Mixture Ratio Research Of Sprayed Steel Fiber Concrete

This topic which is sprayed steel fiber concrete lining project of a mine roadway comes from daxinganling Mountain in Heilongjiang Province. Daxinanling is a famous mountain, is one of the few a virgin land, mineral-rich region, vein complex. Daxinanling Mountain was roughly northeast direction. Geological situation is mainly dominated by rocks, geological conditions are better, which are better geological conditions of sprayed steel fiber concreteconstruction. Sprayed steel fiber concreteis a new composite material, in the roadway, tunnel lining and other construction applications will be more and more, because that is digging its technical superiority and the spray early strength, on the one hand it can be formed early strength delaying the release of rock stress, which can fully mobilize the self-bearing capacity of rock, to maintain the balance of the original earth rock stress, so that when the TBM tunneling process, we can ensure the construction of a great safety factor; On the other hand, from an economic point of view, the construction of sprayed steel fiber concreteout of ordinary reinforced concrete formwork construction sectors, saving labor intensity and labor cycle, saving materials and costs, improving the construction schedule and saving construction cycle. The TBM tunneling speed limit is no longer so obvious, we can keep the machine work continually, which works for the construction process conditions affecting significant.The basic theory of sprayed steel fiber concreteis basically a fiber reinforced material, based on the application and development together, Admixture in concrete with steel fiber, multi-component and non-uniformity, and short steel fibers to be disordered distribution, it must compared to textile fiber enhancement material concrete complex many. Present study on mechanical properties of steel fiber reinforced concrete is more, but for research on mixture ratio of sprayed steel fiber concreteis blank.F0r the preparation of steel fiber reinforced concrete test specimens also refer to the ordinary jetting concrete mix,mixed with a certain fibers instead of steel fiber to achieve a certain aggregate,in reality there is no scientifically rigorous empirical fomula and the proportioning of sprayed steel fiber concretequantitative relationship of the components,which is very inconvenient for guiding the actual production.This article is mainly used for research on mixture ratio of steel fiber sprayed concrete,its vision is based on the ordinary Portland concrete mix design principles,instead of steel fiber quality aggregates,based on the actual spray concrete construction needs,checked out related regulatory information,received general corditions of steel fiber sprayed concrete.The experiments were taken under the conditions of 16 sets of orthogonal mixing ratio,each 12 specimens were produced 192 specimens.In each specimen,we need to measure its slump and density,and in the conservation process,each measure must take three specimens 3d compressive strength,three specimens 7d compressive strength,the three test pieces 28d splitting strength.We use to get the orthogonal analysis of sprayed steel fiber concretegeneral mechanical properties,as well as the components of steel fiber shotcrece various indexes, Using a variety of information to determine the relation between strength of steel fiber on the general empirical formula.Based on experimental data obtained by fitting the compressive strength of sprayed steel fiber concreteis calculated as fcu=Afcec/w-Bfce, where a,b based.n e×perimental data obtained by fitting respectively,0.661 and 0.426,splitting tensile strength is calculated as ft=ARf?+Bfcec/w,where:a=6.66×10-5b=3.46×10-2When selecting the appropriate water-cement ratio,we can be based on empirical formiula to get this splitting tensile strength of steel fiber dosage,other components can be based on the design method of ordinary concrete obtained.For slump indicators,the water-cement ratio significantly affect its index factors,steel fibers are not significant factors.For density indicators,the steel fibers influence their targets significant factor.For strength indicator,the steel fibers significantly affect factors indicators. For splitting strength index, the steel fibers that influence their targets significant factor is the most important factor. Under the influence of water-cement ratio, slump and the density of sprayed steel fiber concreteenhances along with the water ratio enhancement, splitting strength and compressive strength decreases with increased water-cement ratio. Under the influence of sand ratio, the slump and the density of sprayed steel fiber concreteincreases along with increased sand ratio, splitting strength and compressive strength increases with increased sand ratio. Under the influence of the accelerator, the density of sprayed steel fiber concretedecreases with increased accelerator, splitting strength and compressive strength increases with increased accelerator. Under the influence of steel fiber, indicators of sprayed steel fiber concreteslump decreases with increased steel fiber, splitting strength and compressive strength increases with increased steel fiber. Under the influence of the reducing agent, indicators of sprayed steel fiber concreteslump increases with the reducing agent, the relationship between density index and water reducing agent can be ignored, splitting strength and compressive strength increases with increased the reducing agent.