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The November 12, 2025, article entitled “Geosynthetics enhance pavement design life” discussed how geosynthetics can improve the response of the granular materials used for the pavement foundation which can allow the reduction of pavement section thickness and/or increase the pavement design life.
In my opinion, one of the barriers to increasing the use of this technology in the design of pavement foundations is the ability to verify the benefit of the introduction of geosynthetic reinforcement. The issue is that improvement happens over a long period of use because one of the primary mechanisms of the reinforcement is to confine and limit the small strains that accumulate over time due to the cyclic loading from traffic.
It is difficult to evaluate the benefits and demonstrate the improved section performance in a way that can be used during construction as a quality control (QC) measure. The tools we currently use, such as falling weight deflectometer or the dynamic cone tests are too crude to capture the benefits from the effect of the geosynthetic. Long-term tests which can be helpful are costly and not practical to manage during construction.
Instrumented equipment which allows us to measure the response of a fill being compacted has been evolving for the past 20 years. This technology and other instrumentation allow us to track location and number of passes which allows the operator and inspector to verify that the required compaction effort is being done.
In addition, the instrumentation and on-board computer analyses the response from the compaction equipment which is used to output a value which is an indication of the stiffness of the section. These values can be correlated to section strength and stiffness, but they can be different from the various manufacturers of equipment. The result is the ability to see relative performance across the area and for every layer being compacted. An overview of the instrumentation would be a roller compactor which would be equipped with GPS, accelerometers and a computer capable of analyzing the location, number of passes, and a value corresponding to the accelerometer response. This is generally referred to as intelligent compaction (IC).
The question is, can IC capture change in response from an unreinforced to a reinforced section? The combination of these two technologies has the potential to improve the longevity of pavements. There is strong evidence and decades of research that demonstrates the improved performance of reinforced geomaterials vs unreinforced. In addition, IC captures stiffness value which could be used to help verify the improved performance of the reinforced section, providing an opportunity to be used as a QC measure during construction. More research and case studies on this subject would help address the question.
Intelligent compaction has other uses for the construction of an embankment since it not only detects the changes caused by the immediate layer being compacted but also the response of a deeper section. This helps us identify weak spots which were not identified during design. It also allows us to improve our quality control for the placement of the fill by obtaining more uniform support across the site. This allows us to evaluate site uniformity and identify abrupt changes to the pavement support.
As discussed in the earlier article, enhancing pavement design life is a priority. These two technologies individually can address these goals, but the combination could further reduce future maintenance, cost and congestion.
Additional information:
- Alimohammadi, H., Schaefer, V. R., Zheng, J., Jahren, C. T., Zheng, G., & White, D. J. (2021). Effectiveness of geotextiles/geogrids in roadway construction; Determine a Granular Equivalent (GE) Factor (Report No. MN 2021-26). Iowa State University. Institute for Transportation; Minnesota Department of Transportation.
- Mazari, M., Aval, S. F., Satani, S. M., Corona, D., & Garrido, J. (2021). Developing guidelines for assessing the effectiveness of intelligent compaction technology (Report No. 20-56). Mineta Transportation Institute, San José State University.
- NCHRP 933 – “Evaluating Mechanical Properties of Earth Material During Intelligent Compaction”
- White, D. J., Vennapusa, P. K., et al. (2010). Accelerated implementation of intelligent compaction technology for embankment subgrade soils, aggregate base, and asphalt pavement materials: SR-25 West Lafayette, Indiana. (Final Report ER10-09). Institute for Transportation, Iowa State University.
Daniel Alzamora, P.E., is a contributing editor for Geosynthetics and has spent more than three decades in the geosynthetics industry in both the public and private sector.