Large-scale testing of shrinkage mitigating concrete

Early-age cracking on concrete bridge decks is a major concern because it leads to premature deterioration of bridges. This study experimentally investigates the effects of restrained drying shrinkage on bridge decks using three 2 x 3 m experimental concrete slabs designed to simulate a portion of a bridge deck. The large-scale experimental bridge slabs used in this study were designed to closely replicate the restraint found in the field. Three different concrete mixtures are evaluated including (1) a mixture containing 100% portland cement, (2) a mixture incorporating Type-K cement, and (3) a mixture containing partially saturated lightweight fine aggregate to promote internal curing. As expected, the deck-containing Type-K cement had the highest initial expansion, but the internally cured concrete deck exhibited less shrinkage compared to both the control and the Type-K mixtures and adequately reduced the onset of cracking owing to restrained drying shrinkage.