Investigating the Efficacy and Variability of the Bar Linear Shrinkage Test for Aggregates

Aggregate is a widely used construction material in the Virginia Department of Transportation (VDOT) construction projects. Its quality is governed by many properties, including gradation, soundness, and Atterberg limits. Specifically, VDOT sets specification requirements for both the plasticity index (PI) and liquid limit (LL). These limits are determined by Atterberg limit tests. The requirements for PI and LL aim to limit or eliminate contaminants like active clay in aggregate, which negatively impact performance. The fines in aggregates are typically non-plastic (NP) or marginally plastic, which creates challenges when determining PI and LL using conventional test methods—for example, materials may slide on the Casagrande cup or may not roll into 1/8-inch threads. A bar linear shrinkage (BLS) test, which measures the shrinkage limit of fine materials, is proposed as a surrogate test for these properties. The BLS test is simple, repeatable, and sensitive to the presence of active clay particles. Materials with a range of properties will be tested in the laboratory to evaluate the effectiveness of the BLS test in distinguishing low-PI materials across the acceptance range for aggregate materials and to standardize the test method for VDOT use. The study will also include an interlaboratory evaluation to quantify repeatability and reproducibility, ensuring the BLS test can be reliably incorporated into routine VDOT quality‑assurance operations.

Language

• English

Project

• Status: Active
• Funding: $230,776.00
• Contract Numbers:

  130289

• Sponsor Organizations:

  Virginia Transportation Research Council

  530 Edgemont Road
  Charlottesville, VA  United States  22903
• Performing Organizations:

  Virginia Transportation Research Council

  530 Edgemont Road
  Charlottesville, VA  United States  22903
• Principal Investigators:

  Boz, Ilker

  Hossain, Shabbir

• Start Date: 20260909
• Expected Completion Date: 20280731
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Aggregates; Atterberg limits; Liquid limits; Plasticity index; Shrinkage
• Subject Areas: Highways; Materials; Pavements;

Filing Info

• Accession Number: 02001924
• Record Type: Research project
• Source Agency: Virginia Department of Transportation
• Contract Numbers: 130289
• Files: RIP, STATEDOT
• Created Date: Sep 10 2026 9:53AM