Development of Self-Consolidating Concrete for Bridge Girders and Evaluation of Its Fresh Properties

Self-consolidating concrete (SCC) has been developed for use in precast prestressed concrete bridge girders in the state of Minnesota. Locally available materials were used with a number of cementitious and filler materials, including ASTM Type III cement, Class C fly ash, and blast furnace slag. SCC was successfully proportioned with both natural river gravels and crushed stone as coarse aggregates. Moreover, for the mix incorporating natural river gravels, air-entrained SCC was successfully developed without using a viscosity enhancing admixture. The effect of a number of parameters on the fresh properties of SCC, including but not limited to temperature, cement, type of coarse aggregates (natural and crushed), were studied. A number of test methods (e.g., slump flow, L-box, and U-box) have been under development to evaluate the fresh properties of SCC. However, none of these test methods has been integrated into any American standards. A vertical column segregation test has been used to evaluate vertical segregation of SCC mixes. The slump flow test was employed to evaluate the flowability, while self-leveling and passing abilities of the mixes were investigated using a U-box. The L-box test procedure was modified to evaluate, not only flowability and passing ability, but also horizontal segregation resistance of SCC mixes. Although, in general, at least three to four test methods are typically used to evaluate fresh properties, the slump flow test and modified L-box test may be adequate to evaluate the fresh properties of SCC properly.