CN115321860A - Construction waste recycled aggregate surface modification and particle reinforcement method - Google Patents
Construction waste recycled aggregate surface modification and particle reinforcement method Download PDFInfo
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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
- 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
- C04B20/026—Comminuting, e.g. by grinding or breaking; Defibrillating fibres other than asbestos
-
- 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
- C04B18/00—Use of agglomerated or waste materials or refuse as fillers for mortars, concrete or artificial stone; Treatment of agglomerated or waste materials or refuse, specially adapted to enhance their filling properties in mortars, concrete or artificial stone
- C04B18/04—Waste materials; Refuse
- C04B18/16—Waste materials; Refuse from building or ceramic industry
- C04B18/167—Recycled materials, i.e. waste materials reused in the production of the same materials
-
- 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
-
- 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
-
- 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
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Civil Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
The invention provides a method for modifying the surface of recycled aggregate of construction waste and enhancing particles, which comprises the following steps: step one, aggregate shaping: placing the building garbage recycled aggregate mixed filler into a ball mill for ball milling and shaping, and taking out after ball milling to obtain shaped aggregate particles; step two, aggregate modification: and mixing and stirring the dispersant, the sealant and the modifier to obtain a mixed modified solution, placing the shaped aggregate particles into the mixed modified solution, soaking, filtering, taking out the aggregate, and drying to obtain the modified aggregate. According to the invention, by adding the quicklime powder as the filler, microcracks and pores existing on the surface of the construction waste recycled aggregate can be filled, the porosity and water absorption of the recycled aggregate are reduced, and the apparent density and particle strength are improved; the operation process is simple, complex equipment and expensive raw materials are not needed, and the economic benefit is high.
Description
Technical Field
The invention belongs to the technical field of construction waste regeneration treatment, and particularly relates to a method for surface modification and particle reinforcement of construction waste recycled aggregate.
Background
With the increasing pace of urbanization in China, many urban and rural buildings are dismantled, the production amount of building garbage is continuously increased and accounts for 30-40% of the total amount of the urban garbage, and a serious ecological crisis is caused. As the environmental protection policy is tightened, the sandstone exploitation industry is nearly stopped, the price of the natural aggregate is saved and increased, and the construction cost is increased to a certain extent. The construction waste resource utilization concerns the coordinated development of the urban ecological environment, and the comprehensive utilization of the construction waste in China is reluctant.
The construction waste is recycled, so that the consumption of natural resources can be relieved, great economic benefits and social benefits can be generated, and the method conforms to the sustainable development policy of China. At present, the resource utilization of the construction waste is to crush the construction waste, remove light substances from a suspended water system, remove mud and screen the construction waste to obtain recycled aggregates with different particle sizes for different reutilization, and the recycling is generally carried out by backfilling, manufacturing recycled pavement bricks, recycled cement stabilized soil, recycled concrete and the like.
Compared with natural aggregate, the construction waste recycled aggregate has more edges and corners and rough surface, the components contain hardened cement mortar, and a large number of micro cracks are caused in the recycled aggregate due to damage accumulation in the crushing process of the concrete blocks, so that the recycled aggregate has the characteristics of large porosity, large water absorption, small stacking density, high crushing index, high surface inerting degree and the like, and the application range of the recycled aggregate is limited.
Therefore, there is a need to provide an improved solution to the above-mentioned deficiencies of the prior art.
Disclosure of Invention
The invention aims to provide a surface modification and particle reinforcement method for construction waste recycled aggregate, which can repair the construction waste recycled aggregate, reduce the water absorption and crushing value of the recycled aggregate and improve the apparent density and strength of the recycled aggregate.
In order to achieve the above purpose, the invention provides the following technical scheme:
a method for surface modification and particle reinforcement of construction waste recycled aggregate, comprising the steps of:
step one, shaping aggregate: placing the building garbage recycled aggregate mixed filler into a ball mill for ball milling and shaping, and taking out after ball milling to obtain shaped aggregate particles;
step two, aggregate modification: and mixing and stirring the dispersant, the sealant and the modifier to obtain a mixed modified solution, placing the shaped aggregate particles into the mixed modified solution, soaking, filtering, taking out the aggregate, and drying to obtain the modified aggregate.
In the surface modification and particle reinforcement method for the construction waste recycled aggregate, preferably, in the first step, the ball milling shaping time is 8-15min.
In the method for surface modification and particle enhancement of the construction waste recycled aggregate, preferably, in the first step, the construction waste recycled aggregate is obtained by crushing, screening, washing and naturally airing construction waste, and the particle size of the construction waste recycled aggregate is 5-25mm.
In the method for surface modification and particle reinforcement of the construction waste recycled aggregate, preferably, the filler is quicklime powder, and the mass ratio of the quicklime powder to the recycled aggregate is 1: (80-120).
In the surface modification and particle reinforcement method for the construction waste recycled aggregate, preferably, the modifier is 20% by mass of organic silica sol.
In the method for surface modification and particle reinforcement of the construction waste recycled aggregate, preferably, in the second step, the addition amount of the modifier is 10-30% of the mass of the construction waste recycled aggregate.
In the method for surface modification and particle reinforcement of the construction waste recycled aggregate, preferably, the dispersant is polyvinyl alcohol, and the addition amount of the dispersant is 0.01-0.03% of the mass of the organic silica sol.
In the surface modification and particle reinforcement method for the recycled aggregate of the construction waste, preferably, in the second step, the stirring speed of the mixed modification solution is 80 +/-4 r/min.
In the method for surface modification and particle reinforcement of the construction waste recycled aggregate, preferably, the sealant is a silane coupling agent KH-570, and the addition amount of the sealant is 1-3% of the mass of the organic silica sol.
In the method for modifying the surface of the recycled aggregate of the construction waste and enhancing the particles, preferably, in the second step, the drying temperature is 95-105 ℃, and the drying time is 2-4h.
Has the beneficial effects that:
the method firstly performs ball milling treatment on the recycled aggregate to realize particle shaping, so that the particle sphericity of the recycled aggregate is improved. By adding the quicklime powder serving as the filler, microcracks and pores existing on the surface of the recycled aggregate can be filled, the porosity and the water absorption of the recycled aggregate are reduced, and the apparent density and the particle strength are improved.
The modifier adopted by the invention is nano SiO 2 Silica sol solution, in the position of regenerated aggregate grain crack and pore and calcium lime hydrolysate Ca (OH) 2 The in-situ reaction generates C-S-H gel,the surface compactness and strength of the particles are improved, cracks are repaired, the water absorption rate and crushing value of the recycled aggregate are reduced, and the crack propagation resistance of the recycled aggregate can be improved through the bonding effect of the C-S-H gel.
The modified aggregate obtained by the invention can be applied to various products, such as: the recycled paving brick, the recycled cement stabilized soil, the recycled commercial concrete and the like have the advantages of higher strength, lower water absorption, more stable quality and the like, not only save natural resources, but also provide a new idea for absorbing construction waste and bring higher social benefits.
The operation process of the surface modification of the construction waste recycled aggregate is simple, complex equipment and expensive raw materials are not needed, and the method has high economic benefit.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. Wherein:
FIG. 1 is a schematic diagram of surface modification of construction waste recycled aggregate according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments that can be derived by one of ordinary skill in the art from the embodiments given herein are intended to be within the scope of the present invention.
The present invention will be described in detail with reference to examples. It should be noted that the embodiments and features of the embodiments of the present invention may be combined with each other without conflict.
The invention provides a method for surface modification and particle enhancement of construction waste recycled aggregate, and a schematic diagram of the surface modification of the recycled aggregate is shown in figure 1. The recycled aggregate is firstly shaped, cement mortar coated on the surface of the recycled aggregate is removed by utilizing mutual extrusion and collision of grinding balls and the recycled aggregate, and meanwhile, weak components on the surface of the recycled aggregate can be extruded and rubbed off, so that the recycled aggregate tends to be spherical, and the shaping of particles is realized. And then adding quicklime powder to fill microcracks and pores on the surface of the recycled aggregate, reduce the porosity and water absorption of the recycled aggregate, and improve the apparent density and particle strength.
The modifier adopted by the invention is nano SiO 2 Silica sol, the particle aggregation system is a three-dimensional network structure, and nano SiO is 2 Has extremely strong volcanic ash activity, crystal nucleus effect and infiltration crystallization effect, and is mixed with calcium lime hydrolysate Ca (OH) at the positions of cracks and pores of recycled aggregate particles 2 The C-S-H gel is generated through in-situ reaction, the compactness and the strength of the particle surface are improved, cracks are repaired, the water absorption rate and the crushing value of the recycled aggregate are reduced, and meanwhile, the crack expansion resistance of the recycled aggregate can also be improved through the bonding effect of the C-S-H gel.
The dispersing agent adopted by the invention is polyvinyl alcohol and white solid powder, and a large amount of uniformly distributed micro bubbles are introduced in the stirring process to reduce the surface tension of liquid in a modifier blending and modifying solution, so that solid molecule nano SiO in the modifier is caused 2 Better dispersibility.
The sealant adopted by the invention is a silane coupling agent KH-570, and the molecular structural formula of the silane coupling agent is generally Y-R-Si (OR) 3 (wherein Y-organic functional group, siOR-siloxy). The silicon alkoxide group is reactive with inorganic substances, and the organic functional group is reactive with or compatible with organic substances. Thus, when a silane coupling agent is interposed between the inorganic and organic interfaces, a bonding layer of organic matrix-silane coupling agent-inorganic matrix may be formed. According to the invention, the structure of building aggregate-coupling agent-organic silica sol is obtained, so that the combination effect of the modifier and the aggregate is strengthened.
The modified aggregate obtained by the invention can be applied to various products, can be used as a novel building material, realizes regeneration and cyclic utilization of building garbage, and has good economic effect.
The invention provides a method for modifying the surface of recycled aggregate of construction waste and enhancing particles, which comprises the following steps:
step one, shaping aggregate: placing the building garbage recycled aggregate mixed filler into a ball mill for ball milling and shaping, and taking out after ball milling to obtain shaped aggregate particles;
step two, aggregate modification: adding a dispersing agent and a sealing agent into a modifying agent, quickly stirring to obtain a mixed modified solution, wherein the stirring speed is 80 +/-4 r/min (such as 76r/min, 78r/min, 80r/min, 82r/min and 84 r/min), placing the shaped aggregate particles into the mixed modified solution, soaking, filtering, taking out the aggregate, and drying to obtain the modified aggregate.
In the specific embodiment of the invention, in the step one, the ball milling shaping time is 8-15min (10 min, 11min, 12min, 13min, 14 min). The circularity of the recycled aggregate is influenced by the ball milling shaping time, and if the ball milling shaping time is too long, microcracks on the surface of the recycled aggregate can be further expanded, so that the strength of the recycled aggregate is reduced; too short a time is insufficient to break cement mortar adhered to the surface of the recycled aggregate, resulting in an increase in water absorption of the recycled aggregate.
In the specific embodiment of the invention, in the first step, the construction waste recycled aggregate is obtained by crushing, screening, washing and naturally drying construction waste, and has a particle size range of 5-25mm (such as 6mm, 8mm, 10mm, 15mm, 20mm and 23 mm). The recycled aggregate in the particle size range still has the particle size of 5-25mm (such as 6mm, 8mm, 10mm, 15mm, 20mm and 23 mm) after ball milling, shaping and modification treatment, and is suitable for producing recycled products in the particle size range.
In the specific embodiment of the invention, the filler is quicklime powder, and the mass ratio of the quicklime powder to the recycled aggregate is 1: (80-120) (such as 1. The quality ratio of the quicklime powder to the recycled aggregate affects the crack filling condition of the recycled aggregate, the crack and pore filling of the recycled aggregate are insufficient due to too little quicklime powder content, the strength is not remarkably enhanced, the quicklime powder content is too much, residues are generated, the residual powder can additionally consume a mixed modification solution, and the subsequent modification process is not favorably carried out.
In a specific embodiment of the invention, the modifier is 20% of organic silica sol by mass, and the addition amount of the modifier is 10-30% of the mass of the construction waste recycled aggregate (such as 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%). The addition amount of the organic silica sol can influence the amount of the C-S-H gel, and further influence the filling effect of the amount of the C-S-H gel on cracks and pores of the recycled aggregate. The content of the silica sol is too high, the sol is easy to agglomerate, so that the content of silicon is reduced, the generation amount of C-S-H is reduced, and the repair effect of the recycled aggregate is reduced; the content of the silica sol is too low, so that the generated C-H-S gel is insufficient, and the repairing effect of the recycled aggregate is reduced.
In a specific embodiment of the present invention, the dispersant is polyvinyl alcohol, the particle size of the powder is 120 mesh or more, and the amount of the dispersant added is 0.01 to 0.03% (e.g., 0.015%, 0.02%, 0.025%) of the mass of the silicone sol solution. The viscosity of the mixed modified solution is increased and the fluidity of the mixed modified solution is reduced due to the excessively high addition amount of the dispersing agent, so that the flocculation of the mixed modified solution is easily caused; the addition amount of the dispersing agent is too small, the stability of the organic silica sol solution is influenced, and the silicon-containing groups cannot effectively penetrate into cracks on the surface of the recycled aggregate.
In a specific embodiment of the present invention, the sealant is silane coupling agent KH-570, and the addition amount is 1-3% (e.g. 1.2%, 1.5%, 1.8%, 2%, 2.5%, 2.8%) of the mass of the organic silica sol. When the content of the sealant is too high, a large amount of condensation products are generated due to too fast self condensation crosslinking reaction in the early stage, so that the reaction of the 'bridged' recycled aggregate and the modifier solution cannot be carried out; when the content is too low, the number of bridging is lacked, so that the combination effect of the recycled aggregate and the modifier solution is influenced, and the repair effect of the recycled aggregate is weakened.
In the specific embodiment of the invention, in the second step, the drying temperature is 95-105 ℃ (such as 100 ℃, 102 ℃, 104 ℃) and the drying time is 2-4h (such as 2.2h, 2.4h, 2.5h, 3h, 3.2h, 3.4h, 3.5h, 4 h).
In the following examples and comparative examples, the filler used was quicklime powder, the dispersant was polyvinyl alcohol PVA, and the sealant was silane coupling agent KH-570, unless otherwise specified.
Example 1
The method for modifying the surface of the recycled aggregate of the construction waste and enhancing the particles comprises the following steps:
step one, aggregate shaping: mixing 100 parts of construction waste recycled aggregate with 1 part of filler according to the parts by mass, placing the mixture in a ball mill for ball milling and shaping for 10min to strip cement mortar attached to the surface of the construction waste recycled aggregate, simultaneously filling cracks and micropores on the surface of recycled aggregate particles with the filler, and sieving to remove the stripped mortar and the residual filler on the surface of the particles to obtain shaped aggregate particles with the particle size range of 5-25 mm;
step two, aggregate modification: mixing 0.004 part of dispersing agent and 0.4 part of sealant, adding the mixture into 20 parts of organic silica sol solution with the mass fraction of 20%, quickly stirring for 1min at the stirring speed of 80r/min, standing for 1min to obtain a modified mixed solution, placing the obtained shaped aggregate particles into the modified mixed solution, completely covering the regenerated aggregate particles on the liquid surface, soaking for 24h at room temperature, taking out, drying in a 105 ℃ blast drying oven for 3h, and taking out to obtain the modified regenerated aggregate.
The modified recycled aggregate is subjected to performance test, the performance test standard refers to the performance data of the modified recycled aggregate tested in the recycled coarse aggregate for concrete GB/T25177-2010, and the data is shown in the following table 1.
Example 2
The method for surface modification and particle reinforcement of the construction waste recycled aggregate provided by the embodiment comprises the following steps:
step one is the same as that in embodiment 1, and is not described herein again.
Step two, aggregate modification: mixing 0.001 part of dispersing agent and 0.1 part of sealant, adding the mixture into 10 parts of organic silica sol solution with the mass fraction of 20%, quickly stirring for 1min at the stirring speed of 78r/min, standing for 1min to obtain a modified mixed solution, placing the obtained shaped aggregate particles into the modified mixed solution, completely covering the regenerated aggregate particles on the liquid surface, soaking for 24h at room temperature, taking out, and placing in a 100 ℃ forced air drying oven for drying for 3h.
The same performance test method as in example 1 was used in this example, and the data are shown in table 1 below.
Example 3
The method for surface modification and particle reinforcement of the construction waste recycled aggregate provided by the embodiment comprises the following steps:
step one is the same as that in embodiment 1, and is not described herein again.
Step two, aggregate modification: mixing 0.009 parts of dispersant and 0.9 parts of sealant, adding the mixture into 30 parts of organic silica sol solution with the mass fraction of 20%, quickly stirring for 1min at the stirring speed of 80r/min, standing for 1min to obtain a modified mixed solution, placing the obtained shaped aggregate particles into the modified mixed solution, completely covering the regenerated aggregate particles on the liquid surface, soaking for 24h at room temperature, taking out, and placing in a 100 ℃ blast drying oven for drying for 3h.
The same performance test method as in example 1 was used in this example, and the data are shown in table 1 below.
Example 4
In this embodiment, the recycled aggregate in the step one is 80 parts, the quicklime powder is 1 part, and other method steps are the same as those in embodiment 1 and are not described again.
The same performance test method as in example 1 was used in this example, and the data are shown in table 1 below.
Example 5
In this embodiment, the recycled aggregate in the first step is 120 parts, the quicklime powder is 1 part, and other method steps are the same as those in embodiment 1 and are not described again.
The same performance test method as in example 1 was used in this example, and the data is shown in table 1 below.
Comparative example 1
The comparative example differs from example 1 in that no filler is added and no modification treatment is performed in the shaping treatment of the recycled aggregate.
Shaping aggregate: placing 100 parts of construction waste recycled aggregate into a ball mill for ball milling and shaping for 10min to strip cement mortar attached to the surface of the construction waste recycled aggregate, sieving to remove the stripped mortar on the surface of particles to obtain the shaped recycled aggregate with the particle size range of 5-25mm, and placing the shaped recycled aggregate in a 105 ℃ blast drying oven for drying for 3h.
The aggregate obtained in this control was subjected to the same performance test method as in example 1, and the data are shown in table 1 below.
Comparative example 2
The comparative example is different from example 1 in that the aggregate is modified without adding a filler, and the other steps are the same as example 1.
Step one, shaping aggregate: placing 100 parts of construction waste recycled aggregate into a ball mill for ball milling and shaping for 10min to strip cement mortar attached to the surface of the construction waste recycled aggregate, and sieving to remove the stripped mortar on the surface of particles to obtain the shaped recycled aggregate with the particle size range of 5-25 mm;
step two, aggregate modification: adding 0.004 part of dispersing agent into 20 parts of organic silica sol solution with the mass fraction of 20%, quickly stirring for 1min at the stirring speed of 80r/min, standing for 1min to obtain a modified mixed solution, placing the obtained shaped aggregate particles into the modified mixed solution, completely covering the regenerated aggregate particles on the liquid surface, soaking for 24h at room temperature, taking out, placing in a 105 ℃ blast drying oven, drying for 3h, and taking out to obtain the modified regenerated aggregate.
The modified aggregate obtained in the present control was subjected to the same performance test method as in example 1, and the data are shown in table 1 below.
Comparative example 3
The difference between this comparative example and example 1 is that no sealant is added, and other methods and steps are the same as those in example 1, and are not described again here.
The modified aggregate obtained in this control was subjected to the same performance test method as in example 1, and the data are shown in table 1 below.
Comparative example 4
The difference between this comparative example and example 1 is that no dispersant is added, and the other methods and steps are the same as example 1 and are not described again.
The modified aggregate obtained in this control was subjected to the same performance test method as in example 1, and the data are shown in table 1 below.
Comparative example 5
The difference between this comparative example and example 1 is that the modifier is replaced by inorganic silica sol, and the other methods and steps are the same as those in example 1 and are not repeated herein.
The modified aggregate obtained in this control was subjected to the same performance test method as in example 1, and the data are shown in table 1 below.
| Apparent density (kg/m) 3 ) | Water absorption (%) | Crush value (%) | |
| Example 1 | 2770 | 4.1 | 17.4 |
| Example 2 | 2767 | 4.7 | 18.1 |
| Example 3 | 2777 | 4.1 | 17.9 |
| Example 4 | 2791 | 4.6 | 18.2 |
| Example 5 | 2717 | 4.4 | 17.7 |
| Comparative example 1 | 2630 | 7.4 | 23.9 |
| Comparative example 2 | 2697 | 6.7 | 21.3 |
| Comparative example 3 | 2781 | 6.7 | 21.4 |
| Comparative example 4 | 2763 | 5.1 | 18.9 |
| Comparative example 5 | 2743 | 5.7 | 18.8 |
From the above table it can be seen that: (1) The filler plays a role in filling microcracks and micropores on the surface of the recycled aggregate; (2) The dispersant enables silicon-containing groups in the modified solution to be distributed more uniformly, and the surface repair effect of the recycled aggregate is more comprehensive; (3) The coupling agent plays a role between the organic silica sol and the aggregateThe bridging effect is used to form inorganic recycled aggregate particles, a coupling agent, organic silica sol, a coupling agent and Ca (OH) 2 "Structure, strengthen silica sol, ca (OH) 2 The combination effect with recycled aggregate is beneficial to the combination with calcium lime powder hydrolysate Ca (OH) 2 The in-situ reaction is carried out to generate C-H-S gel, thereby repairing the surface crack.
In summary, the following steps: the method firstly carries out ball milling treatment on the recycled aggregate to realize particle shaping, so that the particle sphericity of the recycled aggregate is improved. By adding the quicklime powder serving as the filler, microcracks and pores existing on the surface of the recycled aggregate can be filled, the porosity and the water absorption of the recycled aggregate are reduced, and the apparent density and the particle strength are improved.
The modifier adopted by the invention is nano SiO 2 Organosilicon sol, in the position of crack and pore of regenerated aggregate grain, with calcium lime hydrolysate Ca (OH) 2 The C-S-H gel is generated through in-situ reaction, the compactness and the strength of the particle surface are improved, cracks are repaired, the water absorption rate and the crushing value of the recycled aggregate are reduced, and meanwhile, the crack expansion resistance of the recycled aggregate can also be improved through the bonding effect of the C-S-H gel.
The modified aggregate obtained by the invention can be applied to various products, such as: the recycled paving brick, the recycled cement stabilized soil, the recycled commercial concrete and the like have the advantages of higher strength, lower water absorption, more stable quality and the like, not only save natural resources, but also provide a new idea for absorbing construction waste and bring higher social benefits.
The operation process of the surface modification of the construction waste recycled aggregate is simple, complex equipment and expensive raw materials are not needed, and the method has high economic benefit.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made to the present invention by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A method for surface modification and particle reinforcement of recycled aggregate of construction waste is characterized by comprising the following steps:
step one, aggregate shaping: placing the building garbage recycled aggregate mixed filler into a ball mill for ball milling and shaping, and taking out after ball milling to obtain shaped aggregate particles;
step two, aggregate modification: mixing and stirring the dispersant, the sealant and the modifier to obtain a mixed modified solution, placing the shaped aggregate particles into the mixed modified solution, soaking, filtering, taking out the aggregate, and drying to obtain the modified aggregate.
2. The method for surface modification and particle enhancement of construction waste recycled aggregate according to claim 1, wherein in the first step, the time for ball milling and shaping is 8-15min.
3. The method for surface modification and particle enhancement of construction waste recycled aggregate according to claim 1, wherein in the first step, the construction waste recycled aggregate is obtained by crushing, screening, washing and naturally airing construction waste, and the particle size of the construction waste recycled aggregate is 5-25mm.
4. The method for surface modification and particle reinforcement of construction waste recycled aggregate according to claim 1, wherein the filler is quicklime powder, and the mass ratio of the quicklime powder to the recycled aggregate is 1: (80-120).
5. The method for surface modification and particle reinforcement of construction waste recycled aggregate according to claim 1, wherein the modifier is 20% by mass of an organic silica sol.
6. The method for surface modification and particle enhancement of construction waste recycled aggregate according to claim 1, wherein in the second step, the addition amount of the modifier is 10-30% of the mass of the construction waste recycled aggregate.
7. The method for surface modification and particle reinforcement of construction waste recycled aggregate according to claim 5, wherein the dispersant is polyvinyl alcohol, and the addition amount of the dispersant is 0.01-0.03% of the mass of the organic silica sol.
8. The method for surface modification and particle enhancement of construction waste recycled aggregate according to claim 1, wherein in the second step, the stirring speed of the mixed modification solution is 80 ± 4r/min.
9. The method for surface modification and particle reinforcement of construction waste recycled aggregate according to claim 5, wherein the sealant is silane coupling agent KH-570, and the addition amount of the sealant is 1-3% by mass of the organic silica sol.
10. The method for surface modification and particle enhancement of recycled aggregates from construction wastes according to claim 1, wherein in the second step, the drying temperature is 95-105 ℃ and the drying time is 2-4h.
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| CN116947355A (en) * | 2023-06-12 | 2023-10-27 | 常州大学 | Regenerated coarse aggregate modified by silica sol and preparation method and application thereof |
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