Adiabatic Temperature Rise of Incompletely Hydrated Cement Concrete

Abstract:

The temperature rise of concrete during hardening is intimately related to the mix proportion, among which the cement content is a major factor. However, high-strength concrete mixes are often proportioned with low water contents which leads to incomplete hydration of cement contained therein. Hence, the conventional rule of determining concrete temperature rise solely based on the cement content may not yield accurate estimations. An experimental program has been launched to investigate the coupled effects of cement and water contents on the adiabatic temperature rise of concrete. Eighteen concrete mixes were tested with a newly developed semi-adiabatic curing test method and their adiabatic temperature rise obtained by applying heat loss compensation to the test results. The results revealed that, when the water/cement ratio is lower than 0.36, both cement and water contents have effects on the adiabatic temperature rise of concrete. Prediction formula and design chart of adiabatic temperature rise, which are accurate to ±1.3°C compared with the test results, are developed. Furthermore, prediction formula of the degree of hydration of concrete is recommended.

• Periodical: Key Engineering Materials (Volumes 400-402)
• Pages: 157-162
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.400-402.157
• Online since: October 2008
• Authors: P.L. Ng, I.Y.T. Ng, A.K.H. Kwan
• Keywords: Adiabatic Temperature Rise, Cement Content, Heat Loss Compensation, Semi-Adiabatic Curing Test, Water Content

References

[1] M.E. FitzGibbon, Large pours - 2, heat generation and control, Concrete, Vol. 10, No. 12, 1976, pp.33-35.

[2] P.B. Bamforth, An Investigation into the Influence of Partial Portland Cement Replacement using either Fly Ash or Ground Granulated Blast Furnace Slag on the Early Age and Long-Term Behaviour of Concrete, Taylor Woodrow Research Report 014J/78/2067, Southall, UK, (1978).

DOI: 10.1680/iicep.1980.2377

[3] T.C. Hansen, Physical structure of hardened cement paste, a classical approach, Materials and Structures, Vol. 19, No. 114, 1986, pp.423-436.

DOI: 10.1007/bf02472146

[4] S.J. Pantazopoulou and R.H. Mills, Microstructural aspects of the mechanical response of plain concrete, ACI Materials Journal, Vol. 92, No. 6, 1995, pp.605-616.

[5] S. Smeplass and M. Maage, Heat of hydration of high-strength concretes, in: Proceedings of the Second International Symposium on Utilization of High-Strength Concrete, ACI SP-121, edited by W.T. Hester, American Concrete Institute, USA, 1990, pp.433-456.

DOI: 10.14359/2557

[6] P.L. Ng, I.Y.T. Ng and A.K.H. Kwan, Heat loss compensation in semi-adiabatic curing test of concrete, ACI Materials Journal, Vol. 105, No. 1, 2008, pp.52-61.

DOI: 10.14359/19207

[7] R.H. Mills, Factors influencing cessation of hydration in water cured cement pastes, in: Proceedings of the Symposium on the Structure of Portland Cement Paste and Concrete, Special Report -o. 90, Highway Research Board, Washington D.C., USA, 1966, pp.406-424.

[8] A.K. Schindler and K.J. Folliard, Heat of hydration models for cementitious materials, ACI Materials Journal, Vol. 102, No. 1, 2005, pp.24-33.

[9] I.Y.T. Ng, P.L. Ng and A.K.H. Kwan, Effects of cement and water contents on adiabatic temperature rise of concrete, ACI Materials Journal, 2008, in press.