National Center for Wood Transportation Structures

About the research

The early-age thermal development in mass concrete has a significant impact on the performance and long-term serviceability of mass concrete structures, such as bridge foundations. Great efforts have been made on predicting and controlling the thermal development in mass concrete. ConcreteWorks has been increasingly used for this purpose. However, previous research in Iowa indicated that,although user-friendly, the public ConcreteWorks program has some features that do not fit Iowa concrete well. The present research aimed at modifying the ConcreteWorks software for Iowa’s use, particularly for the prediction of thermal behavior of mass concrete elements with a smallest dimension of 6.5 feet or less.

In this study, the input and output parameters of ConcreteWorks that need to be modified for Iowa’s use were identified. The key properties (heat of hydration, thermal conductivity, mechanical properties, etc.) of typical Iowa concrete mixes required by ConcreteWorks for thermal predictions were tested. The Iowa environmental data and Iowa Department of Transportation (DOT) temperature differential limits were incorporated into the modified ConcreteWorks program. An initial soil temperature model was added.Thermal analyses were conducted on a real-time mass concrete project (the I-35 NB to US 30 WB [Ramp H] bridge) using both the unmodified and modified ConcreteWorks software as well as 4C-Temp&Stress software, and the predicted temperature developments were compared with those monitored from the field site.

The results indicate that the modified ConcreteWorks software predicts the early-age temperature profile, maturity, and strength of Iowa mass concrete quite well. As many default data in the public ConcreteWorks software are replaced with Iowa concrete values, the modified software is even more user-friendly and reliable for Iowa’s use. A hands-on workshop on learning how to use ConcreteWorks was welcomed by Iowa engineers. Recommendations are made in this report for effective use of the modified ConcreteWorks software in Iowa and for further research in this area.