The Application Of Iron And Steel Industrial Waste In The Cement And Concrete Industry

Steel slag, slag and fly ash is three major industrial waste of China’s steel industry,utilization rate of the steel slag has been low, while the high carbon fly ash has not been able todevelop a good way of use. Cement and concrete industry has a unique advantage of absorbingthe solid waste, which can absorb it large and adaptable. Therefore, the main content of thisarticle is experimental study, aiming to study the application of steel slag, electric arc furnace（EAF） slag and high carbon fly ash in the cement and concrete industry, the main contents are asfollows:1．Basic property. The results show that, EAF slag is less basicity than steel slag. The mainchemical components in steel slag are CaO, SiO₂and Fe₂O₃, and the mineral compositions areC₂S, C₃S, C₃A, C₄AF and RO. The main chemical components in EAF slag are CaO, SiO2andAl₂O₃, loss on ignition is7%, and the mineral compositions are C₂S, C₃S and C₃A. The mainchemical components in high carbon fly ash are SiO₂and Al₂O₃, loss on ignition ismore than15%, and the mineral compositions are quartz, mullite, magnetite and plaster.2．Cementious properties of cement mortar. The results show that the steel slag, EAF slag andhigh carbon fly ash has a certain cementitious activity, Control the specific surface area of steelslag between400m²/kg to500m²/kg, and the specific surface area of EAF slag between400m²/kg to600m²/kg are more appropriate. Singly doped dosage of steel slag is less than30%,the dosage of EAF slag is less than20%, and the dosage of high carbon fly ash is less than20%are more appropriate. Steel slag and EAF slag have good binary complex effects with slag, whilethe binary complex effect of high carbon fly ash with slag is not obvious. When mixed with slag,the dosage of steel slag is less than50%, the dosage of EAF slag is less than30%, the dosage ofhigh carbon fly ash is less than10%are more appropriate. There are no obvious binary complexeffects of steel slag and EAF slag with fly ash. Add gypsum or lime as activator has excitationeffect on both singly doped and binary mixed.3．The morphology and mineral composition of the hydration products. The results show thathydration products of cement paste at different ages doped with different admixtures are similar species, mainly Ca （OH）₂crystals, CSH gel and AFt, morphology vary greatly.4． Mechanical properties, performance and durability of concrete. The results show that steelslag has a good compatibility with water-reducing agent, and EAF slag has a bad compatibilitywith water-reducing agent, while high carbon fly ash has an extremely bad compatibility withwater-reducing agent. Singly doped steel slag dosage from10%to30%can make highperformance concrete above the level of C70, singly doped EAF slag dosage from10%to20%can make high performance concrete above the level of C80, while high carbon fly ash is notsuitable for making high performance concrete when singly doped. Steel slag and EAF slag havegood binary complex effects with slag, while the binary complex effect of high carbon fly ashwith slag is not obvious. When mixed with slag, the dosage of steel slag is between30%to70%can make high performance concrete above the level of C80, the dosage of EAF slag is between30%to50%can make high performance concrete above the level of C80, the dosage of highcarbon fly ash is30%can make high performance concrete above the level of C70. Add gypsumor lime as activator, the concrete strength have not risen significantly when steel slag and EAFslag mixed with slag, while the concrete strength has improved when high carbon fly ash mixedwith slag. Mixed with steel slag and EAF slag have little impact with the performance of resistchloride-permeation of concrete, while the performance of resist chloride-permeation of concretewere getting weaker when mixed with high carbon fly ash. Evaluation of concrete permeabilityall reaches a very low level.