The Study On The Durability Of Rubber-high Performance Concreteat Different Temperature Based Upon The Chlorine-ion Penetration

High performance concrete is the concrete with excellent working performance, whichusing the modern concrete technology, with low water/cement ratio, adding a sufficientamount of admixture and additive mixing together. Compared with ordinary concrete, thehigh performance concrete has the character of high strength, good volume stability, etc.Adding rubber powder particles in the high performance concrete in guarantee under thepremise of certain intensity could make concrete a good resistance to impact toughness andcrack resistance, and also solve the problem of the recycling of waste rubber. But the rubberpowder would add air into the concrete, thus changing the microscopic pore structure ofconcrete, and the resulting changes in some traits of concrete, especially changes in terms ofdurability. In addition, with modern reinforced concrete structure has got more and more wideapplication range and building density increased gradually, the resulting problem is buildingfire situation is increasing. The rubber powder is a kind of heat sensitive material, so thechanges of the characteristics of rubber concrete heated has the vital significance. This testwas aimed at studying the influence of concrete durability with high temperature and rubberpowder content，and the main content is as follows:1．Measured the DRCMof several different groups of specimens after high temperatureand studied the effects of high temperature on chloride ion permeability of concrete bycomparing the different DRCMafter different temperature. By comparing DRCMwith differentdosage of rubber concrete after high temperature effect, studied the influence of rubberpowder on the chloride ion permeability of concrete. The results showed that: at a temperatureof200℃to300℃, rubber powder incorporation would increase the DRCMof concrete, and atordinary temperature and temperature range of400℃,500℃, rubber powder incorporationwould decrease the DRCMof concrete, the effect was less and the rules was uncertain when thetemperature exceeded above500℃. Overall, the chloride ion permeability of concrete rise as the temperature rise, and when the temperature was higher than500℃, DRCMhad a fastgrowth rate, in general, the effect of temperature on the concrete chloride ion permeabilitywas much larger than rubber powder.2． Measured the loss on ignition of specimens subjected to high temperature, andanalyzed the reasons for loss of quality of concrete after high temperatures and studied theeffects of rubber powder on the loss on ignition of concrete by comparing the results. Theresults showed that: the loss on ignition of concrete increased as the burning temperature rise,the loss on ignition had a rapid growth in the range of100℃to300℃, with the continuedincrease in temperature, loss on ignition slowdown. When the ignition temperature rise at700℃, ignition loss reached10%. Concrete ignition loss changed little and had no regularityafter mixing rubber powder, and the analysis was that rubber powder had no significant effecton the concrete loss on ignition.3．Predicted the concrete life in the western region of high salt with the theoretical modelbased on Fick’s second law of this experiment, analyzed the effects of different rubber powdercontent and different fire temperatures on the building life. The results showed that: the firehad a tremendous impact on the life of the building; the incorporation of rubber powder wouldbe extended the life of buildings under normal temperature and the temperature of100℃,400℃. and the service life of concrete would be shorten in the200℃to300℃temperaturerange. under high temperature above500℃, and rubber powder has little effect on theconcrete life.4． The study found that rubber concrete damages at high temperatures is mainlycomposed of the following composition：at the temperature of below100℃, the rubberconcrete almost has no damage, and the mass loss of quality is mainly because of the internalfree water evaporation. At the temperature of200℃to300℃, the porosity of the concreteincreases because of the evaporation of inside combined water and the degradation of therubber, and thus lead to the damage of concrete. at the temperature of400℃, the main causeof concrete damage is the bursting of concrete caused by high temperature. At the temperatureabove500℃, bursting and the decomposition of concrete composition substances is the maincause of the damage.