Research On Mechanical Properties Of Fiber Reinforced Concrete Subjected To Medium-high Temperature

Nuclear waste disposal is the focus of international investigations now. The heat radiated by nuclear waste for long term will generate thermal field which causes thermal stress, and degrade the property of concrete, the primary material of container making for nuclear waste. So improving the mechanical properties of concrete after be heated is very signification.Elaborating Strengthening theories of fibre concrete, introducing characters and present condition of it in the paper; The effects of short steel fibre, ultra-short steel fibre, polypropylene fibre and fly ash on the property of concrete under pre-or post-roasting, including slump constant, compressive strength, impermeability, flexural properties, fracture energy, are analyzed by gradation analysis and variance analysis when they are mixed into C50 concrete. The experimentation result is regressively analyzed by multianalysis method and principium; receive the regressive equation of equivalent bend-fold intensity and fracture energy.Durability is very important to concrete of deposit nuclear waste. By the research above concluded that:steel fibre is beneficial to improving durability of concrete, the hybrid effect of short steel fibre and ultra-short steel fibre is fine; impermeability is descend of concrete after be heated, but the heated-concrete still can keeping better impermeability with fibre and fly ash be mixed; fracture energy of concrete after be heated is descend 10% approximately, short steel fibre and ultra-short steel fibre have prominent effect to enhance concrete's fracture energy; the equation can well and truly forecast experimentation result. Experiment result shows that fibre is efficient means to enhance mechanical properties of concrete.