Comparison of tensile and compressive creep of fly ash concretes in the hardening phase

Tensile and compressive creep tests of fly ash concretes in the hardening phase have been performed in the Temperature-Stress Testing Machine (TSTM) at NTNU. All tests were performed under nominally identical conditions, e.g. dimensions, curing conditions, measurement set-up and load-regime. Two concretes with 17% and 33% fly ash (as % by weight of cement and fly ash content) were investigated. Contradictorily to most of the compressive versus tensile creep comparisons found in the literature, both the investigated concretes showed similar creep behaviour in compression and tension throughout the hardening phase. It was also seen that for the investigated time-span, the specific creep development over time was found to increase (i.e. soften) with increasing amount of fly ash.