Organic polymer impregnated artificial aggregate as well as preparation method and application thereof

Abstract

The invention discloses an organic polymer impregnated artificial aggregate as well as a preparation method and application thereof, and relates to the field of building materials. The preparation method of the organic polymer impregnated artificial aggregate comprises the following steps: mixing municipal solid waste incinerator bottom ash, blast furnace slag and cement according to a mass ratio of (5-8): (1-4): 1 to obtain a mixture; the mixture is put into a disc granulator for granulation, and an artificial aggregate blank is obtained; maintaining the artificial aggregate green body to obtain the artificial aggregate; providing an impregnation liquid containing methyl methacrylate, butyl methacrylate and an initiator; and dipping the artificial aggregate in the dipping liquid, taking out the artificial aggregate, and drying the artificial aggregate to obtain the organic polymer dipped artificial aggregate. According to the preparation method, the impregnation liquid is impregnated into the pores of the artificial aggregate, and polymerization reaction is carried out in the pores to form a polymer, so that the mechanical strength of the artificial aggregate is improved, and the organic polymer impregnated artificial aggregate with higher mechanical strength is obtained.

Description

Technical Field

[0001] The invention relates to the field of building materials, and in particular to an organic polymer impregnated artificial aggregate and a preparation method and application thereof. Background Art

[0002] Concrete is generally made by mixing cement, aggregate, water, mineral admixtures and some additives. It has the characteristics of abundant raw materials, low price and simple production process. At present, its usage is increasing. It is not only used in various civil engineering projects, but also widely used in shipbuilding, machinery industry and geothermal engineering.

[0003] However, as the time of use or exposure to the environment increases, concrete will be damaged and its mechanical properties will decrease. The destruction of aggregates (aggregates are used in large amounts in concrete, accounting for about 60% to 70% of the total concrete) is the main factor in the destruction of concrete. Therefore, it is urgent to develop artificial aggregates with high mechanical strength to enhance the strength of concrete and increase the service life of concrete.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] Based on the above-mentioned deficiencies of the prior art, the object of the present invention is to provide an organic polymer impregnated artificial aggregate and a preparation method and application thereof, aiming to provide an artificial aggregate with high mechanical strength.

[0006] The technical solution of the present invention is as follows:

[0007] The first aspect of the present invention provides a method for preparing an organic polymer impregnated artificial aggregate, which comprises the following steps:

[0008] Mixing bottom ash from a municipal solid waste incinerator, blast furnace slag and cement in a mass ratio of (5-8):(1-4):1 to obtain a mixture;

[0009] Putting the mixed material into a disc granulator for granulation to obtain an artificial aggregate blank;

[0010] After curing the artificial aggregate blank, artificial aggregate is obtained;

[0011] Providing an impregnation solution, wherein the impregnation solution comprises methyl methacrylate, butyl methacrylate and an initiator;

[0012] The artificial aggregate is placed in the impregnation liquid for a preset time, taken out and dried to obtain the organic polymer impregnated artificial aggregate.

[0013] Optionally, the initiator includes at least one of dibenzoyl peroxide and azobisisobutyronitrile.

[0014] Optionally, the impregnation solution comprises the following components in parts by weight:

[0015] 47.5 parts of methyl methacrylate, 47.5 parts of butyl methacrylate, 3 parts of dibenzoyl peroxide and 5 parts of water.

[0016] Optionally, the step of feeding the mixed material into a disc granulator for granulation to obtain an artificial aggregate blank specifically comprises:

[0017] The mixture is put into a disc granulator and water is sprayed during the granulation process. The total amount of water used is 20% to 22% of the mass of the mixture. After granulation, an artificial aggregate blank is obtained.

[0018] Optionally, the disc granulator has a disc inclination angle of 35 to 55°, a disc diameter of 1 m, an edge height of 1.5 cm, and a rotation speed of 30 to 55 rpm;

[0019] The granulation time is 10 to 15 minutes.

[0020] Optionally, the particle size of the artificial aggregate is 4 to 20 mm;

[0021] The curing is standard curing, and the curing time is 1 day.

[0022] Optionally, the preset time is 1 to 72 hours.

[0023] Optionally, the drying temperature is 80-100° C., and the drying time is 3-24 hours.

[0024] The second aspect of the present invention provides an organic polymer impregnated artificial aggregate, wherein the organic polymer impregnated artificial aggregate is prepared by the preparation method of the present invention as described above.

[0025] The third aspect of the present invention provides a use of the organic polymer impregnated artificial aggregate as described above in concrete.

[0026] Beneficial effects: The present invention improves the mechanical strength of the artificial aggregate by impregnating an impregnation liquid containing organic polymer monomers methyl methacrylate and butyl methacrylate into the pores of the artificial aggregate, and a polymerization reaction occurs in the pores to form a polymer, thereby obtaining an organic polymer impregnated artificial aggregate with higher mechanical strength, and then adding the organic polymer impregnated artificial aggregate into concrete can improve the mechanical strength of the concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the formation of artificial aggregate green body.

[0028] Figure 2 Schematic diagram of the preparation of the impregnation solution and the immersion of the artificial aggregate in the impregnation solution.

[0029] Figure 3 This is a graph showing the apparent density results of the artificial aggregates impregnated with various organic polymers in Examples 1 to 3.

[0030] Figure 4 This is a graph showing the impregnation rate of artificial aggregates impregnated with various organic polymers in Examples 1 to 3.

[0031] Figure 5 This is a graph showing the compressive strength results of artificial aggregates impregnated with organic polymers in Examples 1 to 3 and Comparative Example 1.

[0032] Figure 6 The figure shows the effect of cracks on the compressive strength of artificial aggregate impregnated with organic polymer.

[0033] Figure 7 This is the cylinder compressive strength result diagram of the aggregate in Example 4. DETAILED DESCRIPTION

[0034] The present invention provides an organic polymer impregnated artificial aggregate and a preparation method and application thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0036] The embodiment of the present invention provides a method for preparing an organic polymer impregnated artificial aggregate, which comprises the following steps:

[0037] S1. Mixing bottom ash from a municipal solid waste incinerator, blast furnace slag and cement (which may be ordinary Portland cement) in a mass ratio of (5-8):(1-4):1 to obtain a mixture;

[0038] S2, putting the mixed material into a disc granulator for granulation to obtain an artificial aggregate blank; curing the artificial aggregate blank to obtain an artificial aggregate;

[0039] S3, providing an impregnation solution, wherein the impregnation solution comprises methyl methacrylate (MMA), butyl methacrylate (BMA) and an initiator;

[0040] S4, placing the artificial aggregate in the impregnation liquid for a preset time, taking it out and drying it to obtain the organic polymer impregnated artificial aggregate.

[0041] In the embodiment of the present invention, during the process of preparing the artificial aggregate blank by the disc granulation method, pores of different pore sizes are formed in the artificial aggregate blank. Therefore, the artificial aggregate is immersed in the impregnation liquid containing MMA and BMA. Since the impregnation liquid containing MMA and BMA has strong fluidity, it can be immersed in the pores of the artificial aggregate at room temperature and pressure to achieve the impregnation of the artificial aggregate (while the impregnation of the artificial aggregate cannot be achieved by using the epoxy resin impregnation liquid). In addition, since the molecular structures of MMA and BMA are complementary, that is, MMA has a small molecular weight and can complete the filling of the tiny pores of the artificial aggregate, while BMA has a relatively large molecular weight and can fill the large pores inside the artificial aggregate, achieving complementary advantages. Then, after the polymerization reaction of MMA and BMA under the action of the initiator, a polymer, namely polyacrylate, is formed in situ in the pores of the artificial aggregate, specifically a homopolymer of MMA (polymethyl methacrylate), a homopolymer of BMA (polybutyl methacrylate), and a copolymer between MMA and BMA, thereby improving the mechanical strength of the artificial aggregate and obtaining an organic polymer-impregnated artificial aggregate with higher mechanical strength. Furthermore, adding the organic polymer-impregnated artificial aggregate into concrete can improve the mechanical strength of the concrete.

[0042] In step S1, the mass ratio of municipal solid waste incinerator bottom ash, blast furnace slag and cement is (5-8):(1-4):1, for example, it can be 5:1:1, 5:2:1, 5:3:1, 5:4:1, 6:1:1, 6:2:1, 6:3:1, 6:4:1, 7:1:1, 7:2:1, 7:3:1, 7:4:1, 8:1:1, 8:2:1, 8:3:1 or 8:4:1, etc.

[0043] When the mass content of municipal solid waste incinerator bottom ash in the mixture is 70%, the best production efficiency can be obtained, while when it exceeds 70%, the production efficiency is significantly reduced.

[0044] like Figure 1 As shown, the mixed material is poured into the disc of the disc granulator. Through the rotation of the disc and the wetting of water, the mixed material collides and agglomerates on the disc to form wet fine particles. Then, the wet fine particles gradually agglomerate and grow into spherical and ellipsoidal particles. Due to the action of centrifugal force and gravity, the formation of the particle structure has an enhanced bonding force, so that the mixed material is tightly bonded together, thus having a certain strength. The granulation process is mainly driven by gravity / centrifugal force, and the operating parameters that control the process are the rotation speed (rotation speed) and inclination (i.e., the disc inclination angle) of the disc granulator and the amount of water in the mixed material.

[0045] Therefore, in step S2, in some embodiments, the mixed material is put into a disc granulator for granulation to obtain an artificial aggregate blank, which specifically includes:

[0046] The mixture is put into a disc granulator and water is sprayed during the granulation process. The total water consumption is 20% to 22% of the mass of the mixture (for example, 20%, 20.5%, 21%, 21.5% or 22%, etc.). After granulation, an artificial aggregate blank is obtained.

[0047] In some embodiments, the disc granulator has a disc inclination angle of 35 to 55° (for example, 35°, 40°, 45°, 50° or 55°, etc.), a disc diameter of 1 m, an edge height of 1.5 cm, and a rotation speed of 30 to 55 rpm (for example, 30 rpm, 35 rpm, 40 rpm, 45 rpm, 50 rpm or 55 rpm, etc.);

[0048] The granulation time is 10 to 15 minutes (for example, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes or 15 minutes, etc.).

[0049] In this way, the preparation of an artificial aggregate body with a certain strength can be achieved.

[0050] In some embodiments, the curing is standard curing (temperature is 20° C., relative humidity is 95% RH), and the curing time is 1 day.

[0051] In some embodiments, the particle size of the artificial aggregate is 4 to 20 mm. In some specific embodiments, the particle size of the artificial aggregate is 4.75 to 16 mm, and the organic polymer impregnated artificial aggregate prepared in this particle size range has higher mechanical strength (compressive strength). In some specific embodiments, the particle size of the artificial aggregate is 4.75 to 9.5 mm, and the organic polymer impregnated artificial aggregate prepared in this particle size range still has higher compressive strength even in the presence of cracks.

[0052] In step S3, in some embodiments, the initiator includes at least one of dibenzoyl peroxide (BPO) and azobisisobutyronitrile (AIBN), but is not limited thereto.

[0053] In some embodiments, the impregnation solution includes the following components in parts by weight:

[0054] 47.5 parts of methyl methacrylate (MMA), 47.5 parts of butyl methacrylate (BMA), 3 parts of dibenzoyl peroxide and 5 parts of water.

[0055] Although azobisisobutyronitrile does not produce side reactions when it decomposes, it will produce N2 and organic cyanide during the decomposition process. Organic fluoride is a toxic gas that is harmful to the human body, and azobisisobutyronitrile has a low efficiency. Therefore, in this embodiment, dibenzoyl peroxide is preferably used as an initiator. Dibenzoyl peroxide decomposes to produce only non-toxic carbon dioxide, which is more environmentally friendly when initiating polymerization, and is cheaper than azobisisobutyronitrile.

[0056] In this embodiment, the components in this mass fraction are selected to make the impregnation liquid more fluid, and the impregnation of artificial aggregate can be achieved under normal temperature and pressure difference. In addition, the molecular structures of MMA and BMA are complementary, that is, MMA has a small molecular weight and can fill the tiny pores of artificial aggregate, while BMA has a relatively large molecular weight and can fill the internal large pores, achieving complementary advantages.

[0057] In step S4, the artificial aggregate is placed in the impregnation liquid so that the liquid level of the impregnation liquid is at least 20 mm higher than the artificial aggregate, so that the artificial aggregate can be impregnated better.

[0058] In some embodiments, the preset time is 1 to 72 hours, for example, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 20 hours, 25 hours, 30 hours, 35 hours, 40 hours, 45 hours, 50 hours, 55 hours, 60 hours, 65 hours, 70 hours or 72 hours, etc. That is, the artificial aggregate is placed in the impregnation liquid and immersed for 1 to 72 hours.

[0059] In some embodiments, the drying temperature is 80-100°C, for example, 80°C, 85°C, 90°C, 95°C or 100°C, and the drying time is 3-24h, for example, 3h, 5h, 6h, 10h, 12h, 15h, 18h, 20h or 24h, etc.

[0060] At this temperature, the polymerization reaction of organic polymer monomers MMA and BMA is rapid and intense, which enables the organic polymer-impregnated artificial aggregate to quickly and efficiently form high mechanical strength and be put into use.

[0061] The embodiment of the present invention also provides an organic polymer impregnated artificial aggregate, wherein the organic polymer impregnated artificial aggregate is prepared by the preparation method of the present invention as described above. The organic polymer impregnated artificial aggregate provided by the embodiment of the present invention has high mechanical strength, with a cylinder pressure strength of up to 8.3MPa and a compressive strength of up to 14.009MPa.

[0062] The embodiment of the present invention also provides an application of the organic polymer impregnated artificial aggregate in concrete. The application of the organic polymer impregnated artificial aggregate in concrete can improve the mechanical strength of the concrete and prevent the concrete from being damaged.

[0063] The present invention will be further described below by means of specific examples.

[0064] The cement used in the following examples is all ordinary Portland cement.

[0065] Example 1

[0066] The present embodiment provides a method for preparing an organic polymer impregnated artificial aggregate, comprising the following steps: mixing municipal solid waste incinerator bottom ash (MSWIBA), blast furnace slag (GGBFS) and cement in a mass ratio of 7:2:1 to obtain a mixture;

[0067] The mixture is put into a disc granulator for granulation, and 20% of water by mass of the mixture is added during the granulation process. After granulation for 15 minutes, an artificial aggregate blank is obtained; wherein the disc inclination angle of the disc granulator is 35°, the disc diameter is 1m, the edge height is 1.5cm, and the rotation speed is 35rpm;

[0068] The artificial aggregate blank is subjected to standard curing for 1 day, and then sieved to obtain an artificial aggregate with a particle size ranging from 4.75 to 9.5 mm;

[0069] like Figure 2 As shown, 47.5 parts of MMA, 47.5 parts of BMA, 3 parts of dibenzoyl peroxide and 5 parts of water were mixed, and stirred on a magnetic stirrer for 1 hour to obtain an impregnation solution;

[0070] At room temperature and pressure, the artificial aggregate was placed in the impregnation liquid (the liquid level of the impregnation liquid was 20 mm higher than the artificial aggregate) and immersed for 1 h, 2 h, 3 h, 4 h, 6 h, 12 h, 24 h, 36 h, 48 h, 60 h and 72 h respectively, and then taken out and placed in an 80° C. blast drying oven for 12 h for drying to obtain organic polymer impregnated artificial aggregates with different impregnation times.

[0071] Example 2

[0072] This embodiment provides a method for preparing an organic polymer impregnated artificial aggregate, comprising the following steps:

[0073] Mixing bottom ash from a municipal solid waste incinerator, blast furnace slag and cement in a mass ratio of 7:2:1 to obtain a mixture;

[0074] The mixture is put into a disc granulator for granulation, and 20% of water by mass of the mixture is added during the granulation process. After granulation for 12 minutes, an artificial aggregate blank is obtained; wherein the disc inclination angle of the disc granulator is 45°, the disc diameter is 1m, the edge height is 1.5cm, and the rotation speed is 45rpm;

[0075] The artificial aggregate blank is subjected to standard curing for 1 day, and then sieved to obtain an artificial aggregate with a particle size range of 9.5 to 16 mm;

[0076] Mix 47.5 parts of MMA, 47.5 parts of BMA, 3 parts of dibenzoyl peroxide and 5 parts of water, and stir on a magnetic stirrer for 1 hour to obtain an impregnation solution;

[0077] At room temperature and pressure, the artificial aggregate was placed in the impregnation liquid (the liquid level of the impregnation liquid was 20 mm higher than the artificial aggregate) and immersed for 1 h, 2 h, 3 h, 4 h, 6 h, 12 h, 24 h, 36 h, 48 h, 60 h and 72 h respectively, and then taken out and placed in an 80° C. blast drying oven for 12 h for drying to obtain organic polymer impregnated artificial aggregates with different impregnation times.

[0078] Example 3

[0079] This embodiment provides a method for preparing an organic polymer impregnated artificial aggregate, comprising the following steps:

[0080] Mixing bottom ash from a municipal solid waste incinerator, blast furnace slag and cement in a mass ratio of 7:2:1 to obtain a mixture;

[0081] The mixture is put into a disc granulator for granulation, and 20% of water by mass of the mixture is added during the granulation process. After granulation for 10 minutes, an artificial aggregate blank is obtained; wherein the disc granulator has a disc inclination angle of 55°, a disc diameter of 1m, an edge height of 1.5cm, and a rotation speed of 55rpm;

[0082] The artificial aggregate blank is subjected to standard curing for 1 day, and then sieved to obtain an artificial aggregate with a particle size ranging from 16 to 20 mm;

[0083] Mix 47.5 parts of MMA, 47.5 parts of BMA, 3 parts of dibenzoyl peroxide and 5 parts of water, and stir on a magnetic stirrer for 1 hour to obtain an impregnation solution;

[0084] At room temperature and pressure, the artificial aggregate was placed in the impregnation liquid (the liquid level of the impregnation liquid was 20 mm higher than the artificial aggregate) and immersed for 1 h, 2 h, 3 h, 4 h, 6 h, 12 h, 24 h, 36 h, 48 h, 60 h and 72 h respectively, and then taken out and placed in an 80° C. blast drying oven for 12 h for drying to obtain organic polymer impregnated artificial aggregates with different impregnation times.

[0085] The organic polymer impregnated artificial aggregates in Examples 1 to 3 were tested:

[0086] (1) Apparent density test

[0087] Pour the organic polymer impregnated artificial aggregate into a 1000mL measuring cylinder and then add 500mL of clean water. If there is a sample floating on the water surface, use a fixed volume V t The round metal plate is pressed into the water, the eyes are flush with the depression of the liquid surface of the measuring cylinder, and the water level V of the measuring cylinder is read. t The apparent density of organic polymer impregnated artificial aggregate is calculated using the following formula (1).

[0088]

[0089] Where:

[0090] ρ ap —Apparent density of artificial aggregate impregnated with organic polymer, unit (g / cm 3 );

[0091] m—mass of artificial aggregate impregnated with organic polymer, unit (g);

[0092] V τ —Volume of round metal plate, unit (mL);

[0093] V t —Total volume of artificial aggregate, circular metal plate and water impregnated with organic polymer, unit (mL).

[0094] The results are shown in Table 1 and Figure 3 As shown ( Figure 3 The >16mm in the above refers to the organic polymer impregnated artificial aggregate with a particle size range of 16 to 20mm, and Figure 4 , Figure 5 and Figure 6 The meaning of ">16mm" is the same as above).

[0095] Table 1. Apparent density of artificial aggregate impregnated with organic polymer (g / cm 3 )

[0096]

[0097] It can be seen that the apparent density of the organic polymer impregnated artificial aggregate prepared in the embodiment of the present invention is 1.78-2.24 g / cm 3 The apparent density of the artificial aggregate impregnated with the organic polymer when the impregnation time is 0 h is the surface density of the artificial aggregate not impregnated with the organic polymer.

[0098] The apparent density of artificial aggregate impregnated with organic polymer shows an upward trend with the increase of impregnation time of artificial aggregate. The apparent density of artificial aggregate impregnated with organic polymer reaches its peak value when the impregnation time is 60h for the three particle size ranges, that is, the optimal impregnation time is 60h.

[0099] In addition, in the early stage of the impregnation time gradient, due to the dense time nodes, the apparent density of the organic polymer impregnated artificial aggregate obtained by impregnating artificial aggregate in the three particle size ranges did not show a significant change. However, with the advancement of the impregnation time, the impregnation time nodes changed from dense to sparse, and the change rate of the apparent density of the organic polymer impregnated artificial aggregate obtained by impregnating artificial aggregate in the three particle size ranges increased significantly.

[0100] After longitudinal observation, after 36 hours of impregnation, the apparent density of the organic polymer impregnated artificial aggregate obtained by impregnating the artificial aggregate in the particle size range of 4.75-16 mm increased by 6.45% (relative to 1 hour of impregnation); the apparent density of the organic polymer impregnated artificial aggregate obtained by impregnating the artificial aggregate in the particle size range of 9.5-16 mm increased by 7.10% (relative to 1 hour of impregnation); the apparent density of the organic polymer impregnated artificial aggregate obtained by impregnating the artificial aggregate in the particle size range of 16-20 mm increased by 11.73% (relative to 1 hour of impregnation). This is because the porosity of the artificial aggregate in the range of 16-20 mm is the largest, which makes it relatively easy for the early impregnation liquid to penetrate into the internal pores, thus showing ρ ap (16~20)>ρ ap (9.5~16)>ρ ap (4.75~9.5). When impregnated for 60h, the apparent density growth rate of the organic polymer impregnated artificial aggregate obtained by impregnating the artificial aggregate in the particle size range of 4.75~9.5mm is 15.59% (relative to 1h of impregnation); the apparent density growth rate of the organic polymer impregnated artificial aggregate obtained by impregnating the artificial aggregate in the particle size range of 9.5~16mm is as high as 22.40% (relative to 1h of impregnation); the apparent density growth rate of the organic polymer impregnated artificial aggregate obtained by impregnating the artificial aggregate in the particle size range of 16~20mm is 19.55% (relative to 1h of impregnation). This phenomenon fully reveals that in the later stage of impregnation, the artificial aggregate in the particle size range of 16~20mm has been fully filled with the impregnation liquid and polymerization has occurred, the artificial aggregate in the particle size range of 9.5~16mm is quickly impregnated and polymerized by the impregnation liquid during this period, and the apparent density increase of the artificial aggregate in the particle size range of 4.75~9.5mm is small due to its relatively small porosity.

[0101] (2) Immersion test

[0102] The impregnation rate is used to characterize the degree of impregnation of the artificial aggregate by the impregnation liquid. The impregnation rate refers to the percentage of the mass of the polymer generated after the polymerization reaction of the polymer monomer occurs in the pores of the artificial aggregate to the mass of the artificial aggregate.

[0103] The impregnation rate mainly reflects the degree of conversion of polymer monomers in the artificial aggregate and the filling effect on the artificial aggregate. The specific test steps are: measuring the mass of artificial aggregate after drying (i.e., first drying artificial aggregates of different particle size ranges at 80°C for 12 hours) and the mass of artificial aggregate impregnated with organic polymer at different impregnation times in three particle size ranges. The three particle size ranges are grouped with 100g (the mass of artificial aggregate after drying), and the average value of the three groups is taken and calculated by the following formula (2).

[0104]

[0105] Where:

[0106] R—impregnation rate, %;

[0107] m′—the total mass of the organic polymer-impregnated artificial aggregate obtained after the polymerization, g;

[0108] m0—weight of artificial aggregate after drying, g.

[0109] The results are shown in Table 2 and Figure 4 shown.

[0110] Table 2. Impregnation rate results

[0111]

[0112] From the above results, we can see that the impregnation rate gradually increases with the increase of impregnation time; when the impregnation time reaches 48h, the impregnation rate growth rate begins to decline. Figure 4In the middle, the slope decreases. In the early stage, the impregnation time gradient was dense, so the impregnation rate increased slowly. The impregnation rates at 12h increased by 24.22% (16-20mm), 17.86% (9.5-16mm), and 18.17% (4.75-9.5mm) compared with those at 1h, respectively. In the middle stage, the impregnation time gradient began to become sparse, resulting in an increase in the growth rate of the impregnation rate. At 48h, the impregnation rates increased by 47.93% (16-20mm), 42.40% (9.5-16mm), and 44.85% (4.75-9.5mm) compared with those at 1h, respectively. Finally, after 48h, the increase in the impregnation rate was relieved, indicating that the artificial aggregates in the three particle size ranges were filled with a large amount of polymer. In addition, it can be seen that the impregnation rate of artificial aggregate in the particle size range of 9.5-16 mm is the largest, followed by that in the particle size range of 16-20 mm, and the impregnation rate of artificial aggregate in the particle size range of 4.75-9.5 mm is the smallest. The reason for this phenomenon may be due to the limited number of particles. During the test, referring to GB_T 17431.2-2010, each group of artificial aggregates in the particle size ranges of 16-20 mm, 9.5-16 mm and 4.75-9.5 mm was 100 g. Due to the determination of mass, the number of artificial aggregates in the particle size range of 4.75-9.5 mm is greater than that of artificial aggregates in the particle size range of 9.5-16 mm; similarly, the number of artificial aggregates in the particle size range of 9.5-16 mm is greater than that of artificial aggregates in the particle size range of 16-20 mm, so the impregnation rates of artificial aggregates in the particle size ranges of 9.5-16 mm and 4.75-9.5 mm are higher than that of artificial aggregates in the particle size range of 16-20 mm. By comparing the impregnation rate results of artificial aggregates in the particle size range of 9.5-16 mm and 4.75-9.5 mm, it can be seen that the porosity of artificial aggregates in the particle size range of 9.5-16 mm is higher than that of artificial aggregates in the particle size range of 4.75-9.5 mm, so artificial aggregates in the particle size range of 9.5-16 mm are more easily impregnated by the impregnation liquid.

[0113] (3) Compressive strength test

[0114] The compressive strength results of artificial aggregates impregnated with various organic polymers are shown in Table 3. Based on the data in Table 3, the relationship curve between the impregnation time and the compressive strength of artificial aggregates impregnated with organic polymers is plotted as follows: Figure 5 shown.

[0115] Table 3. Compressive strength of organic polymer artificial aggregate

[0116]

[0117] Depend on Figure 5It can be found that the impregnation time-compressive strength curve is S-shaped. When the impregnation time is ≤4h, the strength of the organic polymer impregnated artificial aggregate increases slowly and there is no obvious change range. This is related to the fact that the impregnation time gradient is too dense, indicating that the impregnation time interval of 1h has little effect on the impregnation depth. When the impregnation time is 6-60h, the three particle size ranges of organic polymer impregnated artificial aggregates are increased by 10.05%-168.75% (4.75-9.5mm), 25.26%-358.58% (9.5-16mm), and 17.97%-384.07% (16-20mm) respectively compared with the organic polymer impregnated artificial aggregate impregnated for 1h. In the medium term, it is shown that with the increase of impregnation time, the mechanical strength of the organic polymer impregnated artificial aggregate increases rapidly. The highest compressive strength can be obtained when the impregnation time is 60h, so the optimal impregnation time is 60h. Thereafter, when the immersion time reached 72 h, the thickness decreased by 37.62% (4.75-9.5 mm), 50.90% (9.5-16 mm) and 48.16% (16-20 mm) respectively compared with the immersion time of 60 h.

[0118] In addition, during the research process, it was found that when the impregnation liquid was impregnated with artificial aggregate for 72 hours, polymerization at a high temperature of 80°C would cause the organic polymer impregnated artificial aggregate to self-crack. In order to intuitively compare the self-crack phenomenon, the cracked aggregate and the intact aggregate in the organic polymer impregnated aggregate prepared by impregnating the artificial aggregate with the impregnation liquid for 72 hours were picked out and separated, and the compressive strength of the cracked aggregate and the intact aggregate were tested respectively. The results are as follows: Figure 6 As shown in the figure, A (average) represents the compressive strength of cracked aggregate and intact aggregate mixed together, corresponding to Figure 5 From the compressive strength values ​​after 72 hours of impregnation, it can be seen that the generation of cracks has a great influence on the strength of organic polymer impregnated artificial aggregates, and with the increase of particle size, the influence of cracks on organic polymer impregnated artificial aggregates increases accordingly, especially when the particle size range is 16-20mm, the mechanical strength of the aggregate with cracks decreases by up to 91.62% compared with the intact aggregate, and when the particle size range is 9.5-16mm and 4.75-9.5mm, the mechanical strength of the aggregate with cracks decreases by 87.23% and 51.61% respectively compared with the intact aggregate. Therefore, the results of the self-cracking phenomenon can show that the mechanical strength of organic polymer impregnated artificial aggregates with a small particle size range (9.5-16mm and 4.75-9.5mm) is higher, and can effectively resist external damage. Even when cracks are generated by external damage, they have higher mechanical strength than organic polymer impregnated artificial aggregates with a large particle size range. That is, impregnated artificial aggregates with a small particle size range are more conducive to improving the mechanical strength of concrete.

[0119] In addition, the compressive strength of the artificial aggregates in Example 1, Example 2 and Example 3 (i.e., not impregnated with MMA and BMA) was tested respectively, and the compressive strength of the artificial aggregate in Example 1 was 2.044 MPa, the compressive strength of the artificial aggregate in Example 2 was 2.574 MPa, and the compressive strength of the artificial aggregate in Example 3 was 2.258 MPa. By comparing the compressive strengths of the artificial aggregates impregnated with organic polymers in Table 3, it can be seen that the artificial aggregate impregnated with organic polymers provided by the present invention has higher compressive strength.

[0120] Example 4

[0121] This embodiment provides a method for preparing an organic polymer impregnated artificial aggregate, comprising the following steps:

[0122] The artificial aggregate with a particle size range of 4.75 to 9.5 mm in Example 1, the artificial aggregate with a particle size range of 9.5 to 16 mm in Example 2, and the artificial aggregate with a particle size range of 16 to 20 mm in Example 3 were mixed in a mass ratio of 1:5:4 to obtain an artificial aggregate with a particle size range of 4.75 to 20 mm.

[0123] Mix 47.5 parts of MMA, 47.5 parts of BMA, 3 parts of dibenzoyl peroxide and 5 parts of water, and stir on a magnetic stirrer for 1 hour to obtain an impregnation solution;

[0124] At room temperature and pressure, the artificial aggregate is placed in the impregnation liquid (the liquid level of the impregnation liquid is 20 mm higher than the artificial aggregate) for 60 hours, taken out and placed in an 80° C. blast drying oven for 12 hours to obtain an organic polymer impregnated artificial aggregate.

[0125] The cylinder compressive strength test was performed on the artificial aggregate impregnated with the organic polymer in Example 4 and the artificial aggregate (not impregnated with the organic polymer, as a control group):

[0126] The pressure cylinder method is used to determine the average relative strength index of aggregate particles. The pressure cylinder is mainly composed of a cylindrical cylinder, a guide cylinder and a stamping die. The press machine uses a YAW6206 200T electro-hydraulic servo pressure testing machine.

[0127] Based on GB_T 17431.2-2010, the sample is loaded into the pressure cylinder to the top of the cylinder mouth, placed on the concrete test vibration table and vibrated for 3 seconds, then the sample is loaded again to the top of the cylinder mouth, placed on the concrete test vibration table and vibrated for 5 seconds, and finally the sample is scraped flat to the cylinder mouth.

[0128] Install the guide cylinder and the punching die, and make the scale line below the punching die flush with the upper edge of the guide cylinder. Place the pressure cylinder in the press, align it with the center of the pressing plate, and set the load to be applied at a constant speed of 300N / s. When the punching die reaches a depth of 20mm, record the pressure value. Based on the above operations, the cylinder pressure strength under different conditions was obtained.

[0129] At the same time, the cylinder compressive strength of the organic polymer impregnated artificial aggregate in Example 4 was tested after being immersed in water for 24 hours.

[0130] The results are as follows Figure 7 As shown, the cylinder compressive strength of the artificial aggregate in the control group is 4.4MPa (corresponding to Figure 7 The cylinder compressive strength of the organic polymer impregnated artificial aggregate in Example 4 is 8.3MPa (corresponding to Figure 7 After the organic polymer impregnated artificial aggregate in Example 4 was immersed in water for 24 hours, its cylinder compressive strength was 6.8 MPa (corresponding to Figure 7 wetting conditions in the

[0131] It can be seen that the cylinder compressive strength of the dry-treated organic polymer impregnated artificial aggregate increased by 88.64% compared with the control group, while the cylinder compressive strength of the wet-treated organic polymer impregnated artificial aggregate increased by 54.54% compared with the control group. After the wetting treatment, the stacking pores of the polymer impregnated artificial aggregate are affected, so that the cylinder compressive strength is smaller than that of the dry-treated organic polymer impregnated artificial aggregate in the macroscopic sense.

[0132] In summary, the present invention provides an organic polymer impregnated artificial aggregate and a preparation method and application thereof. The present invention improves the mechanical strength of the artificial aggregate by impregnating an impregnating solution containing organic polymer monomers methyl methacrylate and butyl methacrylate into the pores of the artificial aggregate, and a polymerization reaction occurs in the pores to form polyacrylate, thereby obtaining an organic polymer impregnated artificial aggregate with higher mechanical strength. Further, the organic polymer impregnated artificial aggregate is added to concrete to improve the mechanical strength of the concrete.

[0133] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing an organic polymer impregnated artificial aggregate, characterized in that: The steps include: Mixing bottom ash from a municipal solid waste incinerator, blast furnace slag and cement in a mass ratio of (5-8):(1-4):1 to obtain a mixture; Putting the mixed material into a disc granulator for granulation to obtain an artificial aggregate blank; After curing the artificial aggregate blank, artificial aggregate is obtained; Providing an impregnation solution, wherein the impregnation solution comprises methyl methacrylate, butyl methacrylate and an initiator; The artificial aggregate is placed in the impregnation liquid for a preset time, taken out and dried to obtain the organic polymer impregnated artificial aggregate.

2. The preparation method according to claim 1, characterized in that: The initiator includes at least one of dibenzoyl peroxide and azobisisobutyronitrile.

3. The preparation method according to claim 2, characterized in that: The impregnation solution comprises the following components in parts by weight: 47.5 parts of methyl methacrylate, 47.5 parts of butyl methacrylate, 3 parts of dibenzoyl peroxide and 5 parts of water.

4. The preparation method according to claim 1, characterized in that: The step of feeding the mixed material into a disc granulator for granulation to obtain an artificial aggregate blank specifically comprises: The mixture is put into a disc granulator and water is sprayed during the granulation process. The total amount of water used is 20% to 22% of the mass of the mixture. After granulation, an artificial aggregate blank is obtained.

5. The preparation method according to claim 1, characterized in that: The disc granulator has a disc inclination angle of 35 to 55°, a disc diameter of 1 m, an edge height of 1.5 cm, and a rotation speed of 30 to 55 rpm; The granulation time is 10 to 15 minutes.

6. The preparation method according to claim 1, characterized in that: The particle size of the artificial aggregate is 4 to 20 mm; The curing is standard curing, and the curing time is 1 day.

7. The preparation method according to claim 1, characterized in that: The preset time is 1 to 72 hours.

8. The preparation method according to claim 1, characterized in that: The drying temperature is 80-100° C., and the drying time is 3-24 hours.

9. An organic polymer impregnated artificial aggregate, characterized in that: The organic polymer impregnated artificial aggregate is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the organic polymer impregnated artificial aggregate according to claim 9 in concrete.

Images