CN111574133B

CN111574133B - Cement-stabilized macadam base material, preparation method thereof and asphalt pavement

Info

Publication number: CN111574133B
Application number: CN202010581711.8A
Authority: CN
Inventors: 胡乐乐; 张苏龙; 王鹏; 陈广辉; 李华; 王捷; 毛益佳; 张仁豪; 王彤
Original assignee: Jiangsu Dongjiao Intelligent Control Technology Group Co ltd
Current assignee: Jiangsu Dongjiao Intelligent Control Technology Group Co ltd
Priority date: 2020-06-23
Filing date: 2020-06-23
Publication date: 2022-01-28
Anticipated expiration: 2040-06-23
Also published as: CN111574133A

Abstract

The invention discloses a cement stabilized macadam base material, a preparation method thereof and an asphalt pavement, and relates to the technical field of building materials. The raw materials of the cement stabilized macadam base material comprise 70-85 parts of aggregate, 4-5.5 parts of cement, 15-30 parts of regenerated fine aggregate and 4-5.5 parts of water; wherein the regenerated fine aggregate is powder with the particle size of 0-3mm obtained by separating asphalt pavement milling materials by oilstone. The preparation method of the cement stabilized macadam base material comprises the steps of mixing the raw materials of the cement stabilized macadam base material, utilizing the regenerated fine aggregate obtained by oil separation to obviously improve the crack resistance of the cement stabilized macadam, and enabling the asphalt pavement paved with the prepared cement stabilized macadam to have good crack resistance.

Description

Cement-stabilized macadam base material, preparation method thereof and asphalt pavement

Technical Field

The invention relates to the technical field of building materials, in particular to a cement stabilized macadam base material, a preparation method thereof and an asphalt pavement.

Background

The oil-stone separation technology is a novel pavement regeneration method appearing in recent years, and the aggregate in the waste asphalt pavement milling and planing material (RAP) can be separated from aged asphalt by adopting the existing waste asphalt mixture separation and regeneration processing equipment, so that the aggregate can be regenerated into 10-15mm, 5-10mm and 3-5mm clean aggregate and 0-3mm fine RAP powder, wherein the aggregate with a clean surface of more than 3mm can be applied to the asphalt mixture as the new aggregate, but the 0-3mm fine RAP powder is difficult to apply to the regenerated asphalt mixture due to higher asphalt content (usually more than 15 percent), and resource waste is caused.

In view of this, the present application is presented.

Disclosure of Invention

The invention aims to provide a cement stabilized macadam base material which utilizes fine RAP powder as a raw material and improves the crack resistance of cement stabilized macadam.

The invention also aims to provide a preparation method of the cement stabilized macadam base material, which is low in cost and excellent in crack resistance of the prepared cement stabilized macadam.

The third purpose of the invention is to provide an asphalt pavement, which comprises a material layer formed by paving the cement-stabilized macadam base material.

The technical problem to be solved by the invention is realized by adopting the following technical scheme.

The invention provides a cement stabilized macadam base material, which comprises the following raw materials of 70-85 parts of aggregate, 4-5.5 parts of cement, 15-30 parts of regenerated fine aggregate and 4-5.5 parts of water;

wherein the regenerated fine aggregate is powder with the particle size of 0-3mm obtained by separating asphalt pavement milling materials by oilstone.

The invention also provides a preparation method of the cement stabilized macadam base material, which comprises the following steps: mixing the raw materials of the cement stabilized macadam base material.

The invention also provides an asphalt pavement, which comprises a material layer formed by paving the cement-stabilized macadam base material or the cement-stabilized macadam base material prepared by the preparation method.

The embodiment of the invention provides a cement stabilized macadam base material which has the beneficial effects that: the powder with the particle size of 0-3mm obtained by separating asphalt pavement milling materials from oilstone is used as a raw material, and aggregate, cement and water are used as raw materials of a cement stabilized macadam base material, so that the crack resistance of the cement stabilized macadam is further improved by optimizing the using amount of each component.

The embodiment of the invention also provides a preparation method of the cement stabilized macadam base material, which is characterized in that the raw materials of the cement stabilized macadam base material are mixed, the crack resistance of the cement stabilized macadam is obviously improved by using the regenerated fine aggregate obtained by oil separation, and the asphalt pavement paved with the prepared cement stabilized macadam has good crack resistance.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic view of a separation-type regeneration apparatus used in the example of the present invention;

FIG. 2 shows the regenerated fine aggregate of 0-3mm after the oil-stone separation process.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The cement stabilized macadam base material, the preparation method thereof and the asphalt pavement provided by the embodiment of the invention are specifically explained below.

The cement stabilized macadam takes macadam with certain gradation as aggregate, adopts a certain amount of cementing materials (such as cement, fly ash and the like) and water to form mortar for filling gaps of the aggregate, and is paved and compacted according to the embedding and extruding principle, the compactness of the macadam is close to the compactness, the strength mainly depends on the embedding and extruding locking principle among the macadams, and meanwhile, enough mortar volume is provided for filling the gaps of the aggregate. The asphalt pavement has high initial strength, and the strength is increased along with the age and is quickly formed into a plate body, so that the asphalt pavement has the advantages of high strength, good impermeability and good frost resistance, and is a base layer structure which is most applied to asphalt pavements in China.

The traditional cement stabilized macadam can generate reflection cracks on the road surface due to temperature shrinkage and drying shrinkage, the durability of the road surface is seriously affected, and the improvement of the crack resistance of the cement stabilized macadam is one of the important difficulties of the research of the road industry for a long time.

The embodiment of the invention provides a cement stabilized macadam base material which comprises the following raw materials of 70-85 parts of aggregate, 4-5.5 parts of cement, 15-30 parts of regenerated fine aggregate and 4-5.5 parts of water; wherein the regenerated fine aggregate is powder with the particle size of 0-3mm obtained by separating asphalt pavement milling materials by oilstone.

The inventor creatively discovers that powder with the grain diameter of 0-3mm, which is obtained by separating asphalt pavement milling material by oilstone, is applied to the base material of the cement stabilized macadam, and the crack resistance of the cement stabilized macadam can be obviously improved by improving the using amounts of aggregate, cement, regenerated fine aggregate and water. The reason is probably that the addition of the fine RAP material can be used as an elastic filling material, and the cement stabilized macadam can be endowed with better crack resistance, inhibit the generation of reflection cracks and prolong the durability of the pavement on the premise of ensuring the strength of the material.

The raw material formula of the cement stabilized macadam base material provided by the embodiment of the invention is used for recycling the waste material (fine RAP material) which is difficult to utilize, the cost of the raw material is low, the resource recycling is realized, and the popularization value is good.

Specifically, the embodiment of the invention uses a mobile waste asphalt milling material regeneration device produced by Jiangsu Tiannuo new material science and technology GmbH to process and obtain the asphalt pavement milling material.

Specifically, as shown in fig. 1-2, the oilstone separation process in the embodiment of the present invention is to apply a separation type regeneration device in patent No. 201810556402.8 (an asphalt recycled material aggregate regeneration device and method) to perform dry oilstone separation on RAP of an asphalt pavement, where the original pavement can be a mixture of SMA-13, SUP-13, AC-13, SUP-20, AC-20, SUP-25, AC-25, and the like of a lower, middle, and upper layer, and obtain 5-grade materials of clean aggregate of 15mm or more, 10-15mm, 5-10mm, 3-5mm, and fine RAP of 0-3mm, and the present application mainly applies fine RAP of 0-3mm grade.

In order to further improve the crack resistance of the material, the inventor further optimizes the dosage of each component in the raw materials. Preferably, the raw materials comprise 75 to 80 parts of aggregate, 4.5 to 5.0 parts of cement, 20 to 25 parts of regenerated fine aggregate and 4.5 to 5.0 parts of water; the content of aged asphalt in the regenerated fine aggregate is 15-30%.

Further, the aggregate is at least one of limestone aggregate, basalt aggregate and regenerated coarse aggregate, wherein the regenerated coarse aggregate is aggregate with the particle size of more than 3mm obtained by separating asphalt pavement milling material by oilstone; can be single new limestone aggregate or single new basalt aggregate or single regenerated coarse aggregate, and can also be a mixture of the three.

In some embodiments, the aggregate is an aggregate with a particle size of more than 3mm obtained by separating asphalt pavement milling materials by oilstone, and the aggregate can be used as a new aggregate due to low content of aged asphalt, so that the raw material cost can be further reduced. Specifically, the type of the asphalt mixture corresponding to the asphalt pavement milling material is selected from at least one of SMA-13, SUP-13, AC-13, SUP-20, AC-20, SUP-25 and AC-25. The milled material of the asphalt pavement can be waste material obtained by processing the asphalt mixtures of the above types by a milling machine.

In some embodiments, the mixture of aggregate and fine aggregate has a particle size in the range of 0 to 3mm in the range of 15 to 25%, in the range of 3 to 5mm in the range of 5 to 15%, in the range of 5 to 10mm in the range of 10 to 20%, in the range of 10 to 20mm in the range of 20 to 30%, and in the range of 20 to 30% in the range of 15 to 30% by weight. The inventor further regulates and controls the particle size range and the corresponding proportion of the aggregate and the fine aggregate, and can further improve the crack resistance and other comprehensive properties of the cement stabilized macadam base material.

Further, the initial setting time of the cement is more than or equal to 3 hours, and the final setting time is more than or equal to 6 hours; preferably, the cement is selected from the group consisting of grade 42.5 set retarding cements and above. The adoption of the retarded cement is beneficial to improving the strength and the service life of the material.

In some preferred embodiments, the raw materials further comprise additives, and the dosage ratio of the additives to the cement is 0.5-1.5:100, and the addition of the additives can further improve the crack resistance and the strength of the material. The additive is at least one selected from polycarboxylate superplasticizer, super absorbent resin and early strength agent, wherein the main component of the super absorbent resin (SAP) is polyacrylamide. The early strength agent is selected from at least one of nitrite, chromate, triethanolamine, calcium formate and urea to further improve the early strength performance of the material.

The embodiment of the invention also provides a preparation method of the cement stabilized macadam base material, which comprises the following steps: the raw materials of the cement stabilized macadam base material are mixed, and the raw material composition of the cement stabilized macadam base material is optimized, so that the crack resistance of the material is remarkably improved by using the fine RAP powder which is not easy to utilize, and the material has good popularization and application values.

In some preferred embodiments, the raw materials of the cement stabilized macadam base material are mixed in a vibration mixer, the mixing time is 6-11s, the vibration shaft has the amplitude of 0.5-1.5mm, and the rotating speed is 180-220 rad/s. The inventor finds that the cement stabilized macadam can be mixed more uniformly in the mixing process by adopting the vibration stirrer, the agglomeration phenomenon of the cement is effectively prevented, the cement is dispersed in the coarse aggregate more uniformly, the crack resistance of the material can be further improved, and the strength of the material is ensured.

Specifically, the vibration stirring device used in the embodiment of the present invention may be a deutong vibration stirrer, which is a continuous vibration stirring device with two horizontal shafts crossed and recurred, and the continuous stirring system is adopted in the stirring process, as described in application No. 201610681217.2. The inventor finds that the vibration stirring technology is used for forcibly stirring the cement stabilized macadam mixture and simultaneously performing the vibration action, so that the movement speed of the mixture particles is greatly increased, the frequency and the strength of mutual collision among the material particles are increased after the movement speed of the mixture particles is increased, and the cement paste and the regenerated fine aggregate are uniformly attached to the surface of the coarse aggregate after the actions are performed. The process of cement hydration reaction can be increased, the microstructure of the cement stabilized macadam can be improved, the occurrence of segregation phenomenon is reduced, and the uniformity of the water stabilized macadam is improved.

The embodiment of the invention also provides an asphalt pavement, which comprises a material layer paved by the cement stabilized macadam base material or the cement stabilized macadam base material prepared by the preparation method, and has the characteristics of low cost and excellent crack resistance.

Specifically, the cement-stabilized macadam base layer material provided by the embodiment of the invention can be applied to road surface structures such as a roadbed, a 4cm upper surface layer of an SMA-13 asphalt mixture, 6-8cm of a surface layer in a SUP-20 asphalt mixture, 8cm lower surface layer of a SUP-25 asphalt mixture, 36-40cm cement-stabilized macadam base layer doped with 15-20% of RAP fine materials, 18-20cm cement-stabilized macadam base layer doped with 20-25% of RAP fine materials and the like.

The features and properties of the present invention are described in further detail below with reference to examples.

It should be noted that the types of the petroleum separation equipment and the type of the blender in the following examples are described with reference to the specification.

Example 1

The embodiment provides a cement stabilized macadam base material, which comprises the raw materials of 85 parts of limestone aggregate, 4.2 parts of cement, 15 parts of regenerated fine aggregate, 4.5 parts of water and 0.036 part of polyacrylamide type super water-absorbent resin.

Wherein, the regenerated fine aggregate is derived from SMA-13 type mixture; the limestone aggregate and the fine aggregate have the grain diameter of 15 percent in the range of 0-3mm, 15 percent in the range of 3-5mm, 20 percent in the range of 5-10mm, 30 percent in the range of 10-20mm and 20 percent in the range of 20-30 mm; the cement is 42.5-grade retarding cement.

The embodiment also provides a preparation method of the cement stabilized macadam base material, which is characterized in that the raw materials are uniformly mixed by adopting a vibration stirrer, the stirring time is 6s, the amplitude of a vibration shaft is 1.5mm, and the rotating speed is 220 rad/s.

Example 2

The embodiment provides a cement stabilized macadam base material, which comprises 80 parts of basalt aggregate, 4.4 parts of cement, 20 parts of regenerated fine aggregate, 4.6 parts of water and 0.044 part of Subot PCA-I type water reducing agent.

Wherein, the regenerated fine aggregate is derived from SMA-13 type mixture; the proportion of the basalt aggregate and the regenerated fine aggregate in the grain size is 25 percent in the range of 0-3mm, 5 percent in the range of 3-5mm, 10 percent in the range of 5-10mm, 30 percent in the range of 10-20mm and 30 percent in the range of 20-30 mm; the cement is 42.5-grade retarding cement.

The embodiment also provides a preparation method of the cement stabilized macadam base material, which adopts a vibration stirrer to uniformly mix the raw materials, wherein the stirring time is 11s, the amplitude of a vibration shaft is 0.5mm, and the rotating speed is 180 rad/s.

Example 3

The embodiment provides a cement stabilized macadam base material which comprises 75 parts of limestone aggregate, 4.5 parts of cement, 25 parts of regenerated fine aggregate and 4.8 parts of water.

Wherein, the regenerated fine aggregate is derived from SMA-13 type mixture; the limestone aggregate and the regenerated fine aggregate have the grain diameter of 25 percent in the range of 0-3mm, 15 percent in the range of 3-5mm, 20 percent in the range of 5-10mm, 25 percent in the range of 10-20mm and 15 percent in the range of 20-30 mm; the cement is 42.5-grade retarding cement.

The embodiment also provides a preparation method of the cement stabilized macadam base material, which adopts the raw materials for preparation, and the specific method refers to the embodiment 2.

Example 4

The embodiment provides a cement stabilized macadam base material, which comprises 70 parts of aggregate, 5.5 parts of cement, 30 parts of recycled fine aggregate and 5.5 parts of water, wherein the aggregate is aggregate with the particle size of more than 3mm obtained by separating asphalt pavement milling material by oilstone.

Wherein, the regenerated fine aggregate is from a SUP-13 type mixture; the proportion of the grain diameter of the aggregate and the recycled fine aggregate is 10 percent in the range of 0-3mm, 20 percent in the range of 3-5mm, 30 percent in the range of 5-10mm, 15 percent in the range of 10-20mm and 15 percent in the range of 20-30 mm; the cement is 42.5-grade retarding cement.

Comparative example 1

The comparative example provides a cement stabilized macadam base course material, which comprises 75 parts of limestone aggregate, 4.5 parts of cement, 25 parts of common fine RAP and 4.8 parts of water. Namely, on the basis of example 3, the regenerated fine aggregate was replaced with ordinary fine RAP of equal mass, and other raw material parameters were the same as in example 3. Wherein the common fine RAP is fine RAP without an oilstone separation process.

The comparative example also provides a method for preparing a cement stabilized macadam base material, which uses the raw materials for preparation, and the specific method refers to example 2.

Test example 1

The base layer materials prepared in examples 1 to 4 and comparative example 1 were tested for 7d unconfined compressive strength, 28d unconfined compressive strength, average dry shrinkage coefficient, and average temperature shrinkage coefficient, and the results are shown in table 1. The test methods are all from the test regulation of inorganic binder stable materials for highway engineering (JTG E51-2009), the test No. T0805-1994 of unconfined compressive strength, the test T0854-2009 of drying shrinkage and the test T0855-2009 of temperature shrinkage.

Table 1 base material various performance test results

Categories	7d unconfined compressive strength (MPa)	28d confined compressive Strength (MPa)	Average dry shrinkage coefficient (10-6)	Average temperature coefficient (10-6/. degree. C.)
					Example 1	3.82	7.15	165.24	24.74
Example 2	3.66	6.94	136.82	15.68
					Example 3	3.56	6.81	98.25	12.56
Comparative example 1	3.87	7.22	254.88	64.82

As can be seen from the comparison of the strength and the crack resistance of the examples and the comparative examples, the strength of the mixture is reduced to a certain extent with the increase of the fine RAP content, but the dry shrinkage and temperature shrinkage coefficients are greatly reduced, and after the fine RAP content reaches 25%, the dry shrinkage coefficient can be reduced by 60% and the temperature shrinkage coefficient can be reduced by 80%. Therefore, the method can realize the recycling of the RAP material which is difficult to recycle, can also obviously improve the crack resistance of the cement stabilized macadam, and has good popularization and application values.

Test example 2

(1) The materials prepared in example 3 and comparative example 2 were tested for fatigue resistance and tested for fatigue at a stress ratio of 0.7, according to the test protocol for highway engineering inorganic binder stabilizing materials (JTG E51-2009) with the fatigue test number T0856-1994.

Test results show that the fatigue life of the cement stabilized macadam foundation layer using the fine RAP after oil-stone separation can reach 14532 times, while the fatigue life of the cement stabilized macadam foundation layer using the common RAP is improved by 17 times due to 12414 times.

This is probably due to the higher bitumen content in the fine RAP after oilstone separation. According to the results of extraction experiments, taking the common SMA-13 mixture milling material with the upper layer oilstone being 6.0% as an example, after oilstone separation, the asphalt content in the obtained 0-3mm grade fine RAP after oilstone separation can reach 20%, while the asphalt content in the common fine RAP without oilstone separation is only about 8%, and the higher asphalt content can endow the cement stabilized macadam base layer with better elasticity and lower modulus.

(2) The particle size distributions of the reclaimed fine aggregate of example 3 and the ordinary fine RAP of comparative example 1 were tested, and the results are shown in table 2.

The fine RAP powder subjected to oil separation has finer gradation and better construction workability. The gradation of the fine RAP and the common fine RAP after the oilstone separation is shown in the table 2, and as can be seen from the figure, the passing rate of each sieve pore can be improved by 4% -9% after the oilstone separation, which shows that the gradation of the fine RAP is finer after the oilstone separation, so that the phenomenon of powder agglomeration is reduced, the uniformity is better, the mixing in the construction process is more facilitated, and the variability is reduced.

In conclusion, the cement stabilized macadam base material provided by the invention utilizes powder with the particle size of 0-3mm obtained by separating asphalt pavement milling materials from oilstone as a raw material, and aggregates, cement and regenerated fine aggregates as raw materials of the cement stabilized macadam base material, so that the crack resistance of the cement stabilized macadam is further improved by optimizing the use amount of each component.

The invention also provides a preparation method of the cement stabilized macadam base material, which is characterized in that the raw materials of the cement stabilized macadam base material are mixed, the crack resistance of the cement stabilized macadam is obviously improved by using the regenerated fine aggregate obtained by oil separation, and the asphalt pavement paved with the prepared cement stabilized macadam has good crack resistance.

The embodiments described above are some, but not all embodiments of the invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Claims

1. The cement stabilized macadam base material is characterized in that raw materials comprise 75-80 parts of aggregate, 4.5-5.0 parts of cement, 20-25 parts of regenerated fine aggregate and 4.5-5.0 parts of water;

wherein the regenerated fine aggregate is powder with the particle size of 0-3mm obtained by performing oil-stone separation on asphalt pavement milling materials; the content of aged asphalt in the regenerated fine aggregate is 15-30%.

2. The cement stabilized macadam base material as recited in claim 1, wherein said aggregate is at least one of limestone aggregate, basalt aggregate and reclaimed coarse aggregate, wherein said reclaimed coarse aggregate is aggregate having a particle size of more than 3mm obtained by oilstone separation of asphalt road milling material.

3. The cement stabilized macadam base material of claim 2, wherein the asphalt pavement milling material corresponds to an asphalt mix of a type selected from at least one of SMA-13, SUP-13, AC-13, SUP-20, AC-20, SUP-25, and AC-25.

4. The cement stabilized macadam foundation material as claimed in claim 1, wherein the mixture of the aggregate and the recycled fine aggregate has a grain size in the range of 0-3mm in the range of 15-25%, in the range of 3-5mm in the range of 5-15%, in the range of 5-10m in the range of 10-20%, in the range of 10-20mm in the range of 20-30%, and in the range of 20-30mm in the range of 15-30% by mass.

5. The cement stabilized macadam base material as recited in claim 1, wherein the initial setting time of said cement is not less than 3 hours and the final setting time is not less than 6 hours.

6. The cement stabilized macadam base material of claim 1, wherein the cement is selected from the group consisting of grade 42.5 and above set retarding cements.

7. The cement stabilized macadam base material as recited in claim 1, wherein the raw materials further comprise an additive, and the amount ratio of said additive to said cement is 0.5-1.5: 100.

8. The cement stabilized macadam base material of claim 7, wherein the additive is selected from at least one of a polycarboxylate water reducing agent, a super absorbent resin, and an early strength agent.

9. The cement stabilized macadam base material of claim 8, wherein the early strength agent is selected from at least one of nitrite, chromate, triethanolamine, calcium formate, and urea.

10. A preparation method of a cement-stabilized macadam base material is characterized by comprising the following steps: mixing raw materials of the cement stabilized macadam base material according to any one of claims 1 to 9.

11. The method of making a cement stabilized macadam base material of claim 10, comprising: and mixing the raw materials of the cement-stabilized macadam base material in a vibration stirrer.

12. The method as claimed in claim 11, wherein the stirring time is 6-11s, the vibration axis has an amplitude of 0.5-1.5mm, and the rotation speed is 180-220rad/s in the vibration stirrer.

13. An asphalt pavement characterized by comprising a material layer laid with the cement-stabilized macadam base material according to any one of claims 1 to 9 or the cement-stabilized macadam base material produced by the production method according to any one of claims 10 to 12.