STUDENT SPOTLIGHT: Each month, or every other month, a student will provide a 1-page illustrated abstract of the research they are currently conducting. This is a wonderful opportunity for the student, for our International Society for Concrete Pavements (ISCP) Members, and for the transferring and sharing technology/research through our concrete paving industry.
The ISCP “STUDENT RESEARCH SPOTLIGHT” for October 2025 is Connor Anderson, a PhD candidate at Texas A&M University (College Station, USA).
BIO:
Connor Anderson is a Ph.D. student in civil engineering at Texas A&M University whose work advances mechanistic–empirical modeling for concrete pavements. His research centers on the mechanics of concrete–base interfaces—specifically, improved models for bond degradation and subbase erosion and their implications for load transfer, corner deflection, and long‑term performance. He develops rigorous, data‑driven workflows that pair field deflection measurements and inverse analysis with reliability methods to quantify variance, covariance, and parameter sensitivities across materials, geometry, and environmental drivers. These methods support transparent calibration of distress models and enable agencies to better link measured structural response to predicted fatigue, faulting, and erosion over time.
Connor earned an M.S. in Civil Engineering from the University of Illinois at Urbana–Champaign, where his thesis, “Design and Performance of Continuously Reinforced Concrete Pavements,” explored design variables governing crack spacing/width, load transfer efficiency, and punchout risk in continuously reinforced concrete pavements. Earlier work investigated the use of municipal waste‑to‑energy incinerator ash to stabilize expansive soils, assessing chemical reactivity, durability, and environmental compatibility to inform specifications for sustainable ground improvement. He completed a B.S. in Civil Engineering at the University of Florida.
TITLE: Westergaard Solution Improvements
The most recent area of Connor’s addresses longstanding limitations in Westergaard’s classical solutions for rigid pavement corner deflection, with a special focus on non-symmetric slabs and real-world loading scenarios for non CRC pavements. While Westergaard’s mechanics form the basis of many modern design methods, his original formulas often fail to predict deflection accurately when slab geometry, loading position, or reinforcement is asymmetric, or when loads are close to slab corners or edges.
The innovation in Connor’s approach is within a flexible spreadsheet and code-based framework that optimizes asymmetric slab geometry and steel reinforcement to reduce stress and strain induced under corner, edge, and interior loading. This framework accommodates single-wheel and single-axle loads as well as asymmetric slab sizes and steel distributions, and environmental and set temperature stresses, to reduce global cumulative stresses as a function of fracture mechanics rather than fatigue algorithms to predict pavement performance. Importantly, it accounts for asymmetric reinforcement: the steel percentage in the x (longitudinal) and y (transverse) directions can be independently optimized for a fixed corner deflection and loading environment. By interpreting the slab as an orthotropic plate, the model minimizes total stresses while maintaining target deflection limits at the corners—an essential step for maximizing long-term performance and minimizing localized failures.
Connor’s work quantifies how varying the slab size (in both the longitudinal and transverse directions) directly impacts deflections and stresses at critical locations and can be used to optimize slab and steel geometry for a given loading environment. For example, only increasing the slab width in the x-direction or y direction reduces deflections nonlinearly, as shown in Figure 2, a response not captured by the classical theory.
Figure 1: Slab size vs Corner Deflection comparison. As slabs approach the infinite slab size boundary (L/l = 5), deflections are effectively minimized; however, stresses should analyze to avoid high bending stresses.
Through systematic comparison, Connor shows that his solutions align much more closely with numerical finite element results and full-scale field measurements than standard Westergaard models. The models also capture the effects of slab support loss, temperature curling as a function of set temperature, dowel bar efficiency in the transverse and longitudinal directions, and an optimal steel content at a given concrete thickness in both longitudinal and transverse directions, further refining design predictions. Figure 3 illustrates the slab behavior that at a fixed steel content and slab dimensions of 12 feet by 24 feet an optimal or maximum slab thickness is obtained before further increasing the slab thickness reduces the performance of the pavement. The optimal pavement thickness is obtained at the slab thickness where the lowest damage occurs with the highest level of reliability as shown in Figure 4. The green line in Figure 4 indicates the optimal slab thickness at which the least damage occurs with the highest reliability for a given loading environment and is the same thickness as the optimal or max slab thickness in Figure 3. These improvements permit engineers to set desired deflection and stress limits for specific layouts, material strengths, and environmental scenarios—yielding durable, reliable pavements optimized for real-world variability and asymmetric conditions.
Figure 2: Optimal Slab Thickness at Fixed Geometry and Reinforcement Steel percentage
Figure 3: Reliability vs Damage; The optimal pavement thickness is the thickness where the lowest damage occurs at the highest reliability, as indicated by the green line.
In summary, Connor’s research provides both a theoretical and practical advancement in pavement engineering, supplying robust yet user friendly spreadsheet-driven tools for design and evaluation that move beyond the limitations of classical Westergaard theory and address the key factors that truly impact pavement life and performance.
ISCP would like to feature a “STUDENT RESEARCH SPOTLIGHT” each month, or every other month. If you would like to nominate a student, or if you are a student and would like to nominate yourself or a colleague, please send ISCP an email to: newsletter@concretepavements.org