01365571

Component

https://doi.org/10.3141/2310-10

http://scholar.google.com...esta&publication_year=2012

In recent years, the Texas Department of Transportation has observed the heaving of gypsum- or sulfate-bearing subgrade soil when it has been chemically stabilized with calcium-based additives. The occurrence of sulfate or gypsum deposits in these soils is unpredictable and often localized in small areas. Current testing procedures, in which samples are collected at specified intervals for sulfate measurements, often miss these localized concentrations. A method that provides rapid and continuous mapping of sulfate content in subgrades to a depth of at least 1 m is needed. Researchers in precision agriculture have used several devices that rapidly and continuously measure the bulk electrical conductivity of the soil at high spatial resolutions (<10 ft) and depths (≥2 ft). For the research described in this paper, the Veris 3150 was used to measure spatial variability in bulk electrical conductivity across three sulfate-bearing subgrades in Texas. The data were used to construct high-resolution maps of the subgrade conductivity and were compared with soil properties to identify potentially high-risk areas for sulfate heaving. The bulk electrical conductivity, the sulfate content, and the soil plasticity varied in tandem throughout the subgrades. This research identified areas with an electrical conductivity of >100 mS/m as having the greatest potential for sulfate problems of the subgrades tested. It also identified a technique that could be used to rapidly and effectively screen large projects for potential sulfate problems and to map the distribution of high- and low-clay subgrade soils.

01469303

12-3289

English

pp 93–102

2012

Transportation Research Record: Journal of the Transportation Research Board

9780309263078

Print

Figures; References; Tables

Electrical conductivity; Measuring instruments; Pavement distress; Soil mapping; Soil stabilization; Subgrade (Pavements); Sulfates; Swelling soils

Soil heave

Texas

Geotechnology; Highways; Pavements; I42: Soil Mechanics

PRP, TRIS, TRB, ATRI

Feb 8 2012 5:15PM

• Calibration of Side, Tip, and Total Resistance Factors for Load and Resistance Factor Design of Drilled Shafts
• Cement Stabilization of Conventional Granular Base and Recycled Crushed Portland Cement Concrete
• Cement Stabilization of Highly Organic Subgrade Soils to Control Secondary Compression Settlement
• Comprehensive Recalibration of Pile Resistance with WEAP Software in Initial and Restrike Conditions for Load and Resistance Factor Design
• Effect of Skewing and Splaying on Pullout Capacity of Steel Reinforcements in Mechanically Stabilized Earth Structures
• Evaluation of Nonnuclear Soil Moisture and Density Devices for Field Quality Control
• Examination of Roller-Integrated Continuous Compaction Control on Colorado Test Site
• Factors Affecting Strength of Road Base Stabilized with Cement Slurry or Dry Cement in Conjunction with Full-Depth Reclamation
• Full-Scale Evaluation of Geogrid-Reinforced Thin Flexible Pavements
• Interaction Between Carbon Black and Antioxidants in High-Density Polyethylene Pipe Resin
• Locating Soil Tests with Intelligent Compaction Data and Geographic Information System Technology
• Proposed AASHTO Structural Design Properties for Corrugated Polypropylene Storm Sewer Pipe
• Toward a Better Understanding of Benefits of Geosynthetics Embedded in Asphalt Pavements
• Verification of Recommended Load and Resistance Factor Design and Construction of Piles in Cohesive Soils