Investigation into Shrinkage of High-Performance Concrete Used for Iowa Bridge Decks and Overlays – Phase II Shrinkage Control and Field Investigation

Project Details







Kejin Wang, Yifeng Ling, Gilson Lomboy, Sri Sritharan


Iowa Department of Transportation


Bridge decks, Cement, Concrete overlays, Field tests, High performance concrete (HPC), Laboratory tests, Shrinkage

Project description

This Phase II research project on the shrinkage behavior of high-performance concrete (HPC) used in Iowa bridge decks and overlays evaluated several concrete mixes, building off or modifying mixes developed in Phase I. Based on shrinkage behavior and mechanical properties, the mixes studied in Phase I were characterized as having either high, medium, or low cracking potential. In the Phase II study, three concrete mixes (Mixes 6, 8, and 2, characterized in Phase I as having high, medium, and low cracking potential, respectively) were selected for further investigation. The selected mixes were modified using three shrinkage control technologies: shrinkage-reducing admixtures (SRAs), cementitious materials (CM), and internal curing (IC) agents, respectively. The modification methods were first studied in a laboratory until the optimal shrinkage behavior of each concrete mix was achieved. Two pairs of the tested concrete mixes (Mixes 6 and 8 with and without modification) were then used in a field investigation on the US 20 over I-35 dual bridge. The mixes were placed side by side for the bridge overlays, which were monitored for about one year with strain gages, temperature and moisture sensors, and regular visual examinations. The laboratory investigation confirmed positive effects for the concrete shrinkage control technologies used. The laboratory test results also provided specific details for the concrete mix modifications, ensuring optimal concrete performance and shrinkage control.