Internal Curing for Concrete Bridge Decks: Integration of a Social Cost Analysis in Evaluation of Long-Term Benefit

Internal curing is a new approach to the proportioning of concrete mixtures in which a portion of the fine aggregate in concrete is replaced by prewetted lightweight fine aggregate. Internally cured concrete has the potential to extend the service life of bridge decks substantially because of reduced cracking and chloride ingress. Although internally cured concrete has been used, its use is limited because of the slight increase in the initial cost and need for an understanding of batching operations and performance of quality control. Even though some cost–benefit studies have been performed, the potential life-cycle benefits of internal curing may be significantly underestimated because the social costs (network traffic disruptions) have not been integrated into previous studies. This study evaluated the total life-cycle benefits of bridge decks made of high-performance concrete with internal curing (HPC-IC) by a comparison of such bridge decks with bridge decks made of normal concrete (NC). Three bridges on an Interstate highway, an arterial road, and an urban connector were selected to examine the total life-cycle costs of bridge decks made of NC, high-performance concrete, and HPC-IC. The results suggest that the total life-cycle costs of bridge decks made of HPC-IC might be reduced by 50% compared with those of bridge decks made of NC and that the scale of reduction of social costs depends on the bridge traffic volume. The study provides insights that relevant decision makers can use to determine whether the internal curing process should be used in bridge deck management activities so that limited resources can be more effectively allocated on the basis of the potential benefits.