Drench dredging sludge and steel slag synergistic based flow state filling material and preparation method thereof

Abstract

The invention provides a ditch dredging sludge synergistic steel slag-based flow-state filling material and a preparation method thereof. The preparation method comprises the following preparation steps: S1, uniformly mixing 10-30 parts by weight of ordinary Portland cement, 40-60 parts by weight of slag powder and 10-30 parts by weight of an alkaline activator to obtain a curing agent; and S2, adding 1000-1200 parts by mass of dredging sludge, 300-500 parts by mass of steel slag and 100-300 parts by mass of a curing agent into a stirrer, stirring for 3-5 minutes, uniformly mixing, and discharging to obtain the flow-state filling material.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, and in particular to a ditch sludge coordinated steel slag-based fluid filling material and a preparation method thereof. Background Art

[0002] As a type of urban sludge, ditch sludge is mainly the sediment dredged out during the maintenance of drainage pipes. It is a mixture of domestic garbage, slag, sand and gravel, organic sludge and sewage. With the increasing attention paid to the maintenance of drainage pipes, the discharge of ditch sludge is also increasing. The storage and disposal of large amounts of ditch sludge is a thorny problem. Due to the complex composition and high water content of ditch sludge, landfills have gradually refused to accept untreated ditch sludge. Finding a treatment method that can achieve harmlessness and resource utilization of ditch sludge is an urgent need for the current construction of a "zero-waste city". On the other hand, due to its large fluctuations in composition and poor stability, steel slag has limited other uses except for a small amount of iron-containing raw material used in cement raw material batching.

[0003] With the accelerating pace of urbanization, there is a great demand for various backfill projects. Among them, fluidized filling materials are a type of filling material that has emerged and been widely used in recent years. They have the characteristics of high fluidity and controllable strength, and can absorb a large amount of various wastes. Industrial solid wastes such as fly ash and slag, as well as construction waste, engineering mud, and engineering slag have been used to prepare fluidized filling materials at home and abroad, but there has been no research and application of using ditch sludge and steel slag to prepare fluidized filling materials. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a Tongditch sludge synergistic steel slag-based fluid filling material and a preparation method thereof. Steel slag is used to adjust the moisture content and particle size distribution of Tongditch sludge; cement, slag powder and alkaline activator are used to prepare a curing agent suitable for Tongditch sludge; steel slag and high alkaline components in the curing agent are used to neutralize the humic acid of Tongditch sludge; and based on the synergistic effect of multi-source solid waste, Al in the sludge is reduced in an alkaline environment. 2 O 3 、SiO 2 The components are dissolved and recombined to form hydration products such as CS(A)-H and calcium aluminate, which makes the Tongditch sludge-based fluid filling material have good working performance, mechanical properties and durability.

[0005] The technical problem to be solved can be implemented through the following technical solutions.

[0006] A ditch sludge and steel slag-based fluid filling material is characterized in that it comprises the following materials by weight: 1000-1200 parts of ditch sludge, 300-500 parts of steel slag, and 100-300 parts of curing agent.

[0007] Furthermore, the curing agent is composed of the following materials in percentage by weight: 10-30 parts of cement, 40-60 parts of slag powder, and 10-30 parts of alkaline activator.

[0008] Furthermore, the cement is PO42.5 cement.

[0009] Furthermore, the specific surface area of ​​the slag powder is greater than 400m 2 / kg, 7d intensity activity index ≥75%, 28d intensity activity index ≥95%.

[0010] Furthermore, the alkaline activator is one or more of dihydrate desulfurized gypsum, semi-hydrate desulfurized gypsum, dry desulfurized ash and calcium hydroxide.

[0011] Furthermore, the water content of the ditch sludge is 40-60%, the organic matter content is ≤10%, and the heavy metal content meets the requirements of the "Soil Environmental Quality Construction Land Soil Pollution Risk Control Standard" (GB36600-2018).

[0012] Furthermore, the particle size of the steel slag is less than 10 mm.

[0013] Another technical problem to be solved by the present invention is to provide a method for preparing the aforementioned ditch sludge in cooperation with steel slag-based fluid filling material, and the specific preparation steps are as follows:

[0014] (1) mixing ordinary Portland cement, slag powder and alkaline activator in proportion to obtain a curing agent;

[0015] (2) Add the ditch sludge, steel slag and curing agent into a mixer according to a certain proportion and stir for 3 to 5 minutes. After mixing evenly, discharge the materials to obtain the fluidized filling material of the present invention.

[0016] Furthermore, the specific surface area of ​​the slag powder in the method is greater than 400m 2 / kg, 7d intensity activity index ≥75%, 28d intensity activity index ≥95%.

[0017] Furthermore, the alkaline activator in the method is one or a mixture of dihydrate desulfurized gypsum, semi-hydrate desulfurized gypsum, dry desulfurized ash and calcium hydroxide.

[0018] The main mineral components of Tongditch sludge are similar to those of engineering mud. Steel slag as aggregate can improve its filling effect in space, thus improving the flowability and mechanical properties of the material. It is technically feasible to use Tongditch sludge and steel slag to prepare flowable filling materials.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. By selecting the components of the Tongditch sludge solidifying agent, the formula of cement, slag powder and alkaline activator is adjusted to prepare a solidifying agent suitable for the characteristics of Tongditch sludge. It has the characteristics of small dosage and fast solidification speed. It is lower in cost than pure cement solidifying agent and is more low-carbon and environmentally friendly.

[0021] 2. Use steel slag to adjust the moisture content, gradation and density of Tongditch sludge, improve the working performance of the fluid material, and use the alkalinity of steel slag to neutralize the humic acid of organic matter in Tongditch sludge, promote hydration and gelation reaction, and improve mechanical properties.

[0022] 3. The ditch sludge and steel slag are used to prepare the fluid filling material, which has self-leveling and self-compacting filling properties, and does not require vibration. The compressive strength and antifreeze performance also meet the current standard requirements. It has achieved waste treatment with waste, low cost, and good environmental value. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a flow chart of the preparation method of ditch sludge in conjunction with steel slag-based fluid filling material. DETAILED DESCRIPTION

[0024] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0025] Reference Figure 1 The present invention provides a ditch sludge-steel slag-based fluid filling material and a preparation method thereof. The material comprises the following materials by weight: 1000-1200 parts of ditch sludge, 300-500 parts of steel slag, and 100-300 parts of curing agent.

[0026] The preparation method comprises the following steps:

[0027] (1) mixing ordinary Portland cement, slag powder and alkaline activator in proportion to obtain a curing agent;

[0028] (2) Add ditch sludge, steel slag and curing agent into a mixer in proportion and stir for 3 to 5 minutes until they are evenly mixed and then discharged.

[0029] The following is a detailed description through more specific embodiments.

[0030] Embodiment 1:

[0031] The raw materials include ditch sludge, steel slag, cement, slag powder, alkaline activator, etc.

[0032] Among them, the water content of Tongditch sludge is 60%, and the organic matter content is 8%;

[0033] The particle size of steel slag is less than 10mm;

[0034] The cement is PO42.5 cement;

[0035] The specific surface area of ​​slag powder is 456m 2 / kg, 7d intensity activity index 80%, 28d intensity activity index 98%;

[0036] The alkaline activator is a mixture of semi-hydrated desulfurization gypsum and dry desulfurization ash, with a mixing ratio of 1:1.

[0037] The cement, slag powder and alkaline activator are mixed uniformly in a mass ratio of 10:60:30 to obtain a curing agent;

[0038] Add ditch sludge, steel slag and curing agent in a mass ratio of 1000:500:250 into a mixer and stir for 4 minutes. Discharge after mixing evenly.

[0039] The slump expansion of the fluid filling material is 600mm, the setting time is 56h, the 7d compressive strength is 0.6MPa, and the 28d compressive strength is 2.3MPa. The durability meets the standards and construction requirements.

[0040] Embodiment 2:

[0041] The raw materials include ditch sludge, steel slag, cement, slag powder, alkaline activator, etc.

[0042] Among them, the water content of Tongditch sludge is 50%, and the organic matter content is 7%;

[0043] The particle size of steel slag is less than 10mm;

[0044] The cement is PO42.5 cement;

[0045] The specific surface area of ​​slag powder is 420m 2 / kg, 7d intensity activity index 78%, 28d intensity activity index 96%;

[0046] The alkaline activator is a mixture of desulfurized gypsum dihydrate and calcium hydroxide in a mixing ratio of 1:1.

[0047] The cement, slag powder and alkaline activator are mixed uniformly in a mass ratio of 20:60:20 to obtain a curing agent;

[0048] Add ditch sludge, steel slag and curing agent into the mixer in the ratio of 1100:400:100 and stir for 3 minutes. Discharge after mixing evenly.

[0049] The slump expansion of the fluid filling material is 500mm, the setting time is 64h, the 7d compressive strength is 0.5MPa, the 28d compressive strength is 1.7MPa, and the durability meets the standards and construction requirements.

[0050] Embodiment 3:

[0051] The raw materials include ditch sludge, steel slag, cement, slag powder, alkaline activator, etc.

[0052] Among them, the water content of Tongditch sludge is 40%, and the organic matter content is 5%;

[0053] The particle size of steel slag is less than 10mm;

[0054] The cement is PO42.5 cement;

[0055] The specific surface area of ​​slag powder is 432m 2 / kg, 7d intensity activity index 79%, 28d intensity activity index 97%;

[0056] The alkaline activator is desulfurized gypsum.

[0057] The cement, slag powder and alkaline activator are mixed uniformly in a mass ratio of 15:55:30 to obtain a curing agent;

[0058] Add ditch sludge, steel slag and curing agent into a mixer at a mass ratio of 1200:300:150 and stir for 5 minutes. Discharge after mixing evenly.

[0059] The slump expansion of the fluid filling material is 595mm, the setting time is 59h, the 7d compressive strength is 0.4MPa, and the 28d compressive strength is 1.9MPa. The durability meets the standards and construction requirements.

[0060] The above description of the embodiments is to facilitate the understanding and use of the present invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without having to go through creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the principles of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A ditch sludge combined with steel slag based fluid filling material, characterized in that: The material components include the following by weight: 1000-1200 parts of ditch sludge, 300-500 parts of steel slag, and 100-300 parts of curing agent.

2. The ditch sludge combined with steel slag based fluid filling material according to claim 1 is characterized in that: The curing agent is mixed with the following materials in percentage by weight: 10-30 parts of cement, 40-60 parts of slag powder, and 10-30 parts of alkaline activator.

3. The ditch sludge combined with steel slag based fluid filling material according to claim 2 is characterized in that: The cement is PO42.5 cement.

4. The ditch sludge combined with steel slag based fluid filling material according to claim 2 is characterized in that: The specific surface area of ​​the slag powder is greater than 400m 2 / kg, 7d intensity activity index ≥75%, 28d intensity activity index ≥95%.

5. The ditch sludge combined with steel slag based fluid filling material according to claim 2 is characterized in that: The alkaline activator is one or a mixture of dihydrate desulfurized gypsum, semi-hydrate desulfurized gypsum, dry desulfurized ash and calcium hydroxide.

6. The ditch sludge combined with steel slag based fluid filling material according to claim 1 is characterized in that: The water content of the ditch sludge is 40-60%, the organic matter content is ≤10%, and the heavy metal content meets the requirements of the "Soil Environmental Quality Construction Land Soil Pollution Risk Control Standard" GB36600-2018.

7. The ditch sludge combined with steel slag based fluid filling material according to claim 1 is characterized in that: The steel slag particle size is less than 10 mm.

8. A method for preparing ditch sludge and steel slag-based fluid filling material, characterized in that: The method comprises the following preparation steps: S1, according to the weight percentage of 10-30 parts of ordinary Portland cement, 40-60 parts of slag powder, and 10-30 parts of alkaline activator, Portland cement, slag powder, and alkaline activator are uniformly mixed to obtain a curing agent; S2, add 1000-1200 parts of ditch sludge, 300-500 parts of steel slag and 100-300 parts of curing agent by mass into a mixer and stir for 3-5 minutes. After mixing evenly, discharge the materials to obtain a fluidized filling material.

9. The preparation method according to claim 8, characterized in that: The specific surface area of ​​the slag powder is greater than 400m 2 / kg, 7d intensity activity index ≥75%, 28d intensity activity index ≥95%.

10. The preparation method according to claim 8, characterized in that: The alkaline activator is one or more of dihydrate desulfurized gypsum, semi-hydrate desulfurized gypsum, dry desulfurized ash and calcium hydroxide.

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