Sulfate corrosion resistance test of ordinary concrete

Due to the porous material characteristics of concrete, which provides a natural channel for the erosion of various ions in nature, one of the main disadvantages of using ordinary concrete is insufficient durability. Sulfate corrosion is an important part of the durability of concrete, and it is also the most complex and harmful type of corrosion.
In recent years, there have been many examples of structural damage caused by sulfate erosion, and some have even endangered the safe operation of the project. The phenomenon of sulfate corrosion damage to concrete structures by groundwater and underground soil has been found in railways, highways, mines and hydropower projects.
Therefore, it is necessary to conduct a sulfate corrosion resistance test of ordinary concrete to measure the sulfate corrosion resistance of concrete specimens in an alternating dry and wet environment, expressed as the maximum number of dry and wet cycles that they can withstand.
Zhongke Testing Reliability Experiment Center has the ability to test the long-term performance and durability performance of various ordinary concrete, and provides professional sulfate corrosion resistance test services for ordinary concrete.

Ordinary concrete is divided into stages and states: the plastic state before condensation and hardening, that is, fresh concrete or concrete mixture; the hard state after hardening, that is, hardened concrete or concrete.
Ordinary concrete is divided into 14 grades according to its strength: C15, C20, C25, C30, C35, C40, C45, C50, C55, C60, C65, C70, C75 and C80.

1. After the specimen is dried and cooled, the specimen should be immediately put into the specimen box (rack), and the prepared 5% Na2SO4 solution should be placed in the specimen box. The solution should exceed the surface of the uppermost specimen by at least 20mm, and then start soaking. The time from the time the specimen is put into the solution to the end of the soaking process should be (15±0.5) h. The time for injecting the solution should not exceed 30 minutes.
2. After the soaking process is completed, the liquid should be drained immediately and the solution should be emptied within 30 minutes. After the solution is drained, the specimen should be air-dried.
3. The temperature should be raised immediately after the air-drying process is completed. The temperature in the specimen box should be raised to 80°C to start the drying process. The heating process should be completed within 30 minutes. After the drying process is completed, the specimen should be cooled immediately.
4. The total time of each dry and wet cycle should be (24±2) h. The solution should then be added again and the steps followed for the next wet and dry cycle.
5. After reaching the specified number of dry and wet cycles, the compressive strength test should be carried out in time. At the same time, the damage to the concrete surface after dry-wet cycles should be observed and the appearance described. When the specimen has serious defects such as peeling or falling corners, it should be filled with high-strength gypsum before conducting the compressive strength test.

GB/T 50082-2009 Standard for test methods for long-term performance and durability of ordinary concrete (with clauses)
JGJ 52 Standard for quality and inspection methods of sand and stone for ordinary concrete
JG 237 concrete trial mold
GB/T 50081 Concrete physical and mechanical properties test method standard
JG/T 245 vibration table for concrete testing JG 244 mixer for concrete testing