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Accession Number PB2013-100598
Title Self-Consolidating Concrete-Applications for Slip-Form Paving: Phase II.
Publication Date May 2011
Media Count 138p
Personal Author B. Steffes J. Grove K. Wang P. Taylor P. Wiegand S. P. Shah
Abstract The goal of the project was to develop a new type of self-consolidating concrete (SCC) for slip-form paving to simplify construction and make smoother pavements. Developing the new SCC involved two phases: a feasibility study (Phase I sponsored by TPF-5(098) and concrete admixtures industry) and an in-depth mix proportioning and performance study and field applications (Phase II). The phase I study demonstrated that the new type of SCC needs to possess not only excellent self-consolidating ability before a pavement slab is extruded, but also sufficient green strength (the strength of the concrete in a plastic state) after the extrusion. To meet these performance criteria, the new type of SCC mixtures should not be as fluid as conventional SCC but just flowable enough to be self-consolidating. That is, this new type of SCC should be semi-flowable self-consolidating concrete (SFSCC). In the phase II study, effects of different materials and admixtures on rheology, especially the thixotropy, and green strength of fresh SFSCC have been further investigated. The results indicate that SFSCC can be designed to (1) be workable enough for machine placement, (2) be self-consolidating without segregation, (3) hold its shape after extrusion from a paver, and (4) have performance properties (strength and durability) comparable with current pavement concrete. Due to the combined flowability (for self-consolidation) and shape-holding ability (for slip-forming) requirements, SFSCC demands higher cementitious content than conventional pavement concrete. Generally, high cementitious content is associated with high drying shrinkage potential of the concrete. However, well-proportioned and well-constructed SFSCC in a bike path constructed at Ames, IA, has not shown any shrinkage cracks after approximately 3 years of field service. On the other hand, another SFSCC pavement with different mix proportions and construction conditions showed random cracking. The results from the field SFSCC performance monitoring implied that not only the mix proportioning method but also the construction practice is important for producing durable SFSCC pavements. A carbon footprint, energy consumption, and cost analysis conducted in this study have suggested that SFSCC is economically comparable to conventional pavement concrete in fixed-form paving construction, with the benefit of faster, quieter, and easier construction.
Keywords Admixtures
Concretes
Construction
Durability
Flexibility
Flowability
Green strength
Monitoring
Pavements
Performance evaluation
Rheology
Slipform self-consolidating concrete(SFSCC)


 
Source Agency Department of Transportation
Federal Highway Administration
NTIS Subject Category 50C - Construction Equipment, Materials, & Supplies
50A - Highway Engineering
Corporate Author Iowa State Univ., Ames. Institute for Transportation. National Center for Concrete Pavement Technology.
Document Type Technical report
Title Note Final rept.
NTIS Issue Number 1305
Contract Number DTFH61-06-H-00011

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