Experimental Study of the Durability of Concrete Under Coupling Effect of Axial Compression and Sulfate Attack

The time-dependent law of concrete durability under the coupling effects of axial compression load and sulfate attack was investigated by measuring the water absorption of the dry saturation surface and relative dynamic elastic modulus. Microstructure deterioration at non interfacial transition zone was studied by means of Scanning electron microscopy(SEM) and X-ray diffraction(XRD). The effects of various stress ratio(0, 15, 30 and 45%) and different sulfate solution concentration(0, 5 and 10%) were considered in this paper. The investigation showed that, the coupling effect of the stress ratio of 45% with sulfate attack has significantly accelerated the damage deterioration of the relative dynamic elastic modulus of concrete, and the water absorption of the dry saturation surface rate increased significantly. The axial load with stress ration of 30% or less coupled with 5% concentration of sodium sulfate solution attack has inhibitory effect on the degradation of the relative dynamic elastic modulus, and the inhibitory effect of stress ratio of 30% is more significant. Compared with 5% concentration of sodium sulfate solution, 10% concentration of sodium sulfate solution has a significant acceleration effect on the deterioration of concrete. Under the real-time coupling action of axial compression load and sodium sulfate corrosion, with the increase of corrosion time, the erosion products such as ettringite and gypsum have gradually filling effect on microstructure at the early period, and later the expansion effect of the ettringite and gypsum will induce micro cracks and cause gradually deterioration in concrete. © 2020, The Editorial Board of Journal of Basic Science and Engineering. All right reserved.