Abstract: Sulfate resistance tests including long term immersion test and drywet cycle test were conducted on high strength concrete specimens (100 mm SymboltB@ 100 mm SymboltB@ 300 mm) under different axial loading. Through uniaxial compression experiments on the concrete specimens that have exposed to sulfate attack for 180 days, the effects of sulfate concentration and historical load on parameters such as peak stress, peak strain, elastic modulus and stressstrain curve were analyzed. Results revealed that under the same historical load, parameter changes in the presence of long term immersion were different from those of dry wet cycle. In longterm erosion, with the increase of concentration of sulfate solution, peak strain decreased firstly and then increased,whereas peak stress and elastic modulus increased firstly and then decreased. On the contrary, in drywet cycles, with the increase of concentration of sulfate solution, peak strain increased, whereas peak stress and elastic modulus continuously decreased. Furthermore, under a given concentration of sulfate solution, with the increase of historical load, peak strain increased whereas peak stress and elastic modulus decreased both in longterm erosion and dry wet cycles. A superposition effect coefficient K wich describes the joint effect of sulfate attack and uniaxial historical load was introduced, and the results indicated that damage was usually promoted by the combined effect of loading history and sulfate attack.

Key words: high strength concrete, sulfate attack, axial loading history, mechanical properties, damage