Performance of Blended Cements in Iowa Pavements

Abstract

Blended cements incorporate supplementary cementitious materials such as fly ash, slag, silica fume, and natural pozzolans, enhancing resource efficiency and reducing waste. Despite these environmental benefits, concerns remain about their impact on concrete pavement performance and durability. Data from the Iowa Department of Transportation’s pavement management system was used to compare the performance and durability of projects utilizing blended cements against those using I/II cement. Key quality characteristics analyzed included the workability-coarseness factor, air content before and after paving, water-to-cementitious materials ratio, and flexural strength. While some pavement sections showed poor performance, most remained within acceptable ranges, with no practical differences in overall performance between blended cements and I/II cement. Statistical analysis identified specific differences in the pavement condition index, international roughness index, and faulting between IP(25) and IS(20) compared to I/II cement. Significant PCI and faulting differences were also found between IS(25) and I/II cement, along with PCI and IRI differences between IS(35) and I/II cement. Despite these statistical findings, quality characteristic data showed no significant differences, and contractors using blended cements achieved incentives comparable to those using I/II cement. These results suggest that while some differences exist at a detailed level, they do not translate into meaningful disadvantages for blended cements in overall pavement performance. Overall, blended cements can perform comparably to I/II cement in both short-term and long-term durability, allowing the concrete industry to balance performance with sustainability for more durable and eco-friendly pavements. Successful practices included optimized mix design, ternary mixes, contractor quality control, innovative testing methods, and proper curing techniques.