Abstract
To explore the mechanical properties of concrete under true triaxial static compressive load after sulfate attack, uniaxial static compression test and true triaxial static compression test at four stress ratios were carried out on concrete specimens immersed in 15% sulfate solution for 0–120 days by the integrated true triaxial static and dynamic load testing system, and the variation of performance indicators such as the strength and deformation of concrete under the coupling action of sulfate attack and complex stress state was analyzed. The results show that the uniaxial compressive strength of concrete increases at the beginning and then decreases with the increase of sulfate attack time and reaches the peak on the 30th day, with an increase rate of 16.57%; the strength of concrete under triaxial compression increases significantly, and the maximum triaxial compressive strength is 3.18 times of uniaxial compressive strength under the combination of 0-day sulfate attack and 0.2 : 0.8 stress ratio; and the deterioration of concrete under sulfate attack is more prominent at high confining pressure, and as the sulfate attack worsens, the sensitivity of triaxial compressive strength of concrete to lateral compressive stress is reduced. In conclusion, triaxial compression can significantly enhance the ductility of concrete by playing a role in restraining the deformation and cracking of concrete after sulfate attack.
Highlights
Since the 21st century, countries all over the world have paid increasing attention to the exploration and development of underground space resources
Since the 1960s [6, 7], despite the limitation of test conditions and loading equipment, valuable data have been obtained from studies on multiaxial mechanical properties of concrete [8,9,10,11,12,13,14], and there are more conventional triaxial tests than true triaxial tests in existing studies. is is because two-dimensional principal stresses applied on the concrete in the conventional triaxial test are equal, while three-dimensional principal stresses in the true triaxial test are not, making it difficult to carry out a true triaxial test
Each loading subsystem was composed of Jack, reaction frame, displacement sensor, and other components, and can realize three-dimensional (x, y, z-axis) independent loading on the uniaxial static compression test: after smearing the polished specimen surface evenly with butter, the specimen was placed between the loading plates of the true triaxial tester, and an anti-friction cushion was added between the loading surface and the loading plate. e loading mode was uniaxial quasi-static loading. e load was applied at a loading rate of 0.5 MPa/s until the concrete specimen was damaged
Summary
Since the 21st century, countries all over the world have paid increasing attention to the exploration and development of underground space resources. With the rapid development of advanced technology and further economic growth, the application breadth and depth of underground engineering structures are constantly expanding. Both civil infrastructure, such as urban subways and subsea tunnels, and military protective works, such as air raid shelters and underground oil depots, require massive underground building structures [1, 2], making concrete the most commonly used building material in today’s engineering practice. Components and joints are generally under complex multiaxial stress state, resulting in discontinuous, heterogeneous, and anisotropic mechanical properties of the concrete [3,4,5]. The conventional triaxial test cannot represent the real stress state of the building structure, and only the true triaxial test
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
