Application of VFC Mixtures in Rapid Pavement Construction

With over 4 million miles of roadways in the United States, pavement maintenance and construction represents a significant portion of federal and state funding for infrastructure. Compounding these financial burdens are the significant indirect costs to users during construction. The present study aims at applying cost-effective concrete materials for rapid pavement construction. The main idea is to utilize high performance concrete that is being developed in another project of Research on Concrete Applications for Sustainable Transportation (RE-CAST) Center in accelerated pavement construction. To decrease the level of the effort for placing concrete pavements and reduce the cost, and to produce durable pavements are the areas of focus in this project. The approach to develop cost-effective concrete mixtures to be used in accelerated pavement construction is to develop flowable concrete with adaptive rheological properties to be used in slip form paving. Slip form paving is a process including the placement, casting, consolidating and finishing the surface of the concrete. Concrete is usually dumped in front of the paving machine and after the machine has moved over the concrete, concrete is spread out on the base while holding its slab shape. The typical concrete used for slip form paving is a mixture with less than 2.0 in. slump value. In order to consolidate the fresh concrete, extensive vibration energy is introduced to the concrete through equally spaced internal vibrators. However, if the vibration frequency is not set correctly or the paver moves slower than it should, the mixture will be over-vibrated (Tymkowicz and Steffes 1996). This may lead to a decrease in the entrained air content, as well as increasing the bleeding and segregation potential which may result in cracking along the path of vibrators if such pavement is subjected to heavy traffic load (Ardani et al. 2003). Furthermore, a decrease in the entrained air content of the fresh concrete makes the hardened concrete susceptible to damage due to freeze and thaw cycles and scaling. To solve such problems, it would be desirable to eliminate the vibration required for consolidating the concrete. This means that the concrete should be modified to reach higher workability while avoiding the shape stability to be in danger. The goal is to design a concrete mixture that reaches maximum consolidation with minimum compaction energy while maintaining the desired slab shape. This requires improving the flowability of the mixture while maintaining the green strength. Green strength is defined as the strength of the freshly cast concrete determined by the weight of sand that a cylindrical fresh concrete sample can resist until collapse happens. A typical green strength of 0.15 up to 0.6 psi (10-40 kPa) is suggested (Wang et al. 2005). Self-consolidating concrete (SCC) mixtures suitable for use in slip form pavement applications are not as flowable as the typical SCC used for structural applications. A slump value about 8 in. (200 mm) and spread of 13-15 in. (350±25 mm) are obtained with the regular short cone shape after the slump cone was removed (Wang et al. 2005, 2011). Feasibility of producing SCC for pavement applications has been demonstrated in earlier studies (Pekmezci et al 2007). SCC was also reported to be applicable in slip form pavement constructions by Voigt et al. (2010). Increasing the fine content in the concrete mixture, as well as increasing the total cementitious materials was used as a method of producing the desired concrete. Class “F” fly ash, magnesium oxide, and three types of clay were also used as replacements for Portland cement for enhancing both the engineering properties and the environmental aspects (Voigt et al. 2010). To avoid further confusion, the “SCC” for slipforming is named “vibration-free concrete” (VFC) in the remainder of this proposal. Due to the increasing amount of paste and the cementitious materials content in SCC/VFC mixtures, shrinkage and cracking potential will be an issue compared to the conventional concrete mixtures (Lomboy et al. 2011). It is required to focus on optimizing the mix design in terms of the paste content, Portland cement content, w/cm, and incorporation of proper types and amounts of shrinkage reducing admixtures (SRAs) to decrease the shrinkage and control cracking potential in hardened concrete. The project performed at Iowa State University (Wang et al., 2011) has revealed the economical and ecological feasibility of slip-form VFC mixtures. Although the material cost of VFC is higher, the total pavement construction cost can be made comparable to standard slipforming. In the top of Fig. 1, the reference conventional concrete mixture is C3 (slip f). All other mixtures to the left of the QMC (which is an economical and ecological conventional pavement concrete) are VFC mixtures. The bottom graph shows the ecological aspect in terms of CO₂ emissions for materials, production and placement. The VFC mixtures show generally better performance than the conventional C3 (slip f) mixture. With the further advances in selection of aggregates and binders proposed in this project, the research team is convinced that the material and placement costs and CO₂ emission can be further reduced.


  • English


  • Contract Numbers:


  • Sponsor Organizations:

    Office of the Assistant Secretary for Research and Technology

    University Transportation Centers Program
    Department of Transportation
    Washington, DC  United States  20590
  • Managing Organizations:


    Rolla, MO  United States  65409
  • Project Managers:

    Shin, Hak-Chul

    Feys, Dimitri

  • Performing Organizations:


    Rolla, MO  United States  65409
  • Principal Investigators:

    Shin, Hak-Chul

    Feys, Dimitri

  • Start Date: 20160601
  • Expected Completion Date: 20180630
  • Actual Completion Date: 0
  • USDOT Program: University Transportation Centers
  • Subprogram: Research

Subject/Index Terms

Filing Info

  • Accession Number: 01601648
  • Record Type: Research project
  • Source Agency: Research on Concrete Applications for Sustainable Transportation (RE-CAST)
  • Contract Numbers: DTRT13-G-UTC45
  • Files: UTC, RiP
  • Created Date: Jun 1 2016 2:19PM