CN115490467A - Seawater and sea sand recycled concrete with chloride ion curing capability and preparation method thereof - Google Patents
Seawater and sea sand recycled concrete with chloride ion curing capability and preparation method thereof Download PDFInfo
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- 239000004567 concrete Substances 0.000 title claims abstract description 102
- 239000004576 sand Substances 0.000 title claims abstract description 72
- 239000013535 sea water Substances 0.000 title claims abstract description 66
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 title claims abstract description 56
- 238000002360 preparation method Methods 0.000 title description 7
- 229910052500 inorganic mineral Inorganic materials 0.000 claims abstract description 30
- 239000011707 mineral Substances 0.000 claims abstract description 30
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 29
- 239000002699 waste material Substances 0.000 claims abstract description 24
- 239000004568 cement Substances 0.000 claims abstract description 20
- 239000000463 material Substances 0.000 claims abstract description 16
- 235000019353 potassium silicate Nutrition 0.000 claims abstract description 16
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000004575 stone Substances 0.000 claims abstract description 12
- 239000003638 chemical reducing agent Substances 0.000 claims abstract description 11
- 238000007873 sieving Methods 0.000 claims abstract description 9
- 239000002994 raw material Substances 0.000 claims abstract description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 68
- 239000010881 fly ash Substances 0.000 claims description 7
- 239000000843 powder Substances 0.000 claims description 7
- 238000003756 stirring Methods 0.000 claims description 6
- 239000002002 slurry Substances 0.000 claims description 5
- 238000002156 mixing Methods 0.000 claims description 4
- 238000002791 soaking Methods 0.000 claims description 4
- 239000011398 Portland cement Substances 0.000 claims description 3
- 238000010521 absorption reaction Methods 0.000 claims description 3
- 238000000034 method Methods 0.000 claims description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 2
- 150000004645 aluminates Chemical class 0.000 claims description 2
- 229910021487 silica fume Inorganic materials 0.000 claims description 2
- RLQWHDODQVOVKU-UHFFFAOYSA-N tetrapotassium;silicate Chemical compound [K+].[K+].[K+].[K+].[O-][Si]([O-])([O-])[O-] RLQWHDODQVOVKU-UHFFFAOYSA-N 0.000 claims description 2
- 238000010276 construction Methods 0.000 abstract description 5
- 238000011161 development Methods 0.000 abstract description 3
- 238000012360 testing method Methods 0.000 description 13
- 239000000499 gel Substances 0.000 description 10
- 230000036571 hydration Effects 0.000 description 8
- 238000006703 hydration reaction Methods 0.000 description 8
- 239000011148 porous material Substances 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 150000003839 salts Chemical class 0.000 description 5
- 239000011575 calcium Substances 0.000 description 4
- 230000006378 damage Effects 0.000 description 4
- 239000000378 calcium silicate Substances 0.000 description 3
- 229910052918 calcium silicate Inorganic materials 0.000 description 3
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 3
- 239000011083 cement mortar Substances 0.000 description 3
- 239000013505 freshwater Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 229910001653 ettringite Inorganic materials 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000013508 migration Methods 0.000 description 2
- 230000005012 migration Effects 0.000 description 2
- MKTRXTLKNXLULX-UHFFFAOYSA-P pentacalcium;dioxido(oxo)silane;hydron;tetrahydrate Chemical compound [H+].[H+].O.O.O.O.[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O.[O-][Si]([O-])=O MKTRXTLKNXLULX-UHFFFAOYSA-P 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- UFWIBTONFRDIAS-UHFFFAOYSA-N naphthalene-acid Natural products C1=CC=CC2=CC=CC=C21 UFWIBTONFRDIAS-UHFFFAOYSA-N 0.000 description 1
- 125000001624 naphthyl group Chemical group 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 238000001878 scanning electron micrograph Methods 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 238000004642 transportation engineering Methods 0.000 description 1
Images
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
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/20—Resistance against chemical, physical or biological attack
- C04B2111/24—Sea water resistance
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Abstract
The invention discloses seawater sea sand recycled concrete with chloride ion curing capacity, which comprises the following raw materials in parts by weight: 310-540 parts of a cementing material, 170-310 parts of seawater, 1000-1100 parts of a coarse aggregate, 370-500 parts of a fine aggregate, 1-5 parts of a water reducing agent and 0-10 parts of water glass; the cementing material consists of cement and mineral admixture, the fine aggregate consists of sea sand and recycled fine aggregate, and the recycled fine aggregate is undersize obtained by crushing waste concrete and then sieving the crushed waste concrete by a 4.75mm sieve; the coarse aggregate consists of natural crushed stone and regenerated coarse aggregate, and the regenerated coarse aggregate is screen residue obtained by crushing waste concrete and sieving the crushed waste concrete by a 4.75mm sieve. According to the invention, the waste concrete is used as aggregate and is applied to the concrete again, the construction waste is recycled, the sustainable development concept is met, and the prepared seawater and sea sand concrete has excellent chloride ion curing capability and better durability and mechanical property.
Description
Technical Field
The invention belongs to the technical field of recycled concrete preparation, and particularly relates to seawater sea sand recycled concrete with chloride ion curing capability.
Background
In recent years, it has become possible to provide,with the vigorous development of economy, concrete has been widely used as a main building material. The national ready-mixed concrete production in 2021 was reported to be 32.93 billion cubic meters, a comparable increase of 6.9%. The huge concrete yield can cause the problem of excessive exploitation of resources such as fresh water, river sand, natural aggregate and the like, thereby causing certain influence on the ecological environment. China has 1.8 kilometres of continental coastline, 1.4 kilometres of island coastline and 34.2 multiplied by 10 areas of various sand bodies 5 km 3 . Furthermore, 70% of the area on earth is covered by water, where the ratio of fresh water resources to seawater resources is 1. Therefore, if sea sand and seawater can be utilized in the production of concrete, the problems of large sand and stone resources and water demand can be solved, and the problem of shortage of fresh water resources is relieved. However, seawater and sea sand contain a large amount of chloride ions, and the presence of chloride ions affects the hydration process of cement, accelerates the destruction of concrete structures, and thus affects the life of concrete. The chloride ions in the seawater sea sand concrete are divided into two parts, namely free chloride ions and combined chloride ions, wherein the combined chloride ions are the chloride ions physically adsorbed and chemically combined on the surface of a pore structure, the combined chloride ions do not harm the concrete structure, and the free chloride ions have strong penetrating power due to small ionic radius and can enter the concrete through the pore diameter in the concrete to damage the structure of the concrete and influence the durability of the concrete, so that the curing of the chloride ions is one of important means for improving the durability of the seawater sea sand concrete.
With the continuous acceleration of the urbanization process in China, a plurality of buildings are facing to be dismantled all over the country, and the problem of treating building garbage generated by the dismantled buildings is always the focus of the ecological environment problem. According to statistics, the yield of the construction waste in China is up to 18 hundred million tons every year, but the resource utilization rate of the construction waste is less than 5 percent. The construction waste is crushed and screened and then is added into the concrete as coarse aggregate and fine aggregate, so that the recycled concrete becomes a green novel material, the shortage problem of concrete sand and stone resources can be effectively relieved, and the problem of treatment of waste concrete is solved. However, the recycled aggregate has large pores and low density, and the existing of a certain amount of old cement mortar on the surface of the recycled aggregate can reduce the bonding performance between the old and new mortar and the aggregate. The seawater and sea sand are prepared into the seawater and sea sand recycled aggregate concrete together with the recycled aggregate, so that the pore structure of the recycled aggregate can be compensated, the salt substances in the seawater and sea sand can effectively improve the internal structure of the recycled aggregate and the pore structure of an interface transition region, the compactness of the recycled aggregate is enhanced, the compactness of the concrete is improved, and a migration channel of chloride ions is blocked.
At present, scholars at home and abroad make a great deal of research on the aspect of regenerating concrete from seawater and sea sand, and certain research progress is achieved, but reports on improving the chloride ion curing capability of seawater and sea sand concrete are few. The existing seawater and sea sand recycled concrete still has the problems of poor durability and mechanical property.
Disclosure of Invention
The invention aims to solve the problem of poor durability and mechanical property of the existing seawater and sea sand recycled concrete, and provides seawater and sea sand recycled concrete with chloride ion curing capability.
Technical scheme
A seawater and sea sand recycled concrete with chloride ion curing capability comprises the following raw materials in parts by weight: 310-540 parts of cementing material, 170-310 parts of seawater, 1000-1100 parts of coarse aggregate, 370-500 parts of fine aggregate, 1-5 parts of water reducing agent and 0-10 parts of water glass.
The cementing material consists of cement and mineral admixture, the cement is selected from one of portland cement, aluminate cement or sulfate cement, the mineral admixture is selected from one or a combination of more than two of fly ash, mineral powder and silica fume in any proportion, and the composition of the fly ash and the mineral powder is more preferable. According to the invention, a mineral admixture is added into the cementing material. The hydration product Ca (OH) of coarse crystal particles is reduced due to the pozzolanic effect of the mineral admixtures 2 The low-alkalinity hydrated calcium silicate gel (C-S-H) with higher strength and better stability is generated, the chloride ion curing capability of the seawater sea sand concrete is improved by the C-S-H gel, and meanwhile, the content of Al in the mineral admixture is higher 2 O 3 With chloride ions、Ca(OH) 2 Friedel salt is generated, and the chloride ion curing capability of seawater and sea sand concrete can be further improved.
The fine aggregate consists of sea sand and recycled fine aggregate, and the recycled fine aggregate is undersize obtained by crushing waste concrete by a crusher and then sieving the crushed waste concrete by a 4.75mm sieve; the coarse aggregate is composed of 5-10mm continuous graded natural crushed stone and recycled coarse aggregate, and the recycled coarse aggregate is screen residue obtained by crushing waste concrete by a crusher and then sieving the crushed waste concrete by a 4.75mm sieve.
Furthermore, the mud content of the sea sand is 1-2%, the water content is 3-5%, and the fineness modulus is 0.7-1.2.
Further, in the cementing material, cement accounts for 65-80% of the total mass of the cementing material, and mineral admixture accounts for 20-35% of the total mass of the cementing material.
Furthermore, in the fine aggregate, the weight ratio of the sea sand to the recycled fine aggregate is (0.6-4.2): 1.
Furthermore, in the coarse aggregate, the weight ratio of the natural macadam to the recycled coarse aggregate is (1.4-1.6): 1.
Furthermore, the water glass is potassium water glass, and the modulus is 1.0-2.8. The addition of the water glass can greatly excite the activity of the mineral admixture and enable the mineral admixture to react with the alkaline hydration product, and the activity of the mineral admixture depends on SiO 2 And Al 2 O 3 Content and alkali concentration. Incorporation of water glass introduces OH - At OH - The aluminum tetrahedra and silicon tetrahedra in the mineral admixture are destroyed, and more aggregated three-dimensional network gels are generated, and the gels improve the curing capability of the concrete to chloride ions.
The preparation method of the seawater sea sand recycled concrete with chloride ion curing capacity comprises the following steps:
1) Putting the regenerated coarse aggregate and the regenerated fine aggregate into water, soaking for 20-30h for pre-water absorption treatment, taking out, draining water, and airing until no water stain exists on the surface for later use;
2) According to the above metering ratio, the cement, the mineral admixture, the sea sand, the recycled coarse aggregate, the recycled fine aggregate and the natural broken stone are stirred and mixed uniformly, half of the seawater is added firstly for stirring, then the residual seawater and the water reducing agent are added after mixing uniformly to obtain slurry, and finally the water glass is added for stirring uniformly to obtain the seawater sea sand recycled concrete.
Compared with the prior art, the invention has the following beneficial effects:
(1) The invention applies the waste concrete as aggregate to the concrete again, reasonably and effectively recycles the construction waste, and conforms to the concept of sustainable development.
(2) According to the invention, seawater, sea sand and recycled aggregate are used as raw materials of the concrete, the seawater and the sea sand can make up the pore structure of the recycled aggregate, and salt substances in the seawater and the sea sand can effectively improve the pore structures in the recycled aggregate and in an interface transition region, so that the compactness of the concrete is improved, and chloride ions are prevented from obtaining a migration channel.
(3) According to the invention, a mineral admixture is added into the cementing material. The hydration product Ca (OH) of coarse crystal particles is reduced due to the pozzolanic effect of the mineral admixtures 2 The calcium silicate hydrate gel (C-S-H) with low alkalinity and higher stability is generated, the chloride ion curing capability of the seawater sea sand concrete is improved by the C-S-H gel, and meanwhile, the content of Al in the mineral admixture is higher 2 O 3 With chloride ion, ca (OH) 2 Friedel salt is generated, and the chloride ion curing capability of seawater and sea sand concrete can be further improved.
(4) The water glass is added into the concrete, and the alkali excitation effect of the water glass can excite the activity of the mineral admixture to the maximum extent, promote the generation of hydration products and improve the compactness and chloride ion curing capability of the seawater and sea sand recycled concrete.
Drawings
FIG. 1 is a scanning electron micrograph of the seawater sea sand recycled concrete prepared in example 2;
fig. 2 is an XRD pattern of the seawater sea sand recycled concrete prepared in example 2.
Detailed Description
The technical solution of the present invention is further described in detail with reference to the accompanying drawings and examples. The raw materials used in the present invention are known materials and can be purchased from the market.
In the following examples, for the purpose of clearly and specifically illustrating the present invention, P.O.52.5 Portland cement is used as the cement, 5-10mm continuous gradation of natural crushed stone is used, and the bulk density is 1477kg/m 3 The crush index is 9%; the mud content of the natural sea sand is 1.33 percent, and the apparent density is 2526kg/m 3 The bulk density is 1285kg/m 3 The water content is 3.5 percent, and the fineness modulus is 0.9; the recycled fine aggregate is undersize obtained by crushing the waste concrete by a crusher and then sieving the crushed waste concrete by a 4.75mm sieve, and the recycled coarse aggregate is screen residue obtained by crushing the waste concrete by the crusher and then sieving the crushed waste concrete by the 4.75mm sieve; the water reducing agent is a naphthalene high-efficiency water reducing agent, the modulus of the water glass is 1.8 (the medicine used for adjusting the modulus is K) 2 O analytically pure).
Example 1
A seawater and sea sand recycled concrete with chloride ion curing capability comprises the following raw materials in parts by weight: 289 parts of cement, 50 parts of fly ash, 74 parts of mineral powder, 301 parts of sea sand, 75 parts of recycled fine aggregate, 611 parts of natural broken stone, 408 parts of recycled coarse aggregate, 233 parts of seawater, 2.5 parts of a water reducing agent and 8 parts of water glass.
The preparation method of the seawater sea sand recycled concrete with chloride ion curing capability comprises the following steps:
1) Putting the regenerated coarse aggregate and the regenerated fine aggregate into water, soaking for 24 hours for pre-water absorption treatment, taking out, draining water, and airing until no water stain exists on the surface for later use;
2) According to the above metering ratio, the cement, the mineral admixture, the sea sand, the recycled coarse aggregate, the recycled fine aggregate and the natural macadam are uniformly stirred, half of the sea water is added firstly for stirring, then the rest sea water is uniformly mixed with the water reducing agent and added to obtain slurry, finally the water glass is added, and the sea water and sea sand recycled concrete is obtained after uniform stirring.
Example 2
The seawater sea sand recycled concrete with chloride ion curing capability comprises the following raw materials in parts by weight: 289 parts of cement, 50 parts of fly ash, 74 parts of mineral powder, 226 parts of sea sand, 150 parts of recycled fine aggregate, 611 parts of natural broken stone, 408 parts of recycled coarse aggregate, 233 parts of seawater, 2.5 parts of a water reducing agent and 8 parts of water glass.
The preparation method of the seawater sea sand recycled concrete is the same as that of the example 1.
Example 3
A seawater and sea sand recycled concrete with chloride ion curing capability comprises the following raw materials in parts by weight: 289 parts of cement, 50 parts of fly ash, 74 parts of mineral powder, 151 parts of sea sand, 225 parts of recycled fine aggregate, 611 parts of natural broken stone, 408 parts of recycled coarse aggregate, 233 parts of seawater, 2.5 parts of a water reducing agent and 8 parts of water glass.
The preparation method of the seawater sea sand recycled concrete is the same as that of the example 1.
Performance detection
1. Filling the seawater sea sand recycled concrete slurry prepared in the examples 1-3 into a test mould with the diameter of 100mm multiplied by 50mm, moving the test mould to a vibration table for vibration, scraping off redundant parts by a scraper, curing the test mould in a curing room with the temperature of 20 +/-2 ℃ and the humidity of not less than 95% for 24h after the vibration is finished, removing the mould, and continuously curing the test block after the mould is removed in a standard curing box for 28d to obtain the concrete test block. And testing the compressive strength and the flexural strength of the concrete test block, and testing the chloride ion curing capacity of the seawater sea sand concrete.
The chloride ion curing capability test method comprises the following steps: putting the concrete test block into NaCl solution with the mass concentration of 5%, soaking for 28d, taking out and drying, extracting a cuboid with the center of 10mm multiplied by 100mm by adopting a core-taking machine, removing coarse aggregates, grinding and sieving slurry, and measuring the content of water-soluble chloride ions (C) according to JTS/T236-2019 concrete test detection technical Specification for Water transportation engineering f ) And total chloride ion content (C) t ) With a content of solidified chloride ions of C b ，C b ＝C t -C f The chloride ion curing rate R is calculated according to the following formula:
R＝C b /C f
the test results are shown in table 1:
TABLE 1
The test results in table 1 show that the recycled concrete of seawater and sea sand in the embodiment of the invention has better chloride ion curing capability, and the chloride ion curing capability tends to increase first and then decrease with the increase of the mixing amount of the recycled aggregate. Water-soluble chloride ion (C) f ) And total chloride ion (C) t ) The content of the recycled aggregate tends to decrease first and then increase. With the increase of the recycled aggregate, the doping amount of the sea sand in the concrete begins to be reduced, the content of the total chloride ions originally carried in the concrete is reduced, and the hydration product generated by the added mineral admixture is sufficient, so that the effect of curing the chloride ions can be achieved. The cement mortar reacts with unhydrated cement particles on the surface of the recycled aggregate to generate hydrated calcium silicate gel, so that the interface weak area of the recycled aggregate can be improved, and the compactness of concrete is improved. When the mixing amount of the recycled aggregate is further increased, the inferior of the recycled aggregate is greater than the advantage that the recycled aggregate absorbs cement mortar, so that the porosity of concrete is increased, more chloride ions enter the interior of the concrete, and the chloride ions entering the interior do not have enough hydration products to react with the concrete or be cured and are dissociated in the interior of the concrete to cause damage to the concrete.
2. Scanning electron microscope and XRD tests were performed on the seawater sea sand recycled concrete prepared in example 2, and the results are shown in fig. 1 and 2.
Fig. 1 is a scanning electron microscope image of the recycled concrete of seawater sand prepared in example 2, and fig. 2 is an XRD image of the recycled concrete of seawater sand prepared in example 2, from fig. 1, it can be seen that a great amount of flocculent gel is generated inside the concrete, the gel has the ability to fill the pores of the concrete, improve the compactness of the concrete, and cure chloride ions; as can be seen from FIG. 2, the hydration products of the seawater sea sand recycled concrete are C-S-H gel, friedel salt, ettringite (Ettringite), tobermorite (Tobermorite) and Ca (OH) 2 。
Claims (8)
1. The seawater and sea sand recycled concrete with chloride ion curing capability is characterized by comprising the following raw materials in parts by weight: 310-540 parts of a cementing material, 170-310 parts of seawater, 1000-1100 parts of a coarse aggregate, 370-500 parts of a fine aggregate, 1-5 parts of a water reducing agent and 0-10 parts of water glass;
the cementing material consists of cement and mineral admixture, the cement is selected from one of portland cement, aluminate cement or sulfate cement, and the mineral admixture is selected from one or a combination of more than two of fly ash, mineral powder and silica fume in any proportion;
the fine aggregate consists of sea sand and recycled fine aggregate, and the recycled fine aggregate is undersize obtained by crushing waste concrete by a crusher and then sieving the crushed waste concrete by a 4.75mm sieve;
the coarse aggregate is composed of 5-10mm continuous graded natural crushed stone and recycled coarse aggregate, and the recycled coarse aggregate is screen residue obtained by crushing waste concrete by a crusher and then sieving the crushed waste concrete by a 4.75mm sieve.
2. The seawater sea sand recycled concrete having chloride ion-curing ability according to claim 1, wherein the mineral admixture is a combination of fly ash and mineral powder.
3. The seawater sea sand recycled concrete with chloride ion curing capability of claim 1, wherein the sea sand has a mud content of 1-2%, a water content of 3-5%, and a fineness modulus of 0.7-1.2.
4. The seawater sea sand recycled concrete with chloride ion curing capability of claim 1, wherein in the cementing material, cement accounts for 65-80% of the total mass of the cementing material, and mineral admixture accounts for 20-35% of the total mass of the cementing material.
5. The seawater sea sand recycled concrete having chloride ion-curable ability according to claim 1, wherein the weight ratio of the sea sand to the recycled fine aggregate in said fine aggregate is (0.6-4.2): 1.
6. The seawater sea sand recycled concrete having chloride ion-curing ability according to claim 1, wherein the weight ratio of the natural crushed stone to the recycled coarse aggregate in the coarse aggregate is (1.4-1.6): 1.
7. Seawater sea sand recycled concrete having chloride ion-curable ability according to any one of claims 1 to 6, wherein said water glass is potassium water glass having a modulus of 1.0 to 2.8.
8. The method for preparing seawater sea sand recycled concrete with chloride ion curing capability of any one of claims 1 to 7, characterized by comprising the following steps:
1) Putting the regenerated coarse aggregate and the regenerated fine aggregate into water for soaking for 20-30h for pre-water absorption treatment, taking out, draining water, and airing until no water stain exists on the surface for later use;
2) According to the above metering ratio, the cement, the mineral admixture, the sea sand, the recycled coarse aggregate, the recycled fine aggregate and the natural broken stone are stirred and mixed uniformly, half of the seawater is added firstly for stirring, then the residual seawater and the water reducing agent are added after mixing uniformly to obtain slurry, and finally the water glass is added for stirring uniformly to obtain the seawater sea sand recycled concrete.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109437742A (en) * | 2018-12-03 | 2019-03-08 | 中山市武汉理工大学先进工程技术研究院 | Strong maritime concrete of a kind of ecotype superelevation and preparation method thereof |
| CN110194621A (en) * | 2019-05-10 | 2019-09-03 | 广东工业大学 | A kind of high intensity seawater sea sand regeneration concrete and preparation method thereof |
| CN112028565A (en) * | 2020-08-03 | 2020-12-04 | 广东工业大学 | Recycled coarse aggregate seawater sea sand concrete and preparation method and application thereof |
| CN113277803A (en) * | 2021-03-10 | 2021-08-20 | 同济大学 | Fiber seawater sea sand recycled concrete and preparation method thereof |
| CN115057662A (en) * | 2022-06-24 | 2022-09-16 | 华能国际电力江苏能源开发有限公司南通电厂 | Alkali-activated seawater sea sand concrete with chloride ion curing capability and preparation method thereof |
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2022
- 2022-09-28 CN CN202211188285.7A patent/CN115490467A/en active Pending
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109437742A (en) * | 2018-12-03 | 2019-03-08 | 中山市武汉理工大学先进工程技术研究院 | Strong maritime concrete of a kind of ecotype superelevation and preparation method thereof |
| CN110194621A (en) * | 2019-05-10 | 2019-09-03 | 广东工业大学 | A kind of high intensity seawater sea sand regeneration concrete and preparation method thereof |
| CN112028565A (en) * | 2020-08-03 | 2020-12-04 | 广东工业大学 | Recycled coarse aggregate seawater sea sand concrete and preparation method and application thereof |
| CN113277803A (en) * | 2021-03-10 | 2021-08-20 | 同济大学 | Fiber seawater sea sand recycled concrete and preparation method thereof |
| CN115057662A (en) * | 2022-06-24 | 2022-09-16 | 华能国际电力江苏能源开发有限公司南通电厂 | Alkali-activated seawater sea sand concrete with chloride ion curing capability and preparation method thereof |
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