Presentation is loading. Please wait.

Presentation is loading. Please wait.

University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 1 Determination.

Similar presentations


Presentation on theme: "University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 1 Determination."— Presentation transcript:

1 University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 1 Determination of Soil Stabilizer Content Using X-Ray Fluorescence (An Unplanned, yet Fortuitous Product of SPR 2195 and 2207) Amy Cerato & Gerald (Jerry) Miller (OU)

2 University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 2 Motivation How do we make laboratory samples that have an identical stabilizer content as the field site so that we could compare field strength with lab strength? SPR 2195: Evaluation and Field Verification of Strength and Structural Improvement of Chemically Stabilized Subgrade Soil (in collaboration with Dr. Donald Snethen) SPR 2207: Validation and Refinement of Chemical Stabilization Procedures for Pavement Subgrade Soils in Oklahoma (in collaboration with Dr. Donald Snethen)

3 University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 3 Motivation How do we know exactly how much stabilizer is in the field sample? Devise a method that could pinpoint the amount of stabilizer present in the soil. Construction Quality Control ODOT can inspect stabilized subgrade and make a determination if enough stabilizer has been used and have any issues fixed before the pavement is laid. Forensic Geotechnical Investigations ODOT inspectors can collect samples during construction and keep them in case a roadway performs poorly in the future.

4 University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 4 Background Existing Methods to Estimate Stabilizer (CaO) Content in Soils ASTM D3155 – Standard Test Method for Lime Content of Uncured Soil – Lime Mixtures Titration process, cumbersome, lots of chemicals, operator dependent Lime fixation capacity method Initial Consumption of Lime (ICL) Unconfined Compressive Strength test (UCS) Indicator Tests! - Cannot be retroactively used to pinpoint how much stabilizer is actually present in the soil!!!!!

5 University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 5 X-Ray Fluorescence (xrf) Used extensively in environmental applications to measure elemental content in soils, sediments, water sources, and even foods; however has not been used in soil stabilization applications. Test measures elemental content as accurately as 0.01 – 100%. The Whole Rock Analysis Method using XRF was performed by ALS Laboratory Group in Reno, NV. Used to measure Calcium Oxide (CaO) content of natural soils (CaO 0 ), chemical additives (CaO C.A. ), and treated soils (CaO f ).

6 University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 6 Test Soil Site #Soil Name AASHTO Group USCS Group Percent Clay (%) Liquid Limit (%) Plastic Limit (%) Plasticity Index (%) Shrinkage Limit (%) Linear Shrinkage (%) 1 and V1 ^US 281A-4ML10.318NP*NP ^Penn Ave. A-6CL ^US 177A-7-6CH ^US 81A-4ML14.016NP V2^SH7A-6CL V3 $Kirkland Pawhuska A-6CL V4 +Hickory Clay A-7-6CH ^ Data from Holderby 2010 $ Data from Hussey 2010 and Tabet Data from Adams 2008 and Campbell 2010 *NP – Non Plastic

7 University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 7

8 University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 8 StabilizerRegressionr2r2 Combinedy=0.96x Limey=1x CKDy=0.96x0.99 Fly Ashy=0.96x Validation Results

9 University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 9 Site #1Site #2Site #3Site #4Site #5 Class C Fly AshQuick Lime

10 University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 10 Application to Field Sites Site Number Soil Name Type of Stabilizer Design Specified Content (%) XRF Determined Content (%) Predicted XRF Content from Validation Study (%) #1US 281CFA #2Penn Ave.CFA #3US 177Quicklime #5US 81CFA

11 University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 11 Conclusions The Whole Rock Analysis Method using XRF technique could be an extremely useful tool to use for quality control applications or during forensic investigations, where the presence or lack of additive in a stabilized layer is in question.

12 University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 12 Conclusions Portable field XRF units seem like a promising method to get a fast and accurate measurement, as well as spatial heterogeneity assessment, of the stabilization of a subgrade before the pavement is laid. If problem areas are identified, the subgrade can be remixed and compacted in a timely manner.

13 University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 13 Recommendations For projects involving chemical stabilization, samples of additives, untreated soil, and treated soil (after compaction and final grading) should be obtained at three or more representative locations and representing the full design depth of the stabilized layer. The samples are small and can be retained for future testing should disputes arise, or they can be incorporated into the quality control program – recognizing the testing times and limitations involved.

14 University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 14 Questions? REFERENCE: Cerato, A.B. and Miller, G.A., Determination of Soil Stabilizer Content Using X-Ray Fluorescence, Geotechnical Testing Journal, Vol. 36, No.5, 2013, pp.781– 785, doi: /GTJ ISSN


Download ppt "University of Oklahoma - School of Civil Engineering and Environmental Science 2013 ODOT – OkTC Research Day, Thursday, September 12 Slide 1 Determination."

Similar presentations


Ads by Google