Study of High-Performance Concrete Subjected to Coupled Action from Sodium Sulfate Solution and Alternating Stresses

The coupled action from alternating stresses and corrosion agents is the main driving force deteriorating concrete performance. The writers carefully devised some test equipment to investigate the flexural strength of high-performance concrete (HPC) subjected to the action of sodium sulfate $\left({\mathrm{Na}}_2\mathrm{S}{\mathrm{O}}_4\right)$ solution and alternating stresses applied by a third-point loading equipment. The chloride diffusion in the HPC was also studied at different deterioration stages of the test specimens. The influence of water/cement ratio and the dosage of the mineral admixture on the corroded and fatigued concrete were analyzed. By introducing the corrosion factor and the corrosion fatigue factor, the writers developed a method to evaluate the concrete resistance to chemical corrosion agents and/or fatigue loadings. The results show that under the same condition, the corrosion fatigue factor is much smaller than the corrosion factor and the maximum difference between them exceeds 20%. In addition, both water–binder ratio and fine mineral admixture have notable influence on the corrosion factor and the corrosion fatigue factor. Decreasing water dose of concrete, adopting low water–binder ratio, or mixing about 20% fly ash can evidently improve the corrosion fatigue resistance of HPC.