PREVENTION OF CRACKS IN CONCRETE BRIDGE DECKS: REPORT ON LABORATORY INVESTIGATIONS OF CONCRETE SHRINKAGE

Transverse cracking in newly constructed concrete bridge decks is a concern in Pennsylvania. The cause of this type of cracking is shrinkage of hardened concrete. The research reported here focuses on examining the effects of aggregate source, cement source, and fly ash on shrinkage. Laboratory experiments were designed utilizing the types of aggregate, cement, and fly ash typically used in Pennsylvania. Accordingly, concrete mixes were produced and tested for temperature rise during curing (indication of thermal shrinkage) and for drying shrinkage. The results show the significant effect of mix ingredients on shrinkage.