CN103102129A - Air entrained concrete - Google Patents
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- CN103102129A CN103102129A CN2013100580303A CN201310058030A CN103102129A CN 103102129 A CN103102129 A CN 103102129A CN 2013100580303 A CN2013100580303 A CN 2013100580303A CN 201310058030 A CN201310058030 A CN 201310058030A CN 103102129 A CN103102129 A CN 103102129A
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Abstract
The invention provides an air entrained concrete and relates to a concrete. The air entrained concrete provided by the invention comprises cement, a fine aggregate, a coarse aggregate, an additive and water, wherein the additive accounts for 2-3 wt% of the cement. The air entrained concrete provided by the invention can be used in paving to improve performances such as strength and impermeability, so as to greatly improve the durability of the pavement, greatly reduce the cost of repair and maintenance, and ensure the traffic capacity and comfort of the road. The main technical parameters of the air entrained concrete are as follows: 1) design flexural strength of the air entrained concrete: >=5.0Mpa; 2) gas content of the air entrained concrete: 5.5 +/- 0.5%; 3) water-cement ratio (W / C) of the air-entrained concrete: <=0.40; 4) slump of the air entrained concrete mixture: 25-50mm; 5) flexural elastic modulus of the air entrained concrete: >=30000Mpa; and 6) antifreeze grade of the concrete: >=F300.
Description
Technical field
The present invention relates to a kind of concrete, relate in particular to a kind of concrete that uses air entrapment agent.
Background technology
The weather resistance bad phenomenon of China's cold district pavement concrete various degrees, many highways and streets and viaduct engineering etc. do not reach design life, namely produce as durability damage phenomenons such as frost heave decortication, localized delamination, surface abrasions, have to repair frequently and overhaul, certainly will spend huge maintenance and reconstruction expenses, cause the significant wastage of the energy and resource.
The cement concrete pavement of cold district often ruptures prematurely and destroys under the ice and snow unfreezing, does not reach the working life of design objective far away.According to experts' analysis, the one of the main reasons of the shortening cold district highway service time limit is the freeze-thaw damage on roadbed frost heave and road surface.On the other hand, in recent years along with growth in the living standard, public and motor vehicles for civilian use roll up, and for ensureing highway driving safety in winter, prevent that ice and snow from causing cunning, the on the way salting deicing when snowy day of highway administration department.Low due to the freezing point of salt, erosion is strong, deicer-scaling destroys much harsh than common frozen water freeze thawing, only just can make supercrust destruction one or two winter.Bureau of Public Road (FHWA) emphasizes to improve the Synthesis durability of the public journey in road surface, realizes " long lifetime, the low maintenance ", reduces life cycle cost, and topmost technique means is to use high performance air-entraining concrete.
The factor that affects concrete durability is many-sided, and as design, starting material, relevant specification is considered inadequate etc. to concrete durability index.But many experts think, in concrete construction, to fail popularization and application be also an immeasurable factor to air entrapment agent.Although many countries order the application of air entrapment agent into standard, and will use the concrete of air entrapment agent to be decided to be special concrete, and China only had water conservancy project system (03 edition pavement construction standard adds associated viscera) to explicitly call in code for design of concrete structures and must mix air entrapment agent at that time.Even many people are considered as the forbidden zone with the concrete gassiness.To there be the admixture of certain amount of air entrainment to be decided to be and use product.
The principal element that affects the air entrapment agent widespread use is that many engineering technical personnel are unclear to the great technical economic benefit understanding of using air entrapment agent, even there are certain mistaken ideas, always think that mixing air entrapment agent can reduce concrete strength, air entrapment agent is but seldom considered the impact of endurance performance of concrete.The academician of the Chinese Academy of Sciences, in " durability design method " literary composition that professor Chen Zhaoyuan of Tsing-Hua University delivers, drum in " concrete of good endurance should be bleed, low water binder ratio concrete ", " should with durability index as the primary index that detects concrete quality, must pay attention to air entrapment agent applying in concrete ".
The key character of air-entraining concrete is to have good weather resistance, and freeze-thaw damage is one of sixty-four dollar question in concrete durability.
For freeze-thaw-weather resistance and the salt denudation resisting ability that improves cement concrete pavement, most economical easy method is exactly the making air entrained concrete pavement.Increase a large amount of in concrete owing to using air entrapment agent when the mixing concrete and even small steam bubble, improve concrete air content, can free water endure cold when freezing in concrete on the one hand, in time received the supercooled water in the district that endures cold, slow down icing pressure, alleviate concrete frost heaving failure; Concrete capillary channel can be cut off again on the other hand, the cloudy people of oozing who stops exogenous salt solution and moisture reduces the snowmelt of inside concrete, thereby improves its freeze proof and ability salt denudation resisting.
In the general road concrete admixture mostly be composite additive, its Main Function comprises diminishing, bleed and slow setting, wherein air-entraining function is to improve the most important means of concrete durability.After air-entrained agent, with all multi-performance index such as the concrete workability of remarkable road improvement, bending tensile strength, deformation performance and weather resistance, be conducive to improve concrete road quality, improve the working life on road surface.
Through top researching and analysing, using air entrapment agent in the construction of cement concrete road surface of cold district is the important means that improves pavement durability.
Summary of the invention
The purpose of this invention is to provide a kind of air-entraining concrete, by applying of air entrained concrete pavement, improve bending tensile strength and the Frost Resistance of pavement concrete, improve the actual useful year on cold district cement concrete road surface.
Air-entraining concrete of the present invention is mixed by cement, fine aggregate, coarse aggregate, admixture and water, and admixture dosage is 2.0 ~ 3.0% of cement weight.
The present invention uses road silicate cement or ordinary Portland cement to make air-entraining concrete, and consumptive use of water normal consistence should not be greater than 28%.Cement concrete pavement should adopt that intensity is high, drying shrinkage is little, the above ordinary Portland cement of PO42.5 level of resistance to abrasion, weather resistance and good stability.Specific requirement sees Table 1-2.
The Chemical Composition technical requirements of table 1 cement
| The chemistry of cement composition | Technical requirements |
| Tricalcium aluminate | ＜7.0% |
| Tetracalcium aluminoferrite | 15.0% |
| Free calcium oxide | ＜1.0% |
| Magnesium oxide | ＜5.0% |
| Sulphur trioxide | ＜3.5% |
| Alkali content | Na 2O+0.658K 2O≤0.6% |
| The compound kind | Must not mix kiln ash, coal gangue, volcanic ash and clay. |
The physical index technical requirements of table 2 cement
| Cement performance | Standard-required (heavy traffic road surface) |
| Stability | Lei Shi folder or cooking process are qualified |
| The standard consistency water requirement 2. | Unsuitable〉28%, must not 30% |
| Loss on ignition | Must not 3.0% |
| Specific surface area 3. | Should be at 300 ~ 350 m 2/ Kg does not answer〉350m 2/Kg |
| Fineness (80 μ m) | Screen over-size must not 10% |
| Presetting period | Should be at 90 ~ 180min |
| Final setting time | Should be at 300 ~ 600min |
| The 28d contract with dry rate 4. | Must not 0.09% |
| Wear resistance 4. | Must not 3.6Kg/m2 |
Admixture used in the present invention is the composite additive that contains bleed, efficient diminishing and slow setting three large major functions.It is the product of Escin (three note saponins) that air entrapment agent should preferentially be selected major ingredient.It is sulfonated lignin or phosphatic product that retardant should preferentially be selected major ingredient.The product of high efficiency water reducing agent recommend adoption β-naphthalene yellow acid high polycondensate of sodium formaldehyde (naphthalene system) or sulfamate series, the not product of recommend adoption aliphatics and polycarboxylate series.Water-reducing rate should be greater than 18%, should be greater than 20%.For reducing concrete viscosity, reduce the concrete difficulty of unloading, the effective admixture total amount after conversion should not be greater than 1.5% of cement quality.In general, on engineering, admixture used should be the liquid composite additive, and major function has bleed, efficient diminishing and slow setting.Diminishing component recommendation naphthalene water reducer wherein; Induced gas component recommendation colophonium pyrolytic polymer class; Slow setting component recommendation Sodium hexametaphosphate 99.Solid content should be greater than 30% when 20 ℃ of temperature for liquid additive, and volume is 2.8 ~ 3.0% of cement weight.
Fine aggregate in the present invention should be selected river sand, and secondary and above Highway house should preferentially select medium sand with river sand, and secondary is recommended medium sand or coarse sand to get down the highway, and other performance index must not be continuous lower than table 3 and table 3() in technical requirements.For reducing sand to the impact of air content in air-entraining concrete, when using medium sand, its fineness modulus must not be greater than 3.0, and sand coarse aggregate ratio is 32% ~ 38%.
Table 3 fine aggregate performance requriements
Table 3 fine aggregate performance requriements (continuing)
Requirement to coarse aggregate in the present invention is: grating should satisfy the technical requirements in following table 4, and rubble should be preferentially selected on second grade highway above road surface, should strictly carry out experimental examination when adopting crushed gravel or cobble.Rubble should be selected in the following road surface of second grade highway.The coarse aggregate maximum particle diameter that air-entraining concrete uses must not be greater than 31.5mm; 26.5mm the square hole sieve throughput should not be less than 90%.When adopting formate gradation composition, should select 20 ~ 30mm, 10 ~ 20mm on ordinary meaning and 5 ~ 10mm third gear to gather materials and synthesize, wherein gather materials should not be greater than 20% in total content of coarse aggregate for 5 ~ 10mm shelves.As when not having 5 ~ 10mm to gather materials, also can carry out second gear and gather materials syntheticly, but after synthetic, screening result must satisfy the graduation curve requirement of following table 4.
The technical requirements of table 4 coarse aggregate
Requirement to water in the present invention is: the stirring of air-entraining concrete and maintenance water should clean, and should adopt tap water.When adopting undrinkable water, need through chemical examination, and should meet the following requirements:
A) sulphate content (is pressed SO
4 2-Meter) must not surpass 2700mg/L;
B) saltiness must not surpass 5000mg/L;
C) the pH value must not be lower than 5;
D) must not contain greasy dirt, mud and other detrimental impurity.
use air-entraining concrete surfacing of the present invention, except improving intensity, outside the performance such as impervious, most importantly greatly improved the endurance quality on road surface, as long as rationally, correctly use admixture, guarantee that the concrete spacing factor coefficient after completion satisfies code requirement, basically can guarantee road surface work-ing life of 20 years, on year-on-year basis in the past cement concrete pavement less than work-ing life of 10 years, can reduce significantly the maintenance expense, and the traffic capacity and the comfortableness of assurance road, thereby bring certain economic benefit and larger social benefit to highway operation.The key technical indexes of air-entraining concrete of the present invention is as follows:
1) air-entraining concrete design bending tensile strength: 〉=5.0Mpa;
2) air-entraining concrete air content: 5.5 ± 0.5 %;
3) air-entraining concrete water cement ratio (W/C) :≤0.40;
4) the air-entraining concrete mixture slump: 25 ~ 50mm;
5) Young's modulus is drawn in the air-entraining concrete bending resistance: 〉=30000Mpa;
6) the freeze proof grade of air-entraining concrete: 〉=F300.
Embodiment
Embodiment one: the mix-design process of the air-entraining concrete of present embodiment following (sample):
One, determine design objective and design variable value:
1) mix and maturing mechanics index of physics
Air-entraining concrete design bending tensile strength: 〉=5.0MPa;
Air-entraining concrete air content: 5.5 ± 0.5 %;
Air-entraining concrete water cement ratio (W/C) :≤0.40;
The air-entraining concrete mix slump: 25 ~ 50mm;
The freeze proof grade of air-entraining concrete: 〉=F300;
Young's modulus is drawn in the air-entraining concrete bending resistance: 〉=30000MPa.
2) mix-design parameter value
t-fraction coefficient, get 9 groups of samples of motorway corresponding 0.61;
S-flexural tensile strength test sample standard deviation is got motorway 0.40MPa;
-flexural tensile strength the variation coefficient is got motorway 0.05.
5cm is got in the slump-slding form operation;
Sand coarse aggregate ratio-table look-up according to fineness modulus 2.93 and get 37%.
Two, mix calculation
1) calculate cement concrete preparation bending tensile strength
2) calculate water cement ratio
Press the formula of crushed stone concrete:
In formula:
-water cement ratio;
*
Weather resistance is checked:According to " climatic zoning for highway standard " JTJ 003-86, simultaneously with reference to the relevant regulations of " standard specification for construction and acceptance of highway asphalt pavement " JTG F40-2004 appendix A, this project Study on Climate Division should be II-1-2, i.e. district-humid area, summer hot-zone-Dong severe cold.JTG F30-2003 must satisfy the durability Design requirement according to " highway cement concrete pavement construction technique normalizing ".This air-entraining concrete design blending station outlet air content is 5.0 ± 0.5%, by standard as can be known maximum water cement ratio be 0.42, the water cement ratio result of therefore calculating according to intensity meets life requirement.
3) calculate water consumption
The formula of pressing crushed stone concrete calculates water consumption:
In formula:
-do not mix the unit consumption of water (kg) of Fresh Concrete with Admixtures;
With the above-mentioned formula of data substitution, calculate:
。
The maximum unit water consumption of pavement concrete during with Slipform Paving is 156Kg/m
3, getting unit consumption of water herein is 146kg/m
3
4) calculate cement consumption
kg/m
3 (2-4)，
In formula:
-unit cement consumption (kg/m
3).
The minimum cement dosage that satisfies life requirement is 300kg/m
3, getting thus and calculating cement consumption is 370kg/m
3
5) determine coarse aggregate, medium sand consumption
Adopt the supposition densimetry, because being designed to air-entraining concrete, deciding density by the front air content 4% that paves and be: 2450 * (1-0.04)=2352 ≈ 2350kg/m
3
Calculate admixture consumption: 374 * 3.0%=11.22kg/m
3
Calculate sand, stone total amount: 2350-374-146-11.22 ≈ 1819kg/m
3
Calculate the sand consumption: 1819 * 37%=673 kg/m
3
Calculate the rubble consumption: 1819-673=1146 kg/m
3 *
* each grade rubble consumption: calculate according to the rubble ratio of optimum proportion.
6) preliminary proportioning is proposed
Comprehensive above data draw preliminary proportioning and see Table 5:
The preliminary proportioning data sheet of table 5
7) proportioning checking and adjustment
Carry out trial mix by preliminary proportioning, whether test mixing concrete thing satisfies slump requirement, is guaranteeing that under the constant prerequisite of water cement ratio, the adjustment admixture dosage meets the demands mixing concrete thing workability, proposes at last testing laboratory's benchmark proportioning.
8) final testing laboratory proportioning is proposed
In the situation that guarantor unit's water consumption is constant, water cement ratio fluctuates 0.01, preparation concrete tensile test specimen, the 28d intensity of three proportionings of mensuration.Draw intensity-water cement ratio curve, the final proportioning in final optional test chamber sees Table 6:
The final proportioning data sheet of table 6 testing laboratory
Three, mixing concrete physical performance test
According to the proportioning that adjustment is completed, carry out the mix performance test of air-entraining concrete, test-results sees Table 7:
Table 7 mixing concrete physical performance test-results
Four, properties of hardened concrete test
After the adjustment of air-entraining concrete proportioning is completed, namely begin to carry out the physical and mechanical property index Test of maturing.
1, without the lateral confinement bending tensile strength
Test specimen adopts 15 * 15 * 15cm resistance to compression and 15 * 15 * 55cm bending resistance to draw two kinds of specifications, and the longest 28d of preserving period, curing condition are 20 ± 2 ℃ of temperature, and relative humidity is more than 95%.Testing data sees Table 8.
Table 8 concrete is without lateral confinement bending tensile strength test-results
2, Young's modulus is drawn in bending resistance
Adopt and synchronize the test specimen made from bending tensile strength, add to unload through 5 times and circulate, record testing data and calculate bending resistance and draw Young's modulus such as table 9:
The elasticity modulus test result is drawn in the bending resistance of table 9 air-entraining concrete
3, anti-freezing property (quick-freeze method)
Be the freeze-thaw-endurance quality of checking air-entraining concrete, we adopt the quick-freeze method to carry out the frost resistance test, and test-results sees Table 10 ~ table 12:
Table 10 normal concrete antifreezing test result
Mass loss rate (%)
Table 11 air-entraining concrete antifreezing test result
Mass loss rate (%)
Loss of strength after the antifreezing test of table 12 air-entraining concrete
Testing data shows: the maximum freeze-thaw-cycle index of air-entraining concrete has reached maximum value 300 times, and its freeze proof grade reaches F300, meets design requirement.
Embodiment two: the air-entraining concrete mix-design that present embodiment is adopted take certain one-level highway cement concrete pavement is as example, calculate in detail and test adjust as follows:
Suppose that certain one-level Road Design flexural tensile strength is 5.0MPa, for satisfying the frost resistance requirement, air content is (5 ± 0.5) %, adopts synovial membrane to pave, and the slump that paves is controlled to be 3 ~ 5cm.
One, starting material:
1, cement: the inferior safe PO42.5 class g cement in Harbin.
2, rubble: 4.75 ~ 26.5cm continuous grading rubble of selecting third gear to be composited.
3, sand: medium sand, fineness modulus 3.0.
4, water: tap water.
5, admixture: bleed, efficient diminishing and slow setting compound, liquid state, volume≤3.0%.
Two, mix calculation process
1, calculate cement concrete preparation bending tensile strength
The formula of the calculating of the preparation flexural tensile strength of air-entraining concrete is as shown in formula (B-1):
In formula:
The average of-28 Concrete flexural tensile strengths (Mpa);
tThe standard deviation of-bending tensile strength test sample (Mpa);
s-fraction coefficient;
The value explanation:
t-fraction coefficient should be by table B-1 value, get 9 groups of samples of Class I highway corresponding 0.46;
s-flexural tensile strength test sample standard deviation with reference to table B-2 value, is got Class I highway 0.25Mpa;
With the above-mentioned substitution calculation formula that respectively is worth, draw the preparation bending tensile strength:
Table B-1 fraction coefficient t
Table B-2 highway concrete road surface flexural tensile strength at different levels test sample standard deviation s and the variation coefficient
2, calculate water cement ratio
Press the formula of crushed stone concrete:
，
In formula:
-water cement ratio;
-cement 28d bending tensile strength (Mpa).
Weather resistance is checked: according to " climatic zoning for highway standard " JTJ 003-86, while is with reference to the relevant regulations of " standard specification for construction and acceptance of highway asphalt pavement " JTG F40-2004 appendix A, this project Study on Climate Division should be II-1-2, i.e. district-humid area, summer hot-zone-Dong severe cold.JTG F30-2003 must satisfy the durability Design requirement according to " highway cement concrete pavement construction technique normalizing ".This air-entraining concrete design blending station outlet air content is 5.0 ± 0.5%, by standard as can be known maximum water cement ratio be 0.42, the water cement ratio result of therefore calculating according to intensity meets life requirement.
3, determine sand coarse aggregate ratio
By the fineness modulus 3.0 of sand, the B-3 that tables look-up, getting the crushed stone concrete sand coarse aggregate ratio is 36%.
Fineness modulus and the optimum sand coarse aggregate ratio relation of table B-3 sand
4, determine unit consumption of water
Formula (B-2) and the formula (B-3) of pressing crushed stone concrete calculate water consumption:
In formula:
-do not mix the unit consumption of water (Kg) of Fresh Concrete with Admixtures;
-sand coarse aggregate ratio (%) gets 36%;
With the above-mentioned formula of data substitution, calculate:
The maximum unit water consumption of pavement concrete during with Slipform Paving is 156Kg/m
3, getting unit consumption of water herein is 141Kg/m
3
5, determine unit cement consumption
(B-4) direct substitution numerical evaluation by formula:
The minimum cement dosage that satisfies life requirement is 300Kg/m
3, getting thus and calculating cement consumption is 370Kg/m
3
6, determine coarse aggregate, medium sand consumption
Adopt the supposition densimetry, because being designed to air-entraining concrete, calculate by the front air content 4% that paves, suppose that density is: 2450 * (1-0.04)=2352 ≈ 2350Kg/m
3
Calculate admixture consumption: 370 * 2.5%=9.25Kg/m
3
Calculate sand, stone total amount: 2350-370-141-9.25 ≈ 1830 Kg/m
3
Calculate the sand consumption: 1830 * 36%=658.8 Kg/m
3
Calculate the rubble consumption: 1830-658.8=1171.2 Kg/m
3
Large and small rubble consumption: small crushed stone ratio large according to each bid section calculates.
7, preliminary proportioning is proposed
Comprehensive above data draw preliminary proportioning such as table 13:
The preliminary proportioning data sheet of table 13
| Cement (kg/m 3) | Sand (kg/m 3) | Rubble (kg/m 3) | Water (kg/m 3) | Admixture (Kg/m 3) | Unit weight (kg/m 3) | Water cement ratio | |
| Proportioning | 370 | 658.8 | 1171.2 | 141 | 9.25 | 2350 | 0.38 |
| Per-cent | 15.90% | 27.99% | 49.75% | 5.96% | 0.40% | Sand coarse aggregate ratio | Admixture |
| Mass ratio | 1.000 | 1.760 | 3.129 | 0.375 | 0.025 | 36% | 2.5% |
8, proportioning checking and adjustment
Carry out trial mix by preliminary proportioning, whether test mixing concrete thing satisfies slump requirement, is guaranteeing that under the constant prerequisite of water cement ratio, the adjustment admixture dosage meets the demands mixing concrete thing workability, proposes at last testing laboratory's benchmark proportioning.
9, final testing laboratory proportioning is proposed
In the situation that guarantor unit's water consumption is constant, water cement ratio fluctuates 0.01, preparation concrete tensile test specimen, the 28d intensity of three proportionings of mensuration.Draw intensity-water cement ratio curve, the final proportioning in final optional test chamber.
10, the construction proportioning is determined
The construction proportioning needs to measure sand, stone water ratio and admixture solid content according to field condition, deducts in water consumption, provides the site operation proportioning.
Three, the safeguard measure of air-entraining concrete bleed effect
After testing laboratory determined concrete best air content, how next step work will guarantee that exactly in construction process, concrete can reach the working order of anticipation.Introduce gas and be air entrapment agent in the middle of concrete as tensio-active agent and water, cement (perhaps comprising flyash) and the interactive complex process of gathering materials, the bleed effect of cement concrete also is subject to the fineness of cement, grating that thickness is gathered materials and the impact of the factors such as surface property, the temperature of mixing and stirring, mixing time and transportation.
To the north of black motorway cement road surface plate construction process (Slipform Paving) be example, should mainly guarantee in the following ways the bleed effect of cement concrete.
One, reduce the concrete temperature of mixing and stirring
React rapidly because concrete temperature rising can cause mineralogical composition and water in the middle of cement, the hydrated product of cement can absorb bubble; Simultaneously concretely mix and stir the temperature moisture evaporation that also can make cement concrete that raises and accelerate, thereby make the concrete stiff formation that affects bubble that becomes.For reducing the temperature of cement concrete, need to accomplish:
1, do not use high-temperature cement;
2, high temperature season gathers materials and will take certain covering measure, prevents from being exposed to the sun;
3, can carry out mixing and stirring of cement concrete by the lower deep phreatic water of use temperature.
Two, strictly control the slump of cement concrete
The slump is the macro manifestations of the central yielding stress of cement concrete and viscosity, if the slump too small (less than 20mm), although could concrete could be paved by traveling speed and the vibrational frequency of regulating slip form paver.But because concrete viscosity and yielding stress are crossed the formation that conference affects bubble, thereby affect the bleed effect, control the concrete slump between 25mm ~ 50mm for guaranteeing that the bleed effect is strict in the black expressway construction in north.
Three, guarantee the grating of rubble and the granulometric composition of medium sand
Use air entrapment agent to introduce the bubble of tiny densification in the middle of concrete, be water, cement, gather materials and the interactive result of air entrapment agent.If the disproportionately graded of rubble can increase the central shearing force of concrete so, reduce the bleed effect.If find in test and production process that the fineness modulus of medium sand excessive (surpassing 3.0) can make concrete become stiff so equally, the shearing force in the middle of concrete increases, and affects the bleed effect.Therefore use aborning 19mm-26.5mm, 9.5mm-19mm, 4.75mm-9.5mm third gear rubble is mixed and is joined, thereby guarantees that macadam gradating forms.Require the fineness modulus of medium sand should be between 2.5 ~ 3.0 for fine aggregate.
Four, guarantee to mix and stir ability and mixing time
Stirring means also can affect concrete air content.The throughput of blending station will be complementary with Production requirement, and the maximum amount of mixing and stirring of general requirement blending station should not surpass 90% of the specified ability of mixing and stirring of blending station, and the mixing time is not less than 50s, thereby guarantees that mixing concrete is full and uniform.The simultaneously effect of air entrapment agent and concrete composition is abundant, is uniformly dispersed, densification.
Five, strengthen Design of Construction Organization, reduce time of lag
Concrete is after blending station goes out machine, and concrete air content is always in continuous minimizing.Therefore want the concrete haul distance of reasonable arrangement in Design of Construction Organization, reduce bubble loss in transportation.Simultaneously blending station and the paver speed that paves is consistent, even transport the concrete of the showing up moulding that paves.
Claims (10)
1. an air-entraining concrete, comprise cement, fine aggregate, coarse aggregate and water, it is characterized in that described concrete also is added with admixture, and its volume is 2.0 ~ 3.0% of cement weight.
2. air-entraining concrete according to claim 1, is characterized in that described cement is road silicate cement or ordinary Portland cement.
3. air-entraining concrete according to claim 1 and 2, is characterized in that described consumptive use of water normal consistence should not be greater than 28%.
4. air-entraining concrete according to claim 1 and 2, is characterized in that described ordinary Portland cement is the above ordinary Portland cement of PO42.5 level.
5. air-entraining concrete according to claim 1, is characterized in that described admixture is the composite additive that contains bleed, efficient diminishing and slow setting three large major functions.
6. air-entraining concrete according to claim 1, it is characterized in that described fine aggregate should select river sand, secondary and above Highway house should preferentially select medium sand with river sand, secondary is recommended medium sand or coarse sand to get down the highway, for reducing sand to the impact of air content in air-entraining concrete, when using medium sand, its fineness modulus must not be greater than 3.0, and sand coarse aggregate ratio is 32% ~ 38%.
7. air-entraining concrete according to claim 1 is characterized in that described second grade highway above road surface coarse aggregate should preferentially select rubble, and rubble should be selected in second grade highway following road surface.
8. according to claim 1 or 7 described air-entraining concretes, is characterized in that the coarse aggregate maximum particle diameter that described air-entraining concrete uses must not be greater than 31.5mm; 26.5mm the square hole sieve throughput should not be less than 90%; When adopting formate gradation composition, select 20 ~ 30mm, 10 ~ 20mm on ordinary meaning and 5 ~ 10mm third gear to gather materials and synthesize, wherein gather materials should not be greater than 20% in total content of coarse aggregate for 5 ~ 10mm shelves.
9. air-entraining concrete according to claim 1 is characterized in that the key technical indexes of described air-entraining concrete is as follows:
1) air-entraining concrete design bending tensile strength: 〉=5.0Mpa;
2) air-entraining concrete air content: 5.5 ± 0.5 %;
3) air-entraining concrete water cement ratio (W/C) :≤0.40;
4) the air-entraining concrete mixture slump: 25 ~ 50mm;
5) Young's modulus is drawn in the air-entraining concrete bending resistance: 〉=30000Mpa;
6) the freeze proof grade of air-entraining concrete: 〉=F300.
10. air-entraining concrete according to claim 1 is characterized in that the mix-design process of described air-entraining concrete is as follows:
One, determine mix and maturing mechanics index of physics:
Air-entraining concrete design bending tensile strength: 〉=5.0MPa;
Air-entraining concrete air content: 5.5 ± 0.5 %;
Air-entraining concrete water cement ratio :≤0.40;
The air-entraining concrete mix slump: 25 ~ 50mm;
The freeze proof grade of air-entraining concrete: 〉=F300;
Young's modulus is drawn in the air-entraining concrete bending resistance: 〉=30000Mpa;
Two, mix calculation:
1) calculate cement concrete preparation bending tensile strength:
,
t-fraction coefficient,
S-flexural tensile strength test sample standard deviation,
2) calculate water cement ratio
Press the formula of crushed stone concrete:
,
In formula:
-water cement ratio;
-cement 28d bending tensile strength;
3) calculate water consumption
The formula of pressing crushed stone concrete calculates water consumption:
；
In formula:
-do not mix the unit consumption of water of Fresh Concrete with Admixtures;
4) calculate cement consumption:
,
In formula:
-unit cement consumption;
5) determine coarse aggregate, fine aggregate consumption:
According to cement consumption and water consumption, calculate admixture consumption, coarse aggregate content and fine aggregate consumption.
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| CN (1) | CN103102129A (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103362522A (en) * | 2013-07-08 | 2013-10-23 | 上海城建物资有限公司 | Dry powder type synchronous grouting construction technology |
| CN104973834A (en) * | 2015-06-29 | 2015-10-14 | 湖州华仑助剂科技有限公司 | Mixed concrete |
| CN105236865A (en) * | 2015-09-23 | 2016-01-13 | 南通众润混凝土有限公司 | Lightweight concrete |
| CN107268380A (en) * | 2017-08-06 | 2017-10-20 | 新沂市中诺新材料科技有限公司 | A kind of anti-slip pervious type road surface structure |
| CN107459299A (en) * | 2017-08-06 | 2017-12-12 | 新沂市中诺新材料科技有限公司 | A kind of preparation method of frost-resistant concrete |
| CN107673694A (en) * | 2017-10-13 | 2018-02-09 | 河南省三门峡黄河大桥高速公路建设有限公司 | Cracking resistance frost-resistant concrete and preparation method thereof |
| CN108314370A (en) * | 2018-05-14 | 2018-07-24 | 盐城市凯利特商品混凝土有限公司 | A kind of environment-friendly type concrete and its production technology with slag bits |
| CN108708244A (en) * | 2018-06-22 | 2018-10-26 | 杜宇 | A kind of highway road surface and preparation method thereof not cracked |
| CN109485351A (en) * | 2019-01-07 | 2019-03-19 | 河北联众谊诚混凝土有限公司 | A kind of concrete and its processing technology |
| CN110041032A (en) * | 2019-05-31 | 2019-07-23 | 黑龙江省交通科学研究所 | Cold area's cement concrete pavement facing thin layer fast repairing method |
| CN114213074A (en) * | 2022-01-18 | 2022-03-22 | 鞍钢矿山建设有限公司 | Method for calculating mixing proportion of common concrete |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101628797A (en) * | 2009-08-21 | 2010-01-20 | 李珠 | Inorganic heat insulation load-bearing concrete |
| CN101798207A (en) * | 2010-04-07 | 2010-08-11 | 西南科技大学 | Ready-mixed concrete with phosphorus slag powder |
| CN102351477A (en) * | 2011-07-12 | 2012-02-15 | 中铁二十局集团第四工程有限公司 | Mixture for preparing C55 high-intensity ultra-high-pumping concrete |
| CN102690084A (en) * | 2011-08-25 | 2012-09-26 | 江苏荣能集团股份有限公司 | Self-compaction concrete with heavily doped fly ash and preparation method thereof |
-
2013
- 2013-02-25 CN CN2013100580303A patent/CN103102129A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101628797A (en) * | 2009-08-21 | 2010-01-20 | 李珠 | Inorganic heat insulation load-bearing concrete |
| CN101798207A (en) * | 2010-04-07 | 2010-08-11 | 西南科技大学 | Ready-mixed concrete with phosphorus slag powder |
| CN102351477A (en) * | 2011-07-12 | 2012-02-15 | 中铁二十局集团第四工程有限公司 | Mixture for preparing C55 high-intensity ultra-high-pumping concrete |
| CN102690084A (en) * | 2011-08-25 | 2012-09-26 | 江苏荣能集团股份有限公司 | Self-compaction concrete with heavily doped fly ash and preparation method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 中华人民共和国交通部: "《公路水泥混凝土路面施工技术规范》", 28 March 2003, article "混凝土配合比设计", pages: 17-22 * |
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103362522A (en) * | 2013-07-08 | 2013-10-23 | 上海城建物资有限公司 | Dry powder type synchronous grouting construction technology |
| CN103362522B (en) * | 2013-07-08 | 2016-05-11 | 上海城建物资有限公司 | A kind of dry-type synchronization slip casting construction technology |
| CN104973834A (en) * | 2015-06-29 | 2015-10-14 | 湖州华仑助剂科技有限公司 | Mixed concrete |
| CN105236865A (en) * | 2015-09-23 | 2016-01-13 | 南通众润混凝土有限公司 | Lightweight concrete |
| CN107268380A (en) * | 2017-08-06 | 2017-10-20 | 新沂市中诺新材料科技有限公司 | A kind of anti-slip pervious type road surface structure |
| CN107459299A (en) * | 2017-08-06 | 2017-12-12 | 新沂市中诺新材料科技有限公司 | A kind of preparation method of frost-resistant concrete |
| CN107673694A (en) * | 2017-10-13 | 2018-02-09 | 河南省三门峡黄河大桥高速公路建设有限公司 | Cracking resistance frost-resistant concrete and preparation method thereof |
| CN107673694B (en) * | 2017-10-13 | 2020-12-29 | 河南五建混凝土有限公司 | Anti-cracking and anti-freezing concrete and preparation method thereof |
| CN108314370A (en) * | 2018-05-14 | 2018-07-24 | 盐城市凯利特商品混凝土有限公司 | A kind of environment-friendly type concrete and its production technology with slag bits |
| CN108708244A (en) * | 2018-06-22 | 2018-10-26 | 杜宇 | A kind of highway road surface and preparation method thereof not cracked |
| CN109485351A (en) * | 2019-01-07 | 2019-03-19 | 河北联众谊诚混凝土有限公司 | A kind of concrete and its processing technology |
| CN110041032A (en) * | 2019-05-31 | 2019-07-23 | 黑龙江省交通科学研究所 | Cold area's cement concrete pavement facing thin layer fast repairing method |
| CN114213074A (en) * | 2022-01-18 | 2022-03-22 | 鞍钢矿山建设有限公司 | Method for calculating mixing proportion of common concrete |
| CN114213074B (en) * | 2022-01-18 | 2023-02-14 | 鞍钢矿山建设有限公司 | Method for calculating mixing proportion of common concrete |
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Application publication date: 20130515 |