CN105254241A - Method for improving anti-penetrability of recycled concrete - Google Patents
Method for improving anti-penetrability of recycled concrete Download PDFInfo
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- CN105254241A CN105254241A CN201510426492.5A CN201510426492A CN105254241A CN 105254241 A CN105254241 A CN 105254241A CN 201510426492 A CN201510426492 A CN 201510426492A CN 105254241 A CN105254241 A CN 105254241A
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Abstract
The invention provides a method for improving anti-penetrability of recycled concrete. The method comprises 1, partly replacing cement in cementing material by fly ash and slag powder, 2, limiting a recycled coarse aggregate replacement rate use range, 3, adding a proper amount of an entraining-type additive into a recycled concrete mixture, and 4, carrying out complete recycled concrete preparation. The method provides appropriate fly ash, ore powder and tea saponin mixing amounts, a recycled coarse aggregate replacement rate and difference of the recycled concrete from common concrete in preparation. The method is used for improving anti-penetrability and endurance performances of recycled concrete and promotes recycled concrete popularization and application.
Description
Technical field
The invention belongs to building construction field of material technology, relate to a kind of method improving regeneration concrete anti-permeability performance.
Background technology
By waste and old concrete through broken, processing, classification and after cooperatively interacting by a certain percentage regeneration aggregate.And utilize regeneration aggregate partly or entirely to substitute the concrete of natural aggregate preparation, be called regenerated aggregate concrete, be called for short regeneration concrete.Regeneration concrete meets the requirement of Sustainable Construction Industry, has huge social economic environment benefit, day by day receives the concern of people.
Chinese scholars got more and more for the research of regeneration concrete in recent years.From microcosmic, the structural rate normal concrete of regeneration concrete wants complicated many, regeneration concrete is made up of three-phase, three kinds of interfaces, and wherein old cement sand bed and three contact surfaces become the weak link of regeneration concrete, affect recycled concrete strength and weather resistance.Large quantity research shows both at home and abroad, and compared with normal concrete, recycled concrete strength is lower, weather resistance is poor and the regeneration concrete workability of premixing is also poor.And study further and show, regeneration concrete can be made to reach the design strength requirement of general concrete by rational mix-design, and also can realize improving the target of regeneration concrete workability by adding admixture.But regenerated coarse aggregate apparent density is little, crush index is high, water-intake rate is high, and its weather resistance is poor, becomes the important factor that restriction regeneration concrete is applied.Regenerated coarse aggregate is the inner microfracture produced in shattering process, the space of the old mortar of regenerated coarse aggregate attachment, and the existence at the old interface of old mortar and aggregate, all can change the pore structure of regeneration concrete inside, increase the porosity of regeneration concrete, thus affect its impermeability.Concrete anti-permeability performance, except being related to the infiltration of moisture and objectionable impurities, also directly affects concrete frost resistance and resistance to fouling etc., and therefore concrete anti-permeability performance is considered to one of important indicator evaluating concrete durability.
Regenerated coarse aggregate is due to the existence of internal void, microfracture etc., prepared regeneration concrete is compared with normal concrete, anti-permeability performance is poor, the direct endurance quality affecting regeneration concrete, and then have impact on the practical application of regeneration concrete, therefore urgently find the method improving regeneration concrete anti-permeability performance.
Summary of the invention
The shortcoming of prior art in view of the above, the object of the present invention is to provide a kind of method improving regeneration concrete anti-permeability performance, for solving the problem lacking in prior art and improve the impervious endurance quality of regeneration concrete.
For achieving the above object and other relevant objects, the invention provides and a kind ofly improve the method for regeneration concrete anti-permeability performance and prepare the process of regeneration concrete.Improve the method for regeneration concrete anti-permeability performance:
1) in gelling material, part of cement is replaced by flyash and slag powders.
Preferably, described gelling material by weight percentage, comprises following component:
Cement 40-65%;
Flyash 15-30%;
Slag powders 20-45%;
Preferred, in gelling material, also alternative mixes silicon ash 5-10%.The total consumption of composite blend must not be greater than 60% of the total consumption of gelling material.
More preferably, described cement is ordinary Portland cement, and more preferably, described ordinary Portland cement strength grade is P.O42.5 or more.
More preferably, described flyash grade is II level or more, and performance is up to state standards the regulation of GBT-1596-2005 " flyash in cement and concrete ".
More preferably, described slag powders grade is S95 or more, and performance is up to state standards the regulation of GB/T18736-2002 " mineral admixture for high-strength high-performance concrete ".
Total consumption of described gelling material and water-cement ratio should be determined by " design of common concrete proportioning code " JGJ55-2011 or test according to joined concrete strength grade.
2) reasonable selection regenerated coarse aggregate replaces the ratio of natural coarse aggregate
Preferably, the mass ratio that adds of described natural coarse aggregate and regenerated coarse aggregate is: 2:3-7:3, and namely the Replacement rate of regenerated coarse aggregate is: 30-60%(m/m).Described regeneration aggregate Replacement rate refers to ratio regeneration aggregate partly or entirely being replaced natural aggregate.
More preferably, the mass ratio that adds of described natural coarse aggregate and regenerated coarse aggregate is: 1:1, and namely recycled coarse aggregate contents is 50%(m/m).
3) in regeneration concrete, appropriate research work of air entrained type admixture is mixed.
Preferably, described air entrapment agent is tea saponin.Described tea saponin is by the class candy glucoside compound extracted in tea tree seed.More preferably, described tea saponin volume is the 0.01-0.05%(m/m that described gelling material adds quality).
Most preferably, described tea saponin volume is the 0.03%(m/m that described gelling material adds quality).
Prepare the process of regeneration concrete:
1) successively take described gelling material and fine aggregate to be above uniformly mixed, then add natural coarse aggregate and regenerated coarse aggregate continues to stir, mix, obtain siccative;
Preferably, described fine aggregate is natural yellow ground.Sand coarse aggregate ratio is determined according to " design of common concrete proportioning code " JGJ55-2011, and increases by 3% on the basis of normal concrete sand coarse aggregate ratio.
Preferably, described natural coarse aggregate is natural rubble.
Preferably, described regenerated coarse aggregate refers to by waste and old concrete after processing, fragmentation, classification, the regeneration aggregate be mixed to form by a certain percentage.Regenerated coarse aggregate water-intake rate is high, available additional water preabsorption process or stir time additional water is directly added in mixing water.
Described whipping process should meet the regulation of " concrete structure engineering job specifications " GB506666-2011.
2) take above-mentioned air entrapment agent (tea saponin) and mixing water respectively, mix, obtain the first mixed solution;
It is tea saponin is directly dissolved in mixing water or first tea saponin is made into the aqueous solution adding in mixing water that described air entrapment agent (tea saponin) mixes with mixing water again.
Preferably, described mixing water is tap water, and mixing water consumption is determined by joined concrete water-cement ratio.
Described hybrid mode is for be manually stirred to dissolution homogeneity.
3) water reducer is added step 2) in the first mixed solution, be uniformly mixed, obtain the second mixed solution;
Preferably, described water reducer is non-air-entraining water-reducing agent, and more preferably, described non-air-entraining water-reducing agent is naphthalene water reducer.Main component is β base naphthalenesulfonate formaldehyde condensation compound.Water reducer volume is required to determine by water reducer diminishing efficiency and the slump.
4) add in step 1) obtain in siccative by obtaining the second mixed solution in step 3), after stirring, the regeneration concrete of better anti-permeability performance must be had.
The proportionlity of described second mixed solution and described siccative is determined according to joined concrete water-cement ratio.
Described whipping process should meet the regulation of " concrete structure engineering job specifications " GB506666-2011.
The present invention still further provides the application example of above-mentioned raising regeneration concrete impermeability and preparation method thereof in regeneration concrete.
As mentioned above, the invention provides and a kind ofly improve the method for regeneration concrete impermeability and the preparation process of corresponding regeneration concrete.By adding a certain proportion of flyash and breeze (silicon ash), reasonable selection recycled coarse aggregate contents, and add tea saponin in regeneration concrete, thus improve the anti-permeability performance of regeneration concrete, improve the weather resistance of regeneration concrete.
Give the volume of suitable flyash, breeze, silicon ash and tea saponin in the present invention, also proposed rational recycled coarse aggregate contents, finally give the preparation method of regeneration concrete involved in the present invention.The method proposed is easy to realize, and exploitativeness is strong, effectively can improve the impervious endurance quality of regeneration concrete, is the important ring promoting regeneration concrete engineer applied.
The chemical composition of flyash, breeze and silicon ash all contains a large amount of active SiO
2and Al
2o
3, in a humid environment can with Ca (OH)
2deng alkaline matter generation chemical reaction, generate the gum material such as hydrated calcium silicate, drated calcium aluminate, these resultant intensity are high, compactness good, be distributed in Behavior of Hardened Cement Paste, can the open pore of micropore in filling concrete stone, the compactness improving maturing, blocking, can increase again Behavior of Hardened Cement Paste with thickness gather materials boundary and cohesive force, thus improve concrete impermeability.Mix flyash and breeze in addition in concrete and replace part of cement or part sand, due to flyash and breeze particle diameter little compared with cement, be filled in cement granules, improve raw-material mechanical fraction, also concrete microporosity is reduced, improve the density of concrete structure, improve concrete permeability resistance.
Regenerated coarse aggregate internal injury causes the generation of microfracture, becomes the penetrating passage in regeneration concrete, affects the anti-permeability performance of regeneration concrete.Simultaneously regenerated coarse aggregate mechanical property is not as natural aggregate, the increase of regenerated coarse aggregate volume, all can cause disadvantageous effect, therefore need to limit the volume of regenerated coarse aggregate to the anti-permeability performance of regeneration concrete and intensity.Research shows when the Replacement rate of regenerated coarse aggregate is at 30%-60%, and the mechanical property of regeneration concrete and endurance quality are comparatively well and can utilize regenerated coarse aggregate comparatively fully thus reach certain economic benefits.Especially, when volume is 50%, because the absorb water water cement ratio that causes of regenerated coarse aggregate reduces the disadvantageous effect that compensate for regenerated coarse aggregate defect and cause, part achievement in research shows that the mechanical property of now regeneration concrete there is no obvious reduction compared with normal concrete.Because the regenerated coarse aggregate ubiquity grating of current production line output is not good, the problem that large-particle-size aggregate is more, mixes with natural aggregate 1:1 the effect can played and improve gradation of coarse aggregate when volume is 50% mutually, produces Beneficial Effect to the performance of regenerated coarse aggregate.
Air entrapment agent, as one of the most ancient admixture, is generally applied in concrete antifreezing engineering.In addition air entrapment agent also can play a significant role in raising agent on crack resistance of concrete perviousness.Air entrapment agent introduces a large amount of even, stable and closed micro-bubble in concrete-agitating process, these small stable bubbles add slurry volume and produce lubrication to mixed material as balls and concrete workability is improved, and slow down the reduction of concrete work performance; These micro-bubbles change concrete pore structure system simultaneously, enclose many capillary porosity ducts, thus substantially increase concrete anti-permeability performance.Therefore adding air entrapment agent at regeneration concrete is also the important method greatly improving regeneration concrete anti-permeability performance.
Particularly, select tea saponin as air entrapment agent in the present invention, it has good bleed performance, and tiny, stable, the well-formed of bleed bubble, loss of strength is little, water-soluble extremely strong.When tea saponin volume is the 0.02-0.04% of gelling material quality in concrete, the relative permeate property coefficient reduction of regeneration concrete is about 36-60%, anti-permeability performance is improved largely, and recycled concrete strength reduction is about 12-19%, the water-cement ratio of adjustable regeneration concrete is to make up the loss of intensity.Increase with recycled coarse aggregate contents, regeneration concrete anti-permeability performance and intensity all decrease, and suitably can increase tea saponin volume and correspondingly adjust water-cement ratio.Adding preferred air entrapment agent tea saponin, can effectively improve concrete pore structure, is significantly one of technical measures improving concrete durability.
Accompanying drawing explanation
Fig. 1 is shown as the air content of regeneration concrete in the present invention and relation schematic diagram 1a, 1b of anti-permeability performance and air entrapment agent volume.Wherein, 1a is the relation of 100% Replacement rate regeneration concrete air content and air entrapment agent volume; 1b is the relation of 100% Replacement rate regeneration concrete anti-permeability performance and air entrapment agent volume.
Fig. 2 is shown as the air content of regeneration concrete in the present invention and relation schematic diagram 2a, 2b of anti-permeability performance and recycled coarse aggregate contents.Wherein, the relation of regeneration concrete air content and recycled coarse aggregate contents when 2a is 0.02% air entrapment agent volume; The relation of regeneration concrete anti-permeability performance and recycled coarse aggregate contents when 2b is 0.02% air entrapment agent volume.
Fig. 3 is shown as the ultimate compression strength of regeneration concrete in the present invention and relation schematic diagram 3a, 3b of air entrapment agent volume and recycled coarse aggregate contents.Wherein, 3a is ultimate compression strength-air entrapment agent volume relation schematic diagram; 3b is ultimate compression strength-Replacement rate relation schematic diagram.
Embodiment
Set forth the present invention further below in conjunction with specific embodiment, should be understood that these embodiments are only not used in for illustration of the present invention and limit the scope of the invention.
Below by way of specific specific examples, embodiments of the present invention are described, those skilled in the art the content disclosed by this specification sheets can understand other advantages of the present invention and effect easily.The present invention can also be implemented or be applied by embodiments different in addition, and the every details in this specification sheets also can based on different viewpoints and application, carries out various modification or change not deviating under spirit of the present invention.
The starting material used in following examples and mix-design as follows:
1, starting material
1.1 cement: P.O42.5 ordinary Portland cement.
1.2 flyash: II level flyash.
1.3 slag powders: S95 slag powders.
1.4 fine aggregates: common natural yellow ground, specification is middle particle diameter sand, and fineness modulus controls at 2.3-3.0.
1.5 natural coarse aggregate: natural rubble, particle diameter is not more than 25mm.
1.6 regenerated coarse aggregates: new broken waste and old concrete, particle diameter is 5-25mm.
1.7 mixing waters: tap water.
1.8 air entrapment agents: tea saponin.
1.9 water reducers: naphthalene water reducer or other non-research work of air entrained type high efficiency water reducing agents.
2, mix-design
Formed by reasonable selection gelling material in the present invention, recycled coarse aggregate contents, rational air entrapment agent volume thus effectively improve the anti-permeability performance of regeneration concrete.
2.1 gelling material and water cement ratio
Gelling material, by weight percentage, gets cement 40-65%, flyash 15-30%, slag powders 20-45% respectively, and alternative interpolation silicon ash 5%-10%, wherein the total consumption of composite blend is not more than 60% of the total consumption of gelling material.Water-cement ratio is determined according to " design of common concrete proportioning code " JGJ55-2011 and engineering experience.The water-cement ratio of regeneration concrete can reduce 0.01-0.02 on the basis of normal concrete or test is determined.
2.2 sand coarse aggregate ratio
Regeneration concrete fine aggregate should select natural yellow ground.Regenerated coarse aggregate surface is coarse compared with natural rubble, and regenerated coarse aggregate apparent density is little, and when replacing etc. quality, coarse aggregate volume increases, and the value of sand coarse aggregate ratio should suitably increase, especially for high slump, and the regeneration concrete of high workload performance.First determine normal concrete sand coarse aggregate ratio according to " design of common concrete proportioning code " JGJ55-2011 during concrete enforcement, add that 3% as the sand coarse aggregate ratio of regeneration concrete on this basis.
2.3 regenerated coarse aggregate volumes
The Replacement rate of regenerated coarse aggregate should be taken as 30-60%(m/m).Best Replacement rate is 50%(m/m).
2.4 air entrapment agent consumptions
Select tea saponin as preferred air entrapment agent, volume should get the 0.01-0.05%(m/m of gelling material quality).
Embodiment 1
Preparation C30 regeneration concrete, the slump is (180 ± 20) mm.For research recycled coarse aggregate contents and air entrapment agent volume are on the impact of regeneration concrete anti-permeability performance, by waiting water cement ratio design.
First take gelling material, selecting gelling material gross weight from " design of common concrete proportioning code " JGJ55-2011 is 400kg/m
3, water-cement ratio is 0.44.By weight percentage, flyash 20%, slag powders 35%, cement 45% is got respectively.Gelling material is added in concrete mixer and is uniformly mixed.Take natural yellow ground again, from " design of common concrete proportioning code " JGJ55-2011, determine that normal concrete sand coarse aggregate ratio is 42%, increase by 3% and determine that sand coarse aggregate ratio is 45%.Again natural yellow ground is added in concrete mixer, mix with gelling material, stir.Then, then natural coarse aggregate is added in concrete mixer from regenerated coarse aggregate by the mass ratio of the different Replacement rate designed, continue to stir, mix with gelling material, natural yellow ground, obtain siccative.Wherein, the particle diameter of natural coarse aggregate is not more than 25mm; The particle diameter of regenerated coarse aggregate is 5-25mm, through additional water preabsorption process.
Take after tea saponin mixes with mixing water, add water reducer, be made into mixed solution.
Finally, mixed solution to be added in siccative and to stir.The regulation of agitation condition meets " concrete structure engineering job specifications " GB506666-2011, mixing time: 2.5 minutes.
Embodiment 2
Research air entrapment agent volume is on the impact of regeneration concrete anti-permeability performance.Prepare regeneration concrete according to the method steps in embodiment 1, selected tea saponin volume is respectively 0%, 0.02% and 0.04%, and selected tea saponin volume is 100%.
Proportioning is in table 1, and tea saponin volume is the ratio of tea saponin powder and gelling material quality.(wherein RC is regeneration concrete, and in numbering, the 2nd is tea saponin volume, and last position is recycled coarse aggregate contents).
Table 1 concrete mix
| Concrete is numbered | Water | Additional water | Cement | Yellow ground | Natural aggregate | Regeneration aggregate | Flyash | Breeze | Water reducer | Air entrapment agent volume (%) |
| RC-0-100 | 176 | 14.6 | 180 | 797 | 0 | 974 | 80 | 140 | 6.4 | 0 |
| RC-0.02-100 | 176 | 14.6 | 180 | 797 | 0 | 974 | 80 | 140 | 6.4 | 0.02 |
| RC-0.04-100 | 176 | 14.6 | 180 | 797 | 0 | 974 | 80 | 140 | 6.4 | 0.04 |
Embodiment 3
By regeneration concrete prepared by proportioning as shown in table 2 in above-described embodiment 2, measure initial air content and by permeated height method, its anti-permeability performance measured according to " normal concrete long-term behaviour and endurance quality test " GB50082-2009.
The detailed process of carrying out the test of anti-permeability performance by permeated height method is: adopt end face diameter to be 175mm, basal diameter is 185mm, and height is the round platform test specimen of 150mm, often group 6 test specimens, and test specimen length of time is 28d.Testing installation is HS-40 type concrete penetrometer.Adopt a pressurization, to rive after constant voltage (1.6MPa) 24h test specimen, test is on average seeped water highly: using the permeated height mean value of equidistant 10 points of each test specimen as the permeated height of this test specimen, then using the mean value of 6 test specimen permeated heights as test result.In constant voltage process, as infiltration appears in test specimen end face, then stop pressurizeing and recording water discharging time.
Relative coefficient of permeability is the parameter characterizing a certain particular fluid ability of concrete conduction itself, and its size and inside concrete hole, pore texture are relevant with this fluid viscosity, and this paper can evaluate the infiltration ability of regeneration concrete with relative coefficient of permeability.The process calculating relative coefficient of permeability according to testing data is:
In formula: k is relative coefficient of permeability (m/s);
for the water-intake rate of regeneration concrete, normal concrete generally gets 0.03, is taken as 0.05 herein through actual measurement;
H is the height (m) that on average seeps water;
T is the duration (s) of constant voltage;
H is the hydraulic pressure (m) represented with water colunm height, and 1.6Mp is equivalent to the hydraulic pressure of 163.3m water colunm height.
Table 2 test-results
1, anti-permeability performance test result
Concrete air content has material impact to concrete impermeability, there are some researches show in concrete that the air content introducing 4% can make concrete impermeability improve about more than 15%.Improving air entrapment agent volume is the most direct method improving regeneration concrete air content.Fig. 1 indicates when recycled coarse aggregate contents is 100%, and regeneration concrete air content and perviousness are with the Changing Pattern of air entrapment agent volume.From Fig. 1 (a), under identical Replacement rate, be the scope of 0-0.04% at air entrapment agent volume, regeneration concrete air content increases with the increase of air entrapment agent volume.And along with the increase of volume, permeated height and the relative coefficient of permeability of regeneration concrete all reduce (Fig. 1 (b)), show that the ability of regeneration concrete opposing water molecules infiltration strengthens.
The research of this example finds within the scope of the air entrapment agent volume of 0-0.04%, and the anti-permeability performance of regeneration concrete improves with the increase of air entrapment agent volume, but the volume of air entrapment agent should be restricted and can not arbitrarily increase.There are some researches show, cause concrete 's air-containing excessive when air entrapment agent volume is excessive, the part bubble in concrete be combined with each other and throughly becomes penetrating passage, and concrete impermeability is reduced; Air entrapment agent can cause concrete degree of compactness to reduce to cause intensity to reduce simultaneously, reduces more obvious when particularly air content is very large.Therefore in regeneration concrete, use the volume should determining during air entrapment agent to be suitable for.
2, strength test results
Induce one in concrete a large amount of micro-bubble, improves concrete workability, impermeability, but also bring negative impact to concrete performance.Show that the existence of a large amount of bubble reduces concrete density, cause the reduction of concrete crushing strength, special bubble structure of working as is poor, and when there is more polymerization bubble and special-shaped bubble, its loss of strength is more remarkable.
By Fig. 3 (a), 100% Replacement rate recycled concrete strength increases with air entrapment agent volume and obviously reduces.24.5%, 30.2% is reduced respectively during 7d under 0.02% and 0.04% volume.12.5%, 19.2% is reduced respectively during 28d.Therefore the consumption of air entrapment agent blindly can not be increased in order to improve concrete 's air-containing.The suggestion volume scope that the present invention provides is 0.01%-0.05%, within the scope of this anti-permeability performance of regeneration concrete and intensity all comparatively suitable.Test can also find that the early age strength of concrete development of mixing air entrapment agent is not as mixing the concrete of air entrapment agent, and later strength development is very fast.Reason is that a large amount of bubbles that air entrapment agent is introduced are conducive to the maintenance of regeneration concrete workability, plays certain delayed coagulation, makes the strength development in early stage slower.
Embodiment 4
Research recycled coarse aggregate contents is on the impact of regeneration concrete anti-permeability performance.Prepare regeneration concrete according to the method steps in embodiment 1, selected recycled coarse aggregate contents is respectively 0%, 50%, 70% and 100%, and selected tea saponin volume is 0.02%.
Proportioning in Table 3(wherein RC be regeneration concrete, in numbering, the 2nd is tea saponin volume, and last position is recycled coarse aggregate contents).
Table 3 concrete mix
Embodiment 5
By regeneration concrete prepared by proportioning as shown in table 3 in above-described embodiment 4, measure initial air content and anti-permeability performance, process of the test is with embodiment 3.
Table 4 test-results
1, anti-permeability performance test result
Concrete air content has material impact to concrete impermeability, there are some researches show in concrete that the air content introducing 4% can make concrete impermeability improve about more than 15%.The initial air content of blank group of supplementing under 0%, 50% and 70% recycled coarse aggregate contents is respectively 0.8%, 1.0% and 0.9%.Can be found by the content measurement result of Fig. 2 (a) blank group, along with the increase of recycled coarse aggregate contents, concrete air content increases to some extent, reason is that the porosity of regeneration aggregate is larger, and also containing residual bubble in the old mortar of regeneration aggregate surface attachment, therefore the content measurement value of regeneration concrete is slightly higher than normal concrete, and increases along with the increase of recycled coarse aggregate contents.But can also find from Fig. 2 (a), in concrete, add volume is after the air entrapment agent of 0.02%, concrete air content significantly improves, but along with the increase of recycled coarse aggregate contents, the air content of regeneration concrete reduces on the contrary, illustrates that air entrapment agent can be introduced a large amount of bubble but decline along with the bleed ability of the increase air entrapment agent of recycled coarse aggregate contents in concrete.This is because the porosity of regeneration aggregate is large, a part is dispersed in air entrapment agent molecular adsorption in mixing water in the process absorbing moisture in mortar in hole, the air entrapment agent composition effectively playing bleed effect is reduced, reduce bleed ability in mortar.
By the known increase with recycled coarse aggregate contents of Fig. 2 (b), permeated height and the relative coefficient of permeability of regeneration concrete all increase, show that the anti-permeability performance of regeneration concrete reduces, this and regeneration concrete air content are consistent with the rule that recycled coarse aggregate contents changes.
But for regeneration concrete, concrete 's air-containing and impermeability are not on all four relations.As shown in Table 3, the initial air content of RC-0.04-100 test group is 2.8%, has exceeded 2.7% of RC-0.02-0 test group in table 5 and 2.4% of RC-0.02-50 test group, but its permeated height be greater than on the contrary after both.This is that these microfractures become the penetrating passage of regeneration concrete, are unfavorable for the anti-permeability performance of regeneration concrete on the contrary because the air content of regeneration concrete further comprises the holes such as the microfracture that regenerated coarse aggregate internal injury causes.Therefore, under identical air content, the anti-permeability performance of regeneration concrete will lower than normal concrete.
2, strength test results
The blank group 7d intensity of supplementing under 0%, 50% and 70% Replacement rate is respectively 32.1MPa, 31.9MPa and 31.4MPa, and 28d intensity is respectively 45.3MPa, 44.4MPa and 41.1MPa.
From Fig. 3 (b), recycled concrete strength reduces along with the increase of recycled coarse aggregate contents generally, compared with normal concrete, on average reduces by 8.8%, 19.0% under 70% and 100% Replacement rate during 7d.8.9%, 10.2% is on average reduced during 28d.This and existing research are more consistent.And concrete strength does not obviously reduce when 50% Replacement rate, think it may is that now more excellent the and regenerated coarse aggregate of grading of aggregate continues to absorb water the result causing water cement ratio relatively to reduce acting in conjunction to cause.According to anti-permeability performance and strength test results, the suggested range of the recycled coarse aggregate contents that the present invention provides is 30%-60%, and within the scope of this, regeneration concrete anti-permeability performance and the intensity amplitude of reduction compared with normal concrete is less.
Each group of concrete impermeability in embodiment 2 and embodiment 4 is scaled the seepage-resistant grade that specification adopts, result shows that each group of concrete seepage-resistant grade is all more than P15.Result shows that the regeneration concrete prepared by the present invention has very good anti-permeability performance.
In sum, the invention discloses a kind of method improving regeneration concrete impermeability.The problem that the anti-permeability performance that the present invention can be used for facing in solution regeneration concrete engineer applied is not good, improves the endurance quality of regeneration concrete.By for solving the environmental problem that building waste causes, promoting the sustainable use of resource, promoting that the Commercialization application of regeneration concrete makes significant contribution.There is larger environmental benefit, economic benefit and social benefit.So the present invention effectively overcomes various shortcoming of the prior art and tool high industrial utilization.
Above-described embodiment is illustrative principle of the present invention and effect thereof only, but not for limiting the present invention.Any person skilled in the art scholar all without prejudice under spirit of the present invention and category, can modify above-described embodiment or changes.Therefore, such as have in art usually know the knowledgeable do not depart from complete under disclosed spirit and technological thought all equivalence modify or change, must be contained by claim of the present invention.
Claims (8)
1. improve a method for regeneration concrete impermeability, comprise with lower part:
1) in gelling material, part of cement is replaced by flyash and slag powders;
2) reasonable selection regenerated coarse aggregate replaces the ratio of natural coarse aggregate;
3) in regeneration concrete mixture, appropriate air entrapment agent is added;
4) complete regeneration concrete preparation process.
2. a kind of method improving regeneration concrete impermeability according to claim 1, is characterized in that, described gelling material by weight percentage, comprises following component:
Cement 40-65%;
Flyash 15-30%;
Slag powders 20-45%;
3. a kind of method improving regeneration concrete impermeability according to claim 2, is characterized in that, described cement is ordinary Portland cement, and strength grade is P.O42.5 or more; Described flyash grade is II level or more; Described slag powders is S95 or more grade.
4. a kind of method improving regeneration concrete impermeability according to claim 1, is characterized in that, the Replacement rate of described regenerated coarse aggregate is: 30-60%.
5. a kind of method improving regeneration concrete impermeability according to claim 1, is characterized in that, described air entrapment agent is tea saponin, and volume is the 0.01-0.05% of gelling material quality.
6. a kind of method improving regeneration concrete impermeability according to claim 1, is characterized in that, in described regeneration concrete preparation process, sand coarse aggregate ratio is that corresponding normal concrete sand coarse aggregate ratio adds 3%.
7. a high permeability resistant energy regeneration concrete, obtains according to the arbitrary described a kind of preparation method of claim 1-7.
8. preparing the purposes in high permeability resistant energy regeneration concrete according to the arbitrary a kind of described method improving regeneration concrete impermeability of claim 1-7.
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Cited By (8)
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| CN106747125A (en) * | 2017-02-20 | 2017-05-31 | 内蒙古科技大学 | A kind of concrete of anti-sulfur dioxide corrosion |
| CN108218313A (en) * | 2017-12-29 | 2018-06-29 | 上海建工集团股份有限公司 | A kind of regeneration concrete of recycled aggregate Replacement rate 100% |
| CN108623266A (en) * | 2018-08-13 | 2018-10-09 | 武汉华强新型建筑材料有限公司 | Recycled concrete and production process thereof |
| CN109020317A (en) * | 2018-08-14 | 2018-12-18 | 顺裕（龙岩）混凝土有限公司 | A kind of regeneration concrete preparation method that impermeability is strong |
| CN109626855A (en) * | 2019-02-18 | 2019-04-16 | 蒋文昌 | A kind of application method of Tea Saponin in concrete |
| CN111689738A (en) * | 2020-07-01 | 2020-09-22 | 台州四强新型建材有限公司 | Environment-friendly recycled concrete and preparation process thereof |
| CN112521084A (en) * | 2020-11-17 | 2021-03-19 | 合肥水泥研究设计院有限公司 | Recycled concrete with high interface bonding performance and preparation method thereof |
| CN112811866A (en) * | 2021-01-15 | 2021-05-18 | 深圳市宝金华混凝土有限公司 | Recycled aggregate concrete and preparation method thereof |
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| CN1594183A (en) * | 2004-07-16 | 2005-03-16 | 张志峰 | Multifunctional heat insulating plaster |
| CN103102118A (en) * | 2013-03-12 | 2013-05-15 | 三明学院 | Full-machine-made sand recycled concrete batching and prefabricated shield tunnel segment thereof |
| CN104140229A (en) * | 2014-07-07 | 2014-11-12 | 南昌大学 | Shrinkage-compensating recycled concrete and preparation method thereof |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106747125A (en) * | 2017-02-20 | 2017-05-31 | 内蒙古科技大学 | A kind of concrete of anti-sulfur dioxide corrosion |
| CN108218313A (en) * | 2017-12-29 | 2018-06-29 | 上海建工集团股份有限公司 | A kind of regeneration concrete of recycled aggregate Replacement rate 100% |
| CN108623266A (en) * | 2018-08-13 | 2018-10-09 | 武汉华强新型建筑材料有限公司 | Recycled concrete and production process thereof |
| CN109020317A (en) * | 2018-08-14 | 2018-12-18 | 顺裕（龙岩）混凝土有限公司 | A kind of regeneration concrete preparation method that impermeability is strong |
| CN109626855A (en) * | 2019-02-18 | 2019-04-16 | 蒋文昌 | A kind of application method of Tea Saponin in concrete |
| CN111689738A (en) * | 2020-07-01 | 2020-09-22 | 台州四强新型建材有限公司 | Environment-friendly recycled concrete and preparation process thereof |
| CN112521084A (en) * | 2020-11-17 | 2021-03-19 | 合肥水泥研究设计院有限公司 | Recycled concrete with high interface bonding performance and preparation method thereof |
| CN112811866A (en) * | 2021-01-15 | 2021-05-18 | 深圳市宝金华混凝土有限公司 | Recycled aggregate concrete and preparation method thereof |
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Application publication date: 20160120 |