High-temperature-resistant and rutting-resistant asphalt pavement and construction method thereof

Abstract

The present application relates to the field of traffic engineering technology and specifically discloses a high-temperature resistant and rutting-resistant asphalt pavement and a construction method thereof. The high-temperature resistant and rutting-resistant asphalt pavement is paved with an asphalt mixture comprising the following components by weight: 160-180 parts of base asphalt, 1280-1340 parts of modified aggregate, and 100-120 parts of filler. The modified aggregate is granite gravel coated with a cement stone shell, which is a hardened product of cement slurry. In asphalt pavements paved using the asphalt mixture of the present application, the asphalt has a good adhesion effect on the modified aggregate, thereby improving the high-temperature deformation resistance and helping to improve the anti-rutting effect of the asphalt pavement.

Description

Technical Field

[0001] The present application relates to the field of traffic engineering technology, and more specifically, to a high-temperature resistant and rutting-resistant asphalt pavement and a construction method thereof. Background Art

[0002] Asphalt pavement refers to various types of pavement constructed by mixing road asphalt with mineral materials. It is widely used in my country's highway construction. While the widespread construction of asphalt pavement provides convenient transportation, it also places enormous pressure on road maintenance. To minimize road maintenance costs, it is necessary to extend the service life of asphalt pavement.

[0003] In the related art, there is an asphalt pavement paved with an asphalt mixture, wherein the asphalt mixture comprises the following components in parts by weight: 160-180 parts of base asphalt, 1280-1340 parts of crushed stone aggregate, and 100-120 parts of filler; the crushed stone aggregate is granite crushed stone.

[0004] Regarding the aforementioned related technologies, the inventors believe that in areas of southern my country rich in acidic stone, sourcing non-acidic stone from distant sources is difficult due to supply and cost constraints. Granite gravel, an acidic stone, exhibits poor adhesion to asphalt. If asphalt pavement construction using the solutions described in these technologies were carried out locally, it would likely lead to rutting during summer service due to vehicle loads, making it difficult to fully achieve high-temperature stability. Summary of the Invention

[0005] In the related art, the adhesion between granite crushed stone and asphalt is poor, which easily leads to rutting of the asphalt pavement due to vehicle load during summer service, which is not conducive to fully improving the high-temperature stability of the asphalt pavement. To improve this defect, this application provides a high-temperature resistant and rutting-resistant asphalt pavement and its construction method.

[0006] In a first aspect, the present application provides a high temperature resistant and rutting resistant asphalt pavement, which adopts the following technical solution:

[0007] A high-temperature resistant and rutting-resistant asphalt pavement is paved with an asphalt mixture. The asphalt mixture includes the following components in parts by weight: 160-180 parts of base asphalt, 1280-1340 parts of modified aggregate, and 100-120 parts of filler. The modified aggregate is granite gravel coated with a cement stone shell layer. The cement stone shell layer is a hardened product of cement slurry. The components of the cement slurry include silicate cement, petroleum sulfonate air-entraining agent, and water. The water-cement ratio of the cement slurry is 0.35-0.45.

[0008] By adopting the above technical solution, the present application coated the surface of granite crushed stone with a cement shell layer to obtain a modified aggregate. In the cement slurry of the present application, the petroleum sulfonate air-entraining agent increases the number of pores on the surface of the cement shell layer through air entrainment, thereby increasing the contact area between the modified aggregate and the asphalt. Furthermore, the petroleum sulfonate air-entraining agent is itself made from the sulfonation products of petroleum distillates, and therefore has good compatibility with asphalt, which is also a petroleum distillate, facilitating sufficient contact between the asphalt and the modified aggregate. In the cement shell layer on the surface of the modified aggregate, the calcium hydroxide, hydrated calcium silicate, and hydrated calcium sulfoaluminate, etc., produced by cement hydration, are all alkaline minerals. The alkaline minerals in the cement shell layer easily bond to both the acidic granite and the asphalt, resulting in good adhesion of the asphalt to the modified aggregate. The adhesion effect of asphalt to aggregate has a certain contribution to the high-temperature deformation resistance of asphalt. Therefore, as the adhesion effect of asphalt to aggregate improves, the high-temperature deformation resistance of asphalt mixture is also improved, which helps to improve the anti-rutting effect of asphalt pavement.

[0009] Preferably, in the cement slurry, the amount of petroleum sulfonate air entraining agent is 1.2-1.6% by weight of the Portland cement.

[0010] By adopting the above technical solution, the dosage of the petroleum sulfonate air-entraining agent is optimized, which helps to ensure that the asphalt and the modified aggregate are in contact as fully as possible while saving the petroleum sulfonate air-entraining agent.

[0011] Preferably, the modified aggregate is prepared according to the following method:

[0012] (1) Washing and drying the granite gravel, and setting aside; adding water and petroleum sulfonate air entraining agent to silicate cement and mixing and stirring to obtain cement slurry, and setting aside;

[0013] (2) Mixing cement slurry and granite crushed stones until the cement slurry covers the granite crushed stones, then stirring the mixture of cement slurry and granite crushed stones, and sieving the mixture after stirring until no more cement slurry falls from the sieve to obtain slurry-coated aggregate;

[0014] (3) The coated aggregate is stirred every 5-10 minutes until the cement slurry on the surface of the coated aggregate solidifies, and then the coated aggregate is steam cured to obtain modified aggregate.

[0015] By adopting the above technical solution, the present application first cleans the granite gravel and prepares a cement slurry. The cement slurry is then mixed with the granite gravel, allowing the surface of the granite gravel to contact the cement slurry. The excess cement slurry is then filtered out to obtain a slurry-coated aggregate. Stirring the slurry-coated aggregate every 5-10 minutes can prevent adhesion between the slurry-coated aggregates. After the cement slurry on the surface of the slurry-coated aggregate solidifies, the slurry-coated aggregate is steam-cured to obtain a modified aggregate.

[0016] Preferably, in step (3) of preparing the modified aggregate, an alkaline accelerating agent is added to the coated aggregate while the coated aggregate is turned over.

[0017] By adopting the above technical solution, the alkaline accelerator can react with the cement slurry on the surface of the coated aggregate and introduce new alkaline mineral components into the cement slurry, ultimately obtaining modified aggregate with a higher surface alkaline mineral content, thereby improving the adhesion of asphalt to the modified aggregate, thereby enhancing the high-temperature deformation resistance of the asphalt mixture and improving the rutting resistance of the asphalt pavement.

[0018] Preferably, the components of the alkaline accelerating setting agent include water, sodium hydroxide and sodium metaaluminate.

[0019] By adopting the above technical solution, the composition of the alkaline accelerator is optimized. The alkaline accelerator having this component can be obtained by reacting excess aluminum hydroxide and sodium hydroxide in water. The alkaline accelerator finally obtained is in liquid form. The liquid accelerator has good fluidity and is more convenient to apply on the surface of the coated aggregate than the powder accelerator.

[0020] Preferably, the alkaline quick-setting agent is prepared according to the following method:

[0021] Deionized water, aluminum hydroxide and sodium hydroxide were mixed in a weight ratio of 50:26:24, and heated with stirring at 80-90° C. for 4-5 hours to obtain an alkaline quick-setting agent.

[0022] By adopting the above technical solution, the preparation method of the quick-setting agent and the raw material ratio are optimized, and the alkaline quick-setting agent is obtained by mixing the three raw materials, stirring and heating.

[0023] Preferably, the amount of the alkaline quick-setting agent used is 2.5-4.5% by weight of the granite crushed stone used in step (1) of preparing the modified aggregate.

[0024] By adopting the above technical solution, the dosage of the accelerator is optimized, which helps to fully improve the adhesion of asphalt to the modified aggregate while saving the accelerator, and helps to improve the rutting resistance of the asphalt pavement as much as possible while saving costs.

[0025] Preferably, the filler comprises quartzite powder or limestone powder.

[0026] By adopting the above technical solution, both quartzite powder and limestone powder can be used as fillers in asphalt mixtures. Among them, limestone powder has better heat resistance than quartzite powder, and limestone is an alkaline stone with better bonding effect with asphalt. Therefore, the use of limestone powder as a filler component is more conducive to improving the high-temperature deformation resistance of asphalt mixtures and helping to improve the rutting resistance of asphalt pavement.

[0027] Preferably, the filler further comprises cement stone powder, the mass fraction of the cement stone powder in the filler is 10%, and the cement stone powder is obtained by steam curing and crushing the cement slurry falling from the screen in step (2) of preparing the modified aggregate.

[0028] By adopting the above-mentioned technical solution, the present application cures the cement slurry screened out during the preparation of modified aggregate, and then crushes and grinds it after curing to obtain cement stone powder, thereby achieving cement slurry recycling. Cement stone powder contains a large amount of alkaline minerals. When cement stone powder is added to asphalt mixture as a filler, it can be dispersed in the asphalt slurry, improving the cohesiveness of the asphalt slurry, reducing the possibility of asphalt slipping under load, and helping to enhance the rutting resistance of asphalt pavement.

[0029] In a second aspect, the present application provides a construction method for a high-temperature resistant and rutting-resistant asphalt pavement, which adopts the following technical solution.

[0030] A construction method for a high-temperature resistant and rutting-resistant asphalt pavement comprises the following steps:

[0031] (1) Prepare any of the above-mentioned asphalt mixtures and transport them to the construction site;

[0032] (2) Use paving equipment to spread the asphalt mixture, and manually pave the areas that cannot be covered by the paving equipment;

[0033] (3) After paving, the initial compaction, re-compacting and final compaction treatments are carried out in sequence, and then the paved asphalt mixture is allowed to cool naturally before the construction is completed.

[0034] By adopting the above-mentioned technical solution, the present application first prepares an asphalt mixture, then performs paving and compaction processes, and waits for the asphalt mixture to cool to produce an asphalt pavement. The asphalt mixture in the present application has good bonding properties between the asphalt and the aggregate. Therefore, the asphalt pavement paved with this asphalt mixture has good high-temperature deformation resistance and is less likely to develop rutting due to vehicle loads during summer service, which is beneficial to the long-term service life of the road.

[0035] In summary, this application has the following beneficial effects:

[0036] 1. This application coats the surface of granite crushed stone with a cement shell to produce a modified aggregate, which is then applied to an asphalt mixture. In asphalt pavements constructed using this asphalt mixture, the asphalt exhibits excellent adhesion to the modified aggregate, thereby enhancing its high-temperature deformation resistance and contributing to improved rutting resistance.

[0037] 2. In addition to shortening the time required to prepare the modified aggregate, the alkaline accelerator added in this application can also react with the cement slurry on the surface of the coated aggregate to obtain a modified aggregate with a higher surface alkaline mineral content, which helps to improve the adhesion of asphalt to the modified aggregate and improve the rutting resistance of the asphalt pavement. DETAILED DESCRIPTION

[0038] The present application is further described in detail below with reference to the Examples, Preparation Examples and Comparative Examples. The raw materials involved in the present application can all be obtained commercially.

[0039] Preparation example of modified aggregate

[0040] The following is an explanation using Preparation Example 1.

[0041] Preparation Example 1

[0042] In this preparation example, the cement used was P.O42.5 Portland cement.

[0043] In this preparation example, the modified aggregate was prepared according to the following method:

[0044] (1) Wash and dry the granite gravel, and set aside; add water and petroleum sulfonate air-entraining agent to Portland cement and mix and stir to obtain a cement slurry with a water-cement ratio of 0.35, and set aside; in this step, the petroleum sulfonate air-entraining agent is sodium petroleum sulfonate (CAS#: 68608-26-4), and the amount of the petroleum sulfonate air-entraining agent is 1.0% by weight of the Portland cement;

[0045] (2) Mixing cement slurry and granite crushed stones until the cement slurry covers the granite crushed stones, then stirring the mixture of cement slurry and granite crushed stones, and sieving the mixture after stirring until no more cement slurry falls from the sieve to obtain slurry-coated aggregate;

[0046] (3) The coated aggregates were stirred every 10 minutes to prevent them from sticking to each other until the cement slurry on the surface of the coated aggregates was completely solidified. The coated aggregates were then steam cured for 28 days to obtain modified aggregates.

[0047] The criterion for judging whether the cement slurry on the aggregate surface has solidified is as follows: a portion of the cement slurry that has fallen on the screen is collected and placed in a Vicat test mold. The final setting time is then measured in accordance with the provisions of "GB / T 1346-2011 Test Method for Water Consistency, Setting Time, and Stability of Cement Standard Consistency". After the cement slurry in the test mold reaches final setting, it can be switched to steam curing.

[0048] As shown in Table 1, the difference between Preparation Examples 1-5 is the different water-binder ratios of the cement slurries.

[0049] Table 1 Water-binder ratio of cement slurry

[0050] sample Preparation Example 1 Preparation Example 2 Preparation Example 3 Preparation Example 4 Preparation Example 5 Water-cement ratio 0.35 0.38 0.40 0.42 0.45

[0051] Preparation Example 6

[0052] The difference between this preparation example and preparation example 1 is that in the cement slurry, the percentage of the amount of petroleum sulfonate air-entraining agent used in the weight of silicate cement (hereinafter referred to as the air-entraining agent ratio) is different.

[0053] As shown in Table 2, the difference between Preparation Example 1 and Examples 6-9 is that the proportion of air entraining agent is different.

[0054] Table 2 Proportion of air-entraining agent

[0055] sample Preparation Example 1 Preparation Example 6 Preparation Example 7 Preparation Example 8 Preparation Example 9 Air entraining agent proportion / % 1.0 1.2 1.4 1.6 1.8

[0056] Preparation Example 10

[0057] The difference between this preparation example and preparation example 1 is that in step (3) of preparing the modified aggregate, an alkaline accelerator is added to the accelerator while turning the slurry-coated aggregate. The amount of alkaline accelerator (hereinafter referred to as the accelerator ratio) is 1.5% of the weight of the granite crushed stone used in step (1) of preparing the modified aggregate.

[0058] The alkaline quick-setting admixture is prepared as follows:

[0059] Deionized water, aluminum hydroxide, and sodium hydroxide were mixed in a weight ratio of 50:26:24, and heated with stirring at 85° C. for 4.5 hours to obtain an alkaline quick-setting agent.

[0060] As shown in Table 3, the difference between Examples 10-14 is that the proportion of the accelerating agent is different.

[0061] Table 3 Accelerator proportion

[0062]

[0063] Preparation Example 14 also provides a cement stone powder, which is obtained by steam curing and crushing the cement slurry falling from the screen in step (2) of preparing the modified aggregate. The steam curing conditions and curing time of the cement slurry are the same as those of the slurry-coated aggregate, and the average particle size of the cement stone powder is 50 μm.

[0064] Example

[0065] Examples 1-5

[0066] The following description will be given using Example 1 as an example.

[0067] Example 1

[0068] This embodiment provides an asphalt pavement, which is paved with an asphalt mixture. The asphalt mixture adopts an AC-13 gradation and includes the following components: 160 kg of base asphalt, 1280 kg of modified aggregate, and 100 kg of filler. The modified aggregate is prepared according to the method of Preparation Example 1, and the filler is quartz rock powder with an average particle size of 100 μm.

[0069] In this embodiment, the asphalt pavement is constructed according to the following steps:

[0070] (1) Prepare asphalt mixture with base asphalt, modified aggregate and filler, transport it to the construction site and keep it warm for later use;

[0071] (2) Use paving equipment to spread the asphalt mixture, and manually pave the areas that cannot be covered by the paving equipment;

[0072] (3) After paving, the initial compaction, re-compacting and final compaction treatments are carried out in sequence, and then the paved asphalt mixture is allowed to cool naturally before the construction is completed.

[0073] As shown in Table 4, the differences between Examples 1-5 are mainly in the raw material ratio of the asphalt mixture and the preparation of the modified aggregate.

[0074] Table 4 Asphalt mixture raw material ratio and modified aggregate preparation example

[0075]

[0076] As shown in Table 5, the difference between Examples 6-14 and Example 1 is that the preparation examples of the modified aggregates are different.

[0077] Table 6 Preparation example of modified aggregate

[0078]

[0079]

[0080] Example 15

[0081] The difference between this embodiment and embodiment 14 is that the filler is limestone powder with an average particle size of 100 μm.

[0082] Example 16

[0083] The difference between this embodiment and Example 15 is that the filler is a mixture of cement stone powder and limestone powder in a weight ratio of 1:9, and the cement stone powder is the cement stone powder of Preparation Example 14.

[0084] Comparative Example

[0085] Comparative Example 1

[0086] The difference between this comparative example and Example 1 is that the modified aggregate is replaced by granite crushed stone.

[0087] Comparative Example 2

[0088] The difference between this comparative example and Example 1 is that, when preparing the modified aggregate, the cement slurry used also contains a defoamer, which is Subot GPE-30 polyether defoamer, and the amount of the defoamer is 0.05% of the weight of the silicate cement.

[0089] Comparative Example 3

[0090] This comparative example differs from comparative example 2 in that no petroleum sulfonate air entraining agent is added to the cement slurry when preparing the modified aggregate.

[0091] Performance testing methods

[0092] With reference to "T0703-2011 Asphalt Mixture Specimen Preparation Method (Wheel Rolling Method)" in the "JTG E20-2011 Test Procedure for Asphalt and Asphalt Mixtures for Highway Engineering," the asphalt mixtures of each Example and Comparative Example were prepared into asphalt mixture specimens measuring 300 mm x 300 mm x 50 mm. The dynamic stability of the resulting asphalt mixture specimens was measured with reference to "T0719-2011 Asphalt Mixture Rutting Test" in the "JTG E20-2011 Test Procedure for Asphalt and Asphalt Mixtures for Highway Engineering." The specimen temperature was adjusted to 60°C ± 0.5°C during the measurement. After the measurement, the ratio of the dynamic stability of each Example and Comparative Example to the dynamic stability of Comparative Example 1 was calculated, and this ratio was recorded as the relative dynamic stability. The results are shown in Table 7.

[0093] Table 7 Relative dynamic stability

[0094]

[0095]

[0096] Combining Examples 1-5 and Comparative Example 1 and Table 7, it can be seen that the relative dynamic stability measured in Examples 1-5 is greater than that in Comparative Example 1, indicating that in the asphalt pavement paved using the asphalt mixture of the present application, the asphalt has a good adhesion effect on the modified aggregate, and therefore the high-temperature deformation resistance is improved relative to Comparative Example 1, which helps to improve the anti-rutting effect of the asphalt pavement.

[0097] Combining Example 1, Comparative Example 2 and Table 7, it can be seen that the relative dynamic stability measured in Example 1 is greater than that in Comparative Example 2, indicating that the addition of petroleum sulfonate air-entraining agent to the cement slurry for preparing modified aggregate helps to improve the high-temperature deformation resistance of the asphalt mixture and improves the anti-rutting effect of the asphalt pavement.

[0098] Combining Comparative Examples 2 and 3 with Table 7, it can be seen that even when the defoaming agent inhibits the air-entraining effect, the relative dynamic stability measured in Comparative Example 2 is still greater than that in Comparative Example 3. This indicates that the petroleum sulfonate air-entraining agent not only improves the high-temperature deformation resistance of the asphalt mixture through the air-entraining effect, but also because the petroleum sulfonate air-entraining agent has good compatibility with asphalt, it is conducive to sufficient contact between the asphalt and the modified aggregate. Therefore, even when the air-entraining effect is hindered, the high-temperature deformation resistance of the asphalt mixture can be improved, thereby improving the anti-rutting effect of the asphalt pavement.

[0099] Combining Example 1 with Examples 6-9 and Table 7, it can be seen that the relative dynamic stability measured in Example 6-9 is greater than that in Example 1. Therefore, the implementation of Examples 6-9 is more conducive to improving the anti-rutting performance of asphalt pavement. In Examples 6-9, the increase in relative dynamic stability gradually slows with increasing the proportion of air-entraining agent, and the data of Examples 8-9 are similar. Therefore, when the amount of petroleum sulfonate air-entraining agent is 1.2-1.6% by weight of Portland cement, it helps to achieve the most complete contact between asphalt and modified aggregate while saving petroleum sulfonate air-entraining agent. If the cost of petroleum sulfonate air-entraining agent is not considered, the performance of Example 9 is the best among Examples 1 and Examples 6-9.

[0100] Combining Example 9 with Examples 10-14 and Table 7, it can be seen that the relative dynamic stability measured in Examples 10-14 is greater than that in Example 9, indicating that the addition of the alkaline accelerator prepared in this application improves the high-temperature deformation resistance of the asphalt mixture and improves the anti-rutting effect of the asphalt pavement. In Examples 10-14, as the amount of alkaline accelerator increases, the growth rate of the relative dynamic stability gradually decreases. When the amount of alkaline accelerator used is 2.5-4.5% of the weight of the granite crushed stone used in step (1) of preparing the modified aggregate, it helps to fully improve the adhesion of asphalt to the modified aggregate while saving the accelerator. If the cost of the accelerator is not considered, the amount of alkaline accelerator in Example 14 is most conducive to improving the adhesion of asphalt to the modified aggregate.

[0101] Combining Example 14 and Example 15 with Table 7, it can be seen that the relative dynamic stability measured in Example 15 is greater than that in Example 14, indicating that the heat resistance of limestone powder is better than that of quartzite powder, and limestone is an alkaline stone. Therefore, the bonding effect of limestone powder and asphalt is better, and the use of limestone powder as a filler component is more conducive to improving the rutting resistance of asphalt pavement.

[0102] Combining Example 15 and Example 16 with Table 7, it can be seen that the relative dynamic stability measured in Example 16 is greater than that in Example 15, indicating that in the solution of the present application, when cement stone powder and limestone powder are mixed in a weight ratio of 1:9, the cohesiveness of the asphalt slurry can be improved, the possibility of asphalt sliding under load is reduced, and the anti-rutting performance of the asphalt pavement is enhanced.

[0103] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A high temperature resistant and rutting resistant asphalt pavement, characterized in that: The high-temperature resistant and rutting-resistant asphalt pavement is paved with an asphalt mixture, which includes the following components by weight: 160-180 parts of base asphalt, 1280-1340 parts of modified aggregate, and 100-120 parts of filler. The modified aggregate is granite crushed stone with a cement stone shell layer on the surface. The cement stone shell layer is a hardened product of cement slurry. The components of the cement slurry include silicate cement, petroleum sulfonate air-entraining agent and water. The water-cement ratio of the cement slurry is 0.35-0.

45. The modified aggregate is prepared according to the following method: (1) Wash and dry the granite gravel and set aside; add water and petroleum sulfonate air entraining agent to Portland cement and mix and stir to obtain cement slurry and set aside; (2) Mixing cement slurry and granite crushed stones until the cement slurry covers the granite crushed stones, then stirring the mixture of cement slurry and granite crushed stones. After stirring, sieve the mixture until no more cement slurry falls from the sieve to obtain slurry-coated aggregate; (3) Stirring the coated aggregate every 5-10 minutes until the cement slurry on the surface of the coated aggregate solidifies, and then steam curing the coated aggregate to obtain modified aggregate; in this step, while turning the coated aggregate, an alkaline accelerator is added to the coated aggregate, and the components of the alkaline accelerator include water, sodium hydroxide and sodium metaaluminate; The alkaline quick-setting agent is prepared according to the following method: Deionized water, aluminum hydroxide and sodium hydroxide were mixed in a weight ratio of 50:26:24, and heated with stirring at 80-90° C. for 4-5 hours to obtain an alkaline quick-setting agent.

2. The high temperature resistant and rutting resistant asphalt pavement according to claim 1, characterized in that: In the cement slurry, the amount of petroleum sulfonate air entraining agent is 1.2-1.6% by weight of the Portland cement.

3. The high temperature resistant and rutting resistant asphalt pavement according to claim 1, characterized in that: The amount of the alkaline quick-setting agent used is 2.5-4.5% of the weight of the granite crushed stone used in step (1) of preparing the modified aggregate.

4. The high temperature resistant and rutting resistant asphalt pavement according to claim 1, characterized in that: The filler comprises quartzite powder or limestone powder.

5. The high temperature resistant and rutting resistant asphalt pavement according to claim 4, characterized in that: The filler also includes cement stone powder, the mass fraction of which in the filler is 10%. The cement stone powder is obtained by steam curing and crushing the cement slurry dropped from the screen in step (2) of preparing the modified aggregate.

6. A construction method for a high temperature resistant and rutting resistant asphalt pavement, characterized in that: The following steps are involved: (1) preparing the asphalt mixture according to any one of claims 1 to 5 and transporting it to the construction site; (2) Use paving equipment to spread the asphalt mixture, and manually pave the areas that cannot be covered by the paving equipment; (3) After paving, the initial compaction, re-compacting and final compaction treatments are carried out in sequence, and then the paved asphalt mixture is allowed to cool naturally before the construction is completed.

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