Research Of Explosive Spalling Behavior And Permeability Of Reactive Powder Concrete Subjected To High Temperature

In this thesis, an experimental investigation was conducted to study explosive spalling behavior, permeability of unexplosive specimens and permeability of reactive powder concrete (RPC) subjected to high temperature.Firstly, seven kinds of moisture contents and four kinds of PP fiber contents at 0.18 W/B ratio and 2% steel fiber content were designed to investigate the effect of moisture content and PP fiber content on explosive spalling. After explosive spalling test, the specimens that didn't encounter spalling were sawn into two pieces. Water permeability test was conducted on the sawn surfaces of the specimens.Nine mix proportions were designed in the base of explosive spalling test, which referred to the length of steel fiber, W/B ratio, the content of pp fiber and steel fiber. Then, air permeability test was conducted on kinds of specimens after exposure to 200℃,400℃and 600℃high temperatures to investigate the effect of temperature and four factors above-mentioned on permeability.The results of the explosive spalling test indicate that moisture content and PP fiber are significant factors influencing the explosive spalling behavior of RPC. Both spalling occurrence frequency and crack behavior associated with spalling are increased with the add of moisture content. And the optimal content of PP fiber is 0.15%.The results of permeability test of unexplosive specimens and explosive spalling test are coincident, and water permeability is an effective method to estimate the damnification of RPC exposure to high temperature.The results of permeability test of RPC subjected to high temperature indicate that permeability is increased with the increasement of temperature except RPC at 0.16 W/B ratio. Moreover the permeability resistance of RPC exposure to 400℃is still very well, but very bad when temperature is 600℃.The results above-mentioned indicate that explosive spalling occurs when RPC is heated up to 700℃at the rate of 10℃～20℃/min, and the temperature initial explosive spalling occurs at is from 371℃to 480℃. The permeability resistance decreases after exposure to high temperatures of 400℃and 600℃.