CN114230275A - Low-hydration-heat fly ash dry-mixed cement gravel pile material - Google Patents
Low-hydration-heat fly ash dry-mixed cement gravel pile material Download PDFInfo
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- CN114230275A CN114230275A CN202111549325.1A CN202111549325A CN114230275A CN 114230275 A CN114230275 A CN 114230275A CN 202111549325 A CN202111549325 A CN 202111549325A CN 114230275 A CN114230275 A CN 114230275A
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- 239000010881 fly ash Substances 0.000 title claims abstract description 103
- 239000004568 cement Substances 0.000 title claims abstract description 87
- 239000000463 material Substances 0.000 title claims abstract description 25
- 238000006703 hydration reaction Methods 0.000 claims abstract description 41
- 230000036571 hydration Effects 0.000 claims abstract description 39
- 239000002245 particle Substances 0.000 claims abstract description 30
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims abstract description 26
- 238000002791 soaking Methods 0.000 claims abstract description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 22
- 238000000034 method Methods 0.000 claims abstract description 21
- 239000004575 stone Substances 0.000 claims abstract description 18
- 239000000654 additive Substances 0.000 claims abstract description 12
- 230000000996 additive effect Effects 0.000 claims abstract description 12
- 229910052500 inorganic mineral Inorganic materials 0.000 claims abstract description 11
- 239000011707 mineral Substances 0.000 claims abstract description 11
- 238000000227 grinding Methods 0.000 claims abstract description 10
- 239000000843 powder Substances 0.000 claims abstract description 8
- 238000002156 mixing Methods 0.000 claims description 10
- 239000007788 liquid Substances 0.000 claims description 8
- 239000002253 acid Substances 0.000 claims description 5
- 239000003638 chemical reducing agent Substances 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 4
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 4
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 4
- 239000004033 plastic Substances 0.000 claims description 3
- 238000012216 screening Methods 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims description 3
- 238000003756 stirring Methods 0.000 claims description 3
- 239000004566 building material Substances 0.000 abstract description 2
- 238000007781 pre-processing Methods 0.000 abstract 1
- 239000000126 substance Substances 0.000 abstract 1
- 239000004567 concrete Substances 0.000 description 16
- 230000000052 comparative effect Effects 0.000 description 10
- 239000010883 coal ash Substances 0.000 description 6
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 5
- 239000000920 calcium hydroxide Substances 0.000 description 5
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 5
- 230000001603 reducing effect Effects 0.000 description 4
- 238000011160 research Methods 0.000 description 4
- 239000013543 active substance Substances 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000001027 hydrothermal synthesis Methods 0.000 description 2
- 238000010348 incorporation Methods 0.000 description 2
- 239000011777 magnesium Substances 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000003014 reinforcing effect Effects 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 229910021417 amorphous silicon Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- -1 gravel Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
- C04B28/04—Portland 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
- C04B20/00—Use of materials as fillers for mortars, concrete or artificial stone according to more than one of groups C04B14/00 - C04B18/00 and characterised by shape or grain distribution; Treatment of materials according to more than one of the groups C04B14/00 - C04B18/00 specially adapted to enhance their filling properties in mortars, concrete or artificial stone; Expanding or defibrillating materials
- C04B20/02—Treatment
- C04B20/023—Chemical treatment
-
- 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
- C04B2111/76—Use at unusual temperatures, e.g. sub-zero
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
- Road Paving Structures (AREA)
Abstract
The invention relates to the technical field of building materials, and discloses a low-hydration-heat fly ash dry-mixed cement gravel pile material which comprises the following components in parts by weight: 220-280 parts of cement, 100-160 parts of mineral powder, 130-160 parts of pretreated fly ash, 730-790 parts of stone chips, 1000-1040 parts of broken stone, 4.0-5.0 parts of an additive and 95-125 parts of water; the pretreatment process of the fly ash comprises the steps of grinding the fly ash into particles with the particle size of less than 45 mu m, and soaking the particles in hydrofluoric acid. The low-hydration-heat fly ash dry-mixed cement gravel pile material provided by the invention uses the fly ash treated by a preprocessing process combining physical and chemical methods, and the pretreated fly ash is doped into the dry-mixed cement gravel pile, so that the hydration heat release of the dry-mixed cement gravel pile in the using process can be reduced, the early compressive strength of the dry-mixed cement gravel pile is improved, the applicability of the dry-mixed cement gravel pile in permafrost regions is improved, the cost is reduced, and the resources are saved.
Description
Technical Field
The invention relates to the technical field of building materials, in particular to a low-hydration-heat fly ash dry-mixed cement gravel pile material.
Background
The dry-mixed cement gravel pile is a composite foundation reinforcing pile which is made of cement, gravel, sand, slag and the like as main materials. The dry-mixed cement gravel pile not only can improve the bearing capacity of the foundation, but also can save materials, and has the advantages of simple construction, short reinforcing period, low cost and the like. With the continuous expansion of the application range of the dry-mixed cement gravel pile, the dry-mixed cement gravel pile is gradually applied to the design of the pavement foundation under the poor natural environment condition. The permafrost foundation is reinforced by the dry-mixed cement gravel pile in the alpine region, because the dry-mixed cement column body material can generate the hydration heat after pouring into the permafrost foundation, thereby the temperature of the surrounding soil body is raised, the surrounding permafrost is made to melt, the natural permafrost foundation is disturbed, the bearing capacity of the foundation is influenced, so how to improve the dry-mixed cement gravel pile, the hydration heat generated in the alpine region is reduced, the design strength requirement is met while the influence on the surrounding permafrost foundation is reduced, and the anti-freezing performance is good, and the problem to be solved urgently is formed.
A series of research results show that the mineral admixture is effectively applied to the experimental research of the dry-mixed cement gravel pile, wherein the coal ash serving as the mineral admixture is added into the dry-mixed cement gravel pile, so that the hydration heat release quantity of the dry-mixed cement gravel pile can be reduced, the early strength of the dry-mixed cement gravel pile can be improved, and the performances such as durability and the like of the dry-mixed cement gravel pile can be enhanced. At present, research on dry-mixed cement gravel piles with low hydration heat is more and more intensive at home and abroad, and various technologies for reducing hydration heat are generated.
The invention patent (CN201811346245.4) discloses a super-large-volume high-strength low-hydration heat concrete, and provides a super-large-volume high-strength low-hydration heat concrete, which comprises the following components: 200-260 parts of cement; 100-160 parts of mineral powder; 80-100 parts of fly ash; 740-800 parts of fine aggregate; 1010-1050 parts of coarse aggregate; 4.0-5.0 parts of an additive; 155-165 parts of water, and the product prepared by the method can effectively reduce the hydration heat, greatly reduce and control the risk of cracking of the mass concrete from the source and improve the quality of engineering. However, the amount of the fly ash added in the method is about 24%, which is relatively small, and the hydration heat release of the concrete cannot be reduced to the maximum extent.
The national invention patent (CN102898050A) discloses a preparation method of high-magnesium micro-expansion low-heat cement, and the mineral composition of the high-magnesium micro-expansion low-heat cement clinker is C3S10～35％；C2S40～65％；C3A1～5％；C4AF 10-20%, and the MgO content in the cement clinker is 6.0-8.0%, and the concrete prepared by the cement has the characteristics of good fluidity, low hydration heat, high later strength and the like. Due to C of the low heat cement2S contentHigher, which results in lower early strength and is not favorable for application of dry-mixed cement gravel piles.
The national invention patent (CN105174771A) discloses a low-heat cement active agent and a preparation method thereof, wherein the preparation method of the low-heat cement active agent comprises the following steps: mixing a calcareous donor and an amorphous silicon oxide donor for hydro-thermal synthesis treatment, wherein the molar ratio of calcium to silicon is 1.3-2.5, and uniformly mixing and calcining a product obtained by the hydro-thermal synthesis treatment and a regulator to obtain the low-heat cement active agent.
Korean patent (KR20130100543A) discloses a method for producing concrete using fly ash in a large amount, which has a fly ash content of 50-65%, reduces hydration heat release of a concrete structure while reducing the amount of cement used, and exhibits high strength suitable for general structural concrete. However, this method of directly adding a large amount of fly ash into concrete can reduce the hydration heat release of concrete, but because fly ash is not modified, the heat reducing effect of fly ash cannot be exerted to the maximum extent.
In summary, the existing research technologies for reducing hydration heat mainly focus on the aspect of doping a small amount of fly ash or directly doping fly ash, however, the methods reduce the hydration heat to a small extent, and are not beneficial to popularization and application of the dry-mixed cement gravel pile. The prior art can not effectively solve the problems of large hydration heat release, low early strength and the like of the dry-mixed cement gravel pile.
Disclosure of Invention
The invention aims to provide a low-hydration-heat fly ash dry-mixed cement gravel pile material to solve the problems of high hydration heat release and low early strength of a dry-mixed cement gravel pile.
In order to achieve the purpose, the invention adopts the following technical scheme:
a low-hydration-heat fly ash dry-mixed cement gravel pile material comprises the following components in parts by weight: 220-280 parts of cement, 100-160 parts of mineral powder, 130-160 parts of pretreated fly ash, 730-790 parts of stone chips, 1000-1040 parts of broken stone, 4.0-5.0 parts of an additive and 95-125 parts of water;
the pretreated fly ash is obtained by grinding the fly ash into particles with the particle size of less than 45 mu m and soaking the fly ash in hydrofluoric acid.
Preferably, the weight of the pretreated fly ash is 55-65% of the weight of the cement.
In a preferred embodiment of the present invention, the pretreated fly ash is obtained by the following steps:
1) putting the weighed fly ash into a ball mill, and grinding the fly ash into particles with the particle size of less than 45 mu m;
2) soaking the fly ash particles obtained in the step 1) in a hydrofluoric acid solution with the concentration of 4.93mol/L, wherein the liquid-solid mass ratio is 5:1, the soaking time is 10-20 min, and the soaking temperature is room temperature;
3) in the soaking process, stirring once by using a plastic rod every 2-5 min to fully soak the fly ash, and uniformly soaking;
4) after soaking, pouring out the redundant soaking liquid, and heating the solid-liquid mixed system in a water bath to completely volatilize hydrofluoric acid;
5) and after the hydrofluoric acid is completely volatilized, putting the silicon carbide balls and the fly ash in a mass ratio of 2:1 into a ball mill, grinding for 20-30min, and screening to obtain the pretreated fly ash.
Preferably, the fly ash is ground into particles with the particle size of 10-20 mu m.
Further preferably, the fly ash is ground to particles having a particle size of less than 10 μm.
Preferably, the additive is an RP325 polycarboxylic acid water reducer.
Preferably, in the step 4), the solid-liquid mixed system is heated for 5min by using a water bath at the temperature of 80-100 ℃.
When cement is hydrated by combining with water, calcium hydroxide is generated, the heat generated by the solidification of the calcium hydroxide is 78 cal/g, the heat generated by the mixing of the calcium hydroxide and the fly ash as an additive is 45 cal/g, and the heat generated by the mixing of the fly ash and the calcium hydroxide is reduced to about 60 percent compared with the heat generated by only using the calcium hydroxide. The heat of the common concrete reaches the maximum value within 1-2 days after the concrete is poured until the tensile strength of the concrete is formed. However, the low-heating concrete containing the fly ash additive reaches the maximum value within 2-3 days, and when the concrete reaches the maximum temperature, a bonding structure of the concrete is compact, and the tensile strength is increased.
Based on the technical scheme, compared with the prior art, the coal ash pretreatment process has the following advantages:
(1) according to the low-hydration-heat fly ash dry-mixed cement gravel pile material, the grinding and hydrofluoric acid soaking combined mode is adopted for treatment, compared with the conventional fly ash, the pretreated fly ash removes the vitreous coating, so that the specific surface area is increased, the reaction activity is improved, and the early compressive strength of the dry-mixed cement gravel pile is favorably improved.
(2) By adopting the coal ash pretreatment process and combining the optimal mixing amount of the coal ash, the hydration heat release of the dry-mixed cement gravel pile can be effectively reduced, the early strength of the dry-mixed cement gravel pile is improved, the service life of the frozen soil foundation is prolonged, the durability of the dry-mixed cement gravel pile in high and cold areas is improved, and the applicability of the dry-mixed cement gravel pile in permafrost areas is improved.
(3) By adopting the fly ash pretreatment process, the mechanical property, the durability and the hydration characteristic of the dry-mixed cement gravel pile can be improved, the manufacturing cost of the dry-mixed cement gravel pile can be reduced, the resource utilization rate is improved, and the fly ash pretreatment process has important significance for road construction and implementation.
Detailed Description
The invention is further described in detail with reference to specific embodiments, which are intended to be understood more clearly from the theoretical design and practical aspects, and any modifications or changes that can be easily made by a person skilled in the art without departing from the technical solution of the invention fall within the scope of the claims of the present invention.
Example 1
A low-hydration-heat fly ash dry-mixed cement gravel pile material comprises the following components in parts by weight: 220-280 parts of cement, 100-160 parts of mineral powder, 130-160 parts of pretreated fly ash, 730-790 parts of stone chips, 1000-1040 parts of broken stone, 4.0-5.0 parts of an additive and 95-125 parts of water;
the pretreated fly ash is obtained through the following treatment steps:
1) putting the weighed fly ash into a ball mill, and physically grinding for 20-30min to fully disperse and grind the fly ash particles to particles with the particle size of less than 45 mu m;
2) soaking the fully ground fly ash in a hydrofluoric acid solution with the concentration of 4.93mol/L, wherein the liquid-solid mass ratio is 5:1, the soaking time is 10min, and the soaking temperature is room temperature;
3) in the soaking process, stirring once every 2min by using a plastic rod to ensure that the fly ash is fully soaked and uniformly soaked;
4) after soaking, pouring out the redundant soaking liquid, and heating the solid-liquid mixed system in a water bath at 80-100 ℃ for 5min to completely volatilize hydrofluoric acid;
5) after the hydrofluoric acid is completely volatilized, putting silicon carbide balls (SiC) and fly ash in a mass ratio of 2:1 into a ball mill, grinding for 20-30min, and screening to obtain the preprocessed fly ash.
The cement is P.O42.5 cement;
the particle size of the crushed stone is 10-30mm, the mud content is not more than 5%, the crushing value is not more than 35%, and the water content is not more than 1%;
the particle size of the stone chips is 1-5mm, and the mud content is less than 7%;
the additive is an RP325 polycarboxylic acid water reducer.
The low hydration heat fly ash dry-mixed cement gravel pile described in the embodiment is marked as C20, and the composition ratio thereof is cement: water: mineral powder: stone chips: the crushed stone is 1:0.47:0.45:2.8: 3.7.
The low hydration heat fly ash dry-mixed cement gravel pile material is prepared by doping 55% (the weight of fly ash accounts for the weight of cement) of pretreated fly ash by an internal doping method.
Example 2
Low-hydration-heat fly ash dry-mixed cement gravel pile material
The low hydration heat fly ash dry-mixed cement gravel pile adopts P.O42.5 cement, the particle size of gravel is 10-30mm, the mud content is not more than 5%, the crushing value is not more than 35%, and the water content is not more than 1%; the particle size of the stone chips is 1-5mm, and the mud content is less than 7%; the additive is an RP325 polycarboxylic acid water reducer.
The low hydration heat fly ash dry-mixed cement gravel pile is marked as C20, and comprises the following components in percentage by weight: water: mineral powder: stone chips: the crushed stone is 1:0.47:0.45:2.8: 3.7.
The low hydration heat fly ash dry-mixed cement gravel pile material is prepared by mixing 60% of pretreated fly ash by an internal mixing method.
Example 3
Low-hydration-heat fly ash dry-mixed cement gravel pile material
The low hydration heat fly ash dry-mixed cement gravel pile adopts P.O42.5 cement, the particle size of gravel is 10-30mm, the mud content is not more than 5%, the crushing value is not more than 35%, and the water content is not more than 1%; the particle size of the stone chips is 1-5mm, and the mud content is less than 7%; the additive is an RP325 polycarboxylic acid water reducer.
The low hydration heat fly ash dry-mixed cement gravel pile is marked as C20, and comprises the following components in percentage by weight: water: mineral powder: stone chips: the crushed stone is 1:0.47:0.45:2.8: 3.7.
The low hydration heat fly ash dry-mixed cement gravel pile material is prepared by doping 65% of pretreated fly ash by an internal doping method.
Comparative example 1
Comparative example 1 is the same as example 1 except that the amount of fly ash added is 0% as in example 1.
Comparative example 2
Comparative example 2 was the same as example 1 in terms of formulation and operation, the only difference being that the fly ash incorporated was no pre-treated fly ash.
Comparative example 3
Comparative example 3 is the same as example 2 in the proportions and operation, the only difference being that the fly ash incorporated is no pre-treated fly ash.
Comparative example 4
Comparative example 4 was the same as example 3 in the proportions and operation, with the only difference that the fly ash incorporated was no pre-treated fly ash.
The hydration heat release of 3d and 7d and the compressive strength of 3d and 28d of the invention in examples 1 to 3 and comparative examples 1 to 4 were measured, respectively, and the results are shown in Table 1.
TABLE 1 hydration heat and compressive Strength test results
It can be seen from table 1 that compared with the prior art, the technology provided by the invention can fully exert the performance improvement effect of the fly ash on the dry-mixed cement gravel pile. From the perspective of hydration heat, the addition of 65% of the pretreated fly ash can reduce the 3d hydration heat release of the dry-mixed cement gravel pile by 33% and the 7d hydration heat release by 26%; from the aspect of mechanical strength, it can be found that the mixing amount of the pretreated fly ash is from 55% to 65%, and the compressive strength of the dry-mixed cement gravel piles 3d and 28d is similar to that of the non-mixed pretreated fly ash, so that the early strength of the dry-mixed cement gravel pile is not greatly reduced even if the pretreated fly ash with a large mixing amount is used. From the overall examples and comparative examples, the incorporation of pretreated fly ash reduced the heat of hydration better and the compressive strength better than the incorporation of ordinary fly ash. According to the low hydration heat coal ash dry-mixed cement gravel pile material, the cement is replaced by the large-dosage pretreated coal ash, so that the hydration heat release of the dry-mixed cement gravel pile can be effectively reduced, the early strength of the dry-mixed cement gravel pile is improved, the applicability of the dry-mixed cement gravel pile in alpine regions is improved, the cost is reduced, the resources are saved, and the environment is protected.
The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the invention is not limited to the particular embodiments described above, and that equivalent variations in the principles and methods of the invention are intended to be covered by the scope of the invention, which is not to be limited by the claims which follow.
Claims (7)
1. The low-hydration-heat fly ash dry-mixed cement gravel pile material is characterized by comprising the following components in parts by weight: 220-280 parts of cement, 100-160 parts of mineral powder, 130-160 parts of pretreated fly ash, 730-790 parts of stone chips, 1000-1040 parts of broken stone, 4.0-5.0 parts of an additive and 95-125 parts of water;
the pretreated fly ash is obtained by grinding the fly ash into particles with the particle size of less than 45 mu m and soaking the fly ash in hydrofluoric acid.
2. The low hydration heat fly ash dry-mixed cement gravel pile material as claimed in claim 1, wherein the weight of the pretreated fly ash is 55-65% of the weight of the cement.
3. The low hydration heat fly ash dry-mixed cement gravel pile material of claim 1, wherein the pretreated fly ash is obtained by the following treatment steps:
1) putting the weighed fly ash into a ball mill, and grinding the fly ash into particles with the particle size of less than 45 mu m;
2) soaking the fly ash particles obtained in the step 1) in a hydrofluoric acid solution with the concentration of 4.93mol/L, wherein the liquid-solid mass ratio is 5:1, the soaking time is 10-20 min, and the soaking temperature is room temperature;
3) in the soaking process, stirring once by using a plastic rod every 2-5 min to fully soak the fly ash, and uniformly soaking;
4) after soaking, pouring out the redundant soaking liquid, and heating the solid-liquid mixed system in a water bath to completely volatilize hydrofluoric acid;
5) and after the hydrofluoric acid is completely volatilized, putting the silicon carbide balls and the fly ash in a mass ratio of 2:1 into a ball mill, grinding for 20-30min, and screening to obtain the pretreated fly ash.
4. The low hydration heat fly ash dry-mixed cement gravel pile material as claimed in any one of claims 1 to 3, wherein in the pretreatment process of the fly ash, the fly ash is ground into particles with a particle size of 10 to 20 μm.
5. The low hydration heat fly ash dry-mixed cement gravel pile material as claimed in any one of claims 1 to 3, wherein in the pretreatment process of the fly ash, the fly ash is ground into particles with a particle size of less than 10 μm.
6. The low hydration heat fly ash dry-mixed cement gravel pile material of claim 1, wherein the additive is an RP325 polycarboxylic acid water reducer.
7. The low hydration heat fly ash dry-mixed cement gravel pile material as claimed in claim 2, wherein in the step 4), the solid-liquid mixing system is heated in a water bath at 80-100 ℃ for 5 min.
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|---|---|---|---|
| CN202111549325.1A CN114230275A (en) | 2021-12-17 | 2021-12-17 | Low-hydration-heat fly ash dry-mixed cement gravel pile material |
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| CN202111549325.1A CN114230275A (en) | 2021-12-17 | 2021-12-17 | Low-hydration-heat fly ash dry-mixed cement gravel pile material |
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| CN101348578A (en) * | 2008-09-08 | 2009-01-21 | 淮南市金源粉煤灰有限责任公司 | Preparation of modified fly ash micro-sphere rubber filling |
| CN202644518U (en) * | 2012-04-19 | 2013-01-02 | 中铁第四勘察设计院集团有限公司 | Post-inserted reinforcement cage cement fly ash gravel pile |
| CN113213879A (en) * | 2021-04-30 | 2021-08-06 | 中建湛江大道投资建设有限公司 | Reinforced CFG pile mixture, CFG pile and composite foundation suitable for soft soil area and construction method of reinforced CFG pile mixture |
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2021
- 2021-12-17 CN CN202111549325.1A patent/CN114230275A/en active Pending
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Application publication date: 20220325 |