with a temperature of 20 + -2 deg.C and a relative humidity of above 95%, or placing into a non-flowing Ca (OH) with a temperature of 20 + -2 deg.C for curing 2 Curing in a saturated solution. Test in standard curing ChamberThe pieces should be placed on a support with a distance of 10-20 mm from each other, and the surface of the test piece should be kept moist and not directly washed by water.
3.3.3 the time for removing the mold for maintaining the test piece under the same conditions can be the same as the time for removing the mold of the actual component, and after the mold is removed, the test piece still needs to be maintained under the same conditions.
3.3.4 Standard curing age 28 days (time from stirring and water addition).
4 compression strength test
4.1 the test piece is taken out from the curing chamber, dried immediately and measured for its size (to the accuracy of 1 mm) to calculate the pressed area A (mm) of the test piece 2 )。
4.2 the test piece is placed on the lower bearing plate, and the bearing surface of the test piece is vertical to the top surface during molding. The center of the test piece should be aligned with the center of the press plate under the testing machine. And starting the testing machine, and adjusting the ball seat to balance the contact when the upper pressure plate is close to the test piece.
4.3 applying pressure continuously and uniformly at a rate of
When the strength grade of the concrete is less than C30, 0.3-0.5 MPa/S is taken;
when the concrete strength grade is = C30 and is less than C60, 0.5-0.8 MPa/S is selected;
and when the concrete strength grade = C60, taking 0.8-1.0 MPa/S.
And when the test piece is close to damage and deforms rapidly, stopping adjusting the accelerator of the testing machine until the test piece is damaged. The failure load was recorded.
5 calculation of test results
5.1 the compressive strength of the concrete cubic test piece is calculated according to the formula (9) (the result is accurate to 0.1 MPa):
in the formula f ce The compressive strength of the concrete cubic test piece is MPa; f-test piece failure load, N; a-test piece broken bearing area, mm 2 。
5.2 the determination of the intensity values should comply with the following provisions:
the arithmetic mean of the measured values of the three test pieces of 5.2.1 was taken as the strength value (accurate to 0.1 MPa) for the set of test pieces.
And if the difference between the minimum value or one of the maximum values of the three measured values of 5.2.2 and the intermediate value exceeds 15 percent of the intermediate value, the maximum value and the minimum value are divided together, and the intermediate value is taken as the compressive strength value of the group of test pieces.
5.2.3 if the maximum and minimum values differ from the median by more than 15% of the median, the test results for this group of test pieces are invalid.
When the concrete strength grade of 5.3 is less than C60, the strength values measured by the non-standard test pieces are multiplied by a size conversion coefficient, and the value is 1.05 for a test piece of 200mm multiplied by 200mm and 0.95 for a test piece of 100mm multiplied by 100 mm. When the strength grade of the concrete is = C60, a standard test piece is adopted; when non-standard test pieces are used, the size conversion factor should be determined by experiment.
5.4 Test results of 50 test pieces
Table 4: test results of compressive Strength of test pieces No. 1 to 10
Table 5: test results of compressive Strength of test pieces No. 11 to 20
Table 6: test results of compressive Strength of test pieces No. 21-30
Table 7: test results of compressive Strength of test pieces No. 31 to 40
Table 8: test results of compressive Strength of test pieces No. 41 to 50
In the specific implementation process, the calculation formula of the detected concrete strength is shown as formula (10):
wherein n is the maintenance age, and n is more than or equal to 3d.
The indexes of water of the invention meet other regulations of Water for concrete Standard (JGJ 63-2006), and are concretely shown in Table 11;
table 11: provisions of Water Standard for concrete
| Item | Prestressed concrete | Reinforced concrete | Plain concrete |
| pH value | ≥5.0 | ≥4.5 | ≥4.5 |
| Insoluble matter, mg/L | ≤2000 | ≤2000 | ≤5000 |
| Soluble matter, mg/L | ≤2000 | ≤5000 | ≤10000 |
| Cl - ，mg/L | ≤500 | ≤1000 | ≤3500 |
| SO 4 2- ，mg/L | ≤600 | ≤2000 | ≤2700 |
| Alkali content, mg/L | ≤1500 | ≤1500 | ≤1500 |
When the concrete strength grade is equal to or more than C30 grade and the calculated value of the standard deviation of the strength is less than 3MPa, the standard deviation for calculating and preparing the strength is not less than 3MPa.
The mixing amount of the additive and the admixture is determined by tests and is in accordance with the regulations of the national current standard of concrete additive application technical Specification, fly ash application technical Specification in concrete and mortar (JBJ 28), fly ash concrete application technical Specification (GBJ 146), granulated blast furnace slag powder in cement and concrete (GB/T18046) and the like.
The doping amount of the air entraining agent or the air entraining water reducing agent for the concrete which is in a humid and cold environment for a long time is determined by tests according to the air content of the concrete, and the minimum air content of the concrete is in accordance with the specification of the following table; the air content of the concrete should not exceed 7%. The coarse and fine aggregates in the concrete should be tested for consistency.
While specific embodiments of the invention have been described above, it will be appreciated by those skilled in the art that these are by way of example only, and that the scope of the invention is defined by the appended claims. Various changes and modifications to these embodiments may be made by those skilled in the art without departing from the spirit and scope of the invention, and these changes and modifications are within the scope of the invention.
Claims (6)
1. The utility model provides a fair-faced concrete suitable for dysmorphism structure veneer which characterized in that: the composite material is prepared from the following raw materials in parts by weight: 469 parts of cement, 3234 parts of sand 613.12 parts of stones 1151.988 parts of water 230 parts, 37.52-46.9 parts of silica fume and 56.28-84.42 parts of zeolite powder.
2. The fair-faced concrete suitable for the special-shaped structural veneer according to claim 1, wherein: the cement is P042.5 portland cement or ordinary portland cement.
3. The fair-faced concrete suitable for the special-shaped structural veneer according to claim 1, wherein: the water meets the following criteria: the PH value is more than or equal to 4.5; insoluble substances are less than or equal to 2000mg/L; soluble matter is less than or equal to 5000mg/L; chloride ions are less than or equal to 1000mg/L; sulfate ion is less than or equal to 2000mg/L; the alkali content is less than or equal to 1500mg/L.
4. The fair-faced concrete suitable for the special-shaped structural veneer according to claim 1, wherein: the stone is prepared by mixing 5mm-10mm graded aggregate and 10mm-20mm graded aggregate according to any proportion, and has apparent density of 2700kg/m 3 The water content was 1.2%.
5. The water for special-shaped structural veneer according to claim 1Concrete, its characterized in that: the sand is machine-made sand with fineness modulus of 2.3-3, and the apparent density of the sand is 2650kg/m 3 The water content was 2%.
6. The fair-faced concrete suitable for the special-shaped structural veneer according to claim 1, wherein: the determination of the proportion of the bare concrete is realized by adopting the following steps:
s1: calculating the concrete configuration strength f by the formula (1) cu,o ：
f cu,o ＝f cu,k +1.645δ (1)
In the formula, the concrete arrangement strength f cu,o The unit of (A) is Mpa; f. of cu,k Is the designed strength grade of concrete; delta is the standard deviation of concrete strength, when f cu,k When the temperature is less than or equal to C20, delta is 4.0Mpa; when C25 is less than or equal to f cu,k When the pressure is less than or equal to C45, delta is 5.0Mpa; when C50 is less than or equal to f cu,k When the pressure is less than or equal to C55, delta is 6.0Mpa;
s2: calculating the water-to-glue ratio by the formula (2)
In the formula, alpha a 、α b All the coefficients are regression coefficients, different values of the stone types are different, and the crushed stone is respectively 0.53 and 0.49; taking 0.20 and 0.13 of pebbles respectively; f. of ce Is cement strength grade; f. of cu,o Is calculated by the step S1;
s3: determining the unit water consumption m according to the set value of the slump s, the type of the stones and the maximum particle size of the stones wo ；
S4: according to the water-to-glue ratio
And step S3, determining the water consumption m of the design unit wo Calculating the cement dosage m of the design unit co ；
S5: according to the water-to-glue ratio
The type of stone and the maximum particle size of the stone determine the sand rate beta s ；
S6: calculating the unit stone dosage m by the formula (3) and the formula (4) go Design unit sand dosage m so ：
m co +m go +m so +m wo ＝m cp (3)
In the formula, m cp The weight of concrete is designed;
s7: using formula (5) to design unit cement dosage m co Correcting to obtain the cement consumption m of construction unit c '; using formula (6), the unit sand dosage m is designed so Correcting to obtain the sand consumption m of the construction unit s '; using formula (7) to design unit stone dosage m go Correcting to obtain the stone dosage m of a construction unit g '; the water consumption m of the design unit is calculated by the formula (8) wo Corrected to obtain the water consumption m of a construction unit w ′；
m c ′＝m co (5)
m s ′＝m so ×(1+W s ) (6)
m g ′＝m go ×(1+W g ) (7)
m w ′＝m wo -(m so ×W s +m go ×W g ) (8)
In the formula, W s Measuring the water content of the sand for the construction site; w g Measuring the water content of the stones for the construction site;
s8: according to the cement consumption m of a construction unit c ', determining the adding amount of the silica fume and the adding amount of the zeolite powder.
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Citations (5)
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| US20020055558A1 (en) * | 1997-12-09 | 2002-05-09 | Kiyoshi Maehara | Permeable waterproofing agent, waterproofing material, concrete or mortar composition, and method for preventing water leaks |
| CN108824812A (en) * | 2018-06-11 | 2018-11-16 | 贵州建工集团第建筑工程有限责任公司 | A kind of cast-in-place fair-faced concrete wall pours and maintenance process |
| US20190092688A1 (en) * | 2017-09-26 | 2019-03-28 | University Of South Carolina | Fly Ash-Based Geopolymer Concrete and Method of Formation |
| CN112341089A (en) * | 2020-11-13 | 2021-02-09 | 上海宝冶集团有限公司 | Method for designing mix proportion of bare concrete of load-bearing structure |
| CN113773022A (en) * | 2021-09-27 | 2021-12-10 | 明阳智慧能源集团股份公司 | White clear water finish concrete for prefabricated parts and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020055558A1 (en) * | 1997-12-09 | 2002-05-09 | Kiyoshi Maehara | Permeable waterproofing agent, waterproofing material, concrete or mortar composition, and method for preventing water leaks |
| US20190092688A1 (en) * | 2017-09-26 | 2019-03-28 | University Of South Carolina | Fly Ash-Based Geopolymer Concrete and Method of Formation |
| CN108824812A (en) * | 2018-06-11 | 2018-11-16 | 贵州建工集团第建筑工程有限责任公司 | A kind of cast-in-place fair-faced concrete wall pours and maintenance process |
| CN112341089A (en) * | 2020-11-13 | 2021-02-09 | 上海宝冶集团有限公司 | Method for designing mix proportion of bare concrete of load-bearing structure |
| CN113773022A (en) * | 2021-09-27 | 2021-12-10 | 明阳智慧能源集团股份公司 | White clear water finish concrete for prefabricated parts and preparation method thereof |
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