Controllable low-strength material based on sewage treatment plant sludge incineration fly ash and construction waste regenerated mixture

Abstract

The invention discloses a controllable low-strength material based on sludge incineration fly ash of a sewage treatment plant and a construction waste regenerated mixture and a preparation method of the controllable low-strength material. The controllable low-strength material is prepared from the following raw materials in parts by mass: 10-15 parts of cement, 0-8 parts of blast furnace slag powder, 2-15 parts of sludge incineration fly ash of a sewage treatment plant, 100-130 parts of a construction waste regenerated mixture and 30-70 parts of water. The solid waste generated in the urban operation and maintenance process can be treated in a harmless and low-cost mode, and the production cost of the controllable low-strength material is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of controllable low-strength material production, and particularly relates to a controllable low-strength material based on sewage treatment plant sludge incineration fly ash and construction waste recycled mixture and a preparation method thereof. BACKGROUND

[0002] Sewage treatment plant sludge incineration fly ash is a typical solid waste generated in the process of city operation, and its annual output is huge. For example, in Shanghai, the annual output has exceeded 100,000 tons. At present, the main treatment method for sludge incineration fly ash is to prepare it into a “composite fly ash” material through physical and chemical modification, and to apply it as an admixture in concrete production. However, due to the inherent defects of sludge incineration fly ash such as high water demand, low activity index and high impurity content, even after modification, its performance is still significantly lower than that of ordinary fly ash (such as power plant first / second fly ash), which affects the work performance, mechanical properties and durability of the concrete after mixing to different degrees. Specifically, the high water demand of fly ash will reduce the fluidity of concrete and increase the dosage of admixture; its low activity will lead to insufficient cementing efficiency and affect the strength development; in addition, the heavy metals and soluble salts contained in fly ash may also cause concrete cracking, efflorescence or long-term durability problems. The main treatment method for sludge incineration fly ash is also harmless treatment, which requires chemical stabilization, high-temperature treatment and safe landfill of sludge incineration fly ash in sequence, thereby increasing the cost of sludge incineration fly ash treatment in sewage treatment plants.

[0003] Controllable low-strength material (CLSM), also known as flowable backfill material or controllable density filling material, is an engineering material with self-leveling and low-strength characteristics, mainly used in backfilling, pipeline cushioning, roadbed filling and other engineering scenarios. The 28-day unconfined compressive strength of most controllable low-strength materials used in engineering applications is less than 2.1 Mpa, so the performance requirements of raw materials for this material are lower than those of concrete. However, the raw material price of controllable low-strength material is high, resulting in high production cost of controllable low-strength material in the prior art. SUMMARY

[0004] In view of the defects in the prior art, the present application provides a controllable low-strength material based on sewage treatment plant sludge incineration fly ash and construction waste recycled mixture and a preparation method thereof, to solve the technical problems of high cost of sludge incineration fly ash treatment in sewage treatment plants and high cost of controllable low-strength material in the prior art.

[0005] In order to achieve the above-mentioned purposes, the technical solutions provided by the present application are as follows:

[0006] A controllable low-strength material based on a mixture of sludge incineration fly ash from a sewage treatment plant and recycled construction waste is prepared from the following raw materials in parts by mass: 10-15 parts of cement, 0-8 parts of blast furnace slag powder, 2-15 parts of sludge incineration fly ash from a sewage treatment plant, 100-130 parts of a recycled construction waste mixture, and 30-70 parts of water.

[0007] In one embodiment, the cement is 13 parts, the blast furnace slag powder is 4 parts, the sewage treatment plant sludge incineration fly ash is 13 parts, the construction waste recycled mixture is 114 parts, and the water is 38 parts.

[0008] In one embodiment, the cement is P·O42.5 ordinary Portland cement.

[0009] In one embodiment, the specific surface area of ​​the blast furnace slag powder is ≥400m 2 / kg, the 28d activity index of blast furnace slag powder is ≥95%.

[0010] In one embodiment, the wastewater treatment plant sludge incineration fly ash is collected by electrostatic precipitator.

[0011] In one embodiment, the construction waste recycled mixture is a sieve bottom material obtained after crushing and screening out coarse aggregate from construction waste, and the particle size of the construction waste recycled mixture ranges from 0 to 10 mm.

[0012] In one embodiment, the construction waste recycled mixture includes a waste concrete recycled mixture with waste concrete as the main raw material and / or a demolition waste recycled mixture with demolition waste as the main raw material.

[0013] The present application also provides a method for preparing a controllable low-strength material based on a mixture of sewage treatment plant sludge incineration fly ash and construction waste recycling, comprising the following steps: S1, weighing 10-15 parts of cement, 0-8 parts of blast furnace slag powder, 2-15 parts of sewage treatment plant sludge incineration fly ash, 100-130 parts of construction waste recycling mixture, and 30-70 parts of water in parts by mass;

[0014] S2. Pour cement, blast furnace slag powder, sewage treatment plant sludge incineration fly ash and construction waste recycled mixture into the mixer and stir for 1-2 minutes.

[0015] S3. Continue stirring, then add water in batches, adjust the amount of water according to the status, continue stirring for 2-4 minutes, and mix evenly with the solid material.

[0016] Compared with the prior art, this application has at least the following beneficial effects:

[0017] The raw materials in the controllable low-strength material in the application include sewage treatment plant sludge incineration fly ash and construction waste recycled mixture, and the solid waste generated in the urban operation process is treated in a harmless and low-cost manner; in the application, the sewage treatment plant sludge incineration fly ash is used to replace part of the construction waste recycled mixture with high cost in the production process of the controllable low-strength material, and the permeability of the controllable low-strength material produced is much higher than that of loose sand and gravel, so that the demand of the basement outer wall backfilling with permeability requirements can be met, and the production cost of the controllable low-strength material is greatly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The controllable low-strength material prepared for each embodiment and comparative example is compared in terms of the expansion degree;

[0019] Figure 2 The controllable low-strength material prepared for each embodiment and comparative example is compared in terms of the unconfined compressive strength;

[0020] Figure 3 The controllable low-strength material prepared for each embodiment and comparative example is compared in terms of the cost. DETAILED DESCRIPTION

[0021] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be described below by specific embodiments shown in the drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present application.

[0022] The terms used in the present disclosure are merely for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The singular forms "a", "said" and "the" used in the present disclosure and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein means and includes any or all possible combinations of one or more associated listed items.

[0023] It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, these information should not be limited to these terms, and should not be understood as indicating or implying relative importance. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of the present disclosure, the first information can also be referred to as the second information, and similarly, the second information can also be referred to as the first information. Depending on the context, the word "if" as used herein can be interpreted as "when" or "upon determination" or "in response to determining".

[0024] In the description of the present application, unless otherwise specified and limited, it is necessary to explain that the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be mechanical connection, or the connection between two elements, it can be direct connection, or indirect connection through intermediate medium, and the specific meaning of the above terms can be understood by those skilled in the art according to the specific circumstances.

[0025] In order to better understand the technical solutions of the present application, the present application will be described in detail below in combination with examples and comparative examples.

[0026] Example 1:

[0027] A preparation method of controllable low-strength material based on sewage treatment plant sludge incineration fly ash and construction waste recycled mixture, comprising the following steps:

[0028] S1, according to the mass fraction, respectively take: P·O42.5 ordinary Portland cement 13 parts, blast furnace slag powder 4 parts, sewage treatment plant sludge incineration fly ash 13 parts, waste concrete recycled mixture 114 parts, water 38 parts;

[0029] S2, the cement, blast furnace slag powder, sewage treatment plant sludge incineration fly ash and waste concrete recycled mixture are poured into a forced stirrer, and stirred for 1 min.

[0030] S3, continue to stir, then add water in batches, continue to stir for 2 min, mix with solid materials uniformly to prepare controllable low-strength material.

[0031] After measuring the expansion degree of the prepared controllable low-strength material, the controllable low-strength material is formed, and standard test blocks (70.7mmx70.7mmx70.7mm) are obtained, which are cured under standard conditions (20±2℃, RH>90%) to a certain age to measure the compressive strength.

[0032] Example 2:

[0033] A preparation method of controllable low-strength material based on sewage treatment plant sludge incineration fly ash and construction waste recycled mixture, comprising the following steps:

[0034] S1, according to the mass fraction, respectively take: P·O42.5 ordinary Portland cement 15 parts, blast furnace slag powder 5 parts, sewage treatment plant sludge incineration fly ash 13 parts, waste concrete recycled mixture 110 parts, water 38 parts;

[0035] S2, the cement, blast furnace slag powder, sewage treatment plant sludge incineration fly ash and waste concrete recycled mixture are poured into a forced stirrer, and stirred for 1 min.

[0036] S3, continue to stir, then add water in batches, continue to stir for 2 min, mix with the solid materials to obtain the controllable low-strength material.

[0037] After the spread of the prepared controllable low-strength material is measured, the controllable low-strength material is formed to obtain a standard test block (70.7mmx70.7mmx70.7mm), which is cured under standard conditions (20±2℃, RH>90%) to a certain age to measure the compressive strength thereof.

[0038] Example 3:

[0039] A controllable low-strength material preparation method based on sewage treatment plant sludge incineration fly ash and construction waste recycled mixture, comprising the following steps:

[0040] S1, according to the mass fraction, respectively take: P·O42.5 ordinary Portland cement 13 parts, blast furnace slag powder 4 parts, sewage treatment plant sludge incineration fly ash 7 parts, demolition waste recycled mixture 98 parts, water 65 parts;

[0041] S2, pour the cement, blast furnace slag powder, sewage treatment plant sludge incineration fly ash and demolition waste recycled mixture into a forced stirrer and stir for 1 min.

[0042] S3, continue to stir, then add water in batches, continue to stir for 2 min, mix with the solid materials to obtain the controllable low-strength material.

[0043] After the spread of the prepared controllable low-strength material is measured, the controllable low-strength material is formed to obtain a standard test block (70.7mmx70.7mmx70.7mm), which is cured under standard conditions (20±2℃, RH>90%) to a certain age to measure the compressive strength thereof.

[0044] Example 4:

[0045] A controllable low-strength material preparation method based on sewage treatment plant sludge incineration fly ash and construction waste recycled mixture, comprising the following steps:

[0046] S1, according to the mass fraction, respectively take: P·O42.5 ordinary Portland cement 13 parts, blast furnace slag powder 4 parts, sewage treatment plant sludge incineration fly ash 7 parts, demolition waste recycled mixture 98 parts, water 65 parts;

[0047] S2, pour the cement, blast furnace slag powder, sewage treatment plant sludge incineration fly ash and demolition waste recycled mixture into a forced stirrer and stir for 1 min.

[0048] S3, continue to stir, then add water in batches, continue to stir for 2 min, mix with the solid materials to obtain the controllable low-strength material.

[0049] The prepared controllable low-strength material is molded, standard test blocks (70.7mmx70.7mmx70.7mm) are obtained, and the compressive strength is determined after curing under standard conditions (20±2℃, RH>90%) to a certain age.

[0050] Example 5:

[0051] A controllable low-strength material preparation method based on sewage treatment plant sludge incineration fly ash and construction waste recycled mixture, comprising the following steps:

[0052] S1, according to the mass fraction, respectively take: P·O42.5 ordinary Portland cement 19 parts, sewage treatment plant sludge incineration fly ash 7 parts, demolition waste recycled mixture 96 parts, water 64 parts;

[0053] S2, the cement, sewage treatment plant sludge incineration fly ash and demolition waste recycled mixture are poured into a forced stirrer, and stirred for 1 min.

[0054] S3, continue to stir, then add water in batches, continue to stir for 2 min, and mix with solid materials to prepare controllable low-strength material.

[0055] The prepared controllable low-strength material is molded, standard test blocks (70.7mmx70.7mmx70.7mm) are obtained, and the compressive strength is determined after curing under standard conditions (20±2℃, RH>90%) to a certain age.

[0056] Comparative example 1:

[0057] A controllable low-strength material preparation method based on sewage treatment plant sludge incineration fly ash and construction waste recycled mixture, comprising the following steps:

[0058] S1, according to the mass fraction, respectively take: P·O42.5 ordinary Portland cement 19 parts, sewage treatment plant sludge incineration fly ash 7 parts, demolition waste recycled mixture 96 parts, water 64 parts;

[0059] S2, the cement, sewage treatment plant sludge incineration fly ash and demolition waste recycled mixture are poured into a forced stirrer, and stirred for 1 min.

[0060] S3, continue to stir, then add water in batches, continue to stir for 2 min, and mix with solid materials to prepare controllable low-strength material.

[0061] The prepared controllable low-strength material is molded, standard test blocks (70.7mmx70.7mmx70.7mm) are obtained, and the compressive strength is determined after curing under standard conditions (20±2℃, RH>90%) to a certain age.

[0062] Comparative Example 2:

[0063] A preparation method of controllable low-strength material based on sewage treatment plant sludge incineration fly ash and construction waste recycled mixture, comprising the following steps:

[0064] S1, according to the mass fraction, respectively take: P·O42.5 ordinary Portland cement 13 parts, blast furnace slag powder 4 parts, demolition waste recycled mixture 104 parts, water 66 parts;

[0065] S2, pour the cement, blast furnace slag powder and demolition waste recycled mixture into a forced mixer and stir for 1 min.

[0066] S3, continue to stir, then add water in batches, continue to stir for 2 min, mix with solid materials to obtain controllable low-strength material.

[0067] After measuring the expansion degree of the prepared controllable low-strength material, the controllable low-strength material is formed to obtain standard test blocks (70.7mmx70.7mmx70.7mm), which are cured under standard conditions (20±2℃, RH>90%) to a certain age to measure the compressive strength.

[0068] The raw material components of each example and comparative example are shown in Table 1:

[0069] Table 1:

[0070]

[0071] The cost of each raw material per unit of controllable low-strength material prepared in each example and comparative example is shown in Table 2:

[0072] Table 2:

[0073]

[0074] From the above Figure 1 to the above Figure 3It can be seen that the expansion degree and unconfined compressive strength of the controllable low-strength material prepared in Example 1 are lower than those of the controllable low-strength material prepared in Comparative Example 1, but the expansion degree and unconfined compressive strength of the controllable low-strength material prepared in Example 1 meet the engineering requirements of basement outer backfill with anti-permeation requirements (NS, 28d compressive strength > 1.0Mpa), and the production cost of the controllable low-strength material prepared in Example 1 is much lower than that of Comparative Example 1. The 28d unconfined compressive strength of Comparative Example 2 and Examples 3-5 is 0.57-0.84Mpa, which belongs to LS type self-compacting filling material (28d compressive strength > 0.3Mpa) according to the Technical Specification for Building Waste and Engineering Slurry Regeneration Self-compacting Filling DB31 / T1483-2024, and can meet the requirements of no early strength and secondary excavation, but the addition of sludge incineration fly ash in Examples 3-5 can reduce the raw material cost, so that the unit cost is lower than that of Comparative Example 2. By comparing the controllable low-strength materials prepared based on waste concrete building waste fine powder (Comparative Example 1, Examples 2-3) and demolition waste building waste fine powder (Comparative Example 2, Examples 4-5), the strength of the latter is significantly lower than that of the former, and as shown in Examples 4-5, the increase of cement dosage does not significantly improve the strength, therefore, the waste concrete building waste fine powder is suitable for the preparation of NS type self-compacting filling material, and the demolition waste building waste fine powder is used for the preparation of LS type self-compacting filling material.

[0075] The controllable low-strength material in the present application has been applied in the White Dragon Port Sewage Treatment Plant Phase III Extension Project and has achieved good evaluation.

[0076] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application and not to limit them; although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that; the specific embodiments of the application can be modified or some technical features can be replaced by equivalents; without departing from the spirit of the technical solutions of the present application, they should be covered in the technical solution range of the present application claimed.

Claims

1. A controllable low-strength material based on a mixture of fly ash from sewage treatment plant sludge incineration and recycled construction waste, characterized in that: The invention is prepared from the following raw materials in parts by weight: 10-15 parts of cement, 0-8 parts of blast furnace slag powder, 2-15 parts of sewage treatment plant sludge incineration fly ash, 100-130 parts of construction waste recycled mixture, and 30-70 parts of water.

2. The controllable low-strength material according to claim 1, characterized in that: The cement is 13 parts, the blast furnace slag powder is 4 parts, the sewage treatment plant sludge incineration fly ash is 13 parts, the construction waste recycled mixture is 114 parts, and the water is 38 parts.

3. The controllable low-strength material according to claim 1, characterized in that: The cement is P·O42.5 ordinary Portland cement.

4. The controllable low-strength material according to claim 1, characterized in that: The specific surface area of ​​the blast furnace slag powder is ≥400m 2 / kg, the 28d activity index of blast furnace slag powder is ≥95%.

5. The controllable low-strength material according to claim 1, characterized in that: The fly ash from sludge incineration in the sewage treatment plant is collected by electrostatic dust removal.

6. The controllable low-strength material according to claim 1, characterized in that: The construction waste recycled mixture is a sieve bottom material obtained after crushing and screening out coarse aggregates from construction waste, and the particle size of the construction waste recycled mixture ranges from 0 to 10 mm.

7. The controllable low-strength material according to claim 6, characterized in that: The construction waste recycled mixture includes a waste concrete recycled mixture with waste concrete as the main raw material and / or a demolition waste recycled mixture with demolition waste as the main raw material.

8. A method for preparing a controllable low-strength material based on a mixture of fly ash from sewage treatment plant sludge incineration and recycled construction waste, characterized in that: The following steps are involved: S1. Weigh 10-15 parts of cement, 0-8 parts of blast furnace slag powder, 2-15 parts of sewage treatment plant sludge incineration fly ash, 100-130 parts of construction waste recycled mixture, and 30-70 parts of water respectively according to their mass parts; S2. Pour cement, blast furnace slag powder, sewage treatment plant sludge incineration fly ash and construction waste recycled mixture into the mixer and stir for 1-2 minutes. S3. Continue stirring, then add water in batches, adjust the amount of water according to the status, continue stirring for 2-4 minutes, and mix evenly with the solid material.

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