A New Method for Measuring In-Place Density of Asphalt Pavements Using a Low-Activity Nuclear Density Gauge
Publication: Airfield and Highway Pavements 2023
ABSTRACT
In recent years, low-activity nuclear density gauges (LNDG) have become available and are used for soils and asphalt compaction testing. These gauges, which are exempt from licensing and other nuclear regulatory requirements in the United States, use gamma-ray scattering technique for measuring density. A new method was developed for using these gauges for agency acceptance testing of finished asphalt pavements. In this method, the gauge is used in transmission mode, placing the gamma-ray source at a depth of 12.5 mm (0.5 in.) in asphalt layer, using a predrilled hole with a diameter of 19 mm (0.75 in.). This paper presents the measurement method and properties of a gauge using this new method (LNDG/TM). The measurement properties were determined from laboratory and field studies conducted in North Carolina. An LNDG/TM was evaluated by side-by-side testing with a thin-lift type conventional nuclear gauge (TL-NDG) that is allowed to use for acceptance testing. These studies showed that the sensitivity and precision of measuring density by an LNDG/TM were similar to those by a TL-NDG. Based on measurements taken on a 100-mm-thick (4-in.) intermediate layer made from a 19-mm Superpave mix, the precision, repeatability standard deviation, for the LNDG/TM was 5 kg/m3 (0.3 lb/ft3). The measurement time including for site preparation was about 2.5 min. When gauge measurements were correlated to the industry-accepted core-extraction method, the agreement between LNDG/TM and a TL-NDG for measuring density was within 32 kg/m3 (2 lb/ft3).
Get full access to this article
View all available purchase options and get full access to this chapter.
REFERENCES
AASHTO. (2006). In-Place Density of Asphalt Mixtures by Nuclear Method, AASHTO T-355. AASHTO, Washington, DC.
AASHTO. (2016). Standard Method of Test for Bulk Specific Gravity (Gmb) of Compacted Hot Mix Asphalt (HMA) Using Saturated Surface-Dry Specimens, AASHTO T-166. AASHTO, Washington, DC.
AASHTO. (2020). Standard Practice for Sampling Asphalt Mixtures after Compaction (Obtaining Cores), AASHTO R-67. AASHTO, Washington, DC.
ASTM. (2014). Standard Test Method for Density of Bituminous Concrete in Place by Nuclear Methods, ASTM D2950/2950M-14. ASTM International, West Conshohocken, PA.
ASTM. (2016). Standard Practice for Sampling Compacted Asphalt Mixtures for Laboratory Testing, ASTM D5361. ASTM International, West Conshohocken, PA.
ASTM. (2018). Standard Test Method for Density of Bituminous Paving Mixtures in Place by the Electromagnetic Surface Contact Methods, ASTM D7113/7113M. ASTM International, West Conshohocken, PA.
ASTM. (2018). Standard Test Method for In-Place Bulk Density of Soil and Soil- Aggregate by a Low-Activity Nuclear Method (Shallow Depth), ASTM D8167/8167M. ASTM International, West Conshohocken, PA.
ASTM. (2021). Standard Test Method for Bulk Specific Gravity and Density of Non-Absorptive Compacted Bituminous Mixtures, ASTM D2726-21. ASTM International, West Conshohocken, PA.
Berney, E. S., IV, and Mejías-Santiago, M. (2019). “Comparative testing between electrical impedance and hybrid nuclear devices for measuring moisture and density in soils.” Transp. Res. Rec., 2657(1), 29–36.
Belcher, D. J., Cuykendall, T. R., and Sack, H. S. (1950). The Measurements of Soil Moisture and Density by Neutron and Gamma-Ray Scattering,. Civil Aeronautics Administration Technical Development and Evaluation Center, Indianapolis, IN.
Dep, L., Troxler, R. E., and Troxler, W. (2016). “New low-activity nuclear gauge for soil wet density measurement with low regulatory burden.” Proc., 2nd Int. Road Federation Asia Regional Congress and Exhibition, Kuala Lumpur, Malaysia, 445–456.
Dep, L., Troxler, R., Mwimba, S., Croom, C., and Langston, W. (2021a). “Quality control of hot mix asphalt pavement compaction using in-place density measurements from a low-activity nuclear gauge.” Proc., Int. Airfield and Highway Pavements Conf., ASCE, Reston, VA, 92–102, https://doi.org/10.1061/9780784483503.009.
Dep, L., Troxler, R., Sawyer, J., and Mwimba, S. (2021b). “A new low-activity nuclear density gauge for soil density measurements.” J. Test. Eval., 50(1), 44–65.
Dep, L., Troxler, R. E., and Troxler, W. F. (2022). “A New Low-Activity Nuclear Gauge for Compaction Control of Asphalt, Concrete, Soil, and Aggregate Layers in Road Construction.” In Advances in Road Infrastructure and Mobility, A. Akhnoukh, K. Kaloush, M. Elabayad, B. Halleman, N. Erian, S. Enmon III, and C. Henry, eds. Springer Cham, Cham, Switzerland, 3–18.
Dep, L., Troxler, W. F., Sawyer, J., and Croom, C. (Forthcoming). “A new method for quality assurance of asphalt pavements using a low-activity nuclear density gauge.” Transp. Res. Rec.
Farrar, M. J., Grimes, W., Wiseman, S., and Planche, J.-P. (2015). Asphalt Pavements – Micro-sampling and Micro-extraction Methods. Western Research Institute, Laramie, WY.
Krueger, P. G. (1950). Soil density by gamma-ray scattering. M.S. thesis, Cornell University, Ithaca, NY.
Hughes, C. S. (1962). “Investigation of a nuclear device for determining the density of bituminous concrete.” J. Assoc. Asphalt Paving Technol., 31, 400–417.
Troxler Electronic Laboratories. (2020a). Manual of Operation and Instruction for Model 4540 Soil and Asphalt Density Gauge, Troxler Electronic Laboratories, Durham, NC.
Troxler Electronic Laboratories. (2020b). Manual of Operation and Instruction for Model 4590 Soil Density Gauge, Troxler Electronic Laboratories, Durham, NC.
Troxler Electronic Laboratories. (2020c). Manual of Operation and Instruction for Model 4640-B Thin Layer Density Gauge, Troxler Electronic Laboratories, Durham, NC.
North Carolina Department of Transportation. (2019). “2019 asphalt quality management system, materials and test unit.” <https://connect.ncdot.gov/resources/Materials/Pages/Materials-Manual-by-Material.aspx?Method=MM-02-02≥ (Aug. 4, 2020).
Sloane, R. L. (1962). “Development of a nuclear surface density gage for asphaltic pavements.” Highway Res. Board Bull., 360, 1–17.
Information & Authors
Information
Published In
History
Published online: Jun 13, 2023
ASCE Technical Topics:
- Asphalt pavements
- Business management
- Compacted soils
- Compaction (material)
- Density (material)
- Engineering fundamentals
- Field tests
- Geomechanics
- Geotechnical engineering
- Infrastructure
- Laboratory tests
- Management methods
- Material mechanics
- Material properties
- Material tests
- Materials characterization
- Materials engineering
- Pavements
- Practice and Profession
- Quality control
- Soil mechanics
- Soils (by type)
- Tests (by type)
- Transportation engineering
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.