Creep experimental test and analysis of high-performance concrete in bridge

Abstract

Factors that have effect on concrete creep include mixture composition, curing conditions, ambient exposure conditions, and element geometry. Considering concrete mixtures influence and in order to improve the prediction of prestress loss in important structures, an experimental test under laboratory conditions was carried out to investigate compression creep of two high performance concrete mixtures used for prestressed members in one bridge. Based on the experimental results, a power exponent function of creep degree for structural numerical analysis was used to model the creep degree of two HPCs, and two series of parameters of this function for two HPCs were calculated with evolution program optimum method. The experimental data was compared with CEB-FIP 90 and ACI 209(92) models, and the two code models both overestimated creep degrees of the two HPCs. So it is recommended that the power exponent function should be used in this bridge structure analysis.

Keywords

cement / concrete / creep / high-performance concrete (HPC)

References

[1] PerssonB.. Basic deformation of high-performance concrete at early ages [J]. Nord Concr Res, 1997, 20: 59-74

[2] PerssonB.. Seven-year study of the effect of silica fume in concrete [J]. Advanced Cement Based Materials, 1998, 7: 139-155

[3] PerssonB.Quasi-instantaneous and long-term deformations of hpc with some related properties [R], 1998, Lund, Lund Institute of Technology

[4] MÜLLER H S, KÜTTNER K. Characteristics and prediction of creep of HPC [C]// WITTMANN F H, SCHWESINGER P eds. Proceedings of the Fourth Weimar Workshop Held at HAB, Weimar, Freiburg and Unterengstingen, Germany and Switzerland, 1995: 145–162.

[5] PerssonB.. Correlating laboratory and field tests of creep on high-performance concrete [J]. Cement and Concrete Research, 2001, 31: 389-395

[6] JC/T 853-1999. Clinker of Portland Cement 2000 [S]. China Building Materials Industry Association.(in Chinese)

[7] BazantZ. P., BawejaS.. Justification and refinements of model B3 for concrete creep and shrinkage: 1. Statistics and sensitivity [J]. Materials and Structures, 1995, 28: 415-430

[8] ACI (1992). Prediction of creep, shrinkage, and temperature effects in concrete structures[S]. ACI 209R-92 (under revision by ACI Committee 209), 1992: 47.

[9] CebCEB-FIP model code 1990, CEB bulletin D’Information[S], 1993, London, Thomas Telford: 437

[10] NevilleA. M., DilgerW. H., BrooksJ. J.Creep of plain and structure concrete [M], 1983, London and New York, Construction Press

[11] NEN 6720 (TGB 1990). Regulations for concrete, structural requirements and calculation methods [S]. Delft, 1995.

[12] ChenZ.-h., ShanL., GuanF.-ling.. Identification of concrete creep parameters based on evolution programs [J]. Journal of Yangtze River Scientific Research Institute, 2005, 22(2): 47-49

[13] ZHU Bo-fang. Modulus of elasticity, creep degree and stress relax coefficients of concrete [J]. Journal of Hydraulic Engineering, 1985(9): 54–61. (in Chinese)