Experiment Research Into Steel Fiber Shotcrete Durability

Steel fiber shotcrete (Steel Fiber Shotcrete referred SFSC) with the injectionmachinery, and pressure, will be a certain proportion with the mixing material throughthe pipeline and high-speed jet condensation on the surface of the support reinforcementhardening from a steel fiber reinforced concrete. As a new construction method, widelyused in long-span structures, large tunnel lining, the dam structure, and militaryengineering major projects. Ordinary steel fiber reinforced concrete structure, will alsobe a variety of corrosive media in the service process, and lead to structural degradation,reduce carrying capacity, and shortened life expectancy. Construction methods on thedurability of the law of the steel fiber reinforced concrete, designed to lay thefoundation for the durability design and life prediction and its evaluation.In this paper, the actual works on the jet construction and mode of steel fiberreinforced concrete building construction durability pilot study, and ultimately establishthe durability of relationships in the different construction methods, the following majorelements:Take mercury intrusion analysis, to test the micro-pore structure of differentconstruction methods of steel fiber reinforced concrete, steel fiber reinforced concretepore size distribution characteristics, and study the different construction methods onthe microstructure of steel fiber reinforced concrete. The results showed that the sprayedsteel fiber concrete pore structure built concrete than the mold, spray the construction ofthe total porosity has increased, the density of concrete decreased. Injection lower thanthe modulus of the cube compressive strength and splitting tensile strength of steel fiberreinforced concrete built of steel fiber reinforced concrete, compressive strength valuedifference of24%, the tensile strength difference of5%.To carry out a rapid steel fiber reinforced concrete carbonation test, simulated acid rain erosion test, freeze-thaw cycle test, and chloride ion penetration test, carbonationtest results show that: the carbonation depth of the jet construction than the moldbuilding, the maximum difference in56d,12%; acid rain erosion test results show littledifference: the rate of change of the quality of two steel fiber reinforced concrete, whilethe injection rate of change of concrete compressive strength has been higher than themold built of concrete, steel fiber concrete neutralization depth and is still growing,neutral jet of steel fiber reinforced concrete of depth to accelerate the growth of moldbuilding steel fiber reinforced concrete from the fourth cycle until the end of the entirecycle depth of neutral growth stabilized; freeze-thaw cycle test test results show that thequality increases: freeze-thaw process, jet pilot The quality of the parts of the specimenlarge increase than the mold building, mold building concrete resistance to freeze-thawcycle was significantly higher than the sprayed concrete; chloride ion penetration testresults showed that: steel fiber reinforced concrete chloride ion content decreasesgradually with the depth increases to a value and ultimately stabilize the chlorine ioncontent in the concrete of the same depth are increased with increasing immersion time,and depth of the injection capillary adsorption zone of steel fiber reinforced concretespecimen increased slightly built than the mold.