Questions related to Asphalt
The cantabro test is generally used in asphalt mixtures, but I would like to open the discussion of its main applications, and variables that could influence its results.
Software preferable for analyzing the effect of additives on moisture susceptibility of asphalt pavement based on aashto t283, retained stability and water boiling results
Suppose I have several asphalt mixes with different temperatures (each mix has a different temperature, ranging from 25 to 100 C). Could I mix them together to produce one large sample and test the mechanical properties of the large sample? Or do I need to keep the temperature of all samples at the same value before mixing them?
As we know, the thermal stress is produced when the surface layer suffers from the constraints of base layer and the boundary conditions of pavement. Many researches focus on the thermal cracking model of asphalt surface layer itself, and also some focus on the thermal cracking spaces model with considering the constraints of base layer. However, if the constraints of boundary exists, the restraint function of base layer will be weakened. Thus, here is the question, which constraints cause the thermal stress first?
What is the difference between the porous asphalt mixture and draining bituminous concrete ??
I have not found too much information on emulsion-prepared mastics.
Optimal preparation procedure (mechanical or manual mixer)?
Water needed for mixing with high filler %?
Filler/asphalt ratios as in traditional mastics?
I am curious to know if there is a way to observe in real-time microcrack formation and healing in asphalt binders. SEM electron beams seem to have sometimes strong enough to melt the binder and flow and may not be able to capture the actual healing.
I designed a multilayer model of flexible pavement with Geocell in Base layer, but it is not showing significant difference in deformation with and without Geocell in PLAXIS 3D.
Young`s modulus (E) and thickness value for different layers are:
Asphalt (BC + DBM)- 2800MPa & 190mm thick
Granular Layer- 400MPa & 510mm thick
Subgrade Layer- 60MPa.
Poisson Ratio for all layer is 0.35
I have simulated 3 layers (asphalt concrete, base course, and subgrade) to determine the temperature in different depths of asphalt pavement. For this aim, a heat load is applied to the surface, however, after completing the job, I see heat is only at the top and in the first row of the mesh. Does anyone know what is the problem in the simulation?
Cold recycling of asphalt pavements using bitumen emulsion
Maybe it is related to the availability of materials used (RAP & WMA), skills/ awareness of RAP-WMA technology or guidelines in producing/ mixing asphalt mixes?
Is the nature of the reaction of asphalt with the polymer alkylation reaction in the presence of Lewis acid or what?
We know that the TERRATEST 5000 BLU is the Light Weight Deflectometer for dynamic plate load test to check compaction quality in earthworks and road constructions.
I am interested in is it possible to assess the strength of asphalt concrete pavements on highways and urban streets using the TERRATEST 5000 BLU (by definition of elastic deflection)?
I am trying to find ASR/ACR potential of micritic limestone when used as a coarse aggregate in asphalt and concrete.
Apart from considering surface texture for pavement maintenance purposes (Pavement condition evaluation etc.), is there any specification used for freshly constructed asphalt concrete (HMA) pavements? If so, what are the specified limits?
I want to use the static pressure method to make an asphalt specimen with a thickness of 50mm. how could I determine the required pressure strength?
FORTA-FI fiber is synthetic fiber (Aramid+ Polyolefin) that plays a major role in pavement performance. Polyolefin has a melting point of about 150ºC. Polyolefin appears to melt as the asphalt mix is mixed and compacted.
Does aramid only participate in strengthening the asphalt mixture?
What is the role of Polyolefin?
i am working on simulating the cracking initiation and propagation using 2D XFEM by ABAQUS using monotonic and repeated loading.
I did two experimental test, fracture test for semi circular asphalt samples under three point load by using constant loading rate of 50/min, i got the load and displacement for test,
the second test, repeated load test by using low load cycle of 15% of fracture load, i got the load, displacement, and horizontal displacement for the SCB sample, the pic of samples and date are attached.
thank you for your time
Can the 'k' & 'c' values be derived analytically using the volumetric data( % aggregate,%binder, %air voids,% PP replaced) for a hot mix design?
In hot mix recycling, "organic rejuvenators" require lower dosages than "petroleum rejuvenators" to decrease the Performance Grade temperature (PG Temp.) of the hot recycled blend.
We are testing binder linear amplitude Sweep
Instrument: Bohlin DSR II.
Asphalt material: ac-20 . Add to filler(conerete)
The results of our test are as shown in the figure, Strain from 0.1% to 30%,but when the strain exceeds 20%, the trend is weird .
The scientific approach is based on experimental tests, carried out on both the mix components (aggregates and bitumen) and porous asphalt. The main test used for the mix design is the Marshall test for stability. Such a test has been widely used in the pavement engineering community, and Asian and European countries; however, some countries, such as the United States, do not anymore rely on such an approach.
I want to enhance tge thermal performance of asphalt and concretes through adding chemicals, what are these chemicals and thier percentages in mixtures?
The difference between HMA and WMA:
Different authorities have defined different temperature ranges for these two types of mixtures. Based on the Illinois Asphalt Pavement Association Scholarship:
* A batch of HMA consists of aggregate and a viscous binding agent and is produced at a temperature range of about 300-350 ° F (149-177 °C).
** A batch of WMA is produced at a temperature range of 50-100 ° F (10-38°C) less than a batch of HMA.
Laboratory Procedural Differences:
HMA is typically produced between 275-350 ° F (135- 177°C); while WMA can be produced 100 degrees lower (38°C).
The HMA mixture should be poured at a specific temperature (greater than 10°C). The WMA mixture is sensitive to temperature changes because they are produced at a lower temperature. Are there special temperature conditions for WMA mixes that have a lower temperature range?
i just want to know the interaction of PPA with asphalt binder and SBS modified asphalt binder??
Goal: Hi My project is about the feasibility of using pre-prepared hot and cold asphalt to repair the pavement around the manholes. I ask my dear researcher to help me if I have experience or information in this field?
for use in asphalt mix as a filler, we need to know the specific gravity in order to use it for air voids calculations
Usually RTFOT instrument is used to measure short term aging for asphaltic binders under standard conditions.
Under what standard conditions, can we use RTFOT instrument to measure long term aging.
I am trying to simulate the moisture damage phenomena in asphalt mixture using abaqus. I am looking for some suggestions and guidelines to define the contact contact between aggregate and asphalt matrix in abaqus.
Hello Dear Sirs.
I'm looking for test method determine the frost resistance on freezing and thawing compacted asphalt concrete mixtures?
Asphalt mixture durability is defined as the ability of compacted asphalt concrete to maintain. its structural integrity throughout its expected service life when exposed to the damaging effects of the environment and traffic loading. Asphalt mixture durability is one of several factors affecting pavement durability, which is defined as the ability of a pavement to retain a satisfactory level of performance over its expected service life without major maintenance.
-What are the indicators used to measure the durability for asphalt mixtures?
- How can improve the durability of asphalt mixtures?
- How can measure the durability of asphalt mixtures?
What is the best method to extract the SBR modified bitumen? The SBR modified asphalt concrete mixture shows a lower passing percentage at 0.075 sieve compared to the control sample with no modification. Is this caused by the SBR binding the smaller sized material and preventing removal during the extraction process?
In the case of a polymeric additive to the asphaltic materials along with the presence of air oxidation, what is the nature of the reaction that will take place in this case?
First I want to choose some rejuvenators, then by analyzing FTIR results, choose the best one. what is the best considering index from results of FTIR test for better performance of rejuvenators(or oil) in capsules ?
I am looking for an accurate method to measure the water (moisture) content in an asphalt cement specimen (if any) using the thermo-gravimetric analyzer. Can anyone help me with such info?
Is it possible to determine the dynamic modulus of HMA (SUPERPAVE) Mixtures by using the Universal Testing Machine (UTM) rather than the Simple Performance Tester (SPT)? If yes, then what calibration should be made? The specimens are 150 mm in diameter and 120 mm in hight, and they will not be subjected to a coring process.
If anyone have the following manuals, I will be grateful for if you send me on
Standard Specification for Performance-Graded Asphalt Binder
Standard Practice for Grading or Verifying the Performance Grade (PG) of an Asphalt Binder
Generally, semi-rigid pavement is used in China, composed of asphalt mixture surface layers and cement stabilized macadam base layers.
I am looking for hourly temperature data from any urban area for the following land covers. 1. grass cover. 2. lake/water bodies and 3. any pavement (concrete or asphalt).
Any information on such link to any journal/book/conference paper or website containing such data would be highly appreciated.
I am looking for asphalt binder database containing DRS data for frequency or Temperature sweep of Unaged/RTFOT/PAV samples.
It could be modified or neat asphalt.
Can someone assist me with it or give me a link to where I can download an open open-source database?
Modified rheological properties of asphalt using different waste polymers at different partical sizes
i am investigating the resilience of crumb rubber modified asphalt subballast under cyclic loading and extreme weather conditions in Nigeria.
i intend to use polypropylene granules to replace a small percentage of coarse aggregates in the mix.
I just wanted to know hands on experiences regarding "Asphalt mixture" and its facts under any research which you have done so far.
1) In the not very far future the transport fleet (and in fact the economy as a whole) is expected to move gradually to using gasoline to greener modes of transport – such as gas or electricity.
2) One of the outcomes of this change could possibly be sharp reduction in the use of gasoline, diesel fuel and as a result shut down or severe reduction in the activity of crude oil refineries.
3) Bitumen Binder is a residue of the refining of crude oil and as a result, sharp reduction in the refining process may result in severe shortage or probably even disappearance of this product.
4) In that respect we would like to have your answers on the following questions: a. Is the scenario described in 1-3 above relevant to your organization /country? b. If the answer to (a) above is positive – what are the actions taken by your country /organization to solve this problem? Thanks for your kind reply and cooperation
I came upon a real planning case, where a small street with a max speed of 30 km/h requires a complete makeover. The existing cobble stones can either be replaced by new ones or by asphalt. Some aspects beside, like historic ambience, noise emissions, or rainwater infiltration, which alternative would have which global warming potential (GWP), roughly estimated?
In my search for an answer I first found the publication of Santero and Horvath (2009) regarding the "Global warming potential of pavements". Following its citations I came across several publications about asphalt, concrete, and their respective innovations, also regarding their GWP. I even came across a paper by Lo Presti and D'Angelo (2017) regarding their "Review and comparison of freely-available tools for pavement carbon footprinting in Europe". However, I did not find any comparison between asphalt and cobblestone. Probably because the latter does not play a major role for today's streets. Suggestions are welcome!
In estimating the texture distribution of asphalt mixtures, i have managed to use the discrete fourier transform on my idealized surface profile and obtained my spectral power density.
However the process of Transforming constant bandwidth spectral data to constant-percentage
bandwidth spectral data has proved challenging i would appreciate assistance in understanding and progressing from my current stage.
I have attached the excel sheet and an image of the formulas from ISO 13473-4
Attached, a question about pavement design by mechanical empirical approach that comparison between AASHTO 93 and KENPAVE.
AASHTO 93 design life : 20
KENPAVE design life : 9.8
Why does the huge difference occurs ?
During winter on runway of airport appeared blisters. After study, most possibly reason of that are used deicers (potassium formate, sodium formate). Are there test methods, that could confirm or reject my argument?
Has the recycled asphalt concrete (recycled RAP) a good behavior in fatigue? Have you any reference to me propose in this topic? Thank you
please help me with this question
I've been trying to model three-layer pavements (one rigid and one flexible) in Canada and I'm quite new to the design of pavements. My problem is the input. Do you have any suggestions as to where I can find the input data for pavements in Canada? I've been navigating the LTPP website, but it seems the data are not complete for the pavements. For instance, for one particular pavement, say SHRP_ID 0901, the input data are complete for all the layers but not for the Base Layer.
Thank you so much in advance!
I am modelling a 3 point bending test of Asphalt Mixture beam . The beam is modeled as visco-elastic material . After peak load also the material gains strength as it ismodeled as visco elastic but I want to terminated the program once it reaches a yield point how to mention that in ABAQUS .
Please suggest some answers . thank you in advance
can anyone explain the chemistry between SBS and bitumen, if any sort of physical interactions happening between SBS molecules and bitumen, any literatures which conclusively ecxplains this phenomena??
I was working on a pavement model in ANSYS containing asphalt bottom layer with concrete slab panels on top of it. The slabs are tied to an asphalt shoulder at one side as well. The pavement is sitting on an elastic foundation and is subjected to wheel loads. After meshing has been done, I was trying to connect the adjacent slabs for load transfer between them, with springs in longitudinal and transverse direction in ANSYS. I need some idea on how can I do that so that the rigid body movement is restrained effectively when subjected to loads. I am attaching a screenshot of my model for your kind consideration.
I have come across three approaches used by researchers for fabrication of asphalt mix specimens when they study modified asphalt binders with different modifier dosages (or different modifiers):
Approach 1: Determine the optimum asphalt content (OAC) for the mix with control (unmodified) asphalt binder, and use the same binder content while fabricating asphalt mix specimens with modified binders. Mix volumetrics (e.g. air voids) are kept constant for mixes with modified binders. This has the main advantage of avoiding binder content as a secondary variable when your interest is just to see how the different mixes perform under variable modifier dosages.
Approach 2: Determine the OAC for each binder obtained with different dosages of the modifier. This generally results in OAC values that are quite close (but not exactly the same) to the OAC obtained for control (unmodified) asphalt binder. But this approach introduces binder content as a secondary variable (even though the volumetrics are the same) when one is just interested to analyze the mix performance results as a function of modifier dosage. Hence, it becomes difficult to understand whether the observed trends are due to different modifier dosages or due to different binder contents.
Approach 3: Some researchers also suggest keeping a constant binder content by mix volume (instead of a constant binder content by weight of the mix). However, this approach will lead to difference in the binder content by weight of the mix. Also note that expressing binder content by weight is the most common way of specifying binder content in field and during mix design. Hence, this approach is quite rarely used in the literature.
What would you recommend as the 'correct' approach? Will really appreciate your advice!
Thank you for your valuable time!
In the reason for investigating the composite pavement performance in the laboratory, we prepare samples of asphalt overlay portland cement concrete in one mold, so we find some difficulties with how bonding between those two layers.
How to define the loading and recovery time for the Creep-Recovery Test on an asphalt mixture ?
Creep-Recovery Test at varying stress levels and test temperature are perform to determine the linear and nonlinear viscoelastic characteristics of an asphalt mixture. During this experiment the stress is applied for a particular period of time [loading time (t)] and is removed after a certain time [recovery time] as shown in the attached figure.