Nondestructive Testing of Concrete Pavements for Characterization of Effective Built-In Curling
Rao, S
Graduate Research Assistant, Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL.

Roesler, JR
Assistant Professor, Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL.

(Received 4 December 2003; accepted 18 March 2005)

Abstract
Differential expansion and contraction between the top and bottom of a concrete slab results in curling. Curling affects slab stresses and deflections and is an important component of any mechanistic-empirical design procedure for concrete pavements. Although some curling is caused by temperature and moisture gradients that fluctuate daily, a significant portion of the curling can be attributed to the combined effects of nonlinear “built-in” temperature gradients, irreversible shrinkage, and creep, which can be represented by an effective built-in temperature difference (EBITD). A procedure for estimating EBITD of in situ slabs using a falling-weight deflectometer and a finite-element program is presented. This procedure was used to estimate EBITD for instrumented slabs at Palmdale and Ukiah, California. Differences in restraints (from adjacent slabs, shoulder, base friction) and variability in concrete material properties resulted in EBITDs ranging from -5°C to greater than -30°C.

Keywords:
concrete pavement, concrete pavements, curling, falling weight deflectometer, nondestructive testing, temperature and moisture curling

Paper ID: JTE12338
DOI: 10.1520/JTE12338

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Author Rao, S Affiliation Graduate Research Assistant, Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL. Author Roesler, JR Affiliation Assistant Professor, Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL. Author Rao S, Roesler JR Title Nondestructive Testing of Concrete Pavements for Characterization of Effective Built-In Curling Symposium , Committee on