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Zack Briones Group

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Typical duties include: the operation of a wide range of specialist plant machinery such as planers, asphalt pavers, emulsified bitumen sprayers and compacting rollers; the removal of old/existing surfaces using a mechanical breakup process; the visual inspection and preparation of the underlying surface to receive new surfacing material; the resurfacing of the prepared area using a range of road surfacing machinery often covering vast areas; the alignment and then compaction of the new surface; and the visual inspection and testing of the new surface to ensure full compliance with the specified design.


Think back to the last time you watched a construction crew resurfacing a section of roadway. Hot asphalt was most likely poured out onto an uneven surface which had been milled just a few days prior. You probably put up with the construction work and traffic because in just a few short few days, all memories of potholes and noisy roadways would be long forgotten, replaced with the smooth cushion of brand-new pavement.

The three processes for laying FSB and asphalt emulsions named in the methodology do not require many of the steps involved with laying HMA. The first two, Cold In-Place Recycling (CIR) and Full-Depth Reclamation (FDR) both recycle the existing pavement on-site. This reduces the need for the travel of numerous dump trucks, and limits the amount of new material generated in the production process.

The last process, Cold Central Plant Recycling (CCPR), combines methods from both HMA and CIR/FDR. Like HMA, the existing pavement is milled and sent to an off-site facility. Unlike HMA, however, the milled pavement can be recycled at a local temporary central plant with portable machines. In HMA, only 25% of the aggregate used is reclaimed asphalt pavement (RAP) and is heated to make the hot mix. With CCPR, 100% the aggregate used is RAP and only the bitumen is heated, making a smaller energy footprint in the production compared to HMA.

The present study investigates warm mix asphalts (WMA) intended for producing surface, binding, and road base layers in high performing and long-lasting pavements. The investigated production technique involves the utilization of decreased production and paving temperatures enabled by a bio-derived fluxing additive and foaming of asphalt binder. The high performance of the mixtures is provided by using polymer modified asphalt binders and dispersed fiber reinforcement.

Other commonly investigated techniques for producing WMA mixtures is the use of fluxing agents. The high adequacy of using the bio-derived fluxing additive (Bio-Flux) for reducing processing temperatures of asphalt mixtures with polymer modified bitumen was shown in [21]. The additive lowers the viscosity of the asphalt binder blend, allowing for the decrease in processing temperatures at production, but with time it causes an increase in stiffness and the performance of the asphalt mixture [22,23]. Other notable plant derived fluxing additives and their uses include Oleoflux and Green Seal [24], waste cooking oils [25,26,27] and tall oils [28].

Warm mix asphalts, regardless of the production technique are known to differ in mechanical properties from their HMA counterparts. In field studies [16] it was found in this respect that WMA mixtures are typically characterized by lower dynamic stiffness moduli and the asphalt binders in these mixtures are less affected by aging due to lower processing temperatures [29,30]. However, the magnitude of these effects was observed to decrease in time and no specific distress was recorded in WMA test sections. These findings were further confirmed by laboratory [31,32,33] and other field studies [34,35].The efficacy of fiber reinforcement in asphalt mixtures has been shown in several studies to date. Basalt fiber reinforcement increases the stiffness of asphalt mixtures at high service temperatures without impacting their performance at low temperatures and improves their fatigue life [36,37]. In turn, the use of basalt fibers has a positive impact on the service life of asphalt pavements and needs for their rehabilitation [38]. Similar effects were found when using aramid [39] and carbon and glass fibers [40,41]. In warm asphalt mixtures the addition of fiber reinforcement also improves their stress-strain characteristics as it was shown in terms of resilient modulus [42], permanent deformations [42,43] and fatigue life [42,44].

The asphalt binder content amounted to 5.4% (m/m) in the AC-S mixtures and 5.0% in HMAC formulations. An adhesion promoter was added to the bitumen prior to mixing with the aggregates or prior to asphalt binder foaming at a 0.3% rate per bitumen mass. The study included the use of cut basalt fibers, 12 mm (AC-S mixes) and 24 mm (HMAC mixes) in length and approx. 0.03 mm in diameter, added at 0.3% and 0.2% rates per final asphalt mix, respectively. The compositions of the investigated mixtures (grading, asphalt binder content, fiber content, fiber length) were optimized in the course of the preliminary work for this study.

The details regarding the processing of the investigated asphalt mixtures are provided in Table 3. The asphalt mixtures produced as HMAs utilized asphalt binder that was added conventionally to the mineral mixture, whereas the warm mix asphalts included foamed asphalt binders produced either as in [46] when mixed in laboratory, or produced in an industrial scale asphalt plant with a Green Pac (Astec Inc., Chattanooga, TN, USA) foaming system as shown in Figure 2a. Figure 2b shows the weighed bags with the basalt fibers to be manually added to the mineral mixture in the asphalt mixer at the asphalt plant.

Measured versus predicted values of complex stiffness moduli in samples from laboratory produced mixtures: Surface course mixtures (a), high modulus asphalt concrete mixtures (b).

Complex stiffness moduli of laboratory produced mixtures measured at 10 Hz: Surface course mixtures (a), high modulus asphalt concrete mixtures (b), means and 95% confidence intervals (also shown as error bars).

Measured versus predicted values of complex stiffness moduli in samples from plant produced mixtures: Surface course mixtures (a), high modulus asphalt concrete mixtures (b).

The differences between the plant produced reference and warm mix asphalts were consistent throughout the frequency range with the WMAs being characterized by lower values of complex stiffness moduli.

Complex stiffness moduli of plant produced surface course (a) and high modulus asphalt concrete mixtures (b) measured at 10 Hz; means and 95% confidence intervals (also shown as error bars).

With the aforementioned factors plausibly excluded and controlled for, another group of effects, linked strictly to the processing of the asphalt mixtures can be named. The effects of action of high temperature during production (leading to asphalt mixture stiffening due to asphalt binder aging and binder absorption), production temperature and the use of foamed bitumen as a binder differentiated the affected mixtures.

While the observed differences in the dynamic moduli of the HMA and WMA mixtures could not be easily attributed to the effects of bitumen foaming or the presence of the Bio-Flux additive in the asphalt binders, they were similar to those reported by other authors investigating different types of warm asphalt mixtures.

  • Model description MUNICH consists of two main components: (1) the street-canyon component, which represents the atmospheric processes in the volume of theurban canopy, and (2) the street-intersection component, which represents the processes in the volume of the intersection.These components are connected to the Polair3D model at roof level and are also interconnected. A detailed description is found at Hands-on session for MUNICH Simulated NOx concentrations using MUNICH (a) during nighttime at 1 AM (UTC) (b) in the morning rush-hour at 7 AM (UTC)on March 25, 2014. Documents MUNICH v2.0 User's Guide MUNICH v1.0 User's Guide Download Zenodo Git repositoryIf you clone git repository, please use the script munich-public-clone. If you download or clone from the repository, the files of the sub modules are not included. Data and configuration files for MUNICH v2 test case Configuration files Data files Hands-on session for MUNICH v1 DocumentFor the hands-on session, the input data can be downloaded at Data and configuration files or by contact with Youngseob Kim Send MailFor any questions, you can contact Send Mail.If you want to receive news about MUNICH, you can subscribe to munich-user email list NewsMUNICH version 2.1 release (2022-09-29)ModelAdded the dry deposition on tree leaves.

  • Added the aerodynamic effect of trees in the street.

  • Added the possibility to compute particulate concentration with Melchior2.

  • PreprocessingAdded a reader to use Polair3D output as the background concentrations.

  • EnvironmentImproved the compatibility with Intel compiler.

  • MUNICH version 2.0 release (2021-09-01)ModelAdded a new parametrization for the aerosol resuspension.

  • Implemented SSH-Aerosol as a sub module for the modeling of secondaryaerosols using API of SSH-Aerosol.

  • Added a new option for SVOC deposition

  • Added a new option for the computation of friction velocity and wind speed.

  • Added a new gas-phase kinetic mechanism CHIMERE/MELCHIOR2.

  • PreprocessingAdded option for the speciation of particle and ISVOC emissions.

  • Improved in CPU time by rewriting the function arc_streets_same.

  • Map projection type can be selected.

  • EnvironmentTalos/AtmoData/SeldonData changed as a sub module.

  • atmopy added as a sub module.

  • Conversion to Python3 format.

Version 1.1.beta is implemented on AmpliSIM platform (2021-05-15).AmpliSIM platform provides users a GUI environment to run MUNICH 041b061a72

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