01088355

Component

For cast-in-place applications, the self-consolidating concrete (SCC) has to satisfy the basic requirements such as flowing ability, passing ability and resistance to segregation, in addition to pumpability, for delivery times up to 90 minutes. These properties depend on the type of materials used, mix design (e.g. water/cement ratio and admixture content), placing temperature and delivery time. This paper presents the development of SCC mix recipe and testing procedures to confirm ability for on-site bridge applications. The first step involved investigation of the performance of High Range Water Reducers (HRWR) for different delivery times and impact of the viscosity modifying admixture (VMA) on mortar flowability. It was found that the addition of VMA has to be compensated with an extra dosage of the HRWR. Trials on mortars also showed that high dosage of VMA can significantly reduce the workability time. Slump flow retention curves were obtained for the selected SCC mixes. Two different types of retarding admixtures were checked for their ability to extend the workability time. The effect of Air Entraining Admixture (AEA) on air content and compressive strength was investigated. The second step involved testing the selected SCC recipe on four walls (4 ft high), each one with the mix poured at a different delivery time. This test also checked the passing ability of the mix as the minimum spacing between bars was ¾ in. In another test, the mix was pumped for over 300 ft to verify the pumpability and its impact on the fresh concrete properties.

01084478

08-2265

English

15p

2008

Transportation Research Board 87th Annual Meeting

DVD

Figures; Photos; References (16)

Admixtures; Air entrained concrete; Bridge design; Mix design; Self compacting concrete; Types of concrete; Viscosity; Workability

Bridges and other structures; Highways; Materials; I32: Concrete

Transportation Research Board Annual Meeting 2008 Paper #08-2265

TRIS, TRB

Jan 29 2008 4:36PM