Fabrication and Formation Mechanism of FoamedIron Slag-Steel Slag Concrete

In order to achieve the comprehensive utilization of iron slag and steel slag, foamed concrete were prepared by adding small amount of gypsum, lime and clinker in steel slag-iron slag system and using aluminum powder as foaming agent,. The three-day, seven-day and twenty-eight-day bulk density and compressive strength of foamed concrete with the different ratio of the main raw materials were researched. Furthermore, in order to research the hydration mechanism and microstructure of foamed concrete, the XRD and SEM images of the three productions of foamed concrete were analyzed. The results showed that the coordination of the dosage of steel slag and iron slag was better when the former was 30% and the latter was 45%, Meanwhile, the compressive strength was 5.1 MPa, the bulk density was 625 kg/m 3; Ettringite and C-S-H gel synergies generated in steel slag-iron slag system. Besides, hydration activity of steel slag was obviously lower than that of iron slag.     

Preparation of the supplementary cementitious material offerronickel submerged arc furnace slag and its properties

The ferronickel submerged arc furnace slags are stored up more and more, as a result, seriously influenced the sustainable development of the nickel industry. By grinding, the ferronickel submerged arc furnace slag is mechanically activated, then can be used as supplementary cementitious material, thus a comprehensive utilization way of ferronickel submerged arc furnace slag is developed. Using such processed slag to replace cement from 10% to 40% in mass, with the increase of replacing dosage, the water demand of standard consistency of cement paste is lowered, the fluidity of mortar is raised; the compressive strength of mortar is decreased; the flexural strength is increased followed by a decrease after the dosage is above 10%, the ratio of flexural strength to compressive strength is increased. The experimental results indicate that the ferronickel submerged arc furnace slag can be used as supplementary cementitious material and has an increase of flexural strength and effect of plasticizing and water reducing.     

Effects of Cement Additives on Properties of CSA Cement from MSWI

Municipal solid waste incineration fly ash (MSWI) was successfully used as raw material in sintering and preparing a calcium sulphoaluminate (CSA) cement clinker in laboratory. The effects of different types and different addition percentages of cement additives on compressive strength and hydration properties were investigated. The results showed that lime (LI) powder / slag (SL) powder was compatible in CSA cement system while the activities of fly ash(FA)/ MSWI was low. Adding these four types of cement additives in CSA cement system respectively, there were negative effects on compressive strengths of hardened cement at early age while LI/SL improved the compressive strength at later age. The performance of combined additives was better, especially, the specimens with 10%LI+10%SL, 10%LI+10%MSWI, and 5%LI+15%SL.     

Preparation of Cementitious Material Based onAlkali GGBS Manganese Alloy Slag System

Manganese alloy slag is an industrial waste produced from manufacture of manganese alloy. Recent years environment pollution of manganese slag has been becoming heavier and heavier with the development of manganese industry. Aiming to sort out this problem, combination of manganese slag and ground granulated blastfurnace slag (GGBS) were applied to prepare alkali activated cementitious material. Compressive strength and flexural strength of cementitious material prepared with combination of alkali slag manganese slag were measured. And micro structure of hydration production was investigated by scanning electro microscope (SEM). It was shown that the flexural and compressive strength of cementitious material with alkali GGBS manganese slag system were decreased with the increase of replacement of GGBS by manganese slag. The increase of the fineness of manganese slag was favorable for strength improvement of the alkali GGBS manganese slag material. It was concluded that ground manganese slag had hydraulic activity in alkali activated cementitious material and the activity was lower than that of GGBS.     

高MgO镍铁渣作为活性混合材使用的可行性分析

中国镍铁渣排放量很大,但目前尚未找到大量利用的途径。笔者在分析镍铁渣组成、性能的基础上,对镍铁渣作为活性混合材使用的可能性及效果进行了研究。结果表明:镍铁渣中非晶体矿物的含量为88.1%,含量高达27.07%的MgO主要以顽辉石和镁铁橄榄石两种晶体矿物形式存在。镍铁渣的比表面积影响其活性和在水泥中的掺量。作为活性混合材,镍铁渣比表面积需不低于454.6 m²/kg。比表面积越大,活性指数越大,掺量越大。镍铁渣水泥的压蒸安定性合格,即使在水泥中掺入50%比表面积842.9 m²/kg的镍铁渣,水泥的压蒸膨胀率仅为0.11%,大大低于0.5%的GB750-1992要求,由此证明镍铁渣不会因为MgO含量高而影响其作为活性混合材的使用。     

Technology of Mixing High Property Concrete with Large Dosage Fly Ash

Being the largest mass of man-maded material, concrete demands much to resource and energy as well as affects much to environment. Whether concrete can be the dominating constructive material, the key is whether it can become green material and protect the environment at the same time. The important approach of developing is using industrial castoff largely in concrete. The tests note, that high performance concrete used of large mass of fly ash is doable. By grinding fly ash and adding high-efficient water reducer, when the dosage of cement clinker is only 25% and the dosage of fly ash is 70%, concrete with a good workability that 3 day and 28 day strength are bigger than 20 MPa and 50 MPa respectively can be achieved, which later strength develop very well. The large mass of fly ash concrete can utilize fly ash largely and reduce the dosage of clinker, that is very advantageous to protect environmental.     

Study on Autogenous Relative Humidity Change and Autogenous Shrinkage of High-Performance Concrete

Autogenous relative humidity (ARH) reduction and autogenous shrinkage (AS) due to self-desiccation are common phenomena in high performance or high-strength concrete, which are the main reasons resulting in cracking of concrete at early ages. In this paper, the effects of the ratio of water to cementitious material (w/cm), paste volume content and the combined addition of silica fume (SF) and ground blast furnace slag (GBFS) on ARH change and AS of concrete due to self-desiccation were studied, and their relationship was discussed. The results indicate that the w/cm is a main factor affecting ARH change and AS of concrete. With the reduction of w/cm, ARH change and AS of concrete increases. The combined addition of SF and GBFS also augments these properties at later ages. There is significant linear correlation between ARH change and AS of concrete with different w/cm, paste volume content and the combined addition of SF and GBFS.     

STUDY ON THE LOW TEMPERATURE CALCINATION AND THE BEHAVIOUR OF STEEL SLAG COLOUR CLINKER CEMENT

The colourcd clinker cement which fired directly from kiln has the advantages of low cost,bright colour and good colour durability.This paper studies the possibility of using calcium flouridc and gypsum combined mineralizer to calcine the col-outed clindcr cement at low temperature.Different methods such as X-ray diffraction ana ysis,scanning electron microscopy,infrared spectra analysis,combined water content chemical asysis,compressive strength test and so on arc used to study the clinder minerals,the colour,the physical and mechanics properties and behaviour of the coloured clinker cement which made both with high quality raw materials and with electric furnace reduced slag additive.     

Mechanical Properties and Durability of Extruded Fiber Reinforced Cement Mortar Board and Its Composite Beam

The effect of water to cement ratio, fiber types and content, cement types on the bending performance of the extruded fiber reinforced cementitious board were studied. And it was found that polyvinyl alcohol (PVA) fibers can significantly improve the ductility of the board compared with polypropylene (PP) fibers. As PVA fiber content achieved 1.7%, the strain hardening and multiple cracking were occurred on the extruded board, while strain softening were shown on PP fiber reinforced cement board. The difference between the two kinds of board was from the differences of the mechanical properties of the two fibers. In addition, taking the fiber reinforced extruded board as base, the ultimate bending strength, as well as and the corresponded deflection and the resistant to chloride iron penetrating, was improved for a composite beam with fiber board and concrete compared with those of traditional concrete beam.     

油菜秸秆灰分混凝土与钢筋之间粘结性能研究

为了探究油菜秸秆灰分的掺入对钢筋-混凝土之间粘结性能的影响。对3种不同油菜秸秆灰分掺量的钢筋-油菜秸秆灰分混凝土试件进行中心拉拔试验,并与钢筋-普通混凝土粘结性能作对比试验。结果表明:钢筋-油菜秸秆灰分混凝土粘结强度与混凝土抗压强度呈正相关。当水胶比一定时,随着油菜秸秆灰分掺量的增加,钢筋-油菜秸秆灰分混凝土的粘结强度降低。水胶比为0.47时的钢筋-油菜秸秆灰分粘结性能与普通混凝土最为接近,为最优配合比。由试验结果可知,在承重要求较低的普通钢筋混凝土结构中,采用适量油菜秸秆灰分等量替代水泥,对于节省水泥生产能源和科学合理利用农业废弃物两方面均具有重要意义。     

Effects of Stone Powder on Wet Packing Density of Cement and Performances of Concrete

The amount of limestone powder, which is a by product of manufactured fine aggregate, is larger and larger with the increase of manufactured fine aggregate. Environment will be severely polluted if the powder is improperly used. The effects of limestone powder on workability, compressive strength, and impermeability of concrete were studied when cement is substituted for the mass proportion of 0, 10, 15, 20 percent with it. The results show that the performances of concrete are better improved when the percentage of limestone powder is about 10 percent. The wet packing density of mixture of limestone powder and cement was measured, and it shows that the degree of density was biggest when limestone powder is 10 percent. This shows that the best mixing proportion of limestone powder and cement may be determined through measuring the change of compactness of mixture of limestone powder and cement.     

不同钝化材料对农田土壤中砷的钝化效果研究

笔者探究不同添加比例钝化材料对贵州喀斯特岩溶地区农田土壤中有效态As钝化特征,旨在为砷污染土壤修复提供参考.试验通过向砷污染土壤中分别添加生石灰等12种不同比例钝化剂,分析不同钝化剂对土壤pH、有效As和钝化率的影响.6种无机钝化材料中铁矿粉、钢渣和煤渣均能有效降低农田土壤中As有效态含量,以施用煤渣效果最佳,使土壤p...     

The Effect of the Components of VAE Latex Modified Cementitious Compound Waterproofing Coating on Its Properties

In this paper the effect of the components of VAE latex modified cementitious waterproofing coating on its properties is studied. The results show that the tensile strength, bond strength and water resistance of the compound water proofing coating increase greatly in comparison with those of the coating without addition of cement. This compound coating is a new type of waterproofing material with excellent performance.     

Experimental Analysis of Freeze thaw Recycle With Ultra Low Temperature for Cementitious Material

This investigation focuses on influence of ultra low temperature on frost resistance of cementitious material by freeze thaw cycles test in which liquid nitrogen was applied as ambient medium. The appearance, mass and strength change before freeze thaw recycle and after were measured, respectively. Micro structure of cementitious material before and after freeze thaw recycle was tested by using scan electron microscope (SEM). It is found that, under the condition of ultra low temperature, frost resistance of concrete is better than that of mortar. And the frost resistance of concrete increased with the improvement of concrete strength. The SEM results reveal the structure defect is produced clearly when specimen freeze in liquid nitrogen and thawed in water. It is concluded that freeze thaw recycle with ultra Low temperature is an effective quick method to evaluate the frost resistance of cementitious material because destroying progress was accelerated and experimental time was redned.     

Development in Research Rheological Characteristics of Non-newtonian Metallurgical Molten Slags

Most of the former study for metallurgical molten slags (MS) was on the assumption that MS is newtonian fluid, and show lots of limitation. For the reasons such as the existence of gas-liquid phase points, MS shows a property of non-newtonian fluid. For this reason, the advances in some areas are conducted, including the measurement method, the factors influencing the MS and the viscosity computed models, which is prepared for the further research of the physical-chemical properties of blast furnace slag bearing titania.     

Analysis on the viscosity of six different compound smelting reduction slag

In combination with Huimin high-phosphorus iron smelted by smelting reduction and HIsmelt ironmaking technologywhich have the advantages of high efficient dephosphorizationCaO-SiO2-Al2O3-MgO-FeO-P2O5 slags with basicity R (mass ratio of CaO to SiO2)ranging from 0.8 to 1.4Al2O3 ranging from 6.4% to 15.4%P2O5 ranging from 0 to 3% and the content of MgO and FeO fixed as 4% and 6% respectivelyare studied.The slags are synthesized by reagent grade.The mineral composition and microstructure of the slags are studied with scanning electron microscope and the effects of changes in the composition of smelting reduction slags on its viscosity are studied by RTW-10 melt comprehensive physical properties measuring apparatus.Results show that the mineral structure of slags are mainly composed of melilite(gehlenite and akermanite)which is characterized by square and thick skeleton form.The viscosity decreases with the increasing of the slag basicity at fixed P2O5 or Al2O3 mass fractionincreases with the increasing of Al2O3 mass fraction at fixed slag basicity or P2O5 mass fractionand increases with the increasing of P2O5 mass fraction at fixed slag basicity or Al2O3 mass fraction.     

Study on the Seebeck Effect in Steel-slag Concrete

The Seebeck effect of steel slag reinforced concrete was studied in this paper.The effect of steel slag content and curing period on Seebeck effect were focused on especially.The experimental results show that Seebeck effect of steel slag reinforced concrete was discovered,and a good linear relationship was observed between thermoelectric force(TEP)and temperature differential on the specimen;The linear relationship was from enhancing to weakening with increasing steel slag content;As the curing period extends,the Seebeck effect of steel slag reinforced concrete was better,and TEP became steady.     

Watermarking algorithm based on Her transform

Without natural lime stone, clay, shale and sandstone, with the mass fracrion of demolition concrete in raw meal up to 95%~99%, along with ordinary calcining process, the cement clinkers (hereinafter called recycled clinkers for short) were produced. Experiments and analysis were employed to compare these recycled clinkers with the cement clinker which was manufactured by natural lime stone and sandstone. It is shown that the two types of clinkers have completely the same positions of characteristic peaks of XRD; the clinker minerals of recycled clinkers are formed normally; the two clinkers have similar chemical composition, and the rate value design of recycled clinkers are more likely to higher calcium and lower silicon; the content of f-CaO of recycled clinkers meets the requirements of soundness; the 3d strength of cements produced by recycled clinkers reaches the requirements of 42.5 grade Portland cement, and the 28d strength reaches the requirements of 52.5 grade.     

Mechanical and Chloride Diffusion Behavior of Kaolinite Clay Modified Cement-Based Material

The effects of kaolinite clay on the microstructure (pore structure, internal structure) and mechanical properties (workability, early-age and long-term flexural strength, chloride diffusion property) of the cementitious composites were tested. It is shown that the addition of clay improves the micro-pore structure in the cement paste and limits the introduction of chloride ions. As a result, it is suggested that the kaolinite clay would act as both filler and accelerator of cement hydration. Compared with the control specimen, the flexural strength of cement paste with 1% kaolinite clay increased by 30.41%, 39.04%, 36.27% and 38.32% at 1, 3, 7 and 90 curing ages, respectively. The 28-day flexural strength increased slightly. It is observed that the clay modified cement mortar has lower chloride diffusion coefficient values compared to the plain mortar, and the 28-day DCl of cement mortar decreased by 53.03% with 5% clay. Compared with the controlled sample, the increase in compressive strength and the reduction in chloride diffusion coefficient of the concrete with 5% clay addition is 28.4% and 18.87% respectively. The chloride diffusion coefficient of concrete decreases with the amount of clay addition exponentially. The 28-day compressive strength increases linearly with the chloride diffusion coefficient of the concrete.     

Experimental Investigation of Stabilized Soft Soil by New GSC

Soft clay is stabilized by desulphurization gypsum and steel slag-slag blended cementitious materials (GSC), which can not only reuse industrial waste and decrease second pollution, but also can conserve mineral resources and protect natural ecology. The variation of unconfined compressive strength of the clay improved by GSC with different mixing ratios and water-GSC ratio and ages was studied through the laboratory experiments. The long-term strength of stabilized soil is predicted with GSC by quasi-water-GSC ratio. The results show that the more the mixing ratios is, the better the stabilized effect of soft soil is. With increase of curing period, the strength increasing of GSC-soil is consistent with cement-soil, and it has lower strength in the early stage. When mixing ratios of GSC is more than those of cement by 3%, if the water-GSC ratio is less than those of cement, it has the higher strength than cement-soil, after 28 days. The results show that GSC stabilized soil is feasible and it can meet the demand of cure strength.