CAIT project no.: 164 RU9355
Fiscal Year: 2005/2006
Rutgers-CAIT Author(s): Hani Nassif, Husam Najm
External Author(s): Edward Kondrath (NJDOT Project Manager)
Sponsor(s): NJDOT, USDOT
This report summarizes the two-phase research on Self-Consolidating Concrete (SCC) in New Jersey. Phase I involves collecting actual field SCC mixes that were used for casting non-structural concrete components such as tee walls and noise walls. In addition, laboratory mixes were also made to evaluate the mechanical properties and the durability of SCC with various pozzolanic materials. In Phase II, the feasibility of using SCC in drilled shaft construction was evaluated on the new viaduct construction at the intersection of the GSP/I280 near Newark, NJ. SCC was used in the drilled shaft foundations of this project as part of the NJDOT’s SCC implementation plan with support from the Innovative Bridge Research and Construction Federal program.
Fresh mix tests as well as visual inspection were performed; and specimens were collected to perform laboratory tests. All three shafts were instrumented with temperature sensors and cross-hole sonic logging (CSL) along the shaft length. Results from Phase I and II showed that SCC can be successfully made using viscosity modified admixture (VMA) or solely using super plasticizer (namely the polycarboxilate type) by properly adjusting the paste volume and coarse to fine aggregate ratios. SCC can also be made to equivalently match the mechanical properties and durability of high-performance concrete (HPC) by substituting Portland cement with pozzolans and other cementitious materials. Furthermore, based on the observations of the field mixes, more fundamental knowledge on SCC need to be disseminated to the contractor. It is recommended that the spread test be used in the field for classifying the fresh concrete properties of SCC as a screening test. For more quantitative results, it is recommended that the spread test be used in conjunction with other segregation tests, such as the J-ring test in order to determine the consistency of the mix.