American Society of Civil Engineers


Compaction Control of Crushed Concrete and Recycled Asphalt Pavement using Nuclear Gauge


by Chirayus Viyanant, (Graduate Research Assistant, University of Texas at Austin, Department of Civil Engineering, Austin, TX 78712), Ellen M. Rathje, (Assistant Professor, University of Texas at Austin, Department of Civil Engineering, Austin, TX 78712), and Alan F. Rauch, (Assistant Professor, University of Texas at Austin, Department of Civil Engineering, Austin, TX 78712)
Section: Material Characterization for Mechanistic Pavement Design, pp. 958-966, (doi:  http://dx.doi.org/10.1061/40744(154)83)

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Document type: Conference Proceeding Paper
Part of: Geotechnical Engineering for Transportation Projects
Abstract: Crushed concrete (CC) and recycled asphalt pavement (RAP) are sometimes used as substitute fill material in retaining wall and pavement applications. The accuracy of the nuclear gauge device for density and moisture content measurements on these two recycled materials may be unreliable, due to their chemical compositions being different than typical earth fill. An experimental study was initiated to compare moist density and water content measured from the nuclear gauge with those from traditional rubber balloon and test pit methods. Test results show that the nuclear gauge consistently measured larger moist densities than the rubber balloon method for all materials tested. However, the discrepancies were most likely due to the inadequate size of the hole used in the rubber balloon test relative to the maximum particle size of the materials. This result was confirmed with test pit measurements, which showed closer correspondence with the nuclear gauge results. Water content measurements indicate that the nuclear gauge reports larger values of moisture content than oven drying for CC and RAP. This difference can be attributed to the misinterpretation by the nuclear gauge of inherit hydrogen atoms in CC and RAP as water molecules.


ASCE Subject Headings:
Compaction
Recycling
Asphalts
Concrete
Construction materials