The Midwest Transportation Center (MTC) sponsors a competitive research program to fund projects focused on State of Good Repair in infrastructure with attention to safety and Data Driven Performance Measures for Enhanced Infrastructure Condition.
The following details one project led by Iowa State University. Stay up to date on research conducted by the MTC here.
Iowa State University
Development and Evaluation of a Portable Device for Measuring Curling and Warping in Concrete Pavements
Project PI: Halil Ceylan
Portland cement concrete (PCC) pavement undergoes repeated environmental load-related deflection resulting from temperature and moisture variations across the pavement depth. This has been recognized as resulting in PCC pavement curling and warping since the mid-1920s.
Slab curvature can be further magnified under repeated traffic loads and may ultimately lead to fatigue failures, including top-down and bottom-up transverse, longitudinal, and corner cracking. Measuring the true degree of curling and warping in PCC pavements is therefore significant, not only for quality control (QC) and quality assurance (QA), but also for obtaining a better understanding of its relationship to long-term pavement performance.
Several approaches and devices, including linear variable differential transducers (LVDT), digital indicators, and some profilers, have been proposed for measuring curling and warping. However, their application in the field has been limited by cost, inconvenience, and complexity of operation.
Due to this, the objective of this research was to develop a simple, portable, reliable, and economical device to be used primarily for measuring curling and warping in concrete pavements with an accuracy comparable to or better than that of existing methodologies.
Some key findings of this research included the following:
- Based on the field tests, the accuracy and repeatability of the implementation of the finalized ISU curling and warping measurement device satisfy the requirements of curling and warping measurements in the field.
- The final version (fourth generation) of this instrument has two main columns 12 in. high and weighs 18 lbs. The unit can be easily carried and used in the field by one adult.
- Two levels of resolution (0.05 in. and 0.001 in.) can be achieved using either a measuring gauge and/or digital height gauge, depending on project requirements and the total degree of curling and warping. If the degree of curling and warping is small, the higher resolution ruler should be used.
- The horizontal measuring range is 30 ft, depending on the length of string used; longer strings can be used if the slab is longer than 30 ft.
- The total cost of this instrument is about $320.