Setting time: An important criterion to determine the length of the delay period before steam curing of concrete

Some precast concrete plants expose freshly made concrete elements to steam curing immediately after casting. This is detrimental to properties of the product; therefore, some delay prior to the steam curing process is beneficial. This paper contains the results of an investigation on the effects of various delay intervals selected based on initial setting time of concrete. Four different delay periods and two different steam curing periods at 80 °C (5 and 10 h) were used with two concrete types, namely C25 and C40. Compressive strength tests were performed at 1, 3, 7, 28, and 90 days. Setting time of the concrete was found to be an important criterion to determine the length of the delay periods.

[1]  C. D. Lawrence,et al.  Deterioration of heat-cured mortars due to the combined effect of delayed ettringite formation and freeze/thaw cycles , 1997 .

[2]  Michael Gasser,et al.  Mechanism of Sulfate Expansion in Hydrated Portland Cement , 1988 .

[3]  Odd E. Gjørv,et al.  Performance of concrete under different curing conditions , 1996 .

[4]  Significance of pre-existing cracks on nucleation of secondary ettringite in steam cured cement paste , 1994 .

[5]  G. W. Quick,et al.  Microscopic Features of Cracked and Uncracked Concrete Railway Sleepers , 1992 .

[6]  D. Heinz,et al.  Mechanism of Secondary Ettringite Formation in Mortars and Concretes Subjected to Heat Treatment , 1987, SP-100: Concrete Durability: Proceedings of Katharine and Bryant Mather International Symposium.

[7]  A. Poole,et al.  The microstructure of concrete cured at elevated temperatures , 1995 .

[8]  Rachel J. Detwiler,et al.  DEVELOPMENT OF MICROSTRUCTURES IN PLAIN CEMENT PASTES HYDRATED AT DIFFERENT TEMPERATURES , 1991 .

[9]  J.-K. Kim,et al.  Compressive strength development of concrete with different curing time and temperature , 1998 .

[10]  A. Neville.  Properties of Concrete , 1968 .

[11]  Arnon Bentur,et al.  Short-term steam-curing and concrete later-age strength , 1978 .

[12]  S A Mironov.  SOME GENERALIZATIONS IN THEORY AND TECHNOLOGY OF ACCELERATION OF CONCRETE HARDENING , 1966 .

[13]  Johan Alexanderson.  Strength losses in heat cured concrete , 1972 .

[14]  J. J. Shideler,et al.  Early Strength of Concrete as Affected by Steam Curing Temperatures , 1949 .

[15]  Karen Scrivener,et al.  Delayed ettringite formation , 2001 .