CN114956642B - Composite expanding agent based on regenerated micro powder and preparation method thereof - Google Patents
Composite expanding agent based on regenerated micro powder and preparation method thereof Download PDFInfo
- Publication number
- CN114956642B CN114956642B CN202210515615.2A CN202210515615A CN114956642B CN 114956642 B CN114956642 B CN 114956642B CN 202210515615 A CN202210515615 A CN 202210515615A CN 114956642 B CN114956642 B CN 114956642B
- Authority
- CN
- China
- Prior art keywords
- parts
- powder
- micro powder
- regenerated
- regenerated micro
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
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
- C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
- C04B40/0028—Aspects relating to the mixing step of the mortar preparation
- C04B40/0039—Premixtures of ingredients
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
The invention discloses a composite expanding agent based on regenerated micro powder and a preparation method thereof, wherein the composite expanding agent comprises the following components in parts by mass: 5-10 parts of regenerated micro powder, 30-60 parts of low-temperature calcined regenerated micro powder, 5-15 parts of granulated blast furnace slag powder, 5-10 parts of steel slag powder, 20-40 parts of amorphous calcium aluminate, 5-20 parts of gypsum, 0.01-0.05 part of dispersing agent and 0.1-0.4 part of water reducer; the low-temperature calcined regenerated micro powder is obtained by calcining fine micro powder obtained by crushing and collecting concrete at 650-800 ℃ and preserving heat for 60-90 min. The invention surrounds the resource utilization requirement of solid waste, and greatly utilizes the fine powder generated in the construction waste crushing process of waste concrete, red bricks and the like, thereby effectively improving the carbon neutralization efficiency of construction and industry. Compared with the traditional expanding agent, the composite expanding agent has the advantages of high early strength, good fluidity, sulfate erosion resistance and the like.
Description
Technical Field
The invention relates to the technical field of building materials, in particular to a composite expanding agent based on regenerated micro powder and a preparation method thereof.
Background
The existing concrete expansion agent is developed based on expansion cement, and the expansion agent is mixed in the stirring process of the concrete, so that the expansion concrete can be prepared by stirring, and can also be called shrinkage-compensating concrete. The main principle is that the expansion agent has a certain expansion capacity after being hydrated with cement, and the expansion capacity can exactly offset the shrinkage of the cement. At present, concrete expanding agents mainly made of inorganic materials are mainly divided into: hydration reaction to produce calcium sulfoaluminate concrete expanding agent of ettringite; hydration reaction to produce calcium oxide and magnesium oxide as expanding agent for calcium hydroxide/magnesium oxide concrete; hydration reaction to produce ettringite and calcium sulfoaluminate and calcium oxide composite concrete expanding agent. A large amount of natural calcium source materials and sulphoaluminate materials are consumed in the existing production process of the concrete expanding agent, wherein the natural calcium source materials mainly are limestone to be decomposed to form quicklime, and a large amount of carbon dioxide is discharged in the process of exploiting the limestone and calcining to form the quicklime, so that the double-carbon strategic aim of China is not facilitated. The main raw material of the sulphoaluminate material is bauxite, which is a non-renewable resource and is unfavorable for sustainable development. Meanwhile, the expansion rates and the performances of different expansion sources are inconsistent, the calcium sulfoaluminate concrete expansion agent generally needs about 14 days to reach stability, the calcium oxide expansion agent can reach a stability period within 1-4 days after hydration, and both expansion agents can not continuously and stably provide expansion capability from the initial stage to the later stage of hydration. If the calcium sulfoaluminate and calcium oxide composite concrete expanding agent is doped, the expanding rate of the composite concrete expanding agent needs to be controlled by some technical means, such as a more severe curing condition and a larger water demand, otherwise, the expanding effect is greatly reduced, and even the strength is obviously influenced. Therefore, the existing expanding agent mainly has the defects of high cost, environmental protection, discontinuous expansion efficiency, no enhancement effect and the like.
Disclosure of Invention
The invention provides a composite expanding agent based on regenerated micro powder and a preparation method thereof, wherein the composite expanding agent has the characteristics of high early strength, micro expansion, quick coagulation, high solid waste resource recycling rate, good durability and the like, and effectively solves the problems of large shrinkage of cement-based materials and low utilization rate of the regenerated micro powder.
The invention aims at realizing the following technical scheme:
the first object of the invention is to provide a composite expanding agent based on regenerated micro powder, which consists of the following components: regenerated micropowder, low-temperature calcined regenerated micropowder, granulated blast furnace slag powder, steel slag powder, amorphous calcium aluminate, gypsum, dispersing agent and water reducer.
In one embodiment of the invention, the regenerated micro powder composite expanding agent consists of the following components in parts by mass: 5-10 parts of regenerated micro powder, 30-60 parts of low-temperature calcined regenerated micro powder, 5-15 parts of granulated blast furnace slag powder, 5-10 parts of steel slag powder, 20-40 parts of amorphous calcium aluminate, 5-20 parts of gypsum, 0.01-0.05 part of dispersing agent and 0.1-0.4 part of water reducer.
In one embodiment of the present invention, the regenerated micro powder is fine powder obtained by crushing concrete and collecting the fine powder, wherein the fineness of the fine powder is less than or equal to 75 μm.
In one embodiment of the invention, the low-temperature calcined regenerated micro powder is obtained by grinding fine micro powder collected by crushing concrete and low-temperature calcining; the low temperature is 650-800 ℃, the calcination time is 60-90 min, and the powder is ground until the specific surface area is more than or equal to 400m 2 /kg。
In one embodiment of the invention, the main mineral component of the amorphous calcium aluminate is dodecacalcium heptaluminate (C 12 A 7 ) And tricalcium aluminate (C) 3 A) The method comprises the steps of carrying out a first treatment on the surface of the Wherein C is 12 A 7 The content of (2) is more than 90 percent.
In one embodiment of the invention, the specific surface area of the amorphous calcium aluminate is more than or equal to 500m 2 /kg。
In one embodiment of the invention, the water reducing agent is a polycarboxylate superplasticizer and/or a naphthalene superplasticizer.
In one embodiment of the invention, the water reducing rate of the water reducing agent is more than or equal to 30 percent.
In one embodiment of the invention, the dispersant is aluminum stearate and/or cellulose ether.
In one embodiment of the invention, the proportion of the regenerated micro powder composite expanding agent to replace cement is 5-15% (mass percent).
In one embodiment of the invention, the granulated blast furnace slag powder meets the activity index and fluidity ratio requirements of grade S95 specified in GB/T18046-2017 granulated blast furnace slag powder for use in cement, mortar and concrete.
In one embodiment of the invention, the steel slag powder meets the activity index and fluidity ratio requirements of the primary steel powder specified in GB/T20491-2006 Steel slag powder for Cement and concrete.
In one embodiment of the invention, the gypsum is dihydrate gypsum meeting the requirements of GB/T21371-2019 Industrial byproduct gypsum for Cement.
The invention also aims to provide a preparation method of the composite expanding agent based on the regenerated micro powder, which comprises the following steps: and uniformly mixing the regenerated micro powder, the low-temperature calcined regenerated micro powder, the granulated blast furnace slag powder, the steel slag powder, the amorphous calcium aluminate, the gypsum, the water reducing agent and the dispersing agent to obtain the regenerated micro powder composite expanding agent.
The process flow chart of the composite expanding agent is shown in fig. 1, and specifically comprises the following steps:
s1: grinding the fine powder collected in the winnowing process in the waste concrete crushing process to 75 mu m to obtain regenerated micro powder with alkali excitation activity;
s2: placing the regenerated micro powder obtained in the step S1 into a muffle furnace for calcination treatment at 650-800 ℃, preserving the heat for 60-90 min, and grinding until the specific surface area is more than or equal to 400m 2 And (3) kg, obtaining regenerated micro powder by low-temperature calcination;
s3: uniformly mixing 5-10 parts of the regenerated micro powder obtained in the step S1, 30-60 parts of the low-temperature calcined regenerated micro powder obtained in the step S2, 5-15 parts of granulated blast furnace slag powder, 5-10 parts of steel slag powder, 20-40 parts of amorphous calcium aluminate, 5-20 parts of gypsum, 0.01-0.05 part of dispersing agent and 0.1-0.4 part of water reducer to obtain the composite expanding agent based on the regenerated micro powder.
The regenerated micropowder in the composite expanding agent based on the regenerated micropowder is fine powder collected in the winnowing process of the construction waste crushing process, and comprises the following components of SiO 2 、CaCO 3 、Ca(OH) 2 Hydrated calcium silicate, calcium aluminate, and the like. The regenerated micro powder has more surface pores, higher water absorption and no self-cementing hydration capacity, and is prepared by grinding fine powder collected in the winnowing process of the waste concrete crushing process to less than 75 mu m, namely, mechanically activating (grinding) the regenerated micro powder.
The low-temperature calcined regenerated micro powder is prepared by placing the ground regenerated micro powder into a muffle furnace for calcination treatment at 650-800 ℃ and preserving heat for 60-90 min, wherein the components are usually SiO 2 、CaO、Ca 2 SiO 4 And the like, has hydration activity and has synergistic hydration effect with aluminum phase minerals.
Amorphous stateCalcium aluminate is composed of CaO and Al 2 O 3 Mixing at a certain proportion, melting at a high temperature above 1200deg.C, rapidly cooling to form, grinding to a certain fineness to form amorphous calcium aluminate, wherein dodecacalcium heptaluminate (C) 12 A 7 ) The content is more than 90%, and the rest is mainly tricalcium aluminate (C 3 A)。
The granulated blast furnace slag powder is a powder material obtained by grinding water-quenched granulated blast furnace slag to a certain fineness, the surface of the particles is rough, and the active substance SiO is an active substance 2 High content and hydraulic property.
The steel slag powder is powder material with certain fineness produced by grinding waste slag in the steelmaking process, the surface of the particles is rough, and the chemical composition of the steel slag mainly comprises CaO and SiO 2 、Al 2 O 3 、Fe 2 O 3 MgO, which is similar to cement clinker in composition, has higher free calcium oxide component and has micro-expansion effect.
The regenerated micro powder is mixed with aluminum stearate and/or cellulose ether by low-temperature calcination, so that the surface of CaO particles is coated with a layer of thin aluminum stearate and/or cellulose ether to prevent CaO from contacting with the slurry at the initial stage of hydration, prolong the coagulation time of the slurry and play a role in dispersion.
In the process of preparing the composite expanding agent based on the regenerated micro powder, the original C-S-H gel structure surface layer in the regenerated micro powder is damaged due to the mechanical activation effect, the particle size distribution of the regenerated micro powder and the polymerization degree and mode of Si-O bonds and Al-O bonds in the regenerated micro powder are changed, the specific surface area of the regenerated micro powder is further increased, the activity of the regenerated micro powder is improved, and the depolymerization-polycondensation reaction can be carried out in alkaline environments such as slag powder, steel slag powder, gypsum slurry and the like to form multi-mineral hardening slurry. The DSC curve of the multi-mineral hardening slurry of the composite expanding agent based on the regenerated micro powder is shown in figure 2, and the hydraulic mineral in the regenerated micro powder is mainly C by low-temperature calcination 2 S, hydration products are C-S-H gel and Ca (OH) 2 Amorphous C 12 A 7 The hydration product being C 2 AH 8 And C 3 AH 6 。C 2 S-C 12 A 7 The hydration product of the system is C-S-H gelGlue C 2 AH 8 And C 3 AH 6 Ca (OH) was not found 2 . This is because C 12 A 7 Hydration releases Al (OH) 4- And Ca (OH) 2 Reaction to form C 3 AH 6 Thereby accelerating C 2 Hydration of S. C (C) 2 S-C 12 A 7 -CaSO 4 The hydration products of the system are C-S-H gels, AFt, C 3 AH 6 (weaker dehydration peak), no C was found 2 AH 8 And Ca (OH) 2 . Therefore, the hydration products after the low-temperature calcination of the regenerated micro powder, the amorphous calcium aluminate and the gypsum are C-S-H gel, AFt and C 3 AH 6 . This is because the presence of gypsum can be compared with Ca in the liquid phase 2+ And Al (OH) 4- And the calcium sulfoaluminate hydrate is formed by equal combination, so that Al (OH) in a liquid phase is reduced 4- Concentration, the reaction rate is accelerated. If no regenerated micropowder is added, the gypsum is completely reacted, and SO is not supplied to the liquid phase 3 SO in liquid phase 3 Reduced concentration of ettringite and C 12 A 7 The reaction is converted into AFm, and the calcium carbonate in the regenerated micro powder can prevent the conversion of AFt into AFm and continuously provide a micro-expansion effect. Therefore, the composite expanding agent of the invention, ca during the hydration reaction 2+ 、SO 4 2- 、Al(OH) 4- AFt is generated by the reaction, and a large amount of Ca (OH) is consumed 2 C is destroyed 2 S solid-liquid balance, promote C 2 S-hydration releases more Ca 2+ Finally, ca (OH) in hydration products is reduced 2 The content of (2) accelerates the hydration reaction rate of cement, and has obvious expansion effect and sulfate erosion resistance.
Low-temperature calcining regenerated micropowder to produce beta-C 2 S, caO and amorphous calcium aluminate and gypsum to form ettringite, calcium hydroxide and other crystals, and has good micro-expansion effect. The content of calcium carbonate in the regenerated micropowder is high, and after the system is compounded, ettringite can be stabilized, so that the ettringite has the characteristic of micro-expansion continuously. The hydrated products C-S-H gel and hydrated calcium aluminate in the granulated blast furnace slag powder, steel slag powder and regenerated micropowder also have Si-O bond and Al-O bond under the alkaline excitation conditions of gypsum, calcium hydroxide and the likeStructural cleavage and recombination will occur, yielding a new cementitious product. Along with the extension of age, the structure of the solidified body is more and more compact, and the strength is gradually improved.
Therefore, when the silicate cement is mixed with the regenerated micro powder composite expanding agent, ca (OH) 2 And C 12 A 7 Released Al (OH) 4- Reaction to form C 3 AH 6 And ettringite, accelerate hydration reaction of silicate cement and break C 3 S、C 2 S and Ca (OH) 2 The solution has the advantages of solid-liquid balance, accelerating hydration reaction of silicate minerals, shortening setting time, improving early strength of hardened slurry, enabling mass production of ettringite to have micro-expansion effect, promoting hydration process, accelerating hydration of cement and formation of hardened slurry structure, and improving physical and mechanical properties of hardened slurry, namely mortar and concrete.
Compared with the prior art, the invention has the advantages that:
(1) The low-temperature calcined regenerated micro powder used in the invention mainly comprises dicalcium silicate, calcium oxide, quartz and other phases, wherein the dicalcium silicate has hydration activity, and calcium oxide crystals have micro-expansion characteristics. The low-temperature calcined regenerated micro powder is compounded with aluminate minerals and gypsum and then hydrated to form ettringite (AFt) and calcium hydroxide, so that the effect similar to that of the calcium sulfoaluminate and calcium oxide composite concrete expanding agent is formed. Meanwhile, the calcium carbonate in the regenerated micro powder has the function of stabilizing ettringite (AFt), can prevent the ettringite from being converted into mono-sulfur hydrated calcium sulfoaluminate (AFm) in the hydration process, has the synergistic hydration effect of slag powder and steel slag powder, ensures the strength development of the expanding agent in the use process of concrete, and can provide active SiO simultaneously 2 And Al 2 O 3 And (3) accelerating hydration of the composite expanding agent. Aluminum stearate/cellulose ether particles are coated on the surfaces of calcium sulfoaluminate and calcium oxide, contact between CaO and the slurry is blocked at the initial stage of hydration, and the coagulation time of the slurry is prolonged. The water reducing agent can adjust the working performance of the slurry. Therefore, the low-temperature calcined regenerated micro powder, aluminum phase minerals and gypsum are compounded to replace part of cement-based materials, and slag powder, steel slag powder and additives are added, so that the cost can be reduced and the early stage is improvedThe phase strength can achieve the micro-expansion effect, and has important significance for the utilization of a large amount of regenerated micro-powder with high added value in the construction industry.
(2) The composite expanding agent prepared based on the processes of mechanical activation, alkali activation, low-temperature calcination and the like of the regenerated micro powder can realize mass resource utilization of the regenerated micro powder, reduce land occupation, save natural resources and improve environment.
(3) The invention takes regenerated micro powder, low-temperature calcined regenerated micro powder, granulated blast furnace slag powder, steel slag powder, amorphous calcium aluminate, gypsum, dispersant, water reducer and the like as main raw materials, and is added into cement to ensure that the cement has the characteristics of good fluidity, high strength, good durability, micro expansion and the like. Compared with the traditional cement-based expanding agent, the composite expanding agent based on the regenerated micro powder has the advantages of high early strength, good fluidity, sulfate erosion resistance and the like.
(4) The preparation method is simple, does not need large equipment and complex technology, has flexible and adjustable composition and performance, is easy to control, has good applicability, and has the characteristics of low cost, good fluidity, high strength, high utilization rate of regenerated micro powder, good durability, good shrinkage and the like.
Drawings
In order that the invention may be more readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings, in which
FIG. 1 is a schematic process flow diagram of a composite expansion agent of the present invention;
FIG. 2 is a DSC curve of a multi-mineral hardening slurry of the present invention;
FIG. 3 is an XRD spectrum of cement hardened slurries incorporating different complex expansion agents of the present invention.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and specific examples, which are not intended to be limiting, so that those skilled in the art will better understand the invention and practice it.
Example 1
A composite expanding agent based on regenerated micro powder comprises the following components in parts by mass:
the regenerated micro powder composite expanding agent is prepared by uniformly mixing 5 parts of regenerated micro powder, 40 parts of low-temperature calcined regenerated micro powder, 20 parts of amorphous calcium aluminate, 10 parts of gypsum, 15 parts of granulated blast furnace slag powder, 10 parts of steel slag powder, 0.2 part of polycarboxylate superplasticizer and 0.01 part of aluminum stearate. Then, after 5 percent (mass percent) of cement is replaced by the regenerated micro powder composite expansion agent, under the curing condition that the temperature is 20+/-2 ℃ and the relative humidity is 60+/-5 percent, the 7d limiting expansion rate of the cement-based material is measured to be 280 multiplied by 10 -6 。
Example 2
A composite expanding agent based on regenerated micro powder comprises the following components in parts by mass:
the regenerated micro powder composite expanding agent is prepared by uniformly mixing 10 parts of regenerated micro powder, 30 parts of low-temperature calcined regenerated micro powder, 30 parts of amorphous calcium aluminate, 20 parts of gypsum, 5 parts of granulated blast furnace slag powder, 5 parts of steel slag powder, 0.3 part of naphthalene water aqua and 0.05 part of cellulose ether. Then the regenerated micro powder composite expanding agent is substituted for 12 percent
After cement in mass percent, the 7d limit expansion rate of the cement-based material was 460×10 under curing conditions at a temperature of 20±2 ℃ and a relative humidity of 60±5% -6 。
Example 3
A composite expanding agent based on regenerated micro powder comprises the following components in parts by mass:
the regenerated micro powder composite expanding agent is prepared by uniformly mixing 5 parts of regenerated micro powder, 60 parts of low-temperature calcined regenerated micro powder, 20 parts of amorphous calcium aluminate, 5 parts of gypsum, 5 parts of granulated blast furnace slag powder, 5 parts of steel slag powder, 0.2 part of polycarboxylic acid water agent and 0.02 part of cellulose ether. Then, 15 percent (mass percent) of cement is replaced by the regenerated micro powder composite expansion agent, and under the curing condition that the temperature is 20+/-2 ℃ and the relative humidity is 60+/-5 percent, the 7d limiting expansion rate of the cement-based material is measured to be 500 multiplied by 10 -6 。
Example 4
A composite expanding agent based on regenerated micro powder comprises the following components in parts by mass:
the regenerated micro powder composite expanding agent is prepared by uniformly mixing 5 parts of regenerated micro powder, 40 parts of low-temperature calcined regenerated micro powder, 35 parts of amorphous calcium aluminate, 5 parts of gypsum, 10 parts of granulated blast furnace slag powder, 5 parts of steel slag powder, 0.4 part of naphthalene water aqua and 0.03 part of aluminum stearate. Then, after the regenerated micro powder composite expanding agent is used for replacing 8 percent (mass percent) of cement, under the curing condition that the temperature is 20+/-2 ℃ and the relative humidity is 60+/-5 percent, the 7d limiting expansion rate of the cement-based material is measured to be 200 multiplied by 10 -6 。
Comparative example 1
A composite expanding agent based on regenerated micro powder comprises the following components in parts by mass:
40 parts of regenerated micro-particles are calcined at low temperatureThe powder, 30 parts of amorphous calcium aluminate, 15 parts of gypsum, 5 parts of granulated blast furnace slag powder, 10 parts of steel slag powder, 0.3 part of naphthalene water reducer and 0.04 part of cellulose ether are uniformly mixed to prepare the regenerated micro powder composite expanding agent. Then, after 10% of cement is replaced by the regenerated micro powder composite expansion agent, under the curing condition that the temperature is 20+/-2 ℃ and the relative humidity is 60+/-5%, the 7d limit expansion rate of the cement-based material is measured to be-80 multiplied by 10 -6 。
Comparative example 2
A composite expanding agent based on regenerated micro powder comprises the following components in parts by mass:
the regenerated micro powder composite expanding agent is prepared by uniformly mixing 60 parts of low-temperature calcined regenerated micro powder, 20 parts of gypsum, 10 parts of granulated blast furnace slag powder, 10 parts of steel slag powder, 0.3 part of naphthalene water reducer and 0.04 part of cellulose ether. Then, after 10% of cement is replaced by the regenerated micro powder composite expansion agent, under the curing condition that the temperature is 20+/-2 ℃ and the relative humidity is 60+/-5%, the 7d limit expansion rate of the cement-based material is measured to be-200 multiplied by 10 -6 。
Comparative example 3
A composite expanding agent based on regenerated micro powder comprises the following components in parts by mass:
the regenerated micro powder composite expanding agent is prepared by uniformly mixing 40 parts of amorphous calcium aluminate, 20 parts of gypsum, 20 parts of granulated blast furnace slag powder, 20 parts of steel slag powder, 0.3 part of polycarboxylate water reducer and 0.02 part of aluminum stearate. Then, after 15% of cement is replaced by the regenerated micro powder composite expansion agent, under the curing condition that the temperature is 20+/-2 ℃ and the relative humidity is 60+/-5%, the 7d limit expansion rate of the cement-based material is measured to be-50 multiplied by 10 -6 。
Comparative example 4
A composite expanding agent based on regenerated micro powder comprises the following components in parts by mass:
45 parts of regenerated micro powder, 20 parts of amorphous calcium aluminate, 10 parts of gypsum, 15 parts of granulated blast furnace slag powder, 10 parts of steel slag powder, 0.2 part of polycarboxylate water reducer and 0.01 part of aluminum stearate are uniformly mixed to prepare the regenerated micro powder composite expanding agent. Then, the regenerated micro powder composite expanding agent is used for replacing 5 percent (mass percent) of cement, and under the curing condition that the temperature is 20+/-2 ℃ and the relative humidity is 60+/-5 percent, the 7d limiting expansion rate of the cement-based material is measured to be-170 multiplied by 10 -6 。
Comparative example 5
A composite expanding agent based on regenerated micro powder comprises the following components in parts by mass:
the regenerated micro powder composite expanding agent is prepared by uniformly mixing 25 parts of regenerated micro powder, 40 parts of low-temperature calcined regenerated micro powder, 10 parts of gypsum, 15 parts of granulated blast furnace slag powder, 10 parts of steel slag powder, 0.2 part of polycarboxylate water reducer and 0.01 part of aluminum stearate. Then, the regenerated micro powder composite expanding agent is used for replacing 5 percent (mass percent) of cement, and under the curing condition that the temperature is 20+/-2 ℃ and the relative humidity is 60+/-5 percent, the 7d limiting expansion rate of the cement-based material is measured to be-350 multiplied by 10 -6 。
Comparative example 6 conventional Cement-based expansion agent
After 8 percent (mass percent) of cement is replaced by the calcium sulfoaluminate and calcium oxide composite concrete expanding agent, the 7d limiting expansion rate of the cement-based material is measured to be 100 multiplied by 10 under the curing condition that the temperature is 20+/-2 ℃ and the relative humidity is 60+/-5 percent -6 。
The performance of the composite expansive agent of examples 1 to 4 and comparative examples 1 to 6 was examined with reference to national specifications GB/T17671-2021 (ISO method) for testing strength of cement mortar, JC4762017 (concrete expansive agent) and GB/T50082-2009 (Standard for testing Long-term Performance and durability of ordinary concrete), and the measurement results are shown in Table 1 below.
TABLE 1 measurement results of the Properties of the regenerated micropowder composite expander
As shown by the results in Table 1, the initial setting time of examples 1 to 4 was increased by 29% or more, the 3d compressive strength was increased by 25% or more, and the 7d limiting expansion rate was increased from-250X 10, as compared with comparative examples 1 to 6 -6 Lifting to 500X 10 -6 The sulfate erosion resistance is remarkably enhanced.
As can be seen from the comparative examples and examples, when Portland cement is incorporated with a cement containing C 2 S-C 12 A 7 -CaSO 4 After regeneration of the micro-powder expanding agent, ca (OH) 2 And C 12 A 7 Released Al (OH) 4- Reaction to form C 3 AH 6 And ettringite, accelerate hydration reaction of silicate cement and break C 3 S、C 2 S and Ca (OH) 2 The solution has balanced solid and liquid, thus shortening the coagulation time and improving the early strength of the hardened slurry. Therefore, the regenerated micro powder composite expanding agent replaces 5 to 15 percent of silicate cement, and can play a role in promoting the hydration process, accelerating the hydration of cement and the formation of a hardened slurry structure, improving the physical and mechanical properties of the hardened slurry, namely mortar and concrete, and reducing shrinkage in the hydration of calcium oxide crystals and the formation process of ettringite crystals to form the micro-expansive cement-based material.
The composite expansion agent of comparative example 1 lacks the regenerated fine powder, and only ettringite and calcium hydroxide are formed in the system, but the micro expansion effect is not sustainable because the stabilization effect of calcium carbonate (limestone) in the regenerated fine powder on ettringite is not provided, and finally, the shrinkage effect is still exhibited by 7 d.
The composite expansion agent of comparative example 2 lacks amorphous calcium aluminate and regenerated micropowder, and calcium hydroxide is formed in the system, but the micro-expansion effect cannot be achieved due to the low content of calcium oxide in the regenerated micropowder by low-temperature calcination, and finally the shrinkage effect is still shown by 7 d.
The composite expansion agent of comparative example 3 lacks low-temperature calcined regenerated micropowder and regenerated micropowder, and even if ettringite is formed in the system, the calcium hydroxide expansion effect cannot be achieved due to the lack of the stabilization effect of calcium carbonate on ettringite and the calcium oxide expansion effect generated by calcining the regenerated micropowder, and finally the shrinkage effect is still exhibited in 7 d.
The XRD spectra of the cement hardening slurries containing different composite expansion agents of examples 1, 2 and 3 and comparative example 2 according to the present invention are shown in FIG. 3, and the hydration products are substantially identical to those of the pure Portland cement after the composite expansion agents are added to the cements, but the characteristic peaks of the calcium hydroxide and ettringite of examples 1, 2 and 3 are remarkably enhanced. The results show that the proper amount of the compound expansion agent greatly promotes the hydraulic mineral C 3 S and C 2 S, the hydration degree of cement is improved, the ettringite content in the hydrated slurry is increased, amorphous calcium aluminate is not generated in comparative example 2, and the generation amount of ettringite is obviously reduced.
Compared with comparative examples 4 and 5, the compound expansion agent of the invention does not achieve the micro-expansion effect when the compound expansion agent lacks low-temperature calcined regenerated micro powder or amorphous calcium aluminate respectively, and mainly lacks C 2 S and C 12 A 7 The compound expander fails to exhibit a great deal of expansion efficiency.
Compared with comparative example 6, the conventional cement-based composite expanding agent has weaker micro-expansion effect at 7d, and the composite expanding agent has the advantages of quick setting, high strength and continuous expansion efficiency, and has obvious advantages.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations and modifications of the present invention will be apparent to those of ordinary skill in the art in light of the foregoing description. It is not necessary here nor is it exhaustive of all embodiments. And obvious variations or modifications thereof are contemplated as falling within the scope of the present invention.
Claims (7)
1. The composite expanding agent based on the regenerated micro powder is characterized by comprising the following components: regenerated micropowder, low-temperature calcined regenerated micropowder, granulated blast furnace slag powder, steel slag powder, amorphous calcium aluminate, gypsum, dispersing agent and water reducer; the regenerated micro powder is fine powder obtained by crushing concrete and collecting the crushed concrete, and the fineness of the fine powder is less than or equal to 75 mu m;
the regenerated micro powder composite expanding agent consists of the following components in parts by mass: 5-10 parts of regenerated micro powder, 30-60 parts of low-temperature calcined regenerated micro powder, 5-15 parts of granulated blast furnace slag powder, 5-10 parts of steel slag powder, 20-40 parts of amorphous calcium aluminate, 5-20 parts of gypsum, 0.01-0.05 part of dispersing agent and 0.1-0.4 part of water reducer;
the low-temperature calcination regenerated micro powder is obtained by low-temperature calcination of fine micro powder body obtained by crushing and collecting concrete; the low temperature range is 650-800 ℃.
2. The composite expansion agent according to claim 1, wherein the low temperature calcination time is 60min to 90min.
3. The composite expanding agent according to claim 1, wherein the specific surface area of the amorphous calcium aluminate is not less than 500m 2 /kg。
4. The compound expansion agent according to claim 1, wherein the water reducing agent is a polycarboxylic acid high-efficiency water reducing agent and/or a naphthalene-based high-efficiency water reducing agent.
5. The composite expansion agent according to claim 1, wherein the water reducing rate of the water reducing agent is not less than 30%.
6. The compound expansion agent according to claim 1, wherein the dispersant is aluminum stearate and/or cellulose ether.
7. The method for preparing the composite expanding agent according to any one of claims 1 to 6, comprising the steps of: and uniformly mixing the regenerated micro powder, the low-temperature calcined regenerated micro powder, the granulated blast furnace slag powder, the steel slag powder, the amorphous calcium aluminate, the gypsum, the water reducing agent and the dispersing agent to obtain the composite expanding agent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210515615.2A CN114956642B (en) | 2022-05-12 | 2022-05-12 | Composite expanding agent based on regenerated micro powder and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210515615.2A CN114956642B (en) | 2022-05-12 | 2022-05-12 | Composite expanding agent based on regenerated micro powder and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114956642A CN114956642A (en) | 2022-08-30 |
| CN114956642B true CN114956642B (en) | 2023-05-02 |
Family
ID=82980350
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210515615.2A Active CN114956642B (en) | 2022-05-12 | 2022-05-12 | Composite expanding agent based on regenerated micro powder and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114956642B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117105621B (en) * | 2023-08-25 | 2024-04-09 | 广东广物金属产业集团有限公司 | High-strength concrete based on solid waste and preparation method thereof |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105152553A (en) * | 2015-07-10 | 2015-12-16 | 胡相明 | Green expansive cementing material based on salt chemical industry solid waste and building garbage, preparation method and applications thereof |
| US11168029B2 (en) * | 2017-01-10 | 2021-11-09 | Roman Cement, Llc | Use of mineral fines to reduce clinker content of cementitious compositions |
| CN107235646A (en) * | 2017-05-23 | 2017-10-10 | 贵州师范大学 | Concrete regenerating powder microdilatancy eco-cement and preparation method thereof |
| CN110776281B (en) * | 2019-10-28 | 2021-05-28 | 山东大学 | Regenerated powder composite mine cemented filling material and preparation method thereof |
| CN112062533B (en) * | 2020-08-07 | 2022-08-05 | 扬州大学 | Alkali-activated regenerated micro-powder foam concrete and preparation method thereof |
-
2022
- 2022-05-12 CN CN202210515615.2A patent/CN114956642B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN114956642A (en) | 2022-08-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| TWI478891B (en) | Expandable material and its manufacturing method | |
| KR102685380B1 (en) | Ultra-low carbon clinker-free cement and its manufacturing method and application | |
| CN112608047B (en) | Modified sulphoaluminate cement and preparation method and application thereof | |
| CN111847936A (en) | Novel phosphate cement and preparation method thereof | |
| CN114988791B (en) | Flue grouting material doped with sulfur-rich lithium slag, and preparation method and application thereof | |
| Yoon et al. | Physical properties of activated slag concrete using phosphogypsum and waste lime as an activator | |
| CN111847921B (en) | Low clinker cement and preparation method and application thereof | |
| CN112851162A (en) | Cementing material and preparation method thereof | |
| CN115321851A (en) | Green low-carbon high-performance cementing material and preparation method thereof | |
| CN114956642B (en) | Composite expanding agent based on regenerated micro powder and preparation method thereof | |
| CN116409948A (en) | Low-carbon composite cementing material based on regenerated micro powder, and preparation method and application thereof | |
| CN111302677A (en) | Super-sulfate cement and preparation method thereof | |
| CN112209692A (en) | Phosphogypsum anti-cracking plastering mortar and preparation method thereof | |
| CN113939486A (en) | Process for manufacturing a hydraulic binder from water treatment residues | |
| CN109320153B (en) | High-temperature-resistant hydraulic cement material and mortar prepared from same | |
| CN1092747A (en) | High-efficiency concrete expansion admixture and manufacture method thereof | |
| CN108264249B (en) | Ferronickel slag-slag low-hydration-heat cementing material and preparation method thereof | |
| CN115650609A (en) | Carbon-cured cementing material, preparation method and application | |
| CN115368034A (en) | Self-powdering carbon-cured cementing material prepared by utilizing solid wastes and preparation method thereof | |
| CN114920473A (en) | Multi-element low-carbon less-clinker composite cement and preparation method thereof | |
| Beretka et al. | Cementitious mixtures containing industrial process wastes suitable for the manufacture of preformed building elements | |
| CN108840585B (en) | Low-temperature preparation method of concrete anti-cracking agent | |
| CN108585735B (en) | Plugging agent and preparation method thereof | |
| CN109867456B (en) | Application of magnesium sulfate, portland cement containing magnesium sulfate, preparation method and application thereof | |
| CN116768505B (en) | Ion doping prepared alite-belite-calcium sulfoaluminate cement clinker and method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |