Comparison of creep models and experimental verification of creep coefficients for normal and high strength concrete

Abstract

A concrete structure when subjected to sustained load presents progressive strain over time, which is associated with the creep phenomenon. The creep characteristic of high strength concrete assumes importance in the back drop of increase in prestressed concrete constructions. The paper covers the comparison of creep coefficients with different creep models like Bazant’s B-3, ACI, AASHTO, GL-2000 and FIB model code 2010 for concrete mixes having water to cementitious ratio of 0.47, 0.36, 0.27 and 0.20. The comparison of different models are done for a relative humidity of 60 percent and design life of 100 years. For comparison of creep coefficient using different models the age at loading are kept as 7, 28 and 365 days. Thereafter, values are compared with experimentally obtained results of concrete mixes having water to cementitious ratio of 0.47 and 0.20 for age at loading of 28 days and up to 180 days loading period. Time induced creep strain of high strength concrete is determined using creep rig of capacity 2000 kN. Creep strains are measured at regular time intervals on concrete designed with water to cementitious ratio of 0.47 and 0.20 wherein fly ash and silica fume were also used.