Asphalt Fume Exposures by Pavement Construction Workers: Current Status and Project Cases

Chong, Dan; Wang, Yuhong; Zhao, Kecheng; Wang, Dawei; Oeser, Markus

doi:10.1061/(asce)co.1943-7862.0001454

Cited by 32 publications

(11 citation statements)

References 20 publications

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“…It is a mix of aliphatic, aromatic, and naphthenic hydrocarbons and widely employed as protective and waterproof coatings, and binders in road construction. According to the Asphalt Institute [ 1 ], 87 million tons of asphalt are sold every year around the world; 85% of the production is employed in pavements.…”

Section: Introductionmentioning

confidence: 99%

Laboratory Evaluation of Mechanical Properties of Modified Asphalt and Mixture Using Graphene Platelets (GnPs)

et al. 2021

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Recently, nanomaterials have attracted attention in the field of pavement construction as modifiers to endure heavy loads and climate changes. In this study, conventional asphalt (bitumen) of penetration grade AC (60/70) was modified with graphene platelets (GnPs) at three different contents: 0.5%, 1.0%, and 1.5% by weight of asphalt content. Kinematic viscosity, softening point, penetration, and dynamic shear rheology tests were performed to evaluate the mechanical properties of modified binder. The results showed that adding GnPs improves the mechanical properties of asphalt binder; the kinematic viscosities, softening points, and rutting parameters increased but penetrations decreased with the contents of GnPs. Hot mix asphalt specimens with GnPs-modified asphalt were prepared and characterized with Marshall tests, thermal stress restrained specimen tests (TSRST), wheel tracking tests, and indirect tensile tests. Similar to the results of asphalt binder, the mechanical properties of asphalt mixture were improved by GnPs. Marshall stability increased by 21% and flow decreased by 24% with accepted value of 2.8 mm in penetration when the mixture was modified with 1.0 wt% of GnPs. At the same GnPs content, modified asphalt mixture led to lower failure temperature by 2 °C in comparison with unmodified asphalt mixture and the cryogenic failure stress was improved by 12%. The wheel tracking tests showed that GnPs-modified asphalt mixture has outstanding deformation resistance in comparison with unmodified asphalt mixtures: after 5000 cycles, 1.0 wt% of GnPs reduced the rut depth of asphalt mixture by 60%—the rut depth of unmodified asphalt mixture was 6.9 mm compared to 2.75 mm for modified asphalt mixture. After 10,000 cycles, the modified asphalt mixture showed rut depth of 3.24 mm in comparison with 8.12 mm in case of unmodified asphalt mixture. Addition of GnPs into asphalt mixture significantly improved the indirect tensile strength: 1.0 wt% of GnPs increased the indirect tensile strength of unmodified asphalt mixture from 0.79 to 1.1 MPa recording ~40% increment. The results of this study can confirm that graphene platelets enhance the mechanical properties of asphalt mixture and its performance.

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Section: Introductionmentioning

confidence: 99%

Laboratory Evaluation of Mechanical Properties of Modified Asphalt and Mixture Using Graphene Platelets (GnPs)

et al. 2021

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“…WTS AIR = (d 10000 − d 5000 )/5 (1) where WTS AIR is the wheel-tracking slope (mm/10 3 load cycles) and d 5000 and d 10000 are the rut depths (mm) after 5000 load cycles and 10,000 load cycles, respectively.…”

Section: • Study Of the Rut Resistancementioning

confidence: 99%

“…Bitumen is considered to be an essential component of roadways and its demand is increasing with each passing day. According to the Asphalt Institute, 87 million tons of bitumen are produced per year around the globe [1]. A major chunk of this production, approximately 85% of the bitumen, is used in the paving industry.…”

Section: Introductionmentioning

confidence: 99%

“…Nanoparticles are first dispersed in the solvent using a mechanical stirrer and then are mixed with the binder using a high shear mixer. The commonly observed issue with the wet mixing technique is that, if the solvent does not evaporate completely from the binder, it compromises the properties of the binder [1]. The usage of the solvent and the high shear mixer adds to the extra cost, as well as increases the processing time.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Investigation into the Structural and Functional Performance of Graphene Nano-Platelet (GNP)-Doped Asphalt

et al. 2019

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With the increase in the demand for bitumen, it has become essential for pavement engineers to ensure that construction of sustainable pavements occurs. For a complete analysis of the pavement, both its structural and functional performances are considered. In this study, a novel material (i.e., Graphene Nano-Platelets (GNPs)) has been used to enhance both of the types of pavements’ performances. Two percentages of GNPs (i.e., 2% and 4% by the weight of the binder) were used for the modification of asphalt binder in order to achieve the desired Performance Grade. GNPs were homogeneously dispersed in the asphalt binder, which was validated by Scanning Electron Microscope (SEM) images and a Hot Storage Stability Test. To analyze the structural performance of the GNPs-doped asphalt, its rheology, resistance to permanent deformation, resistance to moisture damage, and bitumen-aggregate adhesive bond strength were studied. For the analysis of the functional performance, the skid resistance and polishing effect were studied using a British Pendulum Skid Resistance Tester. The results showed that GNPs improved not only the rutting resistance of the pavement but also its durability. The high surface area of GNPs increases the pavement’s bonding strength and makes the asphalt binder stiffer. GNPs also provide nano-texture to the pavement, which enhances its skid resistance. Thus, we can recommend GNPs as an all-around modifier that could improve not only the structural performance but also the functional performance of asphalt pavements.

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“…1 However, despite many advantageous engineering properties, its use can be a cause for concern, primarily because of the inhalation of fumes by pavement workers. 2 In general, asphalt mixtures need to be heated at temperatures around 130 °C to facilitate its handling. 3 Thus, a considerable amount of fumes containing volatile organic compounds and polycyclic aromatic hydrocarbons (PAHs) are emitted during the placement and compaction of asphalt pavements.…”

Section: Introductionmentioning

confidence: 99%

Emission and Collection of Polycyclic Aromatic Hydrocarbons From Raw Asphalt Samples Heated at 130 °C

et al. 2020

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The emission and collection of polycyclic aromatic hydrocarbons (PAHs) in the aqueous solution and asphalt samples obtained from different refineries in Brazil were evaluated. The aqueous solution and asphalt samples were heated under an argon atmosphere at 50 and 130 °C, respectively, for 60 min in a closed system. The targeted PAHs for the aqueous solution were acenaphthene, anthracene, and fluoranthene, while those for the asphalt samples were naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]anthracene. These were all taken from the US EPA list. The performances of Amberlite XAD-2, high-density polyethylene (HDPE), silica (Si), polyurethane foam (PUF), and granular activated carbon (GAC) in collecting the PAHs from the vapor phase by gas−solid adsorption were compared. High-performance liquid chromatography with a diode array detector was used to quantify the mixtures of PAHs retained by the adsorbents. PUF and XAD-2 had the highest PAH retention capacity. For the aqueous solution, PUF showed adsorption yields of 100% for all the investigated PAHs. XAD-2 was also a good adsorbent (adsorption yields >90%), followed by HDPE (75−90% adsorption yields). For silica and GAC, the adsorption yields depended strongly on the PAHs. Alternatively, for the asphalt samples, the adsorption yield decreased dramatically for all the evaluated PAHs, showing that the asphalt matrix had a strong influence on the adsorption capacity of the adsorbents. In this case, the total PAH retention was 47.2% for PUF, 46.8% for XAD-2, 29.9% for GAC, 27.3% for Si, and 19.8% for HDPE. The retention/elution processes on the adsorbent surfaces were also evaluated by atomic force microscopy.

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Asphalt Fume Exposures by Pavement Construction Workers: Current Status and Project Cases

Cited by 32 publications

References 20 publications

Laboratory Evaluation of Mechanical Properties of Modified Asphalt and Mixture Using Graphene Platelets (GnPs)

Laboratory Evaluation of Mechanical Properties of Modified Asphalt and Mixture Using Graphene Platelets (GnPs)

Experimental Investigation into the Structural and Functional Performance of Graphene Nano-Platelet (GNP)-Doped Asphalt

Emission and Collection of Polycyclic Aromatic Hydrocarbons From Raw Asphalt Samples Heated at 130 °C

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