High-performance supersulfate cement-based pervious concrete and preparation method thereof

Abstract

The invention relates to high-performance super sulfate cement-based pervious concrete and a preparation method thereof, and belongs to the technical field of solid waste building materials, the high-performance super sulfate cement-based pervious concrete comprises the following raw materials by weight: 75-105 parts of high temperature activated powder, 180-240 parts of slag, 15-30 parts of cement, 800-1100 parts of coarse aggregate, 100-120 parts of water, and 6-12 parts of a water reducer; the high-temperature activated powder comprises the following raw materials in parts by weight: 45-60 parts of sludge ash and 30-45 parts of gypsum. According to the high-performance super-sulfate cement-based pervious concrete and the preparation method, solid wastes such as slag and sludge are effectively treated, so that solid waste resources are recycled, land resource shortage caused by solid waste accumulation is reduced, the use of cement clinker is greatly reduced, and the performance of the high-performance super-sulfate cement-based pervious concrete is also provided.

Description

Technical Field

[0001] The invention relates to the technical field of solid waste building materials, and in particular to a high-performance supersulfate cement-based permeable concrete and a preparation method thereof. Background Art

[0002] The most notable feature of permeable concrete is its good water permeability. Through its special pore structure or additives, water can quickly penetrate into the groundwater layer or drainage system through the concrete surface, reducing the risk of surface runoff and flooding. At the same time, it can also absorb noise, becoming the preferred material for urban green ecological pavement. However, traditional cement permeable concrete is usually more vulnerable to sulfate erosion. Sulfate erosion can cause chemical dissolution and physical damage to concrete. Because traditional cement itself has limited resistance to sulfate erosion, it affects the stability and service life of its own structure.

[0003] Supersulfated cement is a low-carbon cementitious material, usually composed of slag, gypsum and alkaline activator, which is widely used in harsh environments due to its excellent corrosion resistance and chemical resistance. Its corrosion resistance is mainly manifested in the following aspects: acid resistance, resistance to chloride ion corrosion and long-term stability.

[0004] Although the performance of concrete prepared by using supersulfate cement is significantly improved compared with traditional concrete, its performance effect needs to be further verified in environments such as ultra-frequent freeze-thaw cycles, high temperatures or severe chemical erosion, and although supersulfate cement can reduce production costs, its cost is higher than that of traditional cement-based concrete due to its special composition and preparation process. In response to the above technical phenomena, the inventors have invented a supersulfate cement-based permeable concrete that can be prepared using solid waste to reduce the production cost of concrete and further improve the performance of concrete in terms of strength, frost resistance, corrosion resistance and wear resistance. Summary of the invention

[0005] The purpose of the present invention is to provide a high-performance supersulfate cement-based permeable concrete and a preparation method thereof, so as to reduce the use of cement clinker, achieve energy conservation and emission reduction, make full use of solid wastes such as slag and sludge, reduce the shortage of land resources caused by solid waste accumulation, and improve the strength and durability of permeable concrete.

[0006] The present invention provides a high-performance supersulfate cement-based permeable concrete, which adopts the following technical solution:

[0007] A high-performance supersulfate cement-based permeable concrete, comprising the following raw materials in parts by weight: 75-105 parts of high-temperature activated powder, 180-240 parts of slag, 15-30 parts of cement, 800-1100 parts of coarse aggregate, 100-120 parts of water, and 6-12 parts of a water reducing agent;

[0008] The high temperature activated powder comprises the following raw materials in parts by weight: 45-60 parts of sludge ash and 30-45 parts of gypsum.

[0009] Preferably, the cement is selected as P.O42.5 ordinary Portland cement.

[0010] Preferably, the gypsum is phosphogypsum.

[0011] Preferably, the high temperature activated powder comprises the following preparation method:

[0012] S1, drying the excavated dredged sludge, placing the dredged sludge after drying in an oven for dehydration and drying, and placing the dredged sludge after dehydration and drying in a ball mill for ball milling to obtain dry sludge ash;

[0013] S2. Evenly mix the sludge ash and gypsum obtained in step S1 to obtain a mixed powder, calcine the mixed powder in a high-temperature furnace, cool it, and mill it in a ball mill to obtain a high-temperature activated powder.

[0014] Preferably, the temperature of the oven in step S1 is set at 100-105°C, and the dehydration and drying time is 48-50h;

[0015] The temperature of the high temperature furnace in step S2 is 750-800° C., and the calcination time is 1-2 hours.

[0016] Preferably, the coarse aggregate includes first crushed stone, second crushed stone and third crushed stone, the particle size of the first crushed stone is 3-5 mm, the particle size of the second crushed stone is 5-10 mm, and the particle size of the third crushed stone is 10-20 mm.

[0017] Preferably, the mass ratio of the first crushed stone, the second crushed stone and the third crushed stone is 1:

[0018] (1.8-2.4):1.2.

[0019] Preferably, the water reducing agent is a polycarboxylic acid water reducing agent.

[0020] The present invention also provides a method for preparing high-performance supersulfate cement-based permeable concrete, using the above-mentioned high-performance supersulfate cement-based permeable concrete, comprising the following preparation steps:

[0021] S1, adding coarse aggregate and part of water into a mixer and stirring to obtain a first mixture;

[0022] S2, keep the mixer running, and add high temperature active powder, slag, cement, gypsum and water reducing agent to the first mixture obtained in step S1 to obtain a second mixture;

[0023] S3, keeping the mixer running, adding the remaining water to the second mixture obtained in step S2 to obtain concrete slurry, and obtaining super sulfate cement and permeable concrete after curing.

[0024] Preferably, 10% water is added in step S1, and the stirring time in step S1 is 20-25s;

[0025] The stirring time in step S2 is 20-25s.

[0026] In summary, the present invention includes the following beneficial technical effects:

[0027] The present invention uses high-temperature activated powder including sludge ash and gypsum. The slag can be excited by sulfate ions in an alkaline environment to generate hydration products. At the same time, the high-temperature calcined sludge exerts a nucleation effect to help the formation of calcium sulfonite. The gelling network formed by interweaving with calcium silicate gel is tighter, which is conducive to improving strength and frost resistance, reducing the use of cement, thereby reducing a large amount of carbon emissions. By high-temperature treatment of phosphogypsum, organic matter, eutectic phosphorus and fluorine impurities can be removed. High-performance supersulfate cement-based permeable concrete has excellent strength, high acid resistance, high frost resistance and high wear resistance, and is suitable for road paving with special needs such as sulfate-containing soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Microstructure of hardened paste formed by hydration of silt ash into cement. DETAILED DESCRIPTION

[0029] The following is combined with the embodiments and the attached Figure 1 The present invention is described in further detail.

[0030] Example 1

[0031] A high-performance supersulfate cement-based permeable concrete, and a preparation method thereof:

[0032] S1, excavating the dredged sludge and drying it, placing the dredged sludge after drying in an oven for dehydration and drying, setting the temperature of the oven to 100-105° C., the dehydration and drying time to 48-50 hours, and placing the dredged sludge after dehydration and drying in a ball mill for ball milling to obtain dry sludge ash;

[0033] S2. Weigh 45kg gypsum, 30kg silt ash, 210kg slag, 15kg cement, 1000kg coarse aggregate, 100kg water and 6kg water reducing agent respectively for use;

[0034] S3, mixing the silt ash and gypsum in step S2 evenly to obtain a mixed powder, placing the mixed powder in a high-temperature furnace for calcining, setting the temperature of the high-temperature furnace to 750-800° C., the calcination time to 2 h, cooling after calcination, and placing in a ball mill for ball milling to obtain a high-temperature activated powder;

[0035] S4, adding the coarse aggregate in step S2 and 10 kg of water into a mixer and stirring for 20-25 seconds to obtain a first mixture;

[0036] S5, keep the mixer running, and add high temperature active powder, slag, cement, gypsum and water reducing agent to the first mixture obtained in step S4, and stir for 20-25 seconds to obtain a second mixture;

[0037] S6, keep the mixer running, add the remaining water to the second mixture obtained in step S5 to obtain concrete slurry, and obtain super sulfate cement and permeable concrete after curing;

[0038] Among them, cement is selected as P.O42.5 ordinary Portland cement; gypsum is selected as phosphogypsum; water reducer is selected as polycarboxylic acid water reducer; coarse aggregate includes first crushed stone with a particle size of 3-5mm, second crushed stone with a particle size of 5-10mm and third crushed stone with a particle size of 10-20mm, and the mass ratio of the first crushed stone, the second crushed stone and the third crushed stone is 1:1.8:1.2.

[0039] Example 2

[0040] A high-performance supersulfate cement-based permeable concrete, which is different from Example 1 in that the mass ratio of the first crushed stone, the second crushed stone and the third crushed stone is 1:2.4:1.2, and the remaining steps are the same as Example 1.

[0041] Example 3

[0042] A high-performance supersulfate cement-based permeable concrete, which is different from Example 1 in that the high-temperature activated powder is 105 kg and the slag is 180 kg, wherein the high-temperature activated powder includes 60 kg of silt ash and 45 kg of gypsum, and the remaining steps are the same as Example 1.

[0043] Example 4

[0044] A high-performance supersulfate cement-based permeable concrete, which is different from Example 3 in that the mass ratio of the first crushed stone, the second crushed stone and the third crushed stone is 1:2.4:1.2, and the remaining steps are the same as Example 3.

[0045] Comparative Example 1

[0046] A high-performance supersulfate cement-based permeable concrete, and a preparation method thereof:

[0047] S1. Weigh 45kg gypsum, 240kg slag, 15kg cement, 1000kg coarse aggregate, 100kg water and 6kg water reducing agent respectively for use;

[0048] S2, adding the coarse aggregate in step S1 and 10 kg of water into a mixer and stirring for 20-25 seconds to obtain a first mixture;

[0049] S3, keep the mixer running, and add high temperature active powder, slag, cement, gypsum and water reducing agent to the first mixture prepared in step S2, and stir for 20-25 seconds to obtain a second mixture;

[0050] S4, keep the mixer running, add the remaining water to the second mixture obtained in step S2 to obtain concrete slurry, and obtain super sulfate cement and permeable concrete after curing;

[0051] Among them, cement is selected as P.O42.5 ordinary Portland cement; gypsum is selected as phosphogypsum; water reducer is selected as polycarboxylic acid water reducer; coarse aggregate includes first crushed stone with a particle size of 3-5mm, second crushed stone with a particle size of 5-10mm and third crushed stone with a particle size of 10-20mm, and the mass ratio of the first crushed stone, the second crushed stone and the third crushed stone is 1:1.8:1.2.

[0052] Comparative Example 2

[0053] A high-performance supersulfate cement-based permeable concrete, which is different from comparative example 1 in that the mass ratio of the first crushed stone, the second crushed stone and the third crushed stone is 1:2.4:1.2, and the remaining steps are the same as comparative example 1.

[0054] Comparative Example 3

[0055] S1, excavating the dredged sludge and drying it, placing the dredged sludge after drying in an oven for dehydration and drying, setting the temperature of the oven to 100-105° C., the dehydration and drying time to 48-50 hours, and placing the dredged sludge after dehydration and drying in a ball mill for ball milling to obtain dry sludge ash;

[0056] S2. Weigh 45kg gypsum, 30kg silt ash, 210kg slag, 15kg cement, 1000kg coarse aggregate, 100kg water and 6kg water reducing agent respectively for use;

[0057] S3, adding the coarse aggregate in step S2 and 10 kg of water into a mixer and stirring for 20-25 seconds to obtain a first mixture;

[0058] S4, keep the mixer running, and add high temperature active powder, slag, cement, gypsum and water reducing agent to the first mixture obtained in step S3, and stir for 20-25 seconds to obtain a second mixture;

[0059] S5, keep the mixer running, add the remaining water to the second mixture obtained in step S4 to obtain concrete slurry, and obtain super sulfate cement and permeable concrete after curing;

[0060] Among them, cement is selected as P.O42.5 ordinary Portland cement; gypsum is selected as phosphogypsum; water reducer is selected as polycarboxylic acid water reducer; coarse aggregate includes first crushed stone with a particle size of 3-5mm, second crushed stone with a particle size of 5-10mm and third crushed stone with a particle size of 10-20mm, and the mass ratio of the first crushed stone, the second crushed stone and the third crushed stone is 1:1.8:1.2.

[0061] Comparative Example 4

[0062] A high-performance supersulfate cement-based permeable concrete, which is different from Comparative Example 3 in that the mass ratio of the first crushed stone, the second crushed stone and the third crushed stone is 1:2.4:1.2, and the remaining steps are the same as Comparative Example 3.

[0063] Comparative Example 5

[0064] S1, excavating dredged sludge and drying it, placing the dredged sludge after drying in an oven for dehydration and drying, setting the temperature of the oven to 100-105° C., the dehydration and drying time to 48-50 hours, placing the dredged sludge after dehydration and drying in a ball mill for ball milling, and then placing it in a high-temperature furnace at 750-800° C. for calcination, the calcination time is 2 hours, cooling after calcination, and placing it in a ball mill for ball milling to obtain sludge ash;

[0065] S2. Weigh 45kg gypsum, 30kg silt ash, 210kg slag, 15kg cement, 1000kg coarse aggregate, 100kg water and 6kg water reducing agent respectively for use;

[0066] S3, adding the coarse aggregate in step S2 and 10 kg of water into a mixer and stirring for 20-25 seconds to obtain a first mixture;

[0067] S4, keep the mixer running, and add high temperature active powder, slag, cement, gypsum and water reducing agent to the first mixture obtained in step S3, and stir for 20-25 seconds to obtain a second mixture;

[0068] S5, keep the mixer running, add the remaining water to the second mixture obtained in step S4 to obtain concrete slurry, and obtain super sulfate cement and permeable concrete after curing;

[0069] Among them, cement is selected as P.O42.5 ordinary Portland cement; gypsum is selected as phosphogypsum; water reducer is selected as polycarboxylic acid water reducer; coarse aggregate includes first crushed stone with a particle size of 3-5mm, second crushed stone with a particle size of 5-10mm and third crushed stone with a particle size of 10-20mm, and the mass ratio of the first crushed stone, the second crushed stone and the third crushed stone is 1:1.8:1.2.

[0070] Comparative Example 6

[0071] A high-performance supersulfate cement-based permeable concrete, which is different from Comparative Example 5 in that the mass ratio of the first crushed stone, the second crushed stone and the third crushed stone is 1:2.4:1.2, and the remaining steps are the same as Comparative Example 5.

[0072] Performance testing

[0073] Super-sulfated cement-based permeable concrete was prepared and cured according to the methods of Examples 1-4 and Comparative Examples 1-6, and the concrete cured for 28 days was tested for performance according to the "Standard for Test Methods for Physical and Mechanical Properties of Concrete" (GB / T50081-2019), "Standard for Test Methods for Long-term Performance and Durability of Ordinary Concrete" (GB / T50082-2009) and "Permeable Concrete" (JC / T 2558-2020). The test results are shown in Table 1.

[0074] Table 1 Test results of Examples 1-4 and Comparative Examples 1-6

[0075]

[0076] From the test data in Table 1, it can be seen that the compressive strength of the high-performance supersulfate cement-based permeable concrete prepared in this application is above 38MPa, the flexural strength is above 8MPa, and the permeability coefficient is above 2.4cm·s -1 The above results show that the compression / flexural and corrosion resistance coefficients of KS120 are above 1.14 / 1.14, and the grinding pit length is below 21mm.

[0077] It can be seen from the test data of Examples 1-4 that the high-performance supersulfate cement-based permeable concrete prepared in the present application has better performance in compressive strength, flexural strength, permeability coefficient, KS120 compressive / flexural corrosion resistance coefficient, wear pit length and strength / mass loss rate after 25 freeze-thaw cycles.

[0078] It can be seen from the test data of Examples 1-4 and Comparative Examples 1-6 that the sludge ash and gypsum in the present application are activated by high temperature, and the slag can be excited by sulfate ions in an alkaline environment to generate hydration products. At the same time, the high-temperature calcined sludge exerts a nucleation effect to help the formation of calcium sulfonite, and the gelling network formed by interweaving with calcium silicate gel is tighter, which is conducive to improving strength and frost resistance, reducing the use of cement, thereby reducing a large amount of carbon emissions. By high-temperature treatment of phosphogypsum, organic matter, eutectic phosphorus and fluorine impurities can be removed. High-performance supersulfate cement-based permeable concrete has excellent strength, high acid resistance, high frost resistance and high wear resistance, and is suitable for road paving with special needs such as sulfate-containing soil.

[0079] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-performance supersulfate cement-based permeable concrete, characterized in that: The raw material composition includes the following parts by weight: 75-105 parts of high temperature activated powder, 180-240 parts of slag, 15-30 parts of cement, 800-1100 parts of coarse aggregate, 100-120 parts of water, and 6-12 parts of water reducing agent; The high temperature activated powder comprises the following raw materials in parts by weight: 45-60 parts of sludge ash and 30-45 parts of gypsum.

2. A high performance supersulfate cement-based permeable concrete according to claim 1, characterized in that: The cement is selected as P.O42.5 ordinary Portland cement.

3. The high performance super sulfate cement-based permeable concrete according to claim 1, characterized in that: The gypsum is selected as phosphogypsum.

4. A high performance supersulfate cement-based permeable concrete according to claim 3, characterized in that: The high temperature activated powder comprises the following preparation method: S1, drying the excavated dredged sludge, placing the dredged sludge after drying in an oven for dehydration and drying, and placing the dredged sludge after dehydration and drying in a ball mill for ball milling to obtain dry sludge ash; S2. Evenly mix the sludge ash and gypsum obtained in step S1 to obtain a mixed powder, calcine the mixed powder in a high-temperature furnace, cool it, and mill it in a ball mill to obtain a high-temperature activated powder.

5. A high performance super sulfate cement-based permeable concrete according to claim 4, characterized in that: The temperature of the oven in step S1 is set at 100-105°C, and the dehydration and drying time is 48-50h; The temperature of the high temperature furnace in step S2 is 750-800° C., and the calcination time is 1-2 hours.

6. The high performance super sulfate cement-based permeable concrete according to claim 1, characterized in that: The coarse aggregate includes first crushed stone, second crushed stone and third crushed stone. The particle size of the first crushed stone is 3-5 mm, the particle size of the second crushed stone is 5-10 mm, and the particle size of the third crushed stone is 10-20 mm.

7. The high performance supersulfate cement-based permeable concrete according to claim 6, characterized in that: The mass ratio of the first crushed stone, the second crushed stone and the third crushed stone is 1:(1.8-2.4):1.

2.

8. The high performance super sulfate cement-based permeable concrete according to claim 1, characterized in that: The water reducing agent is selected as a polycarboxylic acid water reducing agent.

9. A method for preparing high-performance supersulfate cement-based permeable concrete, characterized in that: A high-performance supersulfate cement-based permeable concrete as claimed in any one of claims 1 to 8 is used, comprising the following preparation steps: S1, adding coarse aggregate and part of water into a mixer and stirring to obtain a first mixture; S2, keep the mixer running, and add high temperature active powder, slag, cement, gypsum and water reducing agent to the first mixture obtained in step S1 to obtain a second mixture; S3, keeping the mixer running, adding the remaining water to the second mixture obtained in step S2 to obtain concrete slurry, and obtaining super sulfate cement and permeable concrete after curing.

10. The method for preparing a high-performance supersulfate cement-based permeable concrete according to claim 9, characterized in that: In step S1, 10% water is added, and the stirring time in step S1 is 20-25s; The stirring time in step S2 is 20-25s.

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