CN112500061B - High-strength recycled concrete and preparation method thereof - Google Patents
High-strength recycled concrete and preparation method thereof Download PDFInfo
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- CN112500061B CN112500061B CN202011544780.8A CN202011544780A CN112500061B CN 112500061 B CN112500061 B CN 112500061B CN 202011544780 A CN202011544780 A CN 202011544780A CN 112500061 B CN112500061 B CN 112500061B
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- 239000004567 concrete Substances 0.000 title claims abstract description 89
- 238000002360 preparation method Methods 0.000 title claims abstract description 43
- 239000003607 modifier Substances 0.000 claims abstract description 51
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 45
- 239000000463 material Substances 0.000 claims abstract description 30
- 239000004568 cement Substances 0.000 claims abstract description 27
- 238000003756 stirring Methods 0.000 claims abstract description 21
- 238000002156 mixing Methods 0.000 claims abstract description 19
- 239000000945 filler Substances 0.000 claims abstract description 15
- 238000005303 weighing Methods 0.000 claims abstract description 15
- 239000002994 raw material Substances 0.000 claims abstract description 9
- 239000000654 additive Substances 0.000 claims abstract description 5
- 230000000996 additive effect Effects 0.000 claims abstract description 5
- 239000003292 glue Substances 0.000 claims abstract description 3
- LIOBPVZSSVYQSS-UHFFFAOYSA-N 2-(3,4-diaminophenyl)acetic acid Chemical compound NC1=CC=C(CC(O)=O)C=C1N LIOBPVZSSVYQSS-UHFFFAOYSA-N 0.000 claims description 40
- 238000002791 soaking Methods 0.000 claims description 25
- 238000000227 grinding Methods 0.000 claims description 18
- 239000003795 chemical substances by application Substances 0.000 claims description 16
- 239000002699 waste material Substances 0.000 claims description 13
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims description 12
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 claims description 12
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 claims description 10
- WDIHJSXYQDMJHN-UHFFFAOYSA-L barium chloride Chemical compound [Cl-].[Cl-].[Ba+2] WDIHJSXYQDMJHN-UHFFFAOYSA-L 0.000 claims description 10
- 229910001626 barium chloride Inorganic materials 0.000 claims description 10
- 239000012744 reinforcing agent Substances 0.000 claims description 10
- 229910052938 sodium sulfate Inorganic materials 0.000 claims description 10
- 235000011152 sodium sulphate Nutrition 0.000 claims description 10
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 claims description 9
- 230000004048 modification Effects 0.000 claims description 9
- 238000012986 modification Methods 0.000 claims description 9
- 239000004816 latex Substances 0.000 claims description 8
- 229920000126 latex Polymers 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 8
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 7
- 239000002893 slag Substances 0.000 claims description 7
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims description 6
- 229910001870 ammonium persulfate Inorganic materials 0.000 claims description 6
- 238000004140 cleaning Methods 0.000 claims description 6
- 239000003822 epoxy resin Substances 0.000 claims description 6
- 239000010881 fly ash Substances 0.000 claims description 6
- 229920000647 polyepoxide Polymers 0.000 claims description 6
- 238000012216 screening Methods 0.000 claims description 5
- 239000000843 powder Substances 0.000 claims description 4
- 239000002202 Polyethylene glycol Substances 0.000 claims description 3
- 238000001035 drying Methods 0.000 claims description 3
- 239000002245 particle Substances 0.000 claims description 3
- 229920001223 polyethylene glycol Polymers 0.000 claims description 3
- 238000005406 washing Methods 0.000 claims description 3
- 239000010883 coal ash Substances 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims 1
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 abstract description 35
- 238000005260 corrosion Methods 0.000 abstract description 20
- 230000007797 corrosion Effects 0.000 abstract description 20
- 230000000694 effects Effects 0.000 abstract description 9
- 150000003839 salts Chemical class 0.000 abstract description 2
- 229910001422 barium ion Inorganic materials 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 9
- 238000012360 testing method Methods 0.000 description 9
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- 239000007864 aqueous solution Substances 0.000 description 6
- 239000002002 slurry Substances 0.000 description 6
- 238000003776 cleavage reaction Methods 0.000 description 5
- 230000007017 scission Effects 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- 230000009471 action Effects 0.000 description 4
- 238000004513 sizing Methods 0.000 description 4
- 238000001179 sorption measurement Methods 0.000 description 4
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 3
- 239000004566 building material Substances 0.000 description 3
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000003014 reinforcing effect Effects 0.000 description 3
- 239000004576 sand Substances 0.000 description 3
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000000536 complexating effect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 125000000623 heterocyclic group Chemical group 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 125000001841 imino group Chemical group [H]N=* 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 239000004571 lime Substances 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 238000002715 modification method Methods 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 description 1
- -1 salt barium sulfate Chemical class 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
-
- 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
- C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
- C04B2201/50—Mortars, concrete or artificial stone characterised by specific physical values for the mechanical strength
Abstract
The application relates to the field of concrete, in particular to high-strength recycled concrete and a preparation method thereof, wherein the high-strength recycled concrete is prepared from the following raw materials in parts by weight: cement, water, a filler, coarse aggregates, fine aggregates, modified recycled aggregates and an additive. A preparation method of high-strength recycled concrete comprises the following steps: s1, weighing cement and water, and stirring and mixing uniformly to obtain a cement glue material; s2, weighing the filler, the coarse aggregate, the fine aggregate, the modified recycled aggregate and the admixture, and uniformly stirring and mixing to obtain the high-strength recycled concrete. The strength and the corrosion resistance of the recycled concrete are improved by modifying the recycled aggregate. The recycled aggregate is irradiated by ultraviolet light, so that barium sulfate is closely attached to the surface of the recycled aggregate, and the strength and the corrosion resistance of recycled concrete are further improved. The pH value of the modifier B is 4-5, so that the salt forming effect of barium sulfate is better, and the compactness of the recycled aggregate is improved.
Description
Technical Field
The present application relates to the field of concrete, and more particularly, it relates to a high strength recycled concrete and a method for preparing the same.
Background
The concrete is a building material which is widely applied in modern times, and has the advantages of rich raw materials, low price, simple process, high strength, good durability and the like.
The regenerated concrete is prepared by crushing, cleaning and grading waste concrete blocks, mixing the crushed, cleaned and graded waste concrete blocks with a grading agent according to a certain proportion, partially or completely replacing natural aggregates such as sand stones and the like, and adding cement, water and the like.
However, in the process of crushing the waste concrete blocks, due to the action of mechanical external force, a large number of fine cracks are easy to appear in the concrete blocks, so that the porosity of the concrete blocks is increased, and the prepared recycled concrete has poor compactness and poor strength.
Therefore, the waste concrete blocks are often modified, and the common modification method is to fill the holes and cracks in the concrete blocks by adding the reinforcing components (lime powder, fly ash and the like) in the slurry by soaking the concrete blocks into the slurry, so as to achieve the effect of improving the strength of the waste concrete blocks. However, the slurry is mixed with one or more reinforcing components, so that the consistency of the slurry is high, the surface tension of the slurry is high, the slurry is difficult to permeate and fill in tiny pores or gaps in concrete blocks, the reinforcing effect of the waste concrete is poor, and the strength of the recycled concrete is poor.
Disclosure of Invention
In order to improve the strength of the recycled concrete, the application provides high-strength recycled concrete and a preparation method thereof.
In a first aspect, the present application provides a high strength recycled concrete, which adopts the following technical scheme:
the high-strength recycled concrete and the preparation method thereof are characterized by being prepared from the following raw materials in parts by weight:
cement 450-;
140 portions of water and 160 portions of water;
100 portions and 120 portions of filling agent;
400 portions of coarse aggregate and 500 portions of coarse aggregate;
500 portions and 600 portions of fine aggregate;
400 portions of modified recycled aggregate and 500 portions of modified recycled aggregate;
12-16 parts of an additive;
the preparation method of the modified recycled aggregate comprises the following steps:
s1, preparation of recycled aggregate: crushing, screening and cleaning the waste concrete blocks to obtain recycled aggregate;
s2, modification of recycled aggregate:
s21, soaking the recycled aggregate obtained in the step S1 in a modifier A, taking out and airing to obtain a modifier A, wherein the modifier A comprises nano poly-3, 4-diaminophenylacetic acid and water, and the weight ratio of the nano poly-3, 4-diaminophenylacetic acid: water =1 (7-8);
s22, soaking the modified material A in a modified agent B, taking out and airing to obtain a modified material B, wherein the modified agent B comprises barium chloride and water, and the weight ratio of the barium chloride: water =1 (4-6);
s23, soaking the modified material B in a modifying agent C, taking out and airing, and preparing to obtain a modified material C, namely the recycled aggregate, wherein the modifying agent C comprises sodium sulfate and water, and the weight ratio of the sodium sulfate: water =1 (4-6).
By adopting the technical scheme, the cement is a sizing material of the concrete, and the coarse aggregate, the fine aggregate and the recycled aggregate are frameworks which play a supporting role in the concrete.
The modified recycled aggregate is prepared from waste concrete blocks, so that the generation of building wastes is reduced, and the environment is improved. After the recycled aggregate is soaked by the modifier A, a layer of nano poly-3, 4-diaminophenylacetic acid is attached to the surface of the recycled aggregate, and poly-diaminobenzene is usually used as an adsorption material and has better adsorption capacity on metal ions. The poly-3, 4-diamino phenylacetic acid is obtained by introducing carboxyl into poly-diamino benzene, and the carboxyl is combined with the surface of the recycled aggregate, so that the nano-scale poly-3, 4-diamino phenylacetic acid is attached to the surface of the recycled aggregate.
Soaking the barium sulfate in modifier B to make nano poly-3, 4-diamino phenylacetic acid adsorb barium ions in modifier B, and soaking in modifier C to make the barium ions and sulfate ions in modifier C generate insoluble salt barium sulfate. The modifier B and the modifier C are both solutions which are uniform and stable dispersion systems, and the solutions have lower surface tension, so that the recycled aggregate can be fully soaked. The recycled aggregate is reinforced in a solution salifying mode, so that the barium sulfate can fill tiny holes and cracks in the recycled aggregate, the compactness of the internal structure of the recycled concrete is obviously improved, and the strength of the recycled concrete is improved. The barium sulfate is stable, insoluble in water and good in corrosion resistance, so that the corrosion resistance of the recycled concrete is improved.
Optionally, in S1 of the preparation method of the recycled aggregate, the obtained recycled aggregate is irradiated with ultraviolet light.
By adopting the technical scheme, after the surface of the recycled aggregate is irradiated by ultraviolet light, the number of active groups on the surface of the recycled aggregate is increased, and the bonding rate of carboxyl groups in the poly-3, 4-diaminophenylacetic acid and the active groups on the surface of the poly-3, 4-diaminophenylacetic acid is increased, so that the adhesion area and the adhesion compactness of the nano-scale poly-3, 4-diaminophenylacetic acid on the recycled aggregate are increased, barium sulfate is uniformly and compactly adhered to the surface of the recycled aggregate, the strength of the recycled aggregate is increased, and the strength and the corrosion resistance of recycled concrete are further improved.
Optionally, the preparation method of the modified recycled aggregate further comprises the following steps of S3, and S3: and soaking the modified material C in the epoxy resin latex, taking out and airing to obtain the modified recycled aggregate.
According to the technical scheme, the modified material C is further reinforced by adopting the epoxidized resin latex, so that barium sulfate is not easy to fall off from the recycled aggregate. Meanwhile, the epoxidized resin latex fills larger cracks on the surface of the modified material C, so that the internal compactness of the modified recycled aggregate is further enhanced, and the strength of the recycled concrete is improved.
Optionally, the preparation method of the nanoscale poly-3, 4-diaminophenylacetic acid comprises the following steps:
grinding 3, 4-diaminophenylacetic acid, weighing 3-4 parts of 3, 4-diaminophenylacetic acid powder by weight, adding 0.3-0.6 part of polyethylene glycol, and continuously grinding and mixing for 15-20 min; adding 0.2-0.4 part of ammonium persulfate, continuously grinding and mixing for 15-20min, then adding 0.2-0.4 part of ammonium persulfate again, and continuously grinding for 1-1.5 h; grinding, and reacting at 50-55 deg.C for 3-4 h; washing with diethyl ether, ethanol and water, drying at 60-65 deg.C for 36-48h, taking out, and grinding to average particle diameter of 30-50nm to obtain nanometer poly-3, 4-diamino phenylacetic acid.
By the technical scheme, the nano poly-3, 4-diamino phenylacetic acid required by the formula is obtained.
Optionally, the pH value of the modifier B is adjusted to 4-5 by using phosphoric acid.
Through the technical scheme, the molecular chain of the nano poly-3, 4-diaminophenylacetic acid contains a large number of amino and imino functional groups, and the nano poly-3, 4-diaminophenylacetic acid molecules can effectively adsorb heavy metal ions through electrostatic action and coordination complexing action. When the pH value is 4-5, the nano poly 3, 4-diamino phenylacetic acid molecules adsorb barium ions under the electrostatic action, and when the pH value is less than 4, the nano poly 3, 4-diamino phenylacetic acid molecules are complexed and coordinated with most of barium ions, so that the barium ions are difficult to generate crystals with sulfate ions to fill holes and cracks in the recycled aggregate, the filling effect is poor, and the light degree of the recycled concrete is poor.
Optionally, the filler includes fly ash and slag, and the weight ratio of slag: coal ash = (6-8) 1.
By adopting the technical scheme, the slag can be hydrated with cement to obtain Ca (0H)2The 'secondary hydration reaction' occurs, and can promote the cement to be further hydrated to generate more C-S-H gel, improve the microstructure of the concrete and reduce the porosity of the cement paste. The fly ash is filled in the concrete to ensure that the concrete has lighter weightThe porosity of the cement paste can be reduced, and the compressive strength of the concrete is improved.
Optionally, the admixture is a reinforcing agent.
Through the technical scheme, the compressive strength and the durability of the concrete can be improved by the reinforcing agent.
In a second aspect, the present application provides a method for preparing high-strength recycled concrete, which adopts the following technical scheme:
a preparation method of high-strength recycled concrete comprises the following steps:
s1, weighing cement and water according to the weight parts required by the formula, and uniformly stirring and mixing to obtain a cement glue material;
s2, weighing the filler, the coarse aggregate, the fine aggregate, the modified recycled aggregate and the admixture according to the weight parts required by the formula, and uniformly stirring and mixing to obtain the high-strength recycled concrete.
By the technical scheme, the high-strength recycled concrete with better strength and corrosion resistance is obtained.
In summary, the present application has the following beneficial effects:
1. the strength and the corrosion resistance of the recycled concrete are improved by modifying the recycled aggregate through the modifier A, the modifier B and the modifier C.
2. By irradiating the recycled aggregate with ultraviolet light, barium sulfate is uniformly and densely attached to the surface of the recycled aggregate, and the strength and the corrosion resistance of recycled concrete are further improved.
3. The pH value of the modifier B is adjusted to 4-5, so that the salt forming effect of barium sulfate is better, and the compactness of the recycled aggregate is improved.
Detailed Description
The present application will be described in further detail with reference to examples.
| Raw materials | Species or origin |
| Cement | Guangzhou faithfully, Inc., Huarun Cement 42.5R. |
| Coarse aggregate | And (3) crushing stones, wherein the grading of the crushed stones is 5-31.5 mm. |
| Fine aggregate | River sand, the gradation of river sand is 0-10 mm. |
| Additive agent | Concrete reinforcing agents sold by Yunnan mortar building materials Co. |
| 3, 4-Diaminophenylacetic acid | Xian heterocyclic chemical technology Co., Ltd. |
| Filler | Fly ash (zhhaiming trade limited), slag (shaoguan chang melt building materials limited), and slag: fly ash =7: 1. |
| Epoxy resin latex | JGN805, Guizhou Zonenda building materials, Inc. |
Preparation example
Preparation example 1:
preparation of nano-scale poly-3, 4-diaminophenylacetic acid:
grinding 3, 4-diaminophenylacetic acid, weighing 4 parts of 3, 4-diaminophenylacetic acid powder by weight, adding 0.5 part of polyethylene glycol, and continuously grinding and mixing for 20 min; adding 0.4 part of ammonium persulfate, continuously grinding and mixing for 20min, then adding 0.4 part of ammonium persulfate again, and continuously grinding for 1 h; grinding and placing in 50 ℃ for reaction for 3 h; washing with diethyl ether, ethanol and water, drying at 60 deg.C for 48 hr, taking out, and grinding to average particle diameter of 50nm to obtain nanometer poly-3, 4-diamino phenylacetic acid.
Preparation example 2:
preparing modified recycled aggregate:
s1, preparation of recycled aggregate: crushing, screening and cleaning the waste concrete blocks to obtain recycled aggregate, wherein the grading of the recycled aggregate is 5-31.5 mm;
s2, modification of recycled aggregate:
s21, soaking the recycled aggregate obtained in the step S1 in a modifier A for 0.5h, taking out and airing to obtain a modifier A, wherein the modifier A is a mixture of the nanoscale poly-3, 4-diaminophenylacetic acid prepared in the preparation example 1 and water, and the weight ratio of the nanoscale poly-3, 4-diaminophenylacetic acid: water =1: 7;
s22, soaking the modified material A in a modifying agent B for 1h, taking out and airing to obtain the modified material B, wherein the modifying agent B is an aqueous solution of barium chloride, and the weight ratio of barium chloride: water =1:4, modifier B was determined to have a pH of 6.8;
s23, soaking the modified material B in a modifier C for 1h, taking out and airing to prepare recycled aggregate, wherein the modifier C is an aqueous solution of sodium sulfate, and the weight ratio of the sodium sulfate: water =1:4.
Preparation example 3:
preparing modified recycled aggregate:
s1, preparation of recycled aggregate: crushing, screening and cleaning the waste concrete blocks to obtain recycled aggregate, wherein the grading of the recycled aggregate is 5-31.5 mm;
s2, modification of recycled aggregate:
s21, soaking the recycled aggregate obtained in the step S1 in a modifier A for 0.5h, taking out and airing to obtain a modifier A, wherein the modifier A is a mixture of the nanoscale poly-3, 4-diaminophenylacetic acid prepared in the preparation example 1 and water, and the weight ratio of the nanoscale poly-3, 4-diaminophenylacetic acid: water =1: 8;
s22, soaking the modified material A in a modifying agent B for 1h, taking out and airing to obtain the modified material B, wherein the modifying agent B is an aqueous solution of barium chloride, and the weight ratio of barium chloride: water =1:6, modifier B was determined to have a pH of 6.9;
s23, soaking the modified material B in a modifier C for 1h, taking out and airing to prepare recycled aggregate, wherein the modifier C is an aqueous solution of sodium sulfate, and the weight ratio of the sodium sulfate: water =1: 6.
Preparation example 4:
preparing modified recycled aggregate:
s1, preparation of recycled aggregate: crushing, screening and cleaning the waste concrete blocks to obtain recycled aggregate, wherein the grading of the recycled aggregate is 5-31.5 mm;
s2, modification of recycled aggregate:
s21, soaking the recycled aggregate obtained in the step S1 in a modifier A for 0.5h, taking out and airing to obtain a modifier A, wherein the modifier A is a mixture of the nanoscale poly-3, 4-diaminophenylacetic acid prepared in the preparation example 1 and water, and the weight ratio of the nanoscale poly-3, 4-diaminophenylacetic acid: water =1:7.5, nano-sized poly 3, 4-diaminophenylacetic acid was obtained from preparation example 1;
s22, soaking the modified material A in a modifying agent B for 1h, taking out and airing to obtain the modified material B, wherein the modifying agent B is an aqueous solution of barium chloride, and the weight ratio of barium chloride: water =1:4.5, modifier B was determined to have a pH of 6.8;
s23, soaking the modified material B in a modifier C for 1h, taking out and airing to prepare recycled aggregate, wherein the modifier C is an aqueous solution of sodium sulfate, and the weight ratio of the sodium sulfate: water =1: 4.5.
Preparation example 5:
the difference from preparation example 4 is that in S1 of the method for preparing recycled aggregate, the obtained recycled aggregate was irradiated with ultraviolet light at a wavelength of 274nm, at an irradiation distance of 10cm, for a period of 2 hours.
Preparation example 6:
the difference from preparation example 4 is that the preparation method of the modified recycled aggregate further comprises S3, and the method of S3 is as follows: and soaking the modified material C in the epoxy resin latex, taking out and airing to obtain the modified recycled aggregate.
Examples
Example 1:
the high-strength recycled concrete is prepared from the following raw materials in parts by weight:
450 parts of cement;
140 parts of water;
100 parts of a filling agent;
400 parts of coarse aggregate;
500 parts of fine aggregate;
400 parts of modified recycled aggregate, wherein the modified recycled aggregate is obtained by the preparation example 3;
and 12 parts of a reinforcing agent.
A preparation method of high-strength recycled concrete comprises the following steps:
s1, weighing cement and water according to the weight parts required by the formula, stirring and mixing uniformly, wherein the stirring speed is 500r/min, and the overtime time is 30min to obtain a cement sizing material;
s2, weighing the filler, the coarse aggregate, the fine aggregate, the modified recycled aggregate and the reinforcing agent according to the required weight parts of the formula, stirring and mixing uniformly, wherein the stirring speed is 150r/min, and the stirring time is 30min, so that the high-strength recycled concrete is obtained.
Example 2:
the high-strength recycled concrete is prepared from the following raw materials in parts by weight:
550 parts of cement;
160 parts of water;
120 parts of a filler;
500 parts of coarse aggregate;
600 parts of fine aggregate;
500 parts of modified recycled aggregate, wherein the modified recycled aggregate is obtained by the preparation example 4;
16 parts of reinforcing agent.
A preparation method of high-strength recycled concrete comprises the following steps:
s1, weighing cement and water according to the weight parts required by the formula, stirring and mixing uniformly, wherein the stirring speed is 500r/min, and the overtime time is 30min to obtain a cement sizing material;
s2, weighing the filler, the coarse aggregate, the fine aggregate, the modified recycled aggregate and the reinforcing agent according to the required weight parts of the formula, stirring and mixing uniformly, wherein the stirring speed is 150r/min, and the stirring time is 30min, so that the high-strength recycled concrete is obtained.
Example 3:
the high-strength recycled concrete is prepared from the following raw materials in parts by weight:
500 parts of cement;
150 parts of water;
110 parts of a filling agent;
450 parts of coarse aggregate;
550 parts of fine aggregate;
450 parts of modified recycled aggregate, wherein the modified recycled aggregate is obtained by the preparation example 2;
140 parts of reinforcing agent.
A preparation method of high-strength recycled concrete comprises the following steps:
s1, weighing cement and water according to the weight parts required by the formula, stirring and mixing uniformly, wherein the stirring speed is 500r/min, and the overtime time is 30min to obtain a cement sizing material;
s2, weighing the filler, the coarse aggregate, the fine aggregate, the modified recycled aggregate and the reinforcing agent according to the required weight parts of the formula, stirring and mixing uniformly, wherein the stirring speed is 150r/min, and the stirring time is 30min, so that the high-strength recycled concrete is obtained.
Example 4:
the difference from example 3 is that: the modified recycled aggregate was obtained in preparation example 5.
Example 5:
the difference from example 3 is that: the modified recycled aggregate was obtained in preparation example 6.
Example 6:
the difference from example 3 is that: the pH of modifier B was adjusted to 4 with phosphoric acid.
Example 7:
the difference from example 3 is that: the pH of modifier B was adjusted to 5 with phosphoric acid.
Example 8:
the difference from example 3 is that: the pH of modifier B was adjusted to 4.5 with phosphoric acid.
Example 9:
the difference from example 3 is that: the pH of modifier B was adjusted to 3 with phosphoric acid.
Comparative example
Comparative example 1:
the difference from example 3 is that the recycled aggregate was directly used as a raw material without modification treatment.
Comparative example 2:
the difference from example 3 is that in the preparation of modified recycled aggregate, modifier A was replaced with an equal amount of water.
Performance test
The concrete obtained in the examples and the comparative examples is prepared into cubic test pieces of 100mm multiplied by 100mm, two groups of test pieces are respectively prepared in each group of examples and comparative examples, the test pieces are placed in a standard curing chamber for curing for 28d, and the initial compression strength and the initial splitting tensile strength of one group of concrete test pieces are measured. And (3) placing the other group of test pieces in a 1wt% sulfuric acid corrosion solution to be soaked for 120h (the 1wt% sulfuric acid corrosion solution is changed once every 2 days to prevent the sulfuric acid from influencing test data after being consumed), taking out and airing, and measuring the soaking compressive strength and the soaking cleavage tensile strength of the test pieces.
And testing the compression strength and the splitting tensile strength of the test piece by referring to GB/T50081-2002. The structure of the sample is detailed in table 1.
TABLE 1
| Initial compressive Strength (MPa) | Initial split tensile Strength (MPa) | Crush strength in immersion (MPa) | Tensile strength of immersion cleavage (MPa) | |
| Example 1 | 57.4 | 3.91 | 45.2 | 3.54 |
| Example 2 | 57.9 | 4.01 | 46.0 | 3.57 |
| Example 3 | 58.4 | 4.02 | 46.9 | 3.58 |
| Example 4 | 62.4 | 4.32 | 52.9 | 4.02 |
| Example 5 | 65.7 | 4.51 | 55.7 | 4.33 |
| Example 6 | 60.2 | 4.19 | 49.7 | 3.77 |
| Example 7 | 60.3 | 4.21 | 50.2 | 3.79 |
| Example 8 | 60.5 | 4.23 | 50.3 | 3.82 |
| Example 9 | 51.3 | 3.57 | 39.1 | 3.07 |
| Comparative example 1 | 32.6 | 2.42 | 16.3 | 1.57 |
| Comparative example 2 | 36.7 | 2.66 | 22.7 | 2.01 |
When example 3 and example 4 are combined and table 1 is shown, the difference between the reduction in the compressive strength in soaking and the reduction in the tensile strength at soaking cleavage in example 4 is smaller than that in example 3. Ultraviolet illumination enables the number of active groups on the surface of the recycled aggregate to be increased, so that the nano-scale poly-3, 4-diaminophenylacetic acid is uniformly and densely attached to the recycled aggregate, barium sulfate is uniformly and densely attached to the surface of the recycled aggregate, the inside of the recycled aggregate is more compact, the recycled aggregate is uniformly wrapped, the corrosion resistance of the recycled aggregate is improved, and the compressive strength, the splitting tensile strength and the corrosion resistance of recycled concrete are improved.
By combining the example 3 and the example 5 and combining the table 1, it can be seen that the barium sulfate is not easy to fall off from the recycled aggregate when the modified recycled aggregate and the cement are stirred by wrapping a layer of epoxy resin latex on the surface of the recycled aggregate, so that the compressive strength and the corrosion resistance of the concrete are ensured, and meanwhile, the epoxy resin latex further fills the surface cracks of the modified recycled aggregate, the compactness of the recycled aggregate is improved, the strength of the recycled aggregate is improved, and the strength of the concrete is improved.
By combining example 3 with examples 6 to 9 and table 1, it can be seen that when the pH value of modifier B is 4 to 5, the recycled concrete prepared from the modified recycled aggregate obtained by modification has better compressive strength and corrosion resistance. The nano poly-3, 4-diamino phenylacetic acid molecule adsorbs barium ions under the electrostatic action and has better adsorption effect. When the pH value is less than 4, the barium ions and most of the barium ions are subjected to complex coordination, so that the barium ions and sulfate ions are difficult to generate crystals to fill holes and cracks in the recycled aggregate, the filling effect is poor, and the light degree of the recycled concrete is poor. When the pH value is more than 6, the adsorption effect of nano poly 3, 4-diamino phenylacetic acid molecules on barium ions is weakened, barium sulfate attached to the recycled aggregate is reduced, the internal density of the recycled aggregate is reduced, and the corrosion resistance and the strength of the recycled aggregate are reduced, so that the strength and the corrosion resistance of recycled concrete are influenced.
By combining example 3 and comparative example 1 and table 1, it can be seen that the modified recycled aggregate can significantly enhance the compressive strength, the compressive strength at cleavage and the corrosion resistance of concrete. The modifier A, the modifier B and the modifier C fully soak tiny holes and cracks of the recycled aggregate, barium sulfate with good stability is formed in the tiny holes and cracks, and the tiny holes and cracks in the recycled aggregate are filled with the barium sulfate, so that the compactness of the internal structure of the recycled concrete is remarkably improved, and the strength of the recycled concrete is remarkably improved. Meanwhile, the barium sulfate is stable and hardly dissolved in water, dilute acid and alcohol, so that the recycled concrete has better corrosion resistance, and the corrosion resistance of the recycled concrete is improved.
It can be seen by combining example 3 and comparative example 2 with table 1 that modifier a has a greater effect on modifying recycled aggregate. If the modified recycled aggregate is prepared, the recycled aggregate is not soaked by the modifier A but is directly soaked by the modifier B and the modifier C, so that the generated barium sulfate is difficult to attach to the surface of the recycled concrete, the modification effect is not obvious, and the barium sulfate is tightly attached to the surface of the modified recycled aggregate by adding the nano poly 3, 4-diaminophenylacetic acid molecules, so that the compressive strength, the cleavage strength and the corrosion resistance of the recycled concrete are obviously improved.
The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.
Claims (8)
1. The high-strength recycled concrete is characterized by being prepared from the following raw materials in parts by weight:
cement 450-;
140 portions of water and 160 portions of water;
100 portions and 120 portions of filling agent;
400 portions of coarse aggregate and 500 portions of coarse aggregate;
500 portions and 600 portions of fine aggregate;
400 portions of modified recycled aggregate and 500 portions of modified recycled aggregate;
12-16 parts of an additive;
the preparation method of the modified recycled aggregate comprises the following steps:
s1, preparation of recycled aggregate: crushing, screening and cleaning the waste concrete blocks to obtain recycled aggregate;
s2, modification of recycled aggregate:
s21, soaking the recycled aggregate obtained in the step S1 in a modifier A, taking out and airing to obtain a modifier A, wherein the modifier A comprises nano poly-3, 4-diaminophenylacetic acid and water, and the weight ratio of the nano poly-3, 4-diaminophenylacetic acid: water =1 (7-8);
s22, soaking the modified material A in a modified agent B, taking out and airing to obtain a modified material B, wherein the modified agent B comprises barium chloride and water, and the weight ratio of the barium chloride: water =1 (4-6);
s23, soaking the modified material B in a modifying agent C, taking out and airing, and preparing to obtain a modified material C, namely the recycled aggregate, wherein the modifying agent C comprises sodium sulfate and water, and the weight ratio of the sodium sulfate: water =1 (4-6).
2. A high strength recycled concrete as claimed in claim 1, wherein: in S1 of the method for preparing recycled aggregate, the obtained recycled aggregate is irradiated with ultraviolet light.
3. A high strength recycled concrete as claimed in claim 1, wherein: the preparation method of the modified recycled aggregate also comprises the following steps of S3, and the method of S3 is as follows: and soaking the modified material C in the epoxy resin latex, taking out and airing to obtain the modified recycled aggregate.
4. A high strength recycled concrete as claimed in claim 1, wherein: the preparation method of the nano-scale poly-3, 4-diaminophenylacetic acid comprises the following steps:
grinding 3, 4-diaminophenylacetic acid, weighing 3-4 parts of 3, 4-diaminophenylacetic acid powder by weight, adding 0.3-0.6 part of polyethylene glycol, and continuously grinding and mixing for 15-20 min; adding 0.2-0.4 part of ammonium persulfate, continuously grinding and mixing for 15-20min, then adding 0.2-0.4 part of ammonium persulfate again, and continuously grinding for 1-1.5 h; grinding, and reacting at 50-55 deg.C for 3-4 h; washing with diethyl ether, ethanol and water, drying at 60-65 deg.C for 36-48h, taking out, and grinding to average particle diameter of 30-50nm to obtain nanometer poly-3, 4-diamino phenylacetic acid.
5. A high strength recycled concrete as claimed in claim 1, wherein: the pH value of the modifier B is adjusted to 4-5 by adopting phosphoric acid.
6. A high strength recycled concrete as claimed in claim 1, wherein: the filler comprises fly ash and slag, and the slag comprises the following components in percentage by weight: coal ash = (6-8) 1.
7. A high strength recycled concrete as claimed in claim 1, wherein: the additive is a reinforcing agent.
8. A method for producing a high-strength recycled concrete according to any one of claims 1 to 7, comprising the steps of:
s1, weighing cement and water according to the weight parts required by the formula, and uniformly stirring and mixing to obtain a cement glue material;
s2, weighing the filler, the coarse aggregate, the fine aggregate, the modified recycled aggregate and the admixture according to the weight parts required by the formula, and uniformly stirring and mixing to obtain the high-strength recycled concrete.
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