DEVELOPMENTS IN THE PREDICTION OF POTENTIAL STRENGTH OF CONCRETE FROM RESULTS OF EARLY TESTS

Relationships among degree hours of maturity and compressive strengths of untreated, 1 to 3-day-old concrete cylinders are used to develop equations for predicting minimum potential 28-day strength. The one-sided confidence limit on values is approximately predicted at f - 600 psi (f - 4140 kPa). From the results of early tests, one equation produces predicted values for mixtures of the known maturity and the known cement factor, one requires only that specimens be tested at a constant maturity, and one requires only that the maturity be known. Equations are derived by statistical methods and a regression analysis. The data were obtained from a designed experiment made up of 200 cylinders, 4 cement factors, and tests at 1,2,3, and 28 days. Equations are based on the non-linear time-temperature, or maturity, concept of the rate of gain of strength first advanced by Plowman. Predicted results are limited to 28 days and have an average coefficient of variation of 12 percent. Also discussed are the findings that predictions based on the compressive strengths of untreated cylinders, cured at about 73 F (22.8 C), are as accurate as those based on cylinders conditioned by a 3.5-hour immersion in a 200 F (93.3 C) water bath. It was found that the compressive strengths not exceeding 1,800 psi (12 400 kPa) of early test specimens tested with Celotex pressure pads are nearly equal to and have about the same standard deviation as those tested with sulfur mortar caps.

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 1-12
  • Monograph Title: Recent developments in accelerated testing and maturity of concrete
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00131687
  • Record Type: Publication
  • ISBN: 0309024668
  • Files: TRIS, TRB
  • Created Date: Jun 5 1976 12:00AM