Sludge pyrolysis residue modified asphalt mixture and preparation method thereof

Abstract

The application provides a sludge pyrolysis residue modified asphalt mixture and a preparation method thereof.The modified asphalt mixture comprises the following components in parts by weight: modified sludge pyrolysis residue 30-70 parts, crushed stone 10-30 parts, natural sand 5-15 parts, mineral powder 30-70 parts and asphalt 3.75-14.5 parts; the preparation method of the modified sludge pyrolysis residue comprises mixing municipal sludge and a modifier in proportion and pyrolyzing under the condition of high temperature (500-800 DEG C) and anaerobic environment.The sludge pyrolysis residue modified asphalt mixture of the application uses the modified sludge pyrolysis residue as a raw material component, solves the environmental problems caused by sludge accumulation, reduces the consumption of natural resources, provides an economically feasible resource utilization mode for sludge treatment, and improves the high-temperature rut resistance of the asphalt mixture and the performance of the mixture by matching with other grading components.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of road engineering pavement cementing material, in particular to a sludge pyrolysis residue modified asphalt mixture and a preparation method thereof. BACKGROUND

[0002] The infrastructure construction of urban sewage and the related management system are continuously improved, but the harmless disposal and resource utilization of sludge are not standardized, especially in large cities, the amount of sludge is large, and there is a lack of economic and effective sludge disposal method, and the treatment, disposal and management are difficult. At present, from the final destination of sludge, there are three main ways including land use, sanitary landfill or incineration and sanitary landfill, and building material utilization. In 2019, the annual sludge production in China was 3923 million tons (water content 80%), the total sludge disposal was 3905 million tons, the disposal ratio was 99.53%, the land use accounted for 29.24% of the sludge disposal, the incineration accounted for 26.69% of the total disposal, the sanitary landfill accounted for 20.10% of the total disposal, and the building material utilization accounted for 15.88% of the total disposal (Li Qiaoyang, 2020), which is mainly used as raw materials for cement, bricks, ceramsite and the like. SUMMARY

[0003] The present application aims to overcome the deficiencies in the prior art and provide a sludge pyrolysis residue modified asphalt mixture and a preparation method thereof.

[0004] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows: a sludge pyrolysis residue modified asphalt mixture, the modified asphalt mixture comprises the following components by weight: modified sludge pyrolysis residue 30-70 parts, crushed stone 10-30 parts, natural sand 5-15 parts, mineral powder 30-70 parts and asphalt 3.75-14.5 parts.

[0005] The preparation method of the modified sludge pyrolysis residue comprises the following steps: mixing the municipal sludge with the modifier in proportion, and pyrolyzing under the condition of high temperature (500-800 DEG C) and anaerobic; the proportion of the amount of the municipal sludge and the modifier is that the weight of the modifier is 6%-15% of the weight of the dry municipal sludge; the modifier is one or more of calcium oxide, calcium hydroxide and flocculant, and the flocculant is one or more of polyacrylamide, polyaluminum chloride, ferrous sulfate, aluminum sulfate, ferric chloride, polymeric ferric sulfate, calcium chloride, magnesium chloride, aluminum chloride.

[0006] The modified sludge pyrolysis residue is applied in the sludge pyrolysis residue modified asphalt mixture, which can reduce the consumption of natural resources and provide an environmentally friendly and feasible resource utilization method for sludge treatment. The sludge pyrolysis residue modified asphalt mixture of the present application applies the modified sludge pyrolysis residue as a raw material component, solves the environmental problems caused by sludge accumulation, can reduce the consumption of natural resources, and provides an economically feasible resource utilization method for sludge treatment. Moreover, the combination with other graded components improves the high-temperature rut resistance of the asphalt mixture and improves the performance of the mixture.

[0007] Preferably, the preparation method of the modified sludge pyrolysis residue is that the pyrolysis time under the condition of high temperature and anaerobic environment at 500-800 DEG C is 0.8-1.5 hours.

[0008] Preferably, the asphalt accounts for 3%-10% of the weight of the sludge pyrolysis residue modified asphalt mixture.

[0009] Preferably, the weight ratio of the modified sludge pyrolysis residue to the mineral powder is 1:(0.5-2).

[0010] It is found through research that when the weight ratio of the modified sludge pyrolysis residue to the mineral powder in the sludge pyrolysis residue modified asphalt mixture component is 1:(0.5-2), the sludge pyrolysis residue modified asphalt mixture has more excellent high-temperature rut resistance.

[0011] Preferably, the sludge pyrolysis residue modified asphalt mixture adopts an AC-10 or AC-13 graded form.

[0012] Preferably, in the preparation method of the modified sludge pyrolysis residue, the municipal sludge is at least one of sludge in a sewage treatment plant or sludge in a water purification plant.

[0013] Preferably, the preparation method of the sludge pyrolysis residue modified asphalt mixture comprises the following steps:

[0014] (1) After the crushed stone and natural sand with removed water are mixed at 170-180 DEG C according to the Marshall mixing ratio design for 1-3 min, the asphalt melted at 170-180 DEG C is added and stirred;

[0015] (2) The sludge pyrolysis residue and the mineral powder with removed water are added while stirring until the mixture is uniformly mixed.

[0016] Preferably, the method of removing water in step (1) is heating to 105-110℃; the method of heating the sludge pyrolysis residue and the mineral powder to remove water in step (2) is heating to 105-110℃.

[0017] The present application also provides a preparation method of the sludge pyrolysis residue modified asphalt mixture described above, which comprises the following steps:

[0018] (1) After the water-removed gravel and natural sand are mixed according to the Marshall mixing ratio design for 1-3 min, the asphalt melted at 170-180℃ is added and stirred;

[0019] (2) The water-removed sludge pyrolysis residue and the mineral powder are added while stirring until the mixture is uniform.

[0020] Preferably, the method of removing water in step (1) is heating to 105-110℃; the method of heating the sludge pyrolysis residue and the mineral powder to remove water in step (2) is heating to 105-110℃.

[0021] The present application has the advantages that: the present application provides a sludge pyrolysis residue modified asphalt mixture and a preparation method thereof, the sludge pyrolysis residue modified asphalt mixture of the present application uses modified sludge pyrolysis residue as a raw material component, solves the environmental problems caused by sludge accumulation, reduces the consumption of natural resources, provides an economically feasible resource utilization method for sludge treatment, and improves the high-temperature rutting resistance of the asphalt mixture and the performance of the mixture when combined with other graded components. DETAILED DESCRIPTION

[0022] For better illustrating the purpose, technical solution and advantages of the present application, the present application will be further described below in combination with specific examples.

[0023] Example 1

[0024] As a sludge pyrolysis residue modified asphalt mixture of the present application, the modified asphalt mixture comprises the following components by weight: 50 parts of modified sludge pyrolysis residue, 20 parts of gravel, 5 parts of natural sand, 50 parts of mineral powder and 6 parts of asphalt.

[0025] The preparation method of the modified sludge pyrolysis residue used in this example is as follows:

[0026] (1) The municipal sludge of a sewage treatment plant is mixed with a modifier in proportion, and the weight of the modifier is 9% of the weight of the dry municipal sludge; the modifier is calcium oxide and a flocculant in a weight ratio of 2:1; the flocculant is polyacrylamide.

[0027] (2) Pyrolysis under the condition of 600℃ and no oxygen.

[0028] The preparation method of the sludge pyrolysis residue modified asphalt mixture of the embodiment comprises the following steps:

[0029] The Marshall mix proportion design method is used for the mix proportion design of the AC-13 asphalt mixture; 50 parts of modified sludge pyrolysis residue, 20 parts of crushed stone, 5 parts of natural sand, 50 parts of mineral powder and 6 parts of base asphalt are used. The mineral materials at all levels are dried in an oven at 105±5℃ to constant weight, and then the aggregate required by each test piece is weighed according to the designed gradation, uniformly mixed, and the sludge pyrolysis residue and the mineral powder are not added. The base asphalt is added after 3 minutes of mixing at 170℃; the mixing is paused, and the heated sludge pyrolysis residue and the mineral powder are added, and the mixing is continued until uniform. The sludge pyrolysis residue modified asphalt mixture is obtained.

[0030] Embodiment 2

[0031] As a kind of sludge pyrolysis residue modified asphalt mixture of the embodiment of the application, as a kind of sludge pyrolysis residue modified asphalt mixture of the embodiment of the application, the modified asphalt mixture includes the following components by weight, modified sludge pyrolysis residue 30 parts, crushed stone 10 parts, natural sand 15 parts, mineral powder 70 parts, base asphalt 3.75 parts.

[0032] The preparation method of the modified sludge pyrolysis residue used in the embodiment is as follows:

[0033] (1) Mix the municipal sludge from a sewage treatment plant with a modifier in proportion, and the weight of the modifier is 10% of the weight of the dry basis municipal sludge; the modifier is calcium oxide and a flocculant in a weight ratio of 1:1; the flocculant is polyaluminum chloride.

[0034] (2) Pyrolysis under absolute oxygen conditions at 800℃.

[0035] The preparation method is the same as in embodiment 1, and the mix proportion design of AC-10 asphalt mixture is used.

[0036] Embodiment 3

[0037] As a kind of sludge pyrolysis residue modified asphalt mixture of the embodiment of the application, as a kind of sludge pyrolysis residue modified asphalt mixture of the embodiment of the application, the modified asphalt mixture includes the following components by weight, modified sludge pyrolysis residue 70 parts, crushed stone 30 parts, natural sand 15 parts, mineral powder 30 parts, base asphalt 14.5 parts.

[0038] The preparation method of the modified sludge pyrolysis residue used in the embodiment is as follows:

[0039] (1) Mix the municipal sludge from a sewage treatment plant with a modifier in proportion, and the weight of the modifier is 10% of the weight of the dry basis municipal sludge; the modifier is calcium oxide and a flocculant in a weight ratio of 3:2; the flocculant is a mixture of polyacrylamide and aluminum chloride in a mass ratio.

[0040] (2) Pyrolysis under 600℃ in the absence of oxygen.

[0041] The preparation method is the same as that in Example 1, and the proportioning design of the AC-10 asphalt mixture is used.

[0042] Comparative Example 1

[0043] As a sludge pyrolysis residue modified asphalt mixture of the present application, the only difference between this comparative example and Example 1 is that the modified sludge pyrolysis residue is replaced by mineral powder.

[0044] Specifically, the modified asphalt mixture comprises the following components in parts by weight: 20 parts of macadam, 5 parts of natural sand, 100 parts of mineral powder, and 6 parts of asphalt.

[0045] Comparative Example 2

[0046] As a sludge pyrolysis residue modified asphalt mixture of the present application, the only difference between this comparative example and Example 1 is that the modified sludge pyrolysis residue is replaced by dried sludge.

[0047] The preparation method of the dried sludge is as follows: the municipal sludge from a sewage treatment plant is dried at 105℃ for 2 hours to obtain dried sludge.

[0048] Specifically, the modified asphalt mixture comprises the following components in parts by weight: 50 parts of modified sludge pyrolysis residue, 20 parts of macadam, 5 parts of natural sand, 50 parts of mineral powder, and 6 parts of asphalt.

[0049] I. Experimental Methods

[0050] The T0719-2011 asphalt mixture rutting test according to the “Highway Engineering Asphalt and Asphalt Mixture Test Procedures” (JTG E20-2011) is used for testing, and the Marshall test piece and the rutting plate test piece are pressed by the compaction method and the wheel rolling method, respectively.

[0051] II. Raw Materials

[0052] 1. Asphalt

[0053] The asphalt binder used is 70# base asphalt, and the technical indicators thereof are mainly shown in Table 1.

[0054] Table 1 Technical Performance Indicators of Asphalt

[0055]

[0056] 2. Macadam

[0057] The broken stone is diorite, and the test range is required to be in accordance with the provisions of 4.8 of the Technical Specification for Construction of Highway Asphalt Pavement JTG F40-2004, the coarse aggregate should meet the technical index requirements in the design specification, the test procedure is in accordance with the provisions of the Test Code for Highway Engineering Aggregate JTG E42-2005, and the specific performance index is shown in Table 2.

[0058]

[0059] 3. Natural sand

[0060] According to the provisions of 4.9 of the Technical Specification for Construction of Highway Asphalt Pavement JTG F40-2004, the natural sand should meet the technical index requirements in the design specification, the test procedure is in accordance with the provisions of the Test Code for Highway Engineering Aggregate JTG E42-2005, and the specific performance index is shown in Table 3.

[0061] Table 3 Results of basic performance index of natural sand

[0062]

[0063] 4. Mineral powder

[0064] The mineral powder is limestone powder, and the test is required to be in accordance with the provisions of 4.10 of the Technical Specification for Construction of Highway Asphalt Pavement JTG F40-2004, the mineral powder should meet the technical index requirements in the design specification, the test procedure is in accordance with the provisions of the Test Code for Highway Engineering Aggregate JTG E42-2005, and the specific performance index is shown in Table 4.

[0065] Table 4 Results of basic performance index of mineral powder

[0066]

[0067]

[0068] III. Rutting test

[0069] The rutting test is tested according to the T0719-2011 asphalt mixture rutting test of the Test Code for Highway Engineering Asphalt and Asphalt Mixture (JTG E20-2011). The test temperature is 60 DEG C, and the wheel pressure is 0.7 MPa. The deformation amounts d1 and d2 of the rutting plate at 45 min and 60 min are respectively obtained through the instrument, and the dynamic stability DS is calculated according to the following formula. The rutting test is the most important index in the performance detection of the asphalt mixture, and the dynamic stability can better reflect the ability of the asphalt pavement to resist permanent deformation in the high-temperature season. The rutting test instrument is

[0070]

[0071] DS = Dynamic Stability of the asphalt mixture (cycles / mm)

[0072] d1 = deformation at time t1 (mm);

[0073] d2 = deformation at time t2 (mm);

[0074] C1 = Machine Type Coefficient, 1.0 for crank and lever drive with load wheel in reciprocating mode;

[0075] C2 = Test Piece Coefficient, 1.0 for test pieces prepared in the laboratory with a width of 300 mm;

[0076] N = Number of passes of the test wheel, usually 42 passes / min.

[0077] The results of the dynamic stability test for the modified asphalt mixtures are shown in Table 1

[0078] Table 1 Dynamic Stability of the modified asphalt mixtures

[0079] Sample Dynamic stability DS (mm-1) Example 1 4895.0 Example 2 4157.6 Example 3 4988.3 Comparative Example 1 3654.6 Comparative Example 2 2763.5

[0080] Finally, it should be noted that the above examples are merely intended to illustrate the technical solutions of the present application and not to limit the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application.

Claims

1. A sludge pyrolysis residue modified asphalt mixture, characterized in that, The modified asphalt mixture comprises the following components in parts by weight: 30-70 parts modified sludge pyrolysis residue, 10-30 parts crushed stone, 5-15 parts natural sand, 30-70 parts mineral powder, and 3.75-14.5 parts asphalt. The preparation method of the modified sludge pyrolysis residue includes the following steps: mixing municipal sludge and a modifier in a certain proportion, and pyrolyzing under high temperature and oxygen-free conditions of 500~800℃; the proportion of municipal sludge to modifier is: the weight of the modifier is 6%~15% of the weight of dry municipal sludge; the modifier is calcium oxide and flocculant; the flocculant is polyacrylamide and aluminum chloride.

2. The sludge pyrolysis residue modified asphalt mixture according to claim 1, characterized in that, The asphalt accounts for 3% to 10% of the weight of the sludge pyrolysis residue modified asphalt mixture.

3. The sludge pyrolysis residue modified asphalt mixture according to claim 1, characterized in that, The weight ratio of the modified sludge pyrolysis residue to the mineral powder is 1:(0.5~2).

4. The sludge pyrolysis residue modified asphalt mixture according to claim 1, characterized in that, The modified asphalt mixture made from sludge pyrolysis residue adopts an AC-10 or AC-13 gradation.

5. The sludge pyrolysis residue modified asphalt mixture according to claim 1, characterized in that, In the method for preparing modified sludge pyrolysis residue, the urban sludge is at least one of sewage treatment plant sludge or water purification plant sludge.

6. The sludge pyrolysis residue modified asphalt mixture according to claim 1, characterized in that, The preparation method of the sludge pyrolysis residue modified asphalt mixture includes the following steps: (1) At 170~180℃, according to the Marshall mix design, the dehydrated crushed stone and natural sand are mixed for 1~3 minutes and then added to the molten asphalt at 170~180℃ and stirred. (2) While stirring, add the sludge pyrolysis residue and mineral powder that have been heated to remove moisture, until they are evenly mixed.

7. The sludge pyrolysis residue modified asphalt mixture according to claim 6, characterized in that, The method for removing moisture in step (1) is to heat to 105~110℃; the method for removing moisture from sludge pyrolysis residue and mineral powder in step (2) is to heat to 105~110℃.

8. The method for preparing sludge pyrolysis residue modified asphalt mixture as described in any one of claims 1-5, characterized in that, The preparation method includes the following steps: (1) At 170~180℃, according to the Marshall mix design, the dehydrated crushed stone and natural sand are mixed for 1~3 minutes and then added to the molten asphalt at 170~180℃ and stirred. (2) While stirring, add the sludge pyrolysis residue and mineral powder that have been heated to remove moisture, until they are evenly mixed.

9. The method for preparing sludge pyrolysis residue modified asphalt mixture according to claim 8, characterized in that, The method for removing moisture in step (1) is to heat to 105~110℃; the method for removing moisture from sludge pyrolysis residue and mineral powder in step (2) is to heat to 105~110℃.

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