Completed Research: Treating Highly Plastic Clays with Cement
In partnership with Raba Kistner, CCT completed a study evaluating cement (Type I/II and Type IL) and lime-cement combinations to improve Texas clays with a wide range of plasticity indices. The research confirmed that even highly plastic clays can be successfully stabilized with cement, reducing swell potential while significantly increasing strength and support capacity. Type IL cement also performed comparably to Type I/II, providing an additional sustainable option for future projects.
Researchers tested low-, medium-, and high-plasticity soils using unconfined compressive strength (UCS), California Bearing Ratio (CBR), Dynamic Cone Penetrometer (DCP), and lightweight deflectometer (LWD) evaluations. Results showed that as soil plasticity increased, combined lime-cement treatment often delivered the strongest overall performance. The findings support performance-based specifications that give engineers greater flexibility to select the most effective treatment method for challenging soil conditions.
Ongoing Research: Full-Depth Reclamation (FDR) with Cement
At The University of Texas at El Paso (UTEP), CCT is supporting research on Full-Depth Reclamation (FDR) with cement to better understand structural capacity, strength development, and opening time to traffic. Interim findings show cement-treated recycled pavement mixtures gain strength rapidly, achieving substantial capacity within the first several days of curing. The study also demonstrates that increasing cement content can significantly improve layer stiffness and structural performance.
Figure 3. FDR with Cement Samples in Curing Chamber.
Researchers found that approximately 85% of long-term strength was achieved after seven days of curing, with continued gains thereafter. Analytical modeling further indicated that stronger FDR layers could allow reduced pavement thickness in certain designs, creating more efficient rehabilitation strategies. Ongoing work is evaluating shrinkage-cracking potential and additional mix designs to optimize long-term field performance.
Figure 4. Indirect Tensile Strength Testing of FDR with Cement Sample
Ongoing Research: Advancing Type IL Cement in Concrete Pavements
Texas A&M Transportation Institute (TTI) is leading an ongoing project evaluating Type IL cement from multiple suppliers across Texas and neighboring regions. The study includes material characterization, reactivity testing, and concrete mixture performance assessments to better understand how source variability may influence paving applications. Early findings show relatively consistent chemistry among the cements tested, supporting confidence in broader Type IL implementation.
Ten Type IL cement samples from various producers are undergoing advanced laboratory evaluation, including X-ray fluorescence, particle size analysis, calorimetry, and mineralogical testing. Preliminary results indicate a narrow range of limestone contents and overall composition, while also identifying particle size differences that may affect workability, hydration, and fresh concrete behavior. The next phase will compare hardened concrete performance and durability characteristics relevant to pavement construction.
Investing in Texas Solutions
From expansive soils to pavement rehabilitation and sustainable cement technologies, these projects reflect CCT’s mission to provide research-driven solutions for Texas infrastructure. By partnering with leading universities and research institutions, CCT continues to deliver practical knowledge that improves durability, performance, and long-term value for the communities we serve.