EFFECT OF HIGH CURING TEMPERATURE ON MECHANICAL PROPERTIES OF CONCRETE

Abstract

It has been shown that Concrete increases in strength with age after setting. The strength at a particular age can be further increased by suitable curing of the concrete while it is maturing. Such curing comprises the application of heat and/or the preservation of moisture within the concrete. In this research work, an attempt has been made to study the influence of elevated curing temperature on mechanical properties of concrete. Mechanical properties such as comprehensive strength and pullout strength were investigated. Concrete Specimens were cured under three different temperatures and curing age 30⁰C, 60⁰C and 100⁰C and 7, 14 and 28 days respectively. Compression test and pull out test were conducted on concrete cubes. The results showed strong positive relationship with correlation coefficient 0.779 between number of days and strength of concrete and the P–value 0.004 implies that the relationship is significant at 5% level while the coefficient of Determination (COD) indicates that number of days have 60.75% effect on strength of concrete. Correlation coefficient 0.932 with a P-value 0.013 and COD of 86.79% indicate that temperature has a very strong effect on strength of concrete. The regression analysis showed a unit increase in temperature will lead to 0.062 N/mm² increase in the strength of concrete. However the rate of concrete strength at the increase in temperature is lower than the increase in number of days, this implies a tendency for concrete to be weak in future with increase in temperature especially above boiling point. 

Keywords

• Concrete,curing,compressive strength,pullout strength,elevated temperature

References

1. Chithra S. and Dhinakaran G. 2014, “Effect of hot water Curing and hot air oven curing on admixed concrete”, International Journal of ChemTech Research CODEN (USA); Vol.6, NO.2, PP 1516-1523.
2. Cebeci, O.Z., 1987, “Strength of concrete in Warm and Dry Environment”, Materials and Structures, Vol.20, pp. 270-222.
3. Eliverly, R.H. and Evans, E.P. 1964, “The effect of curing condition on physical properties of concrete”, Magazine of Concrete Research, Vol.16, NO.46, pp. 11-20.
4. Konstantin, K, Isaak, S, Shin, I, and Aron, B, 2000, “Influence of Mixture Proportions and curing conditions on compressive strength of High-performance concrete”. ACI Materials Journal, Vol.97, NO.1, pp.25.
5. Selman, M.H., 2001, “Effect of Hot Weather on the Mechanical Properties of Concrete Produced using local Furnace slag”. M.Sc. Thesis, Al-Mustansiriyah University, Baghdad, Iraq, pp.29,43.
6. Klieger, P.H., 1958, “Effect of Mixing and Curing on Concrete Strength”, ACI Journal, Proceeding, Vol.54, NO.12, pp.1063-1081.
7. Lo. TY, Nadeem A, Tang WCP, Yu PC, 2009, “The effect of high temperature curing on the strength and carbonation of pozzolanic structural lightweight concretes, Construction and Building Materials”, 23: 1306-1310.
8. Cecconello, V and Tutikkian, B 2010 The Influence of low Temperature on the Evolution of Concrete Strength Journal of Rev. IBRACON Estrut. Mater Vol. 5 NO.1, pp. 1-15