A recycled concrete against hydration heat expansion and a preparation method thereof

Abstract

The application discloses recycled concrete resisting hydration heat expansion and a preparation method thereof, which comprises the following raw materials in parts by weight: recycled aggregate 900 parts, sand 600-800 parts, cement 500-720 parts, fly ash 300-400 parts, deformation filler 20-37 parts, and water 380-450 parts; the deformation filler is obtained by uniformly mixing hollow fillers and surface adhesion agents in a mass ratio of 100:8-12, spreading and drying; the hollow fillers are made of liquid-impermeable flexible materials; the surface adhesion agents are made of filler sand, filler cement and water in a mass ratio of 1-2:3:4-5; during preparation, the other raw materials are uniformly mixed and stirred, and then the deformation filler is added and mixed under stirring to obtain the recycled concrete, so that the hydration heat expansion stress influence is reduced, and the final strength of the recycled concrete after final setting and maintenance is enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of recycled concrete, in particular to a recycled concrete resisting hydration heat expansion and a preparation method thereof. BACKGROUND

[0002] Recycled concrete is obtained by crushing and screening old and waste concrete to obtain structural complete and suitable size pieces as recycled aggregate to replace or partially replace natural aggregate.

[0003] Due to mechanical damage in the process of obtaining, the porosity and water absorption of recycled aggregate are significantly increased compared with natural aggregate, which leads to an increase in hydration heat in the setting process of recycled concrete due to the increase of recycled aggregate in the total aggregate. The excessive hydration heat causes excessive thermal expansion stress in recycled concrete, which leads to cracks or cracks in the initial setting to final setting process of recycled concrete, and finally the strength of the obtained recycled concrete is reduced and cannot meet the design expectation, which limits the application of recycled aggregate and recycled concrete in medium and high strength concrete use scenarios. SUMMARY

[0004] In order to increase the application of recycled concrete in medium and high strength use scenarios, a recycled concrete resisting hydration heat expansion and a preparation method thereof are provided to reduce the influence of hydration heat expansion stress and enhance the strength of recycled concrete after final setting and curing.

[0005] The first application purpose of the present application is achieved by the following technical scheme:

[0006] A recycled concrete comprises the following raw materials by weight:

[0007] Recycled aggregate 900 parts;

[0008] Sand 600-800 parts;

[0009] Cement 500-720 parts;

[0010] Fly ash 300-400 parts;

[0011] Deformation filler 20-37 parts;

[0012] Water 380-450 parts;

[0013] The deformation filler is obtained by uniformly mixing hollow filler and surface adhesive agent in a mass ratio of 100:(8-12) and then spreading and drying; the hollow filler is made of liquid-impermeable flexible material, has a particle size or maximum size of 4-7 mm and a wall thickness of 0.5-1 mm, and is hollow inside with a maximum size of the hollow area not less than 2 mm;

[0014] The surface adhesion agent is a mixture of filler sand, filler cement, and water in a mass ratio of (1-2):3:(4-5).

[0015] By adopting the technical scheme, the hollow filler has a density obviously smaller than that of cement mortar and aggregate, and the surface of the hollow filler directly contacts the cement mortar and has poor adhesion. In the application, the hollow filler is mixed with the surface adhesion agent, spread, and dried. The mixing of the hollow filler and the surface adhesion agent is different from the mixing of the raw materials of recycled concrete. There is only the hollow filler and the surface adhesion agent, and there is no impact of collision of large-size and high-density aggregate and no dilution and thickening impact of a large amount of water (more water is added to recycled aggregate than to ordinary concrete). Only the hollow filler and the surface adhesion agent are forcibly mixed. When the amount of the surface adhesion agent is sufficient, the surface adhesion agent can be spread on the surface of the hollow filler and dried and solidified to form mortar adhesion. The solidified mortar on the surface of the hollow filler can be adhered to the cement mortar when the raw materials of recycled concrete are mixed, and the hollow filler can be brought into the recycled concrete and uniformly dispersed.

[0016] The amount of the deformed filler, the ratio of the hollow filler to the surface adhesion agent, and the component ratio in the surface adhesion agent all have an indispensable effect on the effect of the application.

[0017] The amount of the deformed filler cannot be too little or too much. If the amount is too little, the compression space provided is insufficient, and the effect of improving the strength of the recycled concrete is not obvious. If the amount is too much, the negative impact on the original structure of the recycled concrete is stronger than the improvement brought by the reduction of hydration heat expansion.

[0018] The ratio of the amount of the surface adhesion agent in the deformed filler cannot be too little or too much. If the amount is too little, the surface adhesion agent cannot be spread on the surface of the hollow filler in forced mixing. If the amount is too much, the hollow filler will sink into the surface adhesion agent, and the hollow filler cannot be spread to obtain agglomerated and solidified hollow fillers or hollow fillers completely covered by the surface. In this way, the solidified mortar completely covered by the surface cannot provide compression space and cannot achieve the effect of the application.

[0019] If the proportion of filler cement in the component ratio of the surface adhesion agent is too little or the amount of water is too much, the surface adhesion agent will be too dilute and lack adhesion, and the surface adhesion agent cannot be spread on the surface of the hollow filler. If the proportions of filler cement and filler sand are too high, especially if the proportion of filler sand is too high, the surface adhesion agent will be too loose and dry, and the surface adhesion agent cannot be adhered to the surface of the hollow filler.

[0020] The hollow filler finally mixed and uniformly dispersed in the recycled concrete can provide a compression space for the hydration heat expansion of the recycled concrete during the final setting period after pouring, thereby reducing the overall appearance of the hydration heat expansion of the recycled concrete during the final setting period, reducing the cracks and marks caused by the hydration heat expansion of the recycled concrete, and improving the strength of the recycled concrete after final setting maintenance. The recycled concrete can be applied in more medium and high strength demand scenarios.

[0021] Optionally, the surface of the hollow filler is roughened by mixing and stirring the hollow filler with flaky rock particles with a size of 1-2 mm for 10-15 min, and then screening and separating, the amount of flaky rock particles is 0.25-0.3 times the mass of the hollow filler.

[0022] By adopting the above technical solution, the surface friction between the flaky rock particles and the hollow filler will produce scratches, roughen the surface of the hollow filler, and more easily spread the surface adhesive on the local position. Because the scratches are irregular and uneven, the entire surface of the hollow filler is not easy to completely spread the surface adhesive, thereby making the hollow filler better dragged into the recycled concrete by the cement mortar to disperse, and improving the effectiveness of the compression space actually provided by the deformed filler.

[0023] Optionally, the surface of the hollow filler is modified by a silane coupling agent.

[0024] By adopting the above technical solution, the surface adhesive is more easily adhered to the surface of the hollow filler.

[0025] Optionally, the organosilane is 3-acetoxypropyltrimethoxysilane.

[0026] By adopting the above technical solution, 3-acetoxypropyltrimethoxysilane is selected for good modification effect, no amino group, no halogen, no corrosion to metal components, and friendly to concrete application environment.

[0027] Optionally, the surface modification method is to immerse the hollow filler in a 3-acetoxypropyltrimethoxysilane solution with a concentration of 8-12 wt% for more than 8 hours.

[0028] By adopting the above technical solution, combined with the large production of concrete commercial concrete, non-continuous production all day, the surface treatment is carried out in a long-term immersion manner, which is more suitable for production demand, low cost and high efficiency.

[0029] Optionally, the hollow inside the hollow filler is flat or disc-shaped.

[0030] Through the technical scheme, the hollow filler is more easily extruded by the outside to compress the internal hollow, provides a compression space for the thermal expansion of the recycled concrete, and the effect of reducing cracks and flaws caused by the thermal expansion of the recycled concrete is better, and the strength of the recycled concrete after final setting curing is higher.

[0031] A second inventive objective of the present application is achieved by the following technical scheme:

[0032] The preparation method of the recycled concrete comprises the following steps: uniformly mixing, by mass fraction, recycled aggregates, sand, cement, fly ash and other raw materials except for the deformation filler, adding the deformation filler while stirring, and uniformly mixing to obtain the recycled concrete.

[0033] Through the technical scheme, the recycled concrete other raw materials are first uniformly mixed, and the recycled aggregate is wrapped with cement mortar on the surface, so that the recycled aggregate is not easy to pierce or crush the deformation filler under the lubrication and fluid pushing action of the cement mortar, and the deformation filler is more easily dragged into the recycled concrete by the weight of the cement mortar and the recycled aggregate, and the mixing is convenient and convenient.

[0034] In summary, the present application has at least the following beneficial effects:

[0035] 1. In the present application, the deformation filler is prepared by the hollow filler with a specific proportion and specific components of the surface adhesive agent, and the deformation filler is added to the recycled concrete in a specific amount, so that the deformation filler is mixed and uniformly dispersed in the recycled concrete. The hollow filler has a thin wall thickness and a sufficient hollow space, which can provide a compression space for the thermal expansion of the recycled concrete during the final setting period after pouring, thereby reducing the overall thermal expansion of the recycled concrete during the final setting period after pouring, reducing the cracks and flaws caused by the thermal expansion of the recycled concrete, and improving the strength of the recycled concrete after final setting curing. The recycled concrete can be applied in more medium and high strength demand scenarios;

[0036] 2. Through roughening treatment and surface modification treatment, the surface adhesive agent is more easily attached to the surface of the hollow filler, and the attachment is more desirable - attached and not completely covered, so that the improvement effect of the deformation filler on the recycled concrete is better.

[0037] 3. The hollow filler has a flat or disc-shaped internal hollow, which is more easily extruded by the outside to compress the internal hollow to provide a compression space, and the strength of the obtained recycled concrete after final setting curing is higher. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The structure diagram of the hollow filler of Preparation Example 1 is shown in the figure.

[0039] Figure 2 The structure diagram of the hollow filler of Preparation Example 8 is shown in the figure.

[0040] Reference numeral: 1, hollow filler; 11, hollow region. DETAILED DESCRIPTION

[0041] Raw materials:

[0042] Natural aggregate, particle size 5-6 cm;

[0043] Recycled aggregate, particle size 3-4 cm;

[0044] Cement and filler cement, commercially available 42.5 grade ordinary cement;

[0045] Sand and filler sand, particle size 0.5-2 mm machine-made sand;

[0046] Fly ash, commercially available product from Lingshou County Jiagong Mining Products Co., Ltd., fineness 2000 mesh;

[0047] Flaky rock particles, provided by Lingshou County Jiagong Mining Products Co., Ltd., size 1-2 mm.

[0048] 3-acetoxypropyltrimethoxysilane, 3-methacryloyloxypropyltriisopropoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane are commercially available products from Nanjing Nengxin New Material Technology Co., Ltd.

[0049] Preparation Example 1

[0050] Deformed filler, the deformed filler is obtained by uniformly mixing the hollow filler with the surface adhesion agent and then spreading and drying.

[0051] The hollow filler is made of a liquid-impermeable flexible material, which is mainly an organic high molecular polymer material, which can be polyethylene, polypropylene, polyvinyl chloride, etc. In this preparation example, it is polyethylene.

[0052] The outer surface shape of the hollow filler can be spherical, elliptical or disc-shaped, with a particle size or maximum size of 4-7 mm and a wall thickness of 0.5-1 mm, and the inside is hollow.

[0053] The hollow region is flat and elliptical or disc-shaped, with a maximum size of not less than 2 mm.

[0054] The hollow filler is subjected to roughening treatment and surface modification treatment in sequence.

[0055] Roughening treatment: mix the hollow filler with flaky rock particles with a size of 1-2 mm and add them to a stirrer, the amount of flaky rock particles is 3 times the mass of the hollow filler, mix and stir for 13 min, then separate the flaky rock particles by sieving to obtain the hollow filler with roughened surface, and the flaky rock particles are recycled.

[0056] Surface modification treatment: the surface-roughened hollow fillers were filled into a container, 10wt% 3-acetoxypropyltrimethoxysilane solution was poured into the container, and the surface-roughened hollow fillers were pressed down with the aid of a heavy weight, and the surface-roughened hollow fillers were kept soaking in the solution for 8h.

[0057] Figure 1 shows the surface-roughened hollow fillers after the surface modification treatment. Figure 1 In the present preparation example, the hollow fillers 1 and the hollow regions 11 inside the hollow fillers are both flat disc-shaped. The outer surface diameter is 7mm, the outer center thickness is 5mm, and the wall thickness is 1mm.

[0058] The surface-attached agent was obtained by mixing filler sand, filler cement and water in a mass ratio of 2:3:5.

[0059] Preparation method of the deformed fillers:

[0060] The surface-roughened hollow fillers after the surface modification treatment were mixed with the surface-attached agent in a mass ratio of 10:1, and the mixture was evenly mixed and then poured and spread on a plane. After natural drying under the protection from rain and sunlight, the deformed fillers were collected.

[0061] Preparation Example 2

[0062] The deformed fillers were similar to those in Preparation Example 1, except that the surface-attached agent was obtained by mixing filler sand, filler cement and water in a mass ratio of 3:1:4.

[0063] Preparation Example 3

[0064] The deformed fillers were similar to those in Preparation Example 1, except that the surface-attached agent was obtained by mixing filler sand, filler cement and water in a mass ratio of 1:3:4.

[0065] Preparation Example 4

[0066] The deformed fillers were similar to those in Preparation Example 1, except that the amount of the surface-attached agent was 4 parts.

[0067] Preparation Example 5

[0068] The deformed fillers were similar to those in Preparation Example 1, except that the amount of the surface-attached agent was 8 parts.

[0069] Preparation Example 6

[0070] The deformed fillers were similar to those in Preparation Example 1, except that the amount of the surface-attached agent was 12 parts.

[0071] Preparation Example 7

[0072] The deformed fillers were similar to those in Preparation Example 1, except that the amount of the surface-attached agent was 17 parts.

[0073] Preparation Example 8

[0074] Modified filler, similar to Preparation 1, except that the hollow filler has a different shape.

[0075] Preparation 8 Figure 2 The hollow filler 1 in this preparation example has an ellipsoidal outer surface and a hollow interior region 11 with a length of 7 mm, a maximum circular interface diameter of 4 mm at the center, and a wall thickness of 0.5 mm.

[0076] Preparation 9

[0077] Modified filler, similar to Preparation 1, except that the hollow filler is a hollow sphere with a diameter of 7 mm and a wall thickness of 1 mm.

[0078] Preparation 10

[0079] Modified filler, similar to Preparation 1, except that the hollow filler is not surface modified and is not roughened, but is mixed directly with the surface adhesion agent.

[0080] Preparation 11

[0081] Modified filler, similar to Preparation 1, except that the hollow filler is only roughened and is mixed directly with the surface adhesion agent.

[0082] Preparation 12

[0083] Modified filler, similar to Preparation 1, except that the hollow filler is not roughened, but is surface modified and subjected to subsequent preparation processes.

[0084] Preparation 13

[0085] Modified filler, similar to Preparation 1, except that the organosilane used for surface modification of the hollow filler is 3-methacryloyloxypropyltriisopropoxysilane.

[0086] Preparation 14

[0087] Modified filler, similar to Preparation 1, except that the organosilane used for surface modification of the hollow filler is 3-methacryloyloxypropylmethyldiethoxysilane.

[0088] Preparation 15

[0089] Modified filler, similar to Preparation 1, except that the concentration of the 3-acetoxypropyltrimethoxysilane solution used for surface modification of the hollow filler is 4 wt%.

[0090] Preparation 16

[0091] Modified filler, similar to Preparation 1, except that the concentration of the 3-acetoxypropyltrimethoxysilane solution used for surface modification of the hollow filler is 8 wt%.

[0092] Preparation Example 17

[0093] The modified filler is similar to that of Preparation Example 1, except that the concentration of the 3-acryloxypropyltrimethoxysilane solution used in the surface modification treatment of the hollow filler is 12 wt%.

[0094] Preparation Example 18

[0095] The modified filler is similar to that of Preparation Example 1, except that the concentration of the 3-acryloxypropyltrimethoxysilane solution used in the surface modification treatment of the hollow filler is 15 wt%.

[0096] Preparation Example 19

[0097] The modified filler is similar to that of Preparation Example 1, except that the soaking time of the surface modification treatment of the hollow filler is 4 h.

[0098] Preparation Example 20

[0099] The modified filler is similar to that of Preparation Example 1, except that the soaking time of the surface modification treatment of the hollow filler is 10 h.

[0100] Example 1

[0101] A hydration heat expansion recycled concrete comprises the following raw materials by mass fraction:

[0102] The recycled aggregate is 900 parts, the sand is 500 parts, the cement is 500 parts, the fly ash is 300 parts, the modified filler is 20 parts, and the water is 380 parts. The modified filler is the modified filler prepared in Preparation Example 1.

[0103] The preparation method of the hydration heat expansion recycled concrete is as follows: the recycled aggregate, the sand, the cement, the fly ash, and other raw materials except the modified filler are mixed uniformly by mass fraction, and then the modified filler is added while stirring, and the recycled concrete is obtained after mixing uniformly.

[0104] Examples 2-3

[0105] A hydration heat expansion recycled concrete, which is different from Example 1 in that the raw material usage is different.

[0106] The raw material usage parameters of Examples 1-3 are shown in Table 1 below.

[0107] Table 1. Raw material usage parameters of Examples 1-3

[0108]

[0109] Comparative Example 1

[0110] A recycled concrete, which is different from Example 2 in that no modified filler is added to the raw materials.

[0111] Comparative Example 2

[0112] A recycled concrete, which differs from Example 2 in that the amount of the deformed filler in the raw material is 10 parts.

[0113] Comparative Example 3

[0114] A recycled concrete, which differs from Example 2 in that the amount of the deformed filler in the raw material is 50 parts.

[0115] Comparative Example 4

[0116] A recycled concrete, which differs from Example 2 in that the amount of the deformed filler in the raw material is 120 parts.

[0117] Comparative Example 5

[0118] A recycled concrete, which differs from Example 2 in that the deformed filler in the raw material is replaced with hollow fillers in the same amount.

[0119] Comparative Examples 6 to 8

[0120] A recycled concrete, which differs from Example 2 in that the deformed filler in the raw material is replaced with hollow fillers in the same amount.

[0121] Examples 4 to 8

[0122] A recycled concrete, which differs from Example 2 in that the deformed filler in the raw material is replaced with hollow fillers in the same amount.

[0123] Table 2. Sources of deformed fillers for Examples 4 to 8 and Comparative Examples 6 to 8

[0124] Comparative Example 9

[0125] A recycled concrete, which differs from Example 2 in that the deformed filler in the raw material is replaced with solid polyethylene sheets in the same shape and volume.

[0126] Examples 9 to 19

[0127] A recycled concrete, which differs from Example 2 in that the deformed filler in the raw material is replaced with solid polyethylene sheets in the same shape and volume.

[0128] Table 3. Sources of deformed fillers for Examples 9 to 19

[0129] Example 9 Example 10 Example 11 Example 12 Example 13 Example 14 Source of deformable filler Preparation 10 Preparation 11 Preparation 12 Preparation 13 Preparation 14 Preparation 15 Example 15 Example 16 Example 17 Example 18 Example 19 * Source of deformable filler Preparation 16 Preparation 17 Preparation 18 Preparation 19 Preparation 20 *

[0130] The concrete obtained in Examples 1-19 and Comparative Examples 1-9 was cast to prepare samples and cured for 28 days, and the compressive strength of the concrete was detected. The detection structure is shown in Table 4 below.

[0131] Table 4. Compressive strength detection results of the concrete samples obtained in Examples 1-19 and Comparative Examples 1-9 after curing for 28 days

[0132]

[0133] In combination with Table 4,

[0134] Comparative Examples 1-3 and Comparative Example 1, Examples 1-3 in which the deforming filler is added according to the scheme of the present application, have significantly better concrete strength of the samples cured for 28 days than Comparative Example 1 in which the deforming filler is not added. This is because the deforming filler in the present application is mixed and uniformly dispersed in the recycled concrete, and because the hollow filler has a thin wall thickness and sufficient hollow space, it can provide a compression space for the hydration heat expansion of the recycled concrete after casting to final setting, thereby reducing the overall appearance of the hydration heat expansion of the recycled concrete during casting to final setting, reducing the cracks and marks generated by the hydration heat expansion of the recycled concrete, and improving the strength of the recycled concrete after final setting. The recycled concrete can be applied in more high-strength demand scenarios.

[0135] Comparative Example 2 and Comparative Examples 1-4 show that the amount of deforming filler in the present application is crucial to improving the performance of the deforming filler in the recycled concrete. In the case of the same amount of other raw materials, the amount of deforming filler in Comparative Example 2, Example 2, Comparative Example 3, and Comparative Example 4 is 10 parts by mass, 28 parts by mass, 50 parts by mass, and 120 parts by mass, respectively.

[0136] In Comparative Example 2, the amount of filler is insufficient, and the improvement effect of the deforming filler on the strength of the recycled concrete is not obvious.

[0137] In Comparative Examples 3 and 4, the amount of deforming filler is significantly more than in Example 2, but the concrete strength actually decreases. This is because the excessive amount of deforming filler has a stronger negative impact on the original structure of the recycled concrete than the improvement brought by the reduction of hydration heat expansion.

[0138] Comparative Example 2 and Comparative Example 5 can be known that the hollow filler and the deformed filler in the present application are different in that the surface adhesive agent is one of the keys that the deformed filler in the present application can be adhered by the cement mortar and taken into the recycled concrete uniformly during the production of the recycled concrete, the hollow filler is replaced by the deformed filler in Comparative Example 5, although the roughening treatment and the surface modification treatment are carried out, but it is still impossible to obtain the similar effect to Example 2. The reason is that the mixing state of the surface adhesive agent and the blank filler is different from the mixing state during the production of the recycled concrete, the composition of the surface adhesive agent and the cement mortar during the production of the recycled concrete is different.

[0139] Only the mixing of the hollow filler and the surface adhesive agent, without the collision of the large particle size and the large density aggregate, without the dilution and thickening influence of a large amount of water (more water is added to the recycled aggregate than the ordinary concrete), the forced mixing of the two and under the condition of a sufficient amount of the surface adhesive agent, the surface adhesive agent can be spread on the surface of the hollow filler, and finally the surface adhesive agent is dried and solidified into the mortar adhesion.

[0140] Moreover, the component ratio in the surface adhesive agent and the ratio of the hollow filler and the surface adhesive agent have the indispensable influence on the formation of the mortar adhesion in the present application.

[0141] The cement for filler and the water in the component ratio in the surface adhesive agent are too little, which can make the surface adhesive agent too thin and lack of viscosity, so that the surface adhesive agent cannot be spread on the surface of the hollow filler; the cement for filler and the sand for filler are too high, especially the sand for filler, which can make the surface adhesive agent too loose and dry, so that the surface adhesive agent cannot be adhered to the surface of the hollow filler. Comparative Example 2, Comparative Example 6, Example 4 and Comparative Example 1 can be known that the recycled concrete strength of Example 2 and Example 4 is significantly improved compared with Comparative Example 1, although the deformed filler is added in Comparative Example 6, the sand for filler is high and the cement for filler is less, so that the recycled concrete strength is not improved, but slightly deteriorated due to the uneven mixing.

[0142] Comparative Example 7, Example 5, Example 2, Example 6 and Comparative Example 8 are the same in the amount of other raw materials and the amount of the deformed filler, the difference is that the amount of the surface adhesive agent is gradually increased during the preparation of the deformed filler, the strength of Example 5, Example 2 and Example 6 is significantly improved compared with Comparative Example 1, the improvement of Comparative Example 7-8 is not obvious compared with Comparative Example 1, and the strength of Comparative Example 8 is decreased. The reason is that the small amount of the surface adhesive agent can cause the surface of the hollow filler to be difficult to successfully spread the surface adhesive agent, so that the improvement effect is weak; and the excessive amount of the surface adhesive agent can cause the hollow filler to be immersed in the surface adhesive agent, so that the hollow filler is coagulated or the surface of the hollow filler is completely coated, so that the improved effect cannot be obtained due to the influence of the completely coated and solidified mortar.

[0143] For the comparative example 2, comparative example 9 and comparative example 1, the hollow filler in the present application must be hollow, and generally the particle size or the maximum size is 4-7mm, the wall thickness is 0.5-1mm, and the hollow filler is hollow inside, and the maximum size of the hollow area is not less than 2mm. If it is solid, it cannot provide a compression space for the internal expansion stress increase of the recycled concrete under the hydration heat, cannot relieve the expansion stress increase, and cannot make the upper limit of the strength of the fully solidified recycled concrete increase. The comparative example 9 is a solid filler, and the strength of the recycled concrete thereof decreases instead of increasing. In combination with the example 7 and the example 8, the hollow filler in the present application can also be ellipsoidal or hollow spherical, and the effect of the disc-shaped hollow filler in the example 2 and the ellipsoidal hollow filler in the example 7 is due to the hollow spherical hollow filler in the example 8.

[0144] In combination with the examples 9-11, it can be known that the roughening treatment and the surface modification treatment of the hollow filler can make the deformation filler have a better improvement effect on the recycled concrete, and in combination with the comparative example 2, it can be known that the roughening treatment and the surface modification treatment can also have a synergistic effect, and the interaction can obtain a better strength improvement effect of the recycled concrete.

[0145] In combination with the examples 12-17, it can be known that the silane for the surface modification treatment in the present application can also be 3-methacryloxypropyl triisopropoxy silane and 3-methacryloxypropyl methyldiethoxy silane, and when the 3-acetoxypropyl trimethoxysilane solution is used for the surface treatment, the treatment effect is enhanced with the increase of the solution concentration, and when the solution concentration reaches 12wt%, the treatment effect is slightly improved with the further increase of the solution concentration, and therefore the concentration of the 3-acetoxypropyl trimethoxysilane solution is preferably 8-12wt% in the present application.

[0146] In combination with the example 2 and the examples 18-19, it can be known that the soaking time of the hollow filler in the surface modification treatment in the present application has an effect on the treatment effect, and the effect is enhanced with the increase of the soaking time, but the soaking time has an upper limit for the final strength improvement of the recycled concrete, and the reason is that the surface modification treatment of the hollow filler is sufficient to reach the limit; on the other hand, the soaking time in the present application is too long, and does not have a negative effect on the final strength of the recycled concrete, and the surface modification treatment method in the present application is more stable, and is suitable for the continuous production of the concrete, and the treatment and storage of the raw materials are convenient and convenient.

[0147] The specific embodiments are only an explanation of the present application, and are not a limitation of the present application, and the person skilled in the art can make a modification of the embodiments without a creative contribution according to the needs after reading the present specification, but as long as the modification is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A recycled concrete resistant to hydration heat expansion, characterized in that, The raw materials include the following parts by weight: Recycled aggregate 900 parts; Sand 600-800 parts; Cement 500-720 parts; Fly ash 300-400 parts; Deformation filler 20-37 parts; Water 380-450 parts; The deformation filler is a hollow filler (1) mixed with a surface adhesion agent at a mass ratio of 100: (8-12) and then spread and dried; The hollow filler (1) is made of a liquid-impermeable flexible material, has a particle size or maximum dimension of 4-7 mm and a wall thickness of 0.5-1 mm, and has a hollow interior with a maximum dimension of the hollow region (11) of not less than 2 mm; The surface adhesion agent is made by mixing filler sand, filler cement, and water at a mass ratio of (1-2):3:(4-5); The surface of the hollow filler (1) is subjected to roughening treatment, which involves pouring the hollow filler (1) into flaky rock particles with a size of 1-2 mm, mixing and stirring for 10-15 min, and then screening and separating; The surface of the hollow filler (1) is subjected to surface modification treatment with a silane coupling agent; The hollow interior of the hollow filler (1) is flat or disc-shaped.

2. The recycled concrete of claim 1, wherein: The silane coupling agent is 3-acetoxypropyltrimethoxysilane.

3. The recycled concrete of claim 2, wherein: The surface modification treatment method involves pressing the hollow filler (1) into and keeping it soaked in a 3-acetoxypropyltrimethoxysilane solution at a concentration of 8-12 wt% for more than 8 h.

4. Process for the production of regenerated concrete resistant to hydric thermal expansion according to any one of claims 1 to 3, characterized in that: The recycled aggregate, sand, cement, fly ash, and other raw materials except the deformation filler are mixed at a mass ratio, and then the deformation filler is added while stirring, to obtain the recycled concrete.

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