2013 Session: 564

• Evaluating Laboratory Compaction Techniques of Reclaimed Asphalt Pavement
  Abstract: Reclaimed Asphalt Pavement (RAP) is a byproduct of roadway resurfacing. A limited amount can be recycled into new hot mix asphalt; the rest is stockpiled. Some states allow the use of RAP/aggregate blends as base course material. Due to its low strength and susceptibility to creep deformation the Florida Department of Transportation (FDOT) excludes RAP as pavement base course for high traffic areas. The research objective was to determine whether the strength characteristics of RAP could be improved through compaction to make it base suitable in high traffic areas. Modified Proctor, vibratory, and gyratory compaction data was compared. Four RAP sources were used. Specimens compacted by the three methods were tested using Limerock Bearing Ratio (LBR), Unconfined Compressive, and Indirect Split Tensile strength. LBR is Florida’s variation of the California Bearing Ratio. Specimens were compacted to either a density or to a compaction energy level. Vibratory compaction produced the lowest densities and strengths. Modified Proctor produced higher densities and strengths than vibratory but the LBR strengths for all RAP types were consistently below FDOT standards. Gyratory compaction produced the highest densities and strengths. Gyratory specimens of RAP were two to four times stronger than modified Proctor specimens at the same density. Compaction method did not have as significant an effect on creep, although gyratory compacted samples did produce less creep than modified Proctor compacted samples.
  Authors: Cosentino, Paul J.; Bleakley, Albert M.; Perersen, Andrew James; Sajjadi, Amir Mohammad
  Authors: Cosentino, Paul J.; Bleakley, Albert M.; Perersen, Andrew James; Sajjadi, Amir Mohammad
  Year: 2013
  Document Type: Paper
  Subject: Geotechnology; Materials; Pavements
  Session: 564
  Paper Number: 13-1220
  Practice-Ready: Yes
• Cementitiously Stabilized Materials Using Ultrasonic Testing
  Abstract: The effect of curing time, and compaction cementitiously stabilized materials (CSM) was studied using ultrasonic P-wave propagation. In general, the P-wave velocity measurements the mixtures increased with curing time. The trend between unconfined compression strength (UCS) with dry density or compaction water content was the same as the trend with P-wave velocity measurements. For stabilized fine-grained soils, there was a peak in P-wave velocity coinciding with the maximum dry density. The P-wave velocity and constrained modulus were strongly correlated to the UCS for CSMs. A model for prediction of UCS was proposed and verified. These test results provides insights for use of ultrasonic pulse velocity testing method for the determination of mechanical properties of CSM.
  Authors: Su, Zhipeng
  Authors: Su, Zhipeng
  Year: 2013
  Document Type: Paper
  Subject: Geotechnology; Materials; Pavements
  Session: 564
  Paper Number: 13-1435
  Practice-Ready: Yes
• Soil Stiffness Assessment of Stabilized Pavement Foundations
  Abstract: The quality of constructed pavement foundation layers was studied using rapid and near-continuous soil stiffness measurements as alternatives to traditional nuclear gauge moisture/density measurements. Sixteen different stabilized pavement foundation sections covering 4.8 miles were studied with ground conditions ranging from soft to very stiff. Measurements from falling weight deflectometer, light weight deflectometer, and roller-integrated compaction monitoring systems were used to assess soil stiffness. Statistical analyses of the results are reported in the form of coefficient of variation and empirical correlations between measurements. Results of soil stiffness were compared to two independent groups of nuclear moisture/density measurements to demonstrate some of the shortcomings of traditional nuclear gauge testing for quality assessment. The findings from this paper show the value in characterizing ground variations using soil stiffness measurements. Cost data is also reported for the stabilized sections. (135 words)
  Authors: White, David J.; Becker, Peter; Vennapusa, Pavana Kumar Reddy; Dunn, Mark; White, Christianna
  Authors: White, David J.; Becker, Peter; Vennapusa, Pavana Kumar Reddy; Dunn, Mark; White, Christianna
  Year: 2013
  Document Type: Paper
  Subject: Geotechnology; Materials; Pavements
  Session: 564
  Paper Number: 13-5073
  Practice-Ready: Yes
• Estimation of Subgrade Resilient Modulus Using Unconfined Compression Test
  Abstract: Resilient modulus test is the recommended test to characterize subgrade soil for pavement design in 1993 AASHTO pavement design guide as well as new proposed Mechanistic-Empirical Pavement Design Guide (MEPDG). This test requires significant resources including high level of technical capability to conduct. For smaller projects where costly and complex resilient modulus testing is not justified, correlation with other simpler tests could be used. Virginia Department of Transportation uses a simple correlation with California Bearing Ratio (CBR) to estimate resilient modulus for their current AASHTO design. As the correlation with CBR was found to be poor, a simpler unconfined compression test is explored for a better estimation of resilient modulus of fine grained soils. A model is proposed to estimate the resilient modulus of fine grained soil from the results of unconfined compression test.
  Authors: Hossain, Shabbir; Kim, Wan Soo
  Authors: Hossain, Shabbir; Kim, Wan Soo
  Year: 2013
  Document Type: Paper
  Subject: Geotechnology; Materials; Pavements
  Session: 564
  Paper Number: 13-4564
  Practice-Ready: Yes
• Evaluating Laboratory Compaction Techniques of Reclaimed Asphalt Pavement
  Authors: Cosentino, Paul
  Authors: Cosentino, Paul
  Year: 2013
  Document Type: Presentation
  Subject: Geotechnology; Materials; Pavements
  Session: 564
  Paper Number: 13-1220
• Evaluating Laboratory Compaction Techniques of Reclaimed Asphalt Pavement
  Authors: Bleakley, Albert
  Authors: Bleakley, Albert
  Year: 2013
  Document Type: Presentation
  Subject: Geotechnology; Materials; Pavements
  Session: 564
  Paper Number: 13-1220
• Cementitiously Stabilized Materials Using Ultrasonic Testing
  Authors: Edil, Tuncer
  Authors: Edil, Tuncer
  Year: 2013
  Document Type: Presentation
  Subject: Geotechnology; Materials; Pavements
  Session: 564
  Paper Number: 13-1435
• Estimation of Subgrade Resilient Modulus Using Unconfined Compression Test
  Authors: Hossain, Shabbir
  Authors: Hossain, Shabbir
  Year: 2013
  Document Type: Presentation
  Subject: Geotechnology; Materials; Pavements
  Session: 564
  Paper Number: 13-4564
• Soil Stiffness Assessment of Stabilized Pavement Foundations
  Authors: White, David
  Authors: White, David
  Year: 2013
  Document Type: Presentation
  Subject: Geotechnology; Materials; Pavements
  Session: 564
  Paper Number: 13-5073