Evaluating the Application of Reinforcement Correction Factor for Concrete Core Testing

Document Type : Regular Paper

Authors

Department of Civil Engineering, University of Guilan, P.O. Box 3756, Rasht, Iran

Abstract

This study investigates the reinforcement correction factor of concrete core in more detail to prepare appropriate outlines for interpretation of results. This investigation aims to minimize uncertainties involved to carry out the more realistic condition assessment of suspect buildings before taking up retrofitting/strengthening measures. For this purpose, an extensive experimental program including different concrete strength level, moisture condition, core size, length-to-diameter (L/D) ratio of core and steel bar size with various configurations was under taken. The effect of variation of foregoing parameters on the ratio of average compressive strength of cores containing steel bars to that of corresponding plain specimens was probed. The results show that the correction factors are highly dependent on the values of volume percentage and position of reinforcing bars in the core, which are extremely interrelated. Hence, the experimental results do not show a good agreement with the provisions by the British Standard 6089 and Concrete Society Report No.11. Therefore, a statistical analysis on the prediction of cube compressive strength using linear and nonlinear regression models is accomplished. The results showed that regression models have great ability as a feasible tool for prediction of compressive strength on the basis of core testing in the presence of steel bars. However, the most accurate results obtained by nonlinear equations in comparison with linear models.

Keywords

Main Subjects

References

[1] Bungey JH, Millard SG and Grantham MG (2006) Testing of concrete in structures. Fourth ed., Taylor & Francis, London and New York, 352p.
[2] Bungey JH (1979) Determining concrete strength by using small-diameter cores. Magazine of Concrete Research 31(107): 91-98.
[3] Neville AM (1996) Properties of concrete. Fourth ed., John Wiley and Sons, Inc., New York, 844p.
[4] Meininger RC, Wagner FT and Hall KW (1977) Concrete core strength-the effect of Length to Diameter ratio. Journal of Testing and Evaluation, 5(3): 147-153.
[5] Yip WK and Tam CT (1988) Concrete strength evaluation through the use of small diameter cores. Magazine of Concrete Research, 40(143): 99-105.
[6] Munday JGL and Dhir RK (1984) Assessment of in situ concrete quality by core testing. In Situ/Nondestructive Testing of Concrete. SP-82, American Concrete Institute, Detroit, 393-410.
[7] Gaynor RD (1965) Effect of horizontal reinforcing steel on the strength of molded cylinders. J. Am. Concr. Inst., 62(7): 837-840.
[8] Loo YH, Tan CW and Tam CT (1989) Effects of embedded reinforcement on measured strength of concrete cylinders. Magazine of Concrete Research, 41(164): 11-18.
[9] Khoury S, Aliabdo AA and Ghazy A (2014) Reliability of core test – Critical assessment and proposed new approach. Alexandria Engineering Journal 53: 169–184.
[10] Neville A (2001) Core tests – Easy to perform, not easy to interpret. Concrete International, 23(11): 59–68.
[11] ASTM (2008) C42: Standard method of obtaining and testing drilled cores and sawn beams of concrete. American Society for Testing and Materials, Philadelphia.
[12] Meininger RC (1968) Effect of core diameter on measured concrete strength. Journal of Materials, 3(2): 320-336.
[13] Lewis RK (1976) Effect of core diameter on the observed on the strength of concrete cores. Research Report No.50, Commonwealth Scientific and Industrial Research Organization, Division of Building Research, 13 pp.
[14] Campbell RH and Tobin RE (1967) core and cylinder strengths of natural and lightweight concrete. ACI Journal, Proceedings 64(4): 190-195.
[15] Bartlett FM and MacGregor JG (1994) Effect of Moisture Condition on Concrete Core Strengths. ACI Materials Journal, 91(3): 227-236.
[16] Seber GAF and Lee AJ (2003) Linear Regression Analysis. Second Edition, John Wiley & Sons Inc
[17] Montgomery DC (2013) Design and Analysis of Experiments. John Wiley & Sons, Inc., eighth ed., Arizona State University.

Files

Cited by

History

  • Receive Date: 05 May 2018
  • Revise Date: 31 May 2018
  • Accept Date: 14 July 2018

Share

How to cite

Statistics