In finished PCC pavements, over-consolidation may occur if the mix is not properly designed. Over-consolidation is noted when longitudinal trails can be visually observed in the surface. These "vibrator trails" run parallel to each other with spacing similar to that of the vibrators on pavers. Cores taken from vibrator trails have revealed many instances where the hardened concrete contains less than 3% air, rather than 6%-7% as designed, thus significantly reducing concrete freeze-thaw durability. Although measures can be taken to monitor the frequency of vibrations, vibrations are still inevitable. It would be a revolutionary advancement in paving technology if the vibration of pavement concrete could be eliminated.

The goal of the proposed research is to develop a new type of self-consolidating concrete (SCC) for slip form paving. It is envisioned that SCC will produce more workable concrete and smoother pavements, better consolidation of the plastic concrete, and higher rates of production.

The project will begin with a feasibility study to determine whether subsequent phases will be conducted. A technical advisory committee (TAC) will be formed from participants on the project. The TAC will guide the project and make the decision whether or not to proceed past the feasibility phase. The proposed research will have four phases: (1) feasibility study, (2) lab study on mix design of slip form SCC, (3) field investigation of slip form SCC paving and final project report preparation, and (4) performance monitoring.

Phase I - $5,000 by 5 states This project will also include industry and FHWA participation.