Removing heat from mass cement concrete footings during initial construction is vital to ensure the quality of the footings after curing. When the temperature of concrete exceeds 70 deg C, heat released from the hydration of cement can initiate microscopic cracks that may grow larger during or after curing. The temperature of a mass concrete structure can be controlled by various means, depending on the situation. With temperature data collected from a large footing for a bridge column of the ongoing I-580/I-680 Interchange Project, temperature variations were modeled with time and location in a large concrete footing by means of the Fourie-Biot heat conduction equation. Agreement between analytic predictions and field data was found for the physical parameters characterizing the reactions and material properties of the concrete. Possible ways of lowering the concrete temperature are suggested for the future San Francisco-Oakland Bay Bridge East Spans Project.
Samenvatting