Research On The Influence Of Thermal Damage To Concrete With Sulfate Corrosion

The author explored the influence of thermal damage to concrete with sulphate corrosion and analyzed from three aspects about the total content of sulphate inside the concrete after the sulfate solution soaking and the macroscopic and microscopic of the concrete after the sulfate solution soaking in this paper, Based on railway construction in the western region, where has complex geological environment with thermal pollution and sulphate corrosion.(1) The total content of sulphate inside the concreteThe total content of sulphate was measured through chemical analysis methods, which was inside the concrete after the sulfate solution soaking under high temperature and room temperature, the conclusion is as follows:① The sulfate content inside the concrete is linear correlation with the curing temperature and curing age respectively and it increases with the increasing of curing temperature, curing age. Besides, it has the power function relationship with the test depth of the specimens, and it decreases with the increasing of the test depth when other things being equal.② The equation among the sulfate content inside the concrete、the curing temperature、96curing age and the test depth of the specimens can be represented as:Sulfate content=96/80*(0.003*curing temperature+0.002*curing age-0.015*test depth+1.113),accuracy is as high as 81%.③The sulfate content inside the concrete increase along with the decreasing of the concrete strength grade and the increasing of the solution concentration.(2)Macro aspectThe concrete specimen with sulfate corrosion was testd under the environment of high temperature thermal pollution and normal temperature to analysize its quality change,compressive strength and lateral deformation after two kinds of curing temperature and sulfate corrosion for 28days、56days、84days、112days、140days.The conclusion is that:①The quality increase rate of concrete specimen appears the trend of increases then decreases along with the increasing of temperature at the same age stage,and is negative under 80 high temperature less than it when curing under the normal temperature after a certain age,when other things being equal.② The compressive strength of concrete specimen increases first and then decreases with temperature increasing after curing the same age, And the compressive strength loss rate under 80 ℃ high temperature is higher than it when curing under normal temperature.③ The maximul bearing capacity of concrete which is damaged under 80 high temperature is more than it when curing under 20 ℃ normal temperature, When the concentration of solution and the strength grade of concrete is the same. While the lateral deformation of concrete when damaged under 80℃ high temperature is less than it when curing under 20℃ normal temperature. So, the ultimate bearing capacity of concrete may be improved to a certain extent within the scope of the high temperature under the age.(3) Microcosmic aspectsThe differential thermal analysis test was done to part of the specimen with the 10 mm test depth for 56 days of the curing age, the conclusion is that:The quantity of consumption of hydration products Ca(OH)2 and the amount of corrosion products like ettringite, gypsum, etc which reacted from Ca2+ and SO42- under high temperature were more than that under a room temperature when other things being equal.So the high temperature promoted the sulfate corrosion of concrete.