阅读说明：本技术 改进型渣土再生回填材料及其制备方法 (Improved slag soil regeneration backfill material and preparation method thereof ) 是由 薛信恺 徐浩 蒋自胜 邱礼城 苏良缘 陈秋宇 俞静雯 于 2019-09-24 设计创作，主要内容包括：本申请提供了一种改进型渣土再生回填材料及其制备方法,将渣土作为主要成分,掺入适量的水泥、水、粉煤灰、早强剂,混合搅拌制备成改进型渣土再生回填材料；该制备方法包括以下步骤：除去异物、污染变质部分,按照配方分别称取各组分,将称取好的各组分进行混合搅拌至质地均匀,即得成品。上述改进型渣土再生回填材料及其制备方法实现了对渣土的再利用,减小了管道开挖作业对环境的污染,降低了回填作业的工程造价,在保证回填材料具备足够流动性的同时提高了回填材料的后期强度。(The application provides an improved muck regeneration backfill material and a preparation method thereof, wherein muck is used as a main component, and is mixed with a proper amount of cement, water, fly ash and an early strength agent to prepare the improved muck regeneration backfill material by mixing and stirring; the preparation method comprises the following steps: removing foreign matters and polluting deteriorated parts, respectively weighing the components according to the formula, and mixing and stirring the weighed components until the texture is uniform to obtain the finished product. The improved muck regeneration backfill material and the preparation method thereof realize the reutilization of muck, reduce the pollution of pipeline excavation operation to the environment, reduce the construction cost of backfill operation, ensure that the backfill material has enough fluidity and simultaneously improve the later strength of the backfill material.)

1. The improved muck regeneration backfill material is characterized by comprising the following formula components in parts by mass:

2. the improved muck reclamation backfill material according to claim 1, wherein the organic matter content of the muck does not exceed 5 wt%.

3. The improved muck reclamation backfill material according to claim 1, characterized by:

the particle size of the slag soil particles is not more than 40mm, the content of particles with the particle size of less than 2mm is not more than 55 wt%, and the content of particles with the particle size of 5-20mm is not more than 30 wt%.

4. The improved muck reclamation backfill material according to claim 1, wherein the cement is at least one of a general purpose cement, a special purpose cement, or a specialty cement.

5. The muck reclamation backfill material according to claim 4, wherein the universal cement is at least one of portland cement, portland cement, portland slag cement, pozzolanic portland cement, fly ash portland cement, or composite portland cement.

6. The improved muck reclamation backfill material according to claim 1, wherein the fly ash is at least one of class C fly ash and class F fly ash;

the C-type fly ash is fly ash with calcium oxide content higher than 10 wt%;

the F-type fly ash is fly ash with the calcium oxide content not higher than 10 wt%.

7. The improved muck reclamation backfill material according to claim 1, wherein the early strength agent is at least one of a chloride early strength agent, a sulfate early strength agent, a nitrate early strength agent, an organic early strength agent or a composite early strength agent.

8. The preparation method of the improved muck regeneration backfill material is characterized by comprising the following steps:

s1, pretreatment: pretreating the muck to remove foreign matters and pollute a deteriorated part;

s2, proportioning design: weighing the components according to the formula of the improved muck reclamation backfill material according to any one of claims 1 to 7;

s3, sludge removal treatment: mixing and stirring the dregs and water treated by the S1 to obtain a mixture;

s4, mixing operation: and mixing and stirring the mixture, cement, fly ash and the early strength agent to obtain a finished product.

Technical Field

The application relates to the field of civil engineering materials, in particular to an improved muck regeneration backfill material and a preparation method thereof.

Background

At present, China is in a high-speed construction and development period, and urban pipe network construction generates a large number of foundation trenches or pipe ditches to be filled and repaired, so that foundation trench backfilling and pipe ditch backfilling are problems which are frequently faced in the field.

Disclosure of Invention

The application provides an improved muck reclamation backfill material and a preparation method thereof, which take muck as a main material, greatly reduces the preparation cost of the backfill material, and the improved muck reclamation material has good fluidity and later strength.

In order to achieve the technical effects, the first aspect of the application provides an improved muck regeneration backfill material, which comprises the following formula components in parts by mass:

in a first possible implementation form, based on the first aspect of the application, the content of organic matter in the above-mentioned muck is not more than 5 wt%.

In a second possible implementation manner, based on the first aspect of the present application, the particle size of the above-mentioned dregs particles is not more than 40mm, and the content of particles with a particle size of less than 2mm is not more than 55 wt%, and the content of particles with a particle size of 5-20mm is not more than 30 wt%.

In a third possible implementation manner based on the first aspect of the present application, the cement is at least one of general purpose cement, special purpose cement, or special purpose cement.

In a fourth possible implementation manner according to the third possible implementation manner of the first aspect of the present application, the general-purpose cement is at least one of portland cement, ordinary portland cement, portland slag cement, portland pozzolanic cement, portland fly ash cement, or composite portland cement.

Based on the first aspect of the present application, in a fifth possible implementation manner, the fly ash is at least one of class C fly ash and class F fly ash;

the class C fly ash is fly ash with calcium oxide content higher than 10 wt%;

the F-type fly ash is fly ash with the calcium oxide content not higher than 10 wt%.

In a sixth possible implementation manner according to the first aspect of the present application, the early strength agent is at least one of a chloride early strength agent, a sulfate early strength agent, a nitrate early strength agent, an organic early strength agent, or a composite early strength agent.

The second aspect of the application provides a preparation method of an improved muck regenerative backfill material, wherein the preparation method comprises the following steps:

s1, pretreatment: pretreating the muck to remove foreign matters and pollute a deteriorated part;

s2, proportioning design: weighing each component according to the formula of the improved muck reclamation backfill material according to the first aspect and any one of six possible implementation modes based on the first aspect;

s3, sludge removal treatment: mixing and stirring the dregs and water treated by the S1 to obtain a mixture;

s4, mixing operation: and mixing and stirring the mixture, cement, fly ash and early strength agent to obtain a finished product.

According to the improved muck regeneration backfill material and the preparation method provided by the application, muck is used as a main component, a proper amount of cement, water, fly ash and an early strength agent are added, and the materials are mixed and stirred to prepare the improved muck regeneration backfill material. In the mixture prepared according to the formula, various components in the cement and water are subjected to hydration reaction to form various hydrates, wherein one part of the hydrates is hardened by itself to form a skeleton of the cement hydrate, and the other part of the hydrates is reacted with soil particles and fly ash particles with certain activity around the cement hydrate. The large amount of ions in cement hydrate makes soil particles and fly ash particles generate agglomeration, the activity of fly ash is excited, negative ion groups in the vitreous body become small, and the surface has adsorption force. The soil particles, the fly ash particles and the cement hydrate are subjected to physical and chemical reactions of ion exchange, adsorption, coagulation and hardening, and the strength of the mixture is finally improved. Therefore, the technical scheme reasonably recycles the muck, and prepares the improved muck regenerative backfill material by matching with other materials, thereby reducing the pollution of pipeline excavation operation on the environment, lowering the engineering cost of backfill operation, ensuring that the backfill material has enough fluidity and simultaneously improving the later strength of the backfill material.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application more clearly apparent, the present application is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

The weight of the related components mentioned in the description of the embodiments of the present application may not only refer to the specific content of each component, but also represent the proportional relationship of the weight among the components, and therefore, the enlargement or reduction of the proportion of the related components according to the description of the embodiments of the present application is within the scope disclosed in the description of the embodiments of the present application. Specifically, the weight described in the specification of the examples of the present application may be a mass unit known in the chemical industry field such as μ g, mg, g, kg, etc.

The embodiment of the application provides an improved muck regeneration backfill material, which comprises the following formula components in parts by mass (all dry mass of the components):

optionally, the muck is engineering muck (such as muck produced by digging a groove in the pipe network construction process of urban rainwater, domestic sewage, drinking water and the like), the content of organic matters in the muck is not more than 5 wt%, the later strength of the backfill material is influenced by the organic matters, and if the content of the organic matters is too high, the later strength cannot meet the required quality requirement.

Optionally, if the content of particles with the particle size of less than 2mm in the muck exceeds 55 wt%, the prepared improved muck regenerative backfill material has poor effect and is uneconomical; if the content of particles with the particle size of 5-20mm exceeds 30 wt%, the prepared improved muck regeneration backfill material can generate serious bleeding phenomenon, the properties of the backfill material can be uneven, and the quality is not easy to control; if the particle size of the slag soil particles is larger than 40mm, the quality of the backfill material is negatively affected; in summary, the particle size of the residue soil particles is not more than 40mm, the content of particles with particle size less than 2mm is not more than 55 wt%, and the content of particles with particle size of 5-20mm is not more than 30 wt%.

Optionally, the cement is at least one of general cement, special cement or special cement. Further, the general cement is at least one of portland cement, ordinary portland cement, portland slag cement, pozzolanic portland cement, fly ash portland cement or composite portland cement; the special cement is special cement, such as: grade G oil well cement, road portland cement; the characteristic cement is cement with outstanding performance, such as: rapid hardening portland cement, low-heat slag portland cement, expanded sulphoaluminate cement, phosphoaluminate cement or phosphate cement. When the improved muck regeneration backfill material is prepared, which cement needs to be used is considered according to actual conditions, and an appropriate cement type is selected according to the characteristics and the characteristics of the cement required by a construction site;

preferably, when the early strength type backfill material is needed, the cement can adopt sulphoaluminate cement; when the backfill material which needs to keep a longer flowing state is needed, the cement can adopt Portland cement; when the cost of backfill materials (the cost of sulphoaluminate cement is higher) and the early strength characteristic of certain backfill materials need to be considered, sulphoaluminate cement and silicate cement which are mixed according to a certain proportion can be adopted for the cement.

The concrete is cement concrete prepared by mixing cement as a cementing material, auxiliary materials and a proper amount of water.

Optionally, the water meets the regulation of JGJ63-2006 Water for concrete Standard; wherein, if the water meets the drinking water required by the current national standard GB5749-2006 sanitary Standard for Drinking Water, the water can be used as concrete water without inspection.

Optionally, the fly ash is at least one of class C fly ash and class F fly ash;

the class C fly ash is fly ash with calcium oxide content higher than 10 wt%, is usually obtained by burning anthracite or bituminous coal and can meet the technical conditions, and has volcanic ash performance;

the F-type fly ash is fly ash with the calcium oxide content not higher than 10 wt%.

Optionally, the fly ash is at least one of grade I fly ash, grade II fly ash and grade III fly ash;

the classification of class I fly ash and class II and class III fly ash described above follows the criteria set out in fly ash for use in cement and concrete (GB/T1596-2017).

It should be noted that the functions of the fly ash in concrete include:

(1) concrete mix workability is improved

The addition of a proper amount of fly ash can improve the fluidity, cohesiveness and water-retaining property of the concrete mixture, so that the concrete mixture is easy to pump and pour for molding, and the loss of slump over time can be reduced;

(2) temperature rise reduction of concrete

The cement consumption can be reduced after the fly ash is doped, and the hydration heat release of the fly ash is little, so that the hydration heat release is reduced, the temperature rise of concrete during construction is reduced, and the temperature crack can be obviously reduced, which is particularly beneficial to mass concrete engineering;

(3) durability enhancement of concrete

The secondary hydration improves the compactness of the concrete, improves the interface structure, and reduces the quantity of calcium hydroxide which is easy to corrode due to the secondary hydration, so that the impermeability, the sulfate corrosion resistance, the magnesium salt corrosion resistance and the like of the concrete can be improved after the fly ash is added. Reduction in the amount of free base can inhibit or reduce the alkali-aggregate reaction;

(4) distortion reduction

The creep of the fly ash concrete is reduced compared with the common concrete by deformation: the water reducing effect of the fly ash enables the drying shrinkage and early plastic drying crack of the fly ash concrete to be basically the same as or slightly lower than those of common concrete, but the drying shrinkage of the concrete can be increased by the inferior fly ash;

(5) improved wear resistance

The strength and hardness of the fly ash are higher, so that the wear resistance of the fly ash concrete is better than that of common concrete. But poor curing of concrete can lead to reduced wear resistance;

(6) cost reduction

Under the condition of equal strength grade, the addition of fly ash can reduce the cement consumption by about 10-15 wt%, thus reducing the cost of concrete.

Optionally, the early strength agent is at least one of a chloride early strength agent, a sulfate early strength agent, a nitrate early strength agent, an organic early strength agent or a composite early strength agent. The early strength agent has the main functions of accelerating the hydration speed of the cement and promoting the development of the early strength of the concrete; not only has the early strength function, but also has certain water reducing and enhancing functions.

Correspondingly, the embodiment of the application also provides a preparation method of the improved muck reclamation backfill material, which comprises the following steps:

s1, pretreatment: pretreating the muck to remove foreign matters and pollute a deteriorated part;

s2, proportioning design: weighing the components according to the formula of the improved muck regeneration backfill material;

s3, sludge removal treatment: mixing and stirring the dregs and water treated by the S1 to obtain a mixture;

s4, mixing operation: and mixing and stirring the mixture, cement, fly ash and early strength agent to obtain a finished product.

Specifically, the step S1 of pretreating the muck includes:

1) removing foreign matters such as wood chips and iron chips mixed in the residue soil;

2) when the river sediment with foul pollution is used as a raw material, the polluted and deteriorated part is removed;

specifically, in step S2, the target attribute range of the muck is determined according to the use purpose and the engineering requirement of the muck recycled material, and finally the mix proportion design of the muck recycled material is determined. The improved slag soil regeneration backfill material formula comprises the following components in percentage by weight: 2500 parts of slag soil 2200-.

Specifically, in step S3, the soil residue is subjected to a soil-loosening treatment, and the soil residue and water that have been subjected to step S1 are stirred. The desliming treatment aims at the problem that the content of particles with the particle size smaller than 2mm in the residue soil is high (especially when the content of clay particles is high), before the final mixing and stirring, the residue soil and water are desliming treated, so that the uniformity and the mixing property of the backfill material can be improved, and the quality of the backfill material is improved;

optionally, in the step S3, before the muck and water subjected to the step S1 are stirred, the muck subjected to the step S1 is crushed.

Specifically, in the step S4, the mixture of the muck and water obtained in the step S3 is mixed with cement, fly ash and an early strength agent for final mixing and stirring to obtain a finished backfill material;

optionally, the stirring may be performed by using efficient double-shaft stirring (low-speed stirring and high-speed stirring are performed simultaneously), the mixture of cement, fly ash, early strength agent, the muck and water is stirred to a uniform flowing state by using the rapid stirring and scattering effects of the blades, and the specific mixing and stirring time is determined by actual soil quality and machine stirring speed.

After the preparation according to the preparation method is completed, the flow value and the unconfined compressive strength of the finished product are tested, and the method specifically comprises the following steps:

1) flow value test

The flow value testing device consists of a plexiglas flat plate and a plexiglas cylindrical barrel (only the cylindrical side part) with the height of 80mm and the diameter of 80 mm. During the test, firstly, wiping off the dust on the inner wall of the organic glass cylinder and the surface of the organic glass flat plate by using a cleaning cloth, coating a layer of vaseline on the inner wall of the organic glass, placing the organic glass cylinder on the horizontal organic glass flat plate, and wetting the surface of the organic glass flat plate; then, filling the sludge or the newly stirred and solidified sludge into an organic glass cylinder, continuously vibrating in the sample filling process to ensure that the sample is tightly filled, scraping the surface by using a scraper after the sample is filled, and wiping off the sludge scattered on the wall of the outer cylinder and the plate surface by using a rag; after the sample loading is finished, the organic glass cylinder is lifted up slightly vertically, after 30s, the maximum diameter and the minimum diameter of the spread mixture are measured by a steel ruler, and the average value of the maximum diameter and the minimum diameter is taken as a flow value. In order to ensure the reliability of the test, each group of samples needs to be subjected to 2-3 parallel tests, and the average value is taken as a final flow value;

2) unconfined compressive strength test

Unconfined compressive strength testing was performed according to geotechnical test method Standard (GB/T50123-1999). The instrument used in the test is a YYYW-2 strain control type unconfined pressure instrument produced by Nanjing soil instrument factory, and the compression rate is 1.18 mm/min. In order to ensure the reliability of the test, each group of samples needs to be subjected to 2-3 parallel tests, and the average value is taken as the final unconfined compressive strength;

3) CBR test

Pouring mixed fluidized soil into a CBR steel cylinder, curing, performing a penetration test after the curing age is reached, ① placing a test piece on a lifting platform of a pavement material strength tester, adjusting an eccentric seat, aligning, leveling and enabling a penetration rod to be in full contact with the top surface of the test piece, placing 4 load-bearing plates around the penetration rod, ② firstly applying 45N loads to the penetration rodLoading, regulating the pointer of dial indicator for measuring force and deformation to integer, reading initial reading ③, pressing the penetration rod into the specimen at 1-1.25mm/min, measuring the readings of three dial indicators, recording the penetration of some whole readings (20, 40, 60) of dial indicator in load cell, and regulating the penetration to 250X 10 ^-2mm, there can be more than 5 readings. Therefore, the first reading in the dynamometer should be at a penetration of 30 × 10 ^-2About mm. After the reading is finished, the processing is carried out, and the ratio of the unit pressure at the penetration of 2.5mm to the standard pressure is generally used as the bearing ratio (CBR value) of the material. If the bearing ratio when the penetration amount is 5mm is larger than that when the penetration amount is 2.5mm, the test should be redone. If the results are still the same, the load ratio at 5mm is adopted as the load ratio of the material (CBR value).

In the embodiment of the application, the test qualification standard is defined as:

1) the flow value is 200-300 mm;

2) the unconfined compressive strength of 1 day is more than 60-100kPa, the unconfined compressive strength of 7 days is 400-600kPa, and the unconfined compressive strength of 28 days is 800-900 kPa;

3) when the penetration was 2.5mm, the value of the pressure gauge reached 770kPa, which corresponds to a CBR value of about 11%.

The above-mentioned pass standards are within the quality requirements of the "road bed design specification" (JTG D30-2015) and the "エアモルタル and the method of the intake rib エアミルク test" (JHS a313-1992) in japan ministry of construction.

The present application will now be described in further detail with reference to a specific formulation of an improved slag soil reclamation backfill material and a preparation method thereof. Wherein, the water-solid ratio refers to the dry mass ratio of water to solid materials (including muck, cement and fly ash), and the lime-sand ratio refers to the dry mass ratio of cement to muck, so that the water-solid ratio and the lime-sand ratio of the formula are in the following ranges: the water-solid ratio is 0.219-0.292, and the sand-lime ratio is 0.064-0.095.

It should be noted that the backfill material prepared according to the formula and the preparation method has certain fluidity and certain strength, and the specific influence factors are as follows:

1) fluidity: the fluidity is mainly influenced by water, the slag soil contains a large number of powder particles and clay particles, the mineral content of the slag soil is high, hydration reaction can be generated by adding water, so that clay minerals are subjected to expansion deformation, the difference between the cementing material and the cementing material degree can cause the difference of water absorption expansion rates, the speed of the hydration reaction is influenced, the hardening of a mixture is influenced, and the mixture has certain fluidity, so that the fluidity is mainly influenced by the water-solid ratio, and the fluidity is increased along with the increase of the water-solid ratio;

2) strength: the strength is mainly influenced by the hydration of cement, so that the early strength and the later strength are mainly influenced by the sand-lime ratio, and the strength is increased along with the increase of the sand-lime ratio; in addition, the early strength can be improved by increasing the content of an early strength agent or increasing the content of sulphoaluminate cement in cement, and the later strength can be improved by adding a proper amount of fly ash.