The Effect of Mix Variability on Concrete Maturity Systems in Predicting Compressive Strength

The use of cylinders to measure the strength of concrete mixes often leaves much to be desired, particularly in cold weather or for fast track projects. Cylinders cured under lab conditions may not match the environment of the concrete they represent if the concrete in question is exposed to temperature extremes. Even field cures of the specimens may not provide the same conditions, given location problems and the differences in thermal mass. Concrete maturity systems seek to address this problem by embedding sensors in the concrete structure and using a calibrated strength correlation curve based on the concrete mix design properties. The curve shows the maturity function and is created by using compressive strength data. Cylinders are made, some containing temperature sensors. All are cured under the same conditions and at intervals, as specimens are broken, temperature readings are taken. This allows the strength to be referenced to degree hour values. In the field, this curve is used in reverse to obtain strength values. Since the curves are specific to the concrete mix, there is some concern as to how much the variability of plant mixes could affect the predicted results. Normal variations in aggregate, adjustments to the water content or admixtures could potentially alter the effective maturity curve. While the use of a maturity system could greatly benefit the department and the contractors, a certain confidence level is required, before it could be depended upon for quality control and quality assurance. The objective is to study the results of plant concrete mix variations on the prediction of concrete compressive strengths by the maturity method. In particular, to assess the effects on strength of the actual water-cementitious ratio in concrete in those plant concrete mixes.

    Language

    • English

    Project

    • Status: Active
    • Contract Numbers:

      SPR-2282 (202), Stud

    • Sponsor Organizations:

      Rhode Island Department of Transportation

      State Office Building, 2 Capitol Hill
      Providence, RI  United States  02903
    • Project Managers:

      Franco, Collin

    • Performing Organizations:

      Rhode Island Department of Transportation

      State Office Building, 2 Capitol Hill
      Providence, RI  United States  02903
    • Principal Investigators:

      Sock, Michael

      Awad, Haytham

    • Start Date: 20040131
    • Expected Completion Date: 0
    • Actual Completion Date: 0
    • Source Data: RiP Project 9299

    Subject/Index Terms

    Filing Info

    • Accession Number: 01458883
    • Record Type: Research project
    • Source Agency: Rhode Island Department of Transportation
    • Contract Numbers: SPR-2282 (202), Stud
    • Files: RiP, STATEDOT
    • Created Date: Jan 3 2013 12:52PM