CN106904898A - It is a kind of to mix the cement stabilized macadam base material with recovery powders from asphalt plant dirt - Google Patents

Abstract

The invention belongs to field of road, more particularly to a kind of mix the cement stabilized macadam base material with recovery powders from asphalt plant dirt.The technical scheme is that：A kind of to mix the cement stabilized macadam base material with recovery powders from asphalt plant dirt, the material is formulated by cement, recovery powders from asphalt plant dirt, stabilization gravel with certain mass ratio, wherein, cement：Recovery powders from asphalt plant dirt：Stabilization gravel=5：1~5：90~94.Compared with prior art, the beneficial effects of the invention are as follows：Reclaiming dust has certain fineness, effectively can be filled among the microvoid of material, particularly gathers materials and the interface of binder between, so as to improve the microstructure of material, makes it further closely knit, improves performance.

Description

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants

technical field

The invention belongs to the field of road engineering, and in particular relates to a cement-stabilized macadam base material mixed with recovered dust from an asphalt mixing plant.

Background technique

The asphalt mixing plant processes asphalt, stones, binders, etc. into asphalt mixture according to a certain mixing ratio. Among them, asphalt mixing is an important process for the formation of asphalt mixture. In this process, raw materials are transported, conveyed, mixed, Many steps such as heating and stirring generate a lot of dust. Due to the special properties of asphalt, a huge amount of dust particles that seriously pollute the environment are produced, usually with a particle size of less than 0.075mm, which is called recycled dust, or recycled powder for short. The stacking of recycled powder occupies a large area of land, resulting in a reduction in land utilization, and has a more adverse impact on energy production, resource utilization and environmental protection. With the rapid development of road construction, if the recovered dust is not recycled, it will become a major problem affecting sustainable development.

In recent years, the mixing station has adopted the dust removal modes of wind dust removal, wet dust removal and bag dust removal. Due to the wide application of the bag dust removal system, the air quality near the asphalt mixing station has been significantly improved, and the dust recovery situation has been improved. The situation of damaging machinery and equipment, polluting the environment, and endangering people's health has been significantly improved, but how to deal with the recovered dust has become a new problem. According to the data, about 45kg of dust will be recovered per ton of mixture produced, but currently there is no good place for the recycled dust, and there is no way to reduce the cost of disposal. According to the regulations of the environmental protection department, recycled dust cannot be directly piled up, but should be buried for disposal. However, the increase in secondary costs caused by finding landfill sites and handling dust is beyond the budget, and suitable landfill sites are becoming increasingly difficult to find. Therefore, it is imperative to find an effective way to deal with dust.

Cement-stabilized macadam is one of the most commonly used structures for pavement bases. Ordinary cement-stabilized crushed stone materials are mainly composed of large-grained stones in the crushed stones to form a skeleton, stones, cement, and fine aggregates are filled in the gaps formed by the coarse aggregate skeleton, and hardened cement, crushed stones, and fine aggregates The volume of the material is too large to fill in the voids of the mixture. Most of the recycled dust is particles <0.075mm. The use of recycled dust can effectively reduce the void ratio of cement-stabilized gravel. Adding dust as fine aggregate can improve The gradation of the aggregate improves the adaptability of the material to the gradation of the aggregate. Moreover, the formation of cement-stabilized macadam base structure strength is a process from a loose body of a certain specification to a dense skeleton, so the compaction process is very critical. The problem of difficulty in forming the strength of the mixture due to the difficulty of compaction occurs during construction. A proper amount of recycled powder is added to make the coarse aggregate easy to move, the fine aggregate is easier to fill the coarse aggregate, the compacted material is easier to compact, the performance of the cement stabilized gravel is improved, and it is easy to compact during the construction process, which helps construction. The cement macadam mixed with recycled dust can fill in the voids of the mixture and play the role of micro-aggregate, increase the porosity of the cement-stabilized macadam, and enhance the compactness of the mixture. The fine materials in the base material are far from being able to fill the internal pores of the base material. The recycled dust has a certain fineness and can be effectively filled in the gaps of the material, especially between the aggregate and the binder interface, thereby improving the microscopic properties of the material. structure, making it more dense and improving performance. Mixing recycled dust into cement-stabilized gravel can meet the requirements of road performance. Comprehensive utilization of recycled dust mixed into cement-stabilized gravel plays a significant role in protecting the environment. Safety is of great significance to prolonging the service life of the road surface.

Contents of the invention

The purpose of the present invention is to provide a cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants, which solves the problems of unutilized recovered dust and difficulty in molding and compaction caused by the structural voids of the semi-rigid base mix in the prior art. question.

To achieve the above object, the technical solution of the present invention is:

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5:1～5:90～94; Among them, the basic performance of dust recovered from asphalt mixing plants is tested, and its plasticity is guaranteed according to the requirements of "Code for Design of Highway Asphalt Pavement" (JTG D50-2006) The index shall not be greater than 4%, the appearance is free of agglomerates, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm.

As the most preferred solution of the present invention, the mass ratio of the cement, dust recovered from the asphalt mixing plant, and stable crushed stone is 5:3:92.

As one of the preferred schemes of the present invention, the mass ratio of cement, asphalt mixing plant recycled dust and stable gravel is 5:2:93.

As one of the preferred schemes of the present invention, the mass ratio of cement, asphalt mixing plant recycled dust, and stabilized crushed stone is 5:1:94.

As one of the preferred schemes of the present invention, the mass ratio of cement, asphalt mixing plant recycled dust, and stabilized gravel is 5:4:91.

As one of the preferred schemes of the present invention, the mass ratio of cement, asphalt mixing plant recovered dust and stable crushed stone is 5:5:90.

Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTG D50-2006).

Compared with prior art, the beneficial effect of the present invention is:

(1) The content of natural aggregates, especially clean raw stones and crushed stones, is not high enough, the amount of cement added is low, and the fine materials (below 0.075mm) in the base material are far from being able to fill the internal pores of the base material. There are many fine materials in some aggregates, but most of them are clay minerals, light organic matter and mica. These fine particles not only are not conducive to the formation of strength, but also greatly reduce the crack resistance of the base material, and recycled dust has A certain fineness can effectively fill in the micro-voids of the material, especially the interface between the aggregate and the binder, thereby improving the microstructure of the material, making it more dense and improving performance.

(2) Recycled dust is the waste powder produced by the asphalt mixing plant, which is a kind of waste that is harmful to the environment, especially in the Liaoshen area, where the output is huge. The invention is of great significance to the production of energy, the utilization of resources, and environmental protection. It reduces the cost for the construction of asphalt pavement semi-rigid base road engineering in Liaoshen area, promotes the transformation of road development in the whole province to the saving type, and conforms to the construction of resource saving type. and the needs of an environmentally friendly society.

detailed description

In order to make the object, technical solution and advantages of the present invention more clear, the present invention will be further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Example 1

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5:1:94; Among them, the basic performance of the dust recovered from the asphalt mixing plant is tested, and according to the requirements of the "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), the plasticity index is guaranteed to be no greater than 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTG D50-2006).

Example 2

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5:2:93; Among them, the basic performance of the dust recovered from the asphalt mixing plant is tested, and according to the requirements of the "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), the plasticity index is guaranteed to be no greater than 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTG D50-2006).

Example 3

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5:3:92; Among them, the basic performance of dust recovered from asphalt mixing plants is tested, and according to the requirements of "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), its plasticity index shall not be greater than 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTG D50-2006).

Example 4

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5:4:91; Among them, the basic performance of the dust recovered from the asphalt mixing plant is tested, and according to the requirements of the "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), the plasticity index is guaranteed to be no greater than 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTG D50-2006).

Example 5

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5:5:90; Among them, the basic performance of the dust recovered from the asphalt mixing plant is tested, and according to the requirements of the "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), the plasticity index is guaranteed to be no greater than 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTG D50-2006).

Example 6

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5: 4.5: 90.5; Among them, the basic performance of the dust recovered from the asphalt mixing plant is tested, and according to the requirements of the "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), the plasticity index is guaranteed to be no greater than 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTGD50-2006).

Example 7

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5: 3.5: 91.5; Among them, the basic performance of the dust recovered from the asphalt mixing plant is tested, and according to the requirements of the "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), the plasticity index is guaranteed to be no greater than 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTGD50-2006).

Example 8

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5: 2.5: 92.5; Among them, the basic performance of the dust recovered from the asphalt mixing plant is tested, and according to the requirements of the "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), the plasticity index is guaranteed to be no greater than 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTGD50-2006).

Example 9

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5: 1.5: 93.5; Among them, the basic performance of dust recovered from asphalt mixing plants is tested, and according to the requirements of "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), its plasticity index shall not exceed 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTGD50-2006).

Example 10

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5: 1.3: 93.7; Among them, the basic performance of dust recovered from asphalt mixing plants is tested, and according to the requirements of "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), its plasticity index shall not exceed 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTGD50-2006).

Example 11

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5: 1.7: 93.3; Among them, the basic performance of dust recovered from asphalt mixing plants is tested, and according to the requirements of "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), its plasticity index shall not be greater than 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTGD50-2006).

Example 12

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5: 2.3: 92.7; Among them, the basic performance of the dust recovered from the asphalt mixing plant is tested, and according to the requirements of "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), its plasticity index shall not be greater than 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTGD50-2006).

Example 13

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5: 2.7: 92.3; Among them, the basic performance of the dust recovered from the asphalt mixing plant is tested, and according to the requirements of "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), its plasticity index shall not be greater than 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTGD50-2006).

Example 14

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5: 3.3: 91.7; Among them, the basic performance of dust recovered from asphalt mixing plants is tested, and according to the requirements of "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), its plasticity index shall not exceed 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTGD50-2006).

Example 15

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5: 3.7: 91.3; Among them, the basic performance of the dust recovered from the asphalt mixing plant is tested, and according to the requirements of the "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), the plasticity index is guaranteed to be no greater than 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTGD50-2006).

Example 16

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5: 4.3: 90.7; Among them, the basic performance of dust recovered from asphalt mixing plants is tested, and according to the requirements of "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), its plasticity index shall not exceed 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTGD50-2006).

Example 17

A cement-stabilized macadam base material mixed with recycled dust from asphalt mixing plants. The material is prepared from cement, recycled dust from asphalt mixing plants, and stabilized macadam in a certain mass ratio. Among them, cement: recycled from asphalt mixing plants Dust: stabilized crushed stone = 5: 4.7: 90.3; Among them, the basic performance of the dust recovered from the asphalt mixing plant is tested, and according to the requirements of the "Code for Design of Highway Asphalt Pavement" (JTG D50-2006), its plasticity index shall not exceed 4 %, no agglomeration in appearance, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. Wherein, the maximum particle size of the stabilized crushed stone is not greater than 31.5 mm, and the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTGD50-2006).

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Cement: stabilized crushed stone=5:95 cement stabilized crushed stone base material (label is CDM-0) and the cement stabilized gravel base material (label is respectively CDM-1, CDM-2) of the embodiment of the present invention 1～5 gained cement stabilized gravel base material , CDM-3, CDM-4, CDM-5) were subjected to unconfined compression test, compressive modulus of resilience test, dry shrinkage test and temperature shrinkage test. The gradation of the stabilized crushed stone is as follows:

Table 1 Gradation Design of Suspended Dense and Stabilized Crushed Stone Aggregate

Experiment 1: Unconfined Compression Test

According to the "Test Regulations for Inorganic Bonded Stable Materials in Highway Engineering" T0805-1994 Unconfined Compressive Strength Test Method for Inorganic Bonded Stable Materials . According to the above specifications, the cylindrical test piece is made, and the mixture is mixed with the optimum water content obtained from the heavy compaction test and the mix ratio obtained by screening. Since it is a coarse aggregate, the size of the test piece is 150mm in diameter and 150mm in height. 150mm, the number of parallel test pieces is 13. Adopt 7-day standard health preservation, and soak in a water tank with a constant temperature of 20°C and a water surface height 2.5cm higher than the top surface of the specimen for the last 24 hours.

Test operation: Use a universal testing machine to perform a pressure test at a constant speed of 1mm/min. Pressurize until the specimen is destroyed to obtain the maximum pressure that the specimen can withstand, and calculate the unconfined compressive strength of the specimen according to the formula, keep two decimal places for each value, and take the average value.

Experiment 2: Compressive modulus of resilience test

According to the "Test Regulations for Inorganic Bonded Stable Materials in Highway Engineering" T0805-1994 Unconfined Compressive Springback Test Method for Inorganic Bonded Stable Materials, the top surface method was used for the compressive springback test. The process of compressive rebound is the same as that of unconfined compressive strength test, and the test is carried out with the dust content of 0-5% mix ratio, and the number of parallel test pieces for each test is 6. Because the materials we use are crushed stones, we adopt 90 days of curing, and the last 24 hours soak the specimens in water for curing. Take out the specimen soaked in water, dry it with a cloth, put it on the bottom plate of the press, and test the resilience modulus of the specimen with a universal testing machine. The speed of the press is 1mm/min. After the test, read the load Take the average value of the values of the two dial gauges when unloading, and the difference between the two readings when loading and unloading is the rebound deformation of each level of load. Then repeat the process to find the final result.

Experiment 3: Dry shrinkage test

The specimens were prepared according to the specifications. The size of the beam-type specimens selected was 100mm high, 100mm wide, and 300mm long. The number of parallel specimens was 3. In the last 1d, soak the specimen in water for 24h). Dry the surface water of the cured test piece, measure the length and weigh the mass. Then put the test piece vertically on the weighing surface with a flat surface, place the dial gauge after putting it away, and fix the two dial gauges on the top of a test piece at the same time, and observe the placed test piece for 72 hours , the intervals are 2h, 2h, 4h, 4h, 12h, 24h and 24h respectively.

Experiment 4: Temperature shrinkage test

The preparation and curing process of the specimen is the same as that of the drying shrinkage test.

The test operation process is: after the health preservation is over, dry the water on the surface of the test piece after being saturated with water, put the test piece in an oven at 105°C and dry it for 10-12 hours to a constant temperature to ensure that the test piece is dry without free water, and then dry it. Finally, put the specimen in a dry and ventilated place to normal temperature. Attach the 80mm gauge length, 120.01Ω resistance strain gauge to the center of both sides of the beam-type test piece, connect the two strain gauges in series, and then weld the wires. Use the DHDAS dynamic signal acquisition instrument to test the temperature shrinkage strain of the piece. The test starts at a high temperature, and the temperature is lowered once every 10°C. According to the cooling rate requirements, the temperature is kept for 3 hours, and the value is read within 5 minutes before the end of the heat preservation. The temperature range of this test is 30°C to -30°C. When the temperature is high, a constant temperature box is used, and when the temperature is low, a low temperature box is used to control the cooling.

The test data and brief analysis are as follows:

Table 2 7d unconfined compressive strength test values of different dust content

The unconfined compressive test shows that under the same gradation, with the increase of dust content, the 7d unconfined compressive strength generally decreases. However, when the addition amount is less than 3%, it has little effect on the strength, and the minimum strength reaches 3.48MPa, which meets the requirements of medium and heavy traffic; when it exceeds 3%, the strength decreases greatly, and the strength reaches 2.73MPa, which meets the standard of light traffic.

Table 3 Compressive rebound modulus of recycled dust blended with cement-stabilized macadam

The compressive rebound test shows that the decrease in the modulus of compressive resilience below 3% is small, that is, the resistance to deformation is almost the same as that of the basic type, indicating that the dust cement stabilized gravel with a content of less than 3% can meet the road performance requirements. Require.

Table 4 average drying shrinkage strain results

Dust content% 0 1 2 3 4 5 174.36 178.92 182.96 195.34 212.92 220.17 Growth percentage (%) - 2.61 4.93 11.46 19.74 21.51

Table 5 Temperature shrinkage coefficient of dust cement stabilized gravel (10 ^-6 /°C)

The dry shrinkage and temperature shrinkage test shows that the average dry shrinkage strain and temperature shrinkage coefficient of less than 3% cement stabilized macadam mixed with recycled dust are small. If it is used for road paving, the base will not deform violently, causing too much dryness. Shrinkage cracks and temperature shrinkage cracks, and the impact on dry temperature shrinkage when the content exceeds 3% is slightly higher than that of less than 3%.

From the above data, it can be seen that it is feasible to use recycled dust as a fine aggregate for the base. When the amount is less than 3%, the impact on the performance of the base is negligible. When it is greater than 3%, there is a slight impact, but it can still meet the road use requirements. In consideration of dust utilization and road performance, 3% recycled dust is the optimal blending amount. It not only has the ability to resist deformation and shrinkage, which ensures its applicability, but also can utilize as much recycled dust as possible.

In summary, it is feasible to blend 1%-5% recycled dust into cement-stabilized macadam as a roadbed material, while ensuring the best dust utilization rate and road performance at 3% , Structurally improved problems such as gaps and compaction difficulties; Environmentally, the waste utilization of recycled dust reduces the construction cost of semi-rigid base pavement, and for asphalt mixing plants, reducing dust recycling reduces equipment costs, in addition In addition, the use of recycled dust reduces the emission of fine particles, which can bring huge social benefits.

Claims (7)

1. A cement-stabilized crushed stone base material blended with asphalt mixing plant reclaimed dust, characterized in that the material is formulated with a certain mass ratio of cement, asphalt mixed plant reclaimed dust, and stabilized crushed stone, wherein cement : Dust recovered from asphalt mixing plant: stabilized gravel = 5: 1～5: 90～94; among them, the basic performance of dust recovered from asphalt mixing plant is tested, according to "Code for Design of Highway Asphalt Pavement" (JTG D50-2006 ) requirements, to ensure that its plasticity index shall not be greater than 4%, the appearance is free of agglomerates, and the particle size range meets the requirements of 100% less than 0.6mm, 90%-100% less than 0.15mm, and 70-100% less than 0.075mm. 2. a kind of cement-stabilized macadam base material blending asphalt mixing plant reclaimed dust according to claim 1, is characterized in that, the mass ratio of described cement, asphalt mixing plant reclaimed dust, stabilized macadam is 5:3:92. 3. a kind of cement-stabilized crushed stone base material blending asphalt mixing plant reclaimed dust according to claim 1, is characterized in that, described cement, asphalt mixing plant reclaimed dust, the mass ratio of stabilized crushed stone is 5:2:93. 4. a kind of cement-stabilized macadam base material blending asphalt mixing plant reclaimed dust according to claim 1, is characterized in that, the mass ratio of described cement, asphalt mixing plant reclaimed dust, stabilized macadam is 5:1:94. 5. a kind of cement-stabilized crushed stone base material blending asphalt mixing plant reclaimed dust according to claim 1, is characterized in that, described cement, asphalt mixing plant reclaimed dust, the mass ratio of stabilized crushed stone is 5:4:91. 6. a kind of cement-stabilized macadam base material blending asphalt mixing plant reclaimed dust according to claim 1, is characterized in that, the mass ratio of described cement, asphalt mixing plant reclaimed dust, stabilized macadam is 5:5:90. 7. A cement-stabilized gravel base material blended with recovered dust from an asphalt mixing plant according to any one of claims 1 to 6, characterized in that the maximum particle size of the stabilized gravel is not greater than 31.5mm, And the specific grading range meets the requirements for suspended dense cement-stabilized base aggregates in the "Code for Design of Highway Asphalt Pavement" (JTG D50-2006).