Purchase and price of wholesale Asphalt Pavement Moisture
The workability of an asphalt mixture can be improved by using water-foamed asphalt. It has received a lot of use because of its ability to conserve energy and cut emissions.
what is Asphalt Pavement Moisture?
In this article, we are going to talk about the asphalt pavement moisture dissipation.
Water is needed for making water-foamed asphalt mixtures more workable.
However, thorough research on how moisture evaporates from water-foamed asphalt over time and how it affects workability is still lacking.
This study used an analytical balance and a modified rotational viscometer to measure how the residual water content and rotational viscosity of the water-foamed asphalt changed over time (RV).
The analysis using atomic force microscopy (AFM) was done to talk about how the viscosity of water-foamed asphalt is reduced.
The findings demonstrated that moisture evaporation is greatly impacted by ambient temperature and the amount of foaming water present, which causes variations in the stabilizing time of water-foamed asphalt.
The remaining water in the water-foamed asphalt was less than 0.
01% of the asphalt bulk after stabilization.
The AFM investigation demonstrated that the water-foamed asphalt's viscosity was reduced as a result of the foaming process' altered wax distribution.
The initial foaming water content has a significant impact on the viscosity reduction of asphalt.
The viscosity maintains stability after the foaming process and is unaffected by moisture evaporation.
Due to their advantages in terms of energy conservation and emissions reduction when compared to traditional asphalt (HMA) combinations, warm-mix asphalt (WMA) mixtures have lately acquired appeal on a global scale.
In order to create water-foamed asphalt (also known as foamed asphalt in this paper), hot asphalt is mixed with cold water in an expansion chamber.
Asphalt quickly expands as a result of the cold water is instantly heated and turning into water bubbles.
The viscosity of foamed asphalt greatly drops after foaming, making it easier to work with and allowing for easier coating of the aggregate.
As was already indicated, only a small amount of water is used to create the foam in the water-foamed asphalt.
Comparing this to other WMA methods that use chemicals, it is advantageous not only for environmental conservation but also for the decrease in production costs.
Additionally, under the right foaming conditions, any asphalt, including Trinidad Lake asphalt, crumb rubber modified asphalt, and even epoxy asphalt, can froth.
The efficacy of foamed asphalt binders or combinations has been questioned in several research due to the water's presence in foamed asphalt.
The physical, rheological, and thermal characteristics of foamed WMA were assessed by Guo et al.
under the conditions of freeze-thaw (F-T) cycles.
According to the findings, following F-T cycles, fatigue resistance decreased while thermal stability and high-temperature deformation resistance improved.
According to Liu et alresearch,.
's foamed asphalt in stable state binders performed rheologically similarly to unfoamed asphalt.
Hu et al.
discovered that the total surface free energy and work of the cohesiveness of foamed WMA decreased using the surface free energy method.
As a result, it may be concluded that foamed WMA combinations are more susceptible to moisture degradation than conventional HMA mixtures.
However, the test results from Ali et alstudy.
's showed that raising the foaming water content (FWC) of foamed WMA mixtures to 2.
6% did not appear to have a negative impact on their resistance to moisture damage and rutting.
Foamed asphalt is primarily used to increase the workability of asphalt mixtures in construction.
As a result, a number of researchers have looked specifically at the usability of foamed WMA.
Ali et al.
examined the mixing torque of foamed asphalt and conventional asphalt mixtures using a self-designed and self-fabricated mixing apparatus for asphalt mixtures.
The foamed asphalt mixture is said to be easier to work with than the standard asphalt mixture.
Yin et al.
presented the maximum shear stress and coatability index based on Superpave gyratory compactor (SGC) tests to assess the workability and coatability of foamed WMA mixture, respectively.
According to the test results, foamed WMA had higher workability and coatability than HMA because it included the ideal amount of foamy water.
Asphalt Pavement Moisture properties
Additionally, Hailesilassie discovered that raising the FWC helped in coating aggregates.
By using a ball-on-three-plates apparatus in a tribological experiment, Bairgi looked into the tribological properties of foamed asphalt.
According to the findings, the foaming procedure decreased frictional resistance, which is advantageous for coating during mixing and sliding ability between particles during compaction of asphalt mixtures.
In most cases, viscosity is utilized to assess the rheological qualities of asphalt.
The rotational viscosity of asphalt binders at high temperatures as measured by a Brookfield viscometer has a direct association with the workability of the asphalt mixture.
However, because of the volume change of the asphalt and the interference from the water bubbles, it is challenging to determine the viscosity of foamed asphalt reliably using the conventional RV test.
Jenkins used a hand-held viscometer to measure the viscosity of foamed asphalt to determine its workability.
Inspired by the conventional tar viscometer, Sri Sunarjono et al.
evaluated the flow rate of foamed asphalt to determine its viscosity.
The findings demonstrated that when the foam started to dissipate, the viscosity of foamed asphalt increased.
However, since no attemperator was utilized throughout the entire test, it is challenging to demonstrate that the drop in viscosity is caused by water evaporation.
The viscosity of foamed asphalt may also increase as temperature drops.
The foamed asphalt has a lower apparent viscosity than the original asphalt when subjected to high shear rates using DSR equipment.
Although the workability of foamed WMA has been thoroughly explored, the ongoing evaporation of moisture after foaming and its impact on the viscosity of foamed asphalt has not yet been thoroughly investigated.
This study used an analytical balance to examine how foamed asphalt's moisture dissipated.
The modified standard RV was used to gauge the viscosity of foamed asphalt.
The relationship between the moisture dissipation and viscosity of foamed asphalt was studied in light of the results of residual water content and viscosity.
In addition, the microstructure of foamed asphalt was discovered using atomic force microscopy (AFM).
The mechanism of asphalt viscosity reduction following foaming was covered in a study of the AFM results.
The findings demonstrated that temperature and FWC considerably affect how long foamed asphalt takes to stabilize.
The viscosity of foam asphalt is lower than that of original asphalt.
how can you buy Asphalt Pavement Moisture
Although the residual water content of the asphalt does not affect the viscosity reduction of the asphalt binder during moisture dissipation, it is closely related to FWC in the foaming process.
This might be because the process of foaming encourages the spread of wax molecules in asphalt and lessens internal molecular friction.
This study is anticipated to offer recommendations for applying foamed WMA technology in engineering procedures based on the data collected.
To determine if an asphalt mixture is workable, the rotational viscosity (RV) of asphalt has frequently been used.
The mixing and compaction temperatures for the asphalt mixture could be established using the RV test findings.
The uneven and unstable bubbles between the spindle and inner wall of the viscometer cup would interfere with the foamed asphalt's stress response during the RV test, making the typical RV test inappropriate for foamed asphalt.
In addition, when the spindle rotated, the foamed asphalt would spill out of the sample container.
The RV test apparatus was altered to measure the viscosity of foamed asphalt in order to address the issues noted above.
To increase the distance between the spindle and inner wall, an iron jar with a 40 mm radius (Rb = 40 mm) was chosen in place of the typical viscometer cup.
As a result, the disruptions caused by the volume shift and water bubbles could be minimized.
At 140 °C, the viscosity test data were recorded every 9 s.
It employed a conventional spindle (21#, Ra = 8.
35 mm), which rotated at a speed of 50 rpm.
The testing lasted for two hours, and real-time data were automatically captured.
Through a sharp point probing the sample at micro or nano scales, the atomic force microscope (AFM) has frequently been used to examine the microstructure and mechanical properties.
In this study, the foamed asphalt underwent an AFM investigation to determine the cause of viscosity reduction.
Used as the AFM apparatus (Dimension Edge, Bruker, Germany).
The probe's silicon-coated tip has an 8 nm radius and a height of 1015 m.
These tips were held in place by a cantilever with a spring constant of 40 N/m and a drive frequency of 300 kHz.
Four spots were found in the tapping mode for each sample.
The software packages NanoScope Analysis and Image-pro Plus (IPP) was used to process the acquired scanning pictures.
For 105 and 210 minutes, respectively, the foamed asphalt samples containing 3% FWC were held in a preheated oven at 140 °C.
For comparison, the original asphalt sample was also examined.
The preparation of the AFM samples followed the procedures outlined by Qtaish et al.
A square area was created by placing four 20 mm long strips of heat-resistant tape on top of a cleaned glass slide.
The asphalt binder was injected with a syringe into the square area in an amount of around 0.2 mL.
The glass slide was then held in a low-temperature oven while the asphalt binder spread throughout the square area to a constant thickness.
The glass slide was cooled to room temperature after 4–6 minutes.
The heat-resistant adhesives were taken off the glass slide after cooling.
The residual water content of the foamed asphalt mixture can change greatly depending on the fluctuation of construction parameters, such as mixing temperature and transportation duration, in engineering practice when utilizing foaming technology to make WMA.
The results attained are helpful in directing the creation of the foamed asphalt mixture.
For instance, if the FWC is 1%, at least 120 minutes must pass between in-plant production and in-field paving.
If not, a sizable amount of water would continue to mix with the asphalt, causing moisture damage to the surface.
The number of bee structures increased in a particular region for the foamed asphalt, though each bee structure was smaller and distributed more evenly.
The quantity and average area of the bee structure in foamed asphalt do not significantly alter when moisture evaporates (105 to 210 min after foaming).
The development of bee structure is comparable to the development of asphalt foam's viscosity.
According to the bee structure results, the use of foaming technology causes the bee structures to break and disperse more extensively in the asphalt binder.
The water totally evaporates, but this is an irreversible process.
Numerous investigations have demonstrated the role of crystalline wax in the construction of bee structures.
It may be inferred from the variation in bee structural parameters that the foaming process may facilitate wax molecule distribution within the asphalt binder and lessen internal molecular friction.
The viscosity of foamed asphalt is likely lower for this reason compared to the original asphalt, and this will not alter as the moisture evaporates.
Future research will focus on the relationship between the parameters of the bee structure and the viscosity of asphalt as well as the method by which wax distribution is improved by the foaming process.
Through the use of modified RV tests, the impact of moisture loss from foamed asphalt on viscosity was examined in this study.
The findings of the AFM test were examined to determine the mechanism of viscosity reduction.
The following are the primary conclusions:
The exponential equation is suggested to characterize the remaining water content of foamed asphalt during the moisture dissipation process.
The preservation temperature and FWC significantly affect the stabilizing time for foamed asphalt.
The interval between in-plant mixing and in-field paving can be calculated based on the stabilizing time.
Foamed asphalt that has been stabilized has a residual water content that is less than 0.
01% of the asphalt bulk.
The viscosity of the foamed asphalt can be measured using the modified RV.
Although the residual water content of the asphalt does not affect the viscosity reduction of the asphalt binder during moisture dissipation, it is closely related to FWC in the foaming process.
The ability of the foamed asphalt mixture to maintain good workability (construction temperature dropped by more than 20 °C) throughout the entire construction process can be explained in light of this in a logical manner.
According to the AFM findings, the foamed asphalt's bee structure shrinks and displays a homogeneous dispersion as opposed to the original asphalt.
It is obvious that the act of foaming encourages the spread of wax molecules in asphalt and lessens internal molecular friction, which lowers viscosity.
read more:
Asphalt Pavement
asphalt cement
recycled asphalt
asphalt powder
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