CN113248191B - Inert concrete waste slurry solidified material and preparation method thereof - Google Patents
Inert concrete waste slurry solidified material and preparation method thereof Download PDFInfo
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- 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
- C04B28/006—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 mineral polymers, e.g. geopolymers of the Davidovits type
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- 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
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- 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
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- Y02W30/91—Use of waste materials as fillers for mortars or concrete
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Abstract
The invention relates to the technical field of building materials, in particular to an inert concrete waste slurry solidified body material and a preparation method thereof. In the invention, the secondary fly ash and the S95 slag are active raw materials and excited raw materials; the activator is anhydrous sodium carbonate powder and sodium metasilicate pentahydrate powder, the alkali activator is dissolved in the waste water-containing slurry and activates the activity of the activated raw material, so that the strength is developed to form a solidified body, the homogenized concrete waste slurry is used as an auxiliary raw material, and the internal particles of the concrete waste slurry can be uniformly filled in holes in the solidified body, so that the harmless treatment of the concrete waste slurry is realized. Meanwhile, compared with the traditional cement material, the curing effect of the invention on the waste concrete slurry is better, the porosity of the cured body material is low, the microstructure is denser, the mechanical strength is high, and the high-temperature stability is better.
Description
Technical Field
The invention relates to the technical field of building materials, in particular to an inert concrete waste slurry solidified body material and a preparation method thereof.
Background
The inert concrete waste slurry is mainly produced in commercial concrete mixing plants, and is a high-alkalinity and high-moisture particle type waste accumulated at the bottom of a sedimentation tank through a recycling system (sand-stone separation and sedimentation tank filtration), and the main components comprise water, fine aggregates (fine sand, aluminosilicate minerals in the sand-stone aggregates, such as mica minerals and other impurities), cement hydration products, mineral admixtures (fly ash, slag and the like) and a small part of coarse aggregates (pebbles, crushed stones), and the sources of the components are complex. The alkalinity of the waste slurry is generally 11.5-12.5, the waste slurry is stored in a high-alkalinity water-containing sedimentation tank for a long time, the reactivity of the waste slurry is low (the activity index is less than 60 percent), the waste slurry is difficult to be effectively recycled, and although part of concrete mixing plant stations can achieve zero emission, part of plant stations still transport the waste slurry to a landfill site for landfill after digging out the waste slurry from the sedimentation tank, so that the waste of resources and the pollution to the environment are caused.
At present, except for landfill, the treatment means of the inert concrete waste slurry is mainly to regenerate the inert concrete waste slurry for a cement concrete structure (aggregate and cement substitute products):
(1) the concrete waste slurry is used as a substitute for coarse and fine aggregates in a concrete structure by air drying (drying), crushing and sieving, but the concrete waste slurry has complex components, low quality, low strength and high porosity, can deteriorate the flowing property, the mechanical property and the durability of the formed concrete, has low substitution rate (< 30 percent), and wastes time and energy for the pretreatment of the waste slurry. For part of fresh and reactive concrete waste slurry (activity index > 70%) which is just produced, the method can be used in some secondary and non-structural cement concrete materials or combined with carbonization technology to prepare novel concrete products and the like in a grade mode, but the method is not the type of waste slurry for which the invention is aimed.
(2) After the concrete waste slurry is air-dried (dried) and ground to a certain fineness, the concrete waste slurry is used for replacing cement and fly ash as cementing materials and is used for common concrete structures, but the problems of high pretreatment energy consumption (the grinding fineness is required to be high, generally, the higher the fineness is, the higher the reactivity is), lower substitution rate and the like exist.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide an inert concrete waste slurry solidified material and a preparation method thereof, the inert concrete waste slurry solidified material provided by the present invention effectively utilizes waste resources, inert concrete waste slurry, and the obtained inert concrete waste slurry solidified material has better mechanical properties and high temperature stability than cement materials under the same mixing ratio.
The invention provides a preparation method of an inert concrete waste slurry solidified body material, which comprises the following steps:
A) homogenizing the inert concrete waste slurry;
B) stirring and mixing the slurry treated in the step A), the secondary fly ash, the S95-grade slag powder, the anhydrous sodium carbonate powder and the sodium metasilicate pentahydrate powder to obtain mixed slurry;
C) and forming the mixed slurry to obtain the inert concrete waste slurry solidified body material.
Preferably, the concentration of the inert concrete waste slurry is 40-60 wt%;
the pH value of the inert concrete waste slurry is 11.5-12.5;
the 28d activity index of the inert concrete waste slurry is 50-60%.
Preferably, the homogenization treatment is vortex homogenization treatment; d of homogenized concrete waste slurry50Is 3 to 5 μm.
Preferably, the homogenization treatment comprises:
and stirring the concrete waste slurry for 45-60 min under the conditions that the temperature is not lower than 20 ℃ and the rotating speed frequency is 35-45 Hz.
Preferably, D of the secondary fly ash50<23 mu m, and the activity index is 70-75%;
d of the S95 grade slag powder50<16 mu m, and the activity index is 95-98%;
the mass ratio of the secondary fly ash to the S95 grade slag powder is 2-5: 5-8;
the mass ratio of the anhydrous sodium carbonate powder to the sodium metasilicate pentahydrate powder is 1-2: 0.5 to 1.5.
Preferably, the ratio of the total mass of the anhydrous sodium carbonate powder and the sodium metasilicate pentahydrate powder to the total mass of the secondary fly ash and the S95 slag powder is 15-25: 100.
preferably, the mass ratio of the inert concrete waste slurry to the total mass of the secondary fly ash and the S95 slag powder is 0.5-1.5: 0.5 to 1.5.
Preferably, in the step B), the rotating speed frequency of stirring and mixing is 40-45 Hz.
Preferably, in step C), after the forming, the method further comprises: naturally maintaining;
the natural curing temperature is 20-30 ℃.
The invention also provides an inert concrete waste slurry solidified body material prepared by the preparation method.
The invention provides a preparation method of an inert concrete waste slurry solidified body material, which comprises the following steps: A) homogenizing the inert concrete waste slurry; B) stirring and mixing the slurry treated in the step A), the secondary fly ash, the S95-grade slag powder, the anhydrous sodium carbonate powder and the sodium metasilicate pentahydrate powder to obtain mixed slurry; C) and forming the mixed slurry to obtain the inert concrete waste slurry solidified body material. In the invention, the secondary fly ash and the S95 slag are active raw materials and excited raw materials; the activator is anhydrous sodium carbonate powder and sodium metasilicate pentahydrate powder, the alkali activator is dissolved in the waste water-containing slurry and activates the activity of the activated raw material, so that the strength is developed to form a solidified body, the homogenized concrete waste slurry is used as an auxiliary raw material, and the internal particles of the concrete waste slurry can be uniformly filled in holes in the solidified body, so that the harmless treatment of the concrete waste slurry is realized. Meanwhile, compared with the traditional cement material, the curing effect of the invention on the waste concrete slurry is better, the porosity of the cured body material is low, the microstructure is denser, the mechanical strength is high, and the high-temperature stability is better.
Drawings
FIG. 1 is an XRD pattern of an inert concrete waste slurry of example 1 of the present invention.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a preparation method of an inert concrete waste slurry solidified body material, which comprises the following steps:
A) homogenizing the inert concrete waste slurry;
B) stirring and mixing the slurry treated in the step A), the secondary fly ash, the S95-grade slag powder, the anhydrous sodium carbonate powder and the sodium metasilicate pentahydrate powder to obtain mixed slurry;
C) and forming the mixed slurry to obtain the inert concrete waste slurry solidified body material.
The waste inert concrete slurry is mainly from commercial concrete mixing plant, and is a high-water-content granular waste which is formed by the waste concrete slurry, is subjected to sand-stone separation and is filtered by a sedimentation tank and is accumulated at the bottom of the sedimentation tank. The inert concrete waste slurry comprises water, fine aggregates, cement hydration products, mineral admixtures and coarse aggregates. The fine aggregate includes fine sand and aluminosilicate minerals. The mineral admixture includes a minor proportion of fly ash and slag particles of low reactivity. The coarse aggregate includes pebbles and crushed stones.
In certain embodiments of the present invention, the concentration of the inert concrete waste slurry is 40 wt% to 60 wt%. In certain embodiments, the inert concrete waste slurry has a concentration of 50 wt%. The inert concrete waste slurry with high water content can be naturally air-dried, and when the concentration of the inert concrete waste slurry meets 40-60 wt%, homogenization is performed.
In some embodiments of the invention, the inert concrete waste slurry has a pH of 11.5 to 12.5. In certain embodiments, the inert concrete waste slurry has a pH of 12.0.
In certain embodiments of the invention, D of the inert concrete waste slurry50<20 μm，D10<5.4 μm，D90<62.4 μm. In certain embodiments, D of inert concrete waste slurry5019.271 μm, D105.362 μm, D9062.319 μm.
In certain embodiments of the invention, the inert concrete waste slurry has a 28d activity index of 50% to 60% (measured according to GB/T17671). In certain embodiments, the inert concrete waste slurry has a 28d activity index of 55%.
In certain embodiments of the invention, the homogenization treatment is a vortex homogenization treatment.
In certain embodiments of the invention, the homogenization process comprises:
and stirring the inert concrete waste slurry for 45-60 min under the conditions that the temperature is not lower than 20 ℃ and the rotating speed frequency is 35-45 Hz.
The homogenization treatment can fully disperse the inert concrete waste slurry, and the inert concrete waste slurry is changed into a flowable state again from an agglomerated and viscous state.
In certain embodiments of the invention, D of the homogenized concrete waste slurry503 to 5 μm, D101 to 3 μm, D905 to 10 μm. In certain embodiments, D of the homogenized concrete waste slurry50It was 3.757 μm. In certain embodiments, D of the homogenized concrete waste slurry10It was 1.747 μm. In certain embodiments, D of the homogenized concrete waste slurry908.423 μm.
And after the homogenization treatment is finished, stirring and mixing the homogenized slurry, the secondary fly ash, the S95-grade slag powder, the anhydrous sodium carbonate powder and the sodium metasilicate pentahydrate powder to obtain mixed slurry.
In certain embodiments of the invention, the secondary fly ash is a low calcium fly ash, the calcium content of the secondary fly ash being <10 wt%.
In certain embodiments of the invention, D of the secondary fly ash50<23 μm，D10<2.4 μm，D90<92.4 μm. In certain embodiments, D of the secondary fly ash5022.546 μm, D102.374 μm, D9092.322 μm. In certain embodiments of the present invention, the secondary fly ash has a 28d activity index of 70% to 75%. In certain embodiments, the secondary fly ash has a 28d activity index of 73%.
In certain embodiments of the invention, D of the grade S95 slag powder50<16 μm，D10<1.9 μm，D90<43.8 μm. In certain embodiments, D of the grade S95 slag powder5015.974 μm, D101.822 μm, D9043.764 μm. In certain embodiments of the present invention, the S95The grade slag powder is S95 grade granulated blast furnace slag powder, and the 28d activity index is 95-98%. In certain embodiments, the grade S95 slag powder has a 28d activity index of 96%.
In the invention, the secondary fly ash and the S95 slag powder are active raw materials. In certain embodiments of the invention, the mass ratio of the secondary fly ash to the S95 grade slag powder is 2-5: 5 to 8. In certain embodiments, the mass ratio of the secondary fly ash to the S95 grade slag powder is 1: 1.
in the present invention, the anhydrous sodium carbonate powder and the sodium metasilicate pentahydrate powder are alkali activators. In certain embodiments of the invention, the anhydrous sodium carbonate powder is reagent grade, with a purity > 99.8%. In certain embodiments of the invention, the sodium metasilicate pentahydrate powder is reagent grade, has a modulus of 0.93, and has a modulus equal to the ratio of the sodium oxide to the silica molecular weight.
In certain embodiments of the invention, the mass ratio of the anhydrous sodium carbonate powder to the sodium metasilicate pentahydrate powder is 1-2: 0.5 to 1.5. In certain embodiments, the anhydrous sodium carbonate powder and sodium metasilicate pentahydrate powder are in a mass ratio of 1.5: 1.
in certain embodiments of the invention, the ratio of the total mass of the anhydrous sodium carbonate powder and the sodium metasilicate pentahydrate powder to the total mass of the secondary fly ash and the S95 slag powder is 15-25: 100. in certain embodiments, the ratio of the total mass of the anhydrous sodium carbonate powder and sodium metasilicate pentahydrate powder to the total mass of the secondary fly ash and S95 slag powder is 20: 100. 15: 100 or 25: 100.
in certain embodiments of the invention, the mass ratio of the inert concrete waste slurry to the total mass of the secondary fly ash and the S95 slag powder is 0.5-1.5: 0.5 to 1.5. In certain embodiments, the mass ratio of the inert concrete waste slurry to the total mass of the secondary fly ash and S95 slag powder is 1: 1.
in some embodiments of the invention, the rotation speed frequency of the stirring and mixing is 40-45 Hz.
Specifically, the method comprises the following steps:
b1) adding the secondary fly ash and the S95-grade slag powder into the homogenized slurry, and stirring and mixing;
b2) and adding anhydrous sodium carbonate powder and sodium metasilicate pentahydrate powder, and stirring and mixing to obtain mixed slurry.
b1) The method comprises the following steps:
in some embodiments of the invention, the rotation speed frequency of the stirring and mixing is 40 to 45Hz, and the time is 1 to 2 min. In certain embodiments, the rotational frequency of the agitation mixing is 42 Hz. In certain embodiments, the time for mixing with stirring is 1 min.
b2) The method comprises the following steps:
in some embodiments of the invention, the rotation speed frequency of the stirring and mixing is 40 to 45Hz, and the time is 1 to 2 min. In certain embodiments, the rotational frequency of the agitation mixing is 42 Hz. In certain embodiments, the time for mixing with stirring is 1 min.
And after the mixed slurry is obtained, forming the mixed slurry to obtain the inert concrete waste slurry solidified body material.
In certain embodiments of the present invention, the mixed slurry formation is performed in a mold.
In some embodiments of the present invention, after the forming, further comprising: and (5) naturally maintaining.
In some embodiments of the invention, the natural curing temperature is 20-30 ℃.
In some embodiments of the invention, the natural curing may be an outdoor curing.
When the natural curing temperature is higher than 30 ℃, a jute bag or a sunshade needs to be paved to avoid direct sunlight, and construction at noon in summer needs to be avoided.
The source of the above-mentioned raw materials is not particularly limited, and the raw materials may be generally commercially available.
The invention also provides an inert concrete waste slurry solidified body material prepared by the preparation method.
In the invention, the secondary fly ash and the S95 slag are active raw materials and excited raw materials; the activator is anhydrous sodium carbonate powder and sodium metasilicate pentahydrate powder, the alkali activator is dissolved in the waste water-containing slurry and activates the activity of the activated raw material, so that the strength is developed to form a solidified body, the homogenized concrete waste slurry is used as an auxiliary raw material, and the internal particles of the concrete waste slurry can be uniformly filled in holes in the solidified body, so that the harmless treatment of the concrete waste slurry is realized.
The waste inert concrete slurry is pumped out of the sedimentation tank, and can be recycled only by 5-10 min of homogenization treatment, so that the treatment efficiency and the utilization efficiency are greatly improved.
The invention takes the industrial waste and the inert concrete waste slurry as main components, takes the anhydrous sodium carbonate powder and the sodium metasilicate pentahydrate powder as the alkali activator to solidify the inert concrete waste slurry, not only realizes the recycling of the inert concrete waste slurry, but also processes a large amount of industrial waste, avoids the consumption of cement (the cement production has high energy consumption, high carbon discharge amount and is not environment-friendly).
Compared with the traditional mode of regenerating the waste slurry for a cement system, the invention has better curing effect on the concrete waste slurry compared with the traditional cement material, and the cured body material has low porosity, more compact microstructure, high mechanical strength and better high-temperature stability.
In order to further illustrate the present invention, the following will describe in detail an inert concrete waste slurry solidified body material and a method for preparing the same in connection with the examples, which should not be construed as limiting the scope of the present invention.
The starting materials used in the following examples are all generally commercially available.
In the embodiment, the 28d activity index of the secondary fly ash is 70-75%; the S95-grade slag powder is S95-grade granulated blast furnace slag powder, and the 28d activity index is 95% -98%.
Example 1
Extracting the waste concrete slurry from the bottom of a sedimentation tank of a commercial concrete mixing plant, drying to obtain inert waste concrete slurry with the concentration of 50 wt%, wherein the pH value of the waste concrete slurry is 12.0, the 28D activity index is 55% (measured according to GB/T17671 standard), and D5019.271 μm, D105.362 μm, D9062.319 μm;
the inert concrete waste slurry is converted at 25 DEG CStirring for 50 min at a speed of 38 Hz to obtain homogenized inert concrete waste slurry (D)50Is 3.757 μm, D101.747 μm, D908.423 μm);
after the homogenization treatment is finished, adding secondary fly ash (the calcium content of the secondary fly ash) into the homogenized slurry<10 wt%，D5022.546 μm, D102.374 μm, D9092.322 μm, 73% activity index at 28D) and S95 grade slag powder (D of the slag powder)5015.974 μm, D101.822 μm, D9043.764 mu m, and the 28d activity index is 96%), and the mass ratio of the second-grade fly ash to the S95-grade slag powder is 1: 1, stirring and mixing for 1 min at 42 Hz, and then adding anhydrous sodium carbonate powder (reagent grade, purity)>99.8%) and sodium metasilicate pentahydrate powder (reagent grade, modulus of 0.93), the mass ratio of the anhydrous sodium carbonate powder to the sodium metasilicate pentahydrate powder is 1.5: 1, stirring and mixing for 1 min at 42 Hz to obtain mixed slurry; the ratio of the total mass of the anhydrous sodium carbonate powder and the sodium metasilicate pentahydrate powder to the total mass of the secondary fly ash and the S95-grade slag powder is 20: 100, respectively; the mass ratio of the inert concrete waste slurry to the total mass of the secondary fly ash and the S95 slag powder is 1: 1;
placing the mixed slurry in a mold for molding, and maintaining outdoors, wherein the temperature is 20-35 ℃, and a jute bag or a sunshade is required to be paved when the temperature is higher than 30 ℃ so as to avoid direct sunlight; construction in the noon needs to be avoided in summer; obtaining the inert concrete waste slurry solidified material.
Table 1 is a table for measuring the XRF component content of the inert concrete waste slurry of example 1 of the present invention.
Table 1 table for measuring XRF component content of inert concrete waste slurry of example 1 of the present invention
As can be seen from Table 1, the waste concrete slurry contains higher amounts of silica, alumina and iron oxide than cement, and the larger LOI value indicates that more carbonate material is present in the waste concrete slurry.
The inert concrete waste slurry was analyzed by an X-ray diffractometer to obtain the XRD pattern of the inert concrete waste slurry (CSW) of example 1, as shown in fig. 1. FIG. 1 is an XRD pattern of an inert concrete waste slurry of example 1 of the present invention.
In FIG. 1, FA is fly ash, BFS is slag, and good crystallinity indicates that substances in CSW are very stable and have low reactivity at normal temperature and pressure; the amorphous region refers to a portion protruding in a diffraction pattern, and indicates that a vitreous body exists in a substance and is likely to react with the outside under a specific condition (the specific condition in the present invention is the alkali activator powder in the present invention).
Comparative example 1
Extracting the inert concrete waste slurry from the bottom of a sedimentation tank of a commercial concrete mixing plant, and drying to obtain the inert concrete waste slurry with the concentration of 50 wt%, wherein the pH value of the inert concrete waste slurry is 11.5, the 28D activity index is 52%, and D5019.271 μm, D105.362 μm, D9062.319 μm;
stirring the inert concrete waste slurry at 25 deg.C and rotation speed frequency of 38 Hz for 50 min to obtain homogenized inert concrete waste slurry (D)505 to 10 μm, D101 to 3 μm, D 9020 to 30 μm);
after the homogenization treatment is finished, adding cement into the homogenized slurry, wherein the cement is P ‧ O42.5-grade ordinary portland cement, and stirring and mixing for 1 min at 42 Hz to obtain mixed slurry; the mass ratio of the inert concrete waste slurry to the cement is 1: 1;
placing the mixed slurry in a mold for molding, and maintaining outdoors, wherein the temperature is 20-35 ℃, and a jute bag or a sunshade is required to be paved when the temperature is higher than 30 ℃ so as to avoid direct sunlight; construction in the noon needs to be avoided in summer; obtaining the inert concrete waste slurry solidified material.
Comparative example 2
The mass ratio of the inert concrete waste slurry in the example 1 to the total mass of the secondary fly ash and the S95 slag powder is changed to 4: 1, the other steps are the same as the example 1, and the inert concrete waste slurry solidified material is prepared.
Comparative example 3
The ratio of the total mass of the anhydrous sodium carbonate powder and the sodium metasilicate pentahydrate powder in example 1 to the total mass of the secondary fly ash and the S95-grade slag powder was changed to 10: 100, and other steps are the same as the example 1, and the inert concrete waste slurry solidified body material is prepared.
Example 2
The ratio of the total mass of the anhydrous sodium carbonate powder and the sodium metasilicate pentahydrate powder in example 1 to the total mass of the secondary fly ash and the S95 slag powder was changed to 15: 100, respectively; the other steps are the same as the example 1, and the inert concrete waste slurry solidified material is prepared.
Example 3
The ratio of the total mass of the anhydrous sodium carbonate powder and the sodium metasilicate pentahydrate powder in example 1 to the total mass of the secondary fly ash and the S95 slag powder was changed to 25: 100, respectively; the other steps are the same as the example 1, and the inert concrete waste slurry solidified material is prepared.
The high temperature stability of the inert concrete waste slurry cured material obtained in examples 1 to 3 and comparative examples 1 to 3 was measured, and the results are shown in Table 2.
The detected temperature is 20-1000 ℃, the heating rate is 10 ℃/min, the nitrogen gas tests the environment, and the test block size of the inert concrete waste slurry solidified body material is 1cm3；
Wherein, the weight loss rate is the ratio of the mass of the test block reduced at high temperature to the original mass of the test block multiplied by 100 percent.
TABLE 2 high-temperature stability test results of the cured concrete materials of examples 1 to 3 and comparative examples 1 to 3
As can be seen from Table 2, the inert concrete waste slurry solidified material prepared by the invention has lower weight loss rate and better stability under the action of high temperature.
Although the total weight loss ratios of comparative examples 2 and 3 were low, it could not be said that the mechanical properties were much lower than those of comparative example 1 (cement cured material), but the cured material prepared therefrom was extremely likely to crack in a high-temperature water loss environment if the strength was insufficient. And when the amount of the activator is the same (20: 100), the water loss rate from carbonate and hydration products in comparative example 2 decreases rapidly, which indicates that when the concrete waste slurry quality: (fly ash + slag) total mass = 4: 1, the increase of the mass of the waste slurry seriously inhibits the excitation effect of the exciting agent, and results in the reduction of the product, which is even lower than that of the exciting agent in the comparative example 3, wherein the mass ratio of the exciting agent is 10: 100 corresponds to the water loss of the product, while the formation of the product directly affects the strength development of the cured body material.
The mechanical properties of the inert concrete waste slurry cured material prepared in examples 1 to 3 and comparative examples 1 to 3 were measured, and the results are shown in table 3.
TABLE 3 test results of mechanical properties of the cured concrete materials of examples 1 to 3 and comparative examples 1 to 3
As can be seen from Table 3, after 28d, the mechanical properties of the inert concrete waste slurry solidified body material prepared by the invention substantially reach (the compressive strength and the flexural strength of example 28d substantially reach 90% of those of comparative example 1) or exceed those of a cement solidified system. The strength increase rate of the inert concrete waste slurry solidified material in 7-28 days is obviously higher than that of a cement solidified system, and the later strength development of the inert concrete waste slurry solidified material has obvious advantages.
The mechanical strength result of comparative example 2 is much smaller than that of comparative example 1 and any other examples appearing in the present invention, and when compared with the result of example 1, it can be found that the compressive strength of the cured material 28d is less than one tenth of that of example 1 at the same amount of the activator (20: 100), indicating that the ratio of the concrete waste slurry to the (fly ash + slag) is in a limited range; in comparative example 3, when the amount of the activator added was reduced to 10: at 100, the mechanical strength of the material is also greatly reduced and is not comparable to that of the comparative example 1, so that when the related proportioning parameter index is beyond or below the range provided by the invention, the prepared waste slurry solidified body material cannot achieve or is comparable to the solidification effect of cement; similarly, comparison of high temperature stability/weight loss ratio is not meaningful where strength is not comparable.
The inert concrete waste slurry cured body materials obtained in examples 1 to 3 and comparative examples 1 to 3 were naturally cured for 28d, and then the pore size distribution (according to the mercury intrusion test) of the inert concrete waste slurry cured body materials was analyzed, and the results are shown in table 4.
TABLE 4 pore diameter distribution after natural curing of the concrete waste mortar cured body materials of examples 1 to 3 and comparative examples 1 to 3 for 28d
As can be seen from Table 4, the inert concrete waste slurry cured body material of the present invention has smaller pores and average pore diameter after natural curing for 28 d.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (8)
1. A preparation method of an inert concrete waste slurry solidified body material comprises the following steps:
A) homogenizing the inert concrete waste slurry;
B) stirring and mixing the materials to obtain mixed slurry; the material consists of the slurry treated in the step A), secondary fly ash, S95-grade slag powder, anhydrous sodium carbonate powder and sodium metasilicate pentahydrate powder;
the ratio of the total mass of the anhydrous sodium carbonate powder and the sodium metasilicate pentahydrate powder to the total mass of the secondary fly ash and the S95 slag powder is 20-25: 100, respectively;
the mass ratio of the inert concrete waste slurry to the total mass of the secondary fly ash and the S95 slag powder is 0.5-1.5: 0.5 to 1.5;
C) and forming the mixed slurry to obtain the inert concrete waste slurry solidified body material.
2. The preparation method according to claim 1, wherein the concentration of the inert concrete waste slurry is 40-60 wt%;
the pH value of the inert concrete waste slurry is 11.5-12.5;
the 28d activity index of the inert concrete waste slurry is 50-60%.
3. The method of claim 1, wherein the homogenization treatment is a vortex homogenization treatment; d of homogenized concrete waste slurry50Is 3 to 5 μm.
4. The method for preparing according to claim 1, wherein the homogenization treatment comprises:
and stirring the concrete waste slurry for 45-60 min under the conditions that the temperature is not lower than 20 ℃ and the rotating speed frequency is 35-45 Hz.
5. The method of claim 1, wherein the secondary fly ash has a D value50<23 μm, and the activity index is 70-75%;
d of the S95 grade slag powder50<16 μm, and the activity index is 95-98%;
the mass ratio of the secondary fly ash to the S95 grade slag powder is 2-5: 5-8;
the mass ratio of the anhydrous sodium carbonate powder to the sodium metasilicate pentahydrate powder is 1-2: 0.5 to 1.5.
6. The preparation method according to claim 1, wherein in the step B), the rotation frequency of stirring and mixing is 40-45 Hz.
7. The method according to claim 1, wherein the step C) further comprises, after the forming: naturally maintaining;
the natural curing temperature is 20-30 ℃.
8. The method of any one of claims 1 to 7, wherein the inert concrete waste slurry solidified material is prepared.
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