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.     

A Primary Investigation on Concrete Made from Iron and Steel Slags for Building Ecological Artifical Reefs

A method of orthogonal test was used to optimize the strength of the cementitious material for preparing the concrete of high-strength artifical reefs.The results show that with the ratio of iron slag:steel slag=7:1,and when 10% cement clinker and 10% gypsum of Flue Gas Desulfurization Waste (FGDW) was mixed with 80% iron and steel slags powder,the mixed cementitious material had an optimized strength.The optimized specific surface area are 480 m 2/kg and 550 m 2/kg for iron slag and steel slag powder respectively.The ordinary portland cement can be totally substituted by such a mixed cementitious material with iron and steel slags as its major components in preparing the concrete for building high-strength artificial reefs.A concrete with a compressive strengh over 65MPa can be prepared by using such a mixture as a cementitious material and steel slag grains as its fine and coarse aggregats which have been stubilized by a hot-simmering method. Hydration processes of net slurry were analysized by XRD and SEM methods. The results show that the hydration products in the system are mainly AFt and C-S-H gel. The results also show that the pozzolanic reaction of iron slags could be largely promoted by the coordinations of steel slags,clinker and FGDW.     

Drying shrinkage characteristics of alkali slag cement mortar

The drying shrinkage characteristics of alkali slag cement mortar from the view of irreversibility are studied. It is found that the shrinkage of alkali slag cement mortar water curing after drying is significantly greater than that of OPC mortar which is cured under the same conditions. The drying shrinkage (14 d) of alkali slag cement mortar activated with NaOH solution and water glass is respectively 5.5 and 2.2 times of those of OPC mortar. Moreover, the majority of drying shrinkage of alkali slag cement mortar is irreversible, and the proportion of this part is up to 86%(activated with water glass) and 68%(activated with NaOH solution).     

Smelting AlMnSi alloy by Using High-bearing Manganese Slag

First smelting MnSi alloy by using high-bearing manganese slag of BF by electric smelting process in a 25 kVA arc furnace in lab has been introduced. In order to increase the content of manganese and silicon in MnSi alloy , a little amount of MgO is added into the slag and the lower alkalinity has been adapted. Then smelting AlMnSi alloy using MnSi alloy containing high silicon that obtained by experiments and waste Al with an induction furnace has been studied. The controlling of temperature is the key in smelting process. The high quality AlMnSi alloy has been obtained successfully,Which can be extensively used for the compound oxygen removal agent for making steel and the metal alloy additive.     

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 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.     

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.     

掺入工业废料的改性生土材料抗压试验

为合理利用废弃材料改善生土材料力学性能,通过在素土中掺入糯米浆、废玻璃渣和橡胶,形成改性土体材料,设计5种配合比方案,制作Φ102 mm×116 mm圆柱体试块。通过对其进行轴心抗压强度试验,对比不同配比试件的试验现象、抗压强度、变形能力、荷载位移曲线,分析不同掺合料的作用机理、研究不同掺料不同掺量对抗压强度的影响规律,提出了玻璃渣和橡胶掺量的合理范围。试验结果表明,在素土中掺入糯米浆能提高素土抗压强度,掺入糯米浆、玻璃渣和橡胶,可提高抗压强度和变形能力,但其抗压强度随玻璃渣和橡胶掺量的增多增至3.12 MPa后下降。     

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.     

固化疏浚淤泥作路基材料工程特性试验研究

为了探讨粉煤灰和工业矿粉固化疏浚淤泥作路基材料的可行性，通过一系列室内实验研究了不同固化剂配比对固化淤泥击实特性、水稳定性、承载力和抗剪强度的影响。实验结果表明，不同固化剂配比下固化淤泥的最大干密度均超过1.50 g/cm³，最优含水率约为20~21%；淤泥固化处理后浸水4 d的膨胀率均不超过1.1%，水稳性大幅提升；矿粉含量越高，粉煤灰含量越低，CBR（California Bearing Ratio）值越高，土样的承载力越高，抗剪强度也越高。不同工况浸水4 d的CBR值均达到了较高的水平，工况SD10FA20MP（淤泥：粉煤灰：矿粉=7：1：2）CBR值最高，达到了34.8%，是规范中高速、一级公路路基填料要求最低CBR值的4.35倍，作路基填料使用可行。     

G550高强冷弯薄壁槽钢受弯构件力学性能与设计方法

为了研究高强冷弯薄壁槽钢受弯构件的力学性能和设计方法,对3种板件加劲形式的G550高强冷弯薄壁型钢槽形截面受弯构件进行了试验研究和有限元参数分析。结果表明,板件加劲形式对高强冷弯薄壁槽钢受弯构件屈曲模式和受弯承载力有显著影响,翼缘V形加劲比腹板V形加劲能够更有效地提高构件抗弯承载力,构件抗弯承载力的变化规律与屈曲模式有关。根据有限元参数分析结果,在已有直接强度法基础上回归出适用于高强冷弯薄壁槽钢受弯构件的直接强度法修正公式。     

Preparation Technology of Fiber Toughened Self compacting High strength Concrete

Preparation technology of fiber toughened self compacting high strength concrete was tested by measuring influence of water/binder ratio, sand percentage, and steel fiber content on spread, T500 time , U shape value, and L shape value of fresh concrete. Mechanical properties were analyzed in case of different water/binder ratio, sand percentage, and steel fiber content. The test results show that suitable W/B and sand percentage were necessary to satisfy self compacting performance of the fresh concrete. With the increase of steel fiber content, the compressive strength and flexural strength were improved while workability of fresh concrete was cut down. Steel fiber toughened self compacting high strength concrete was prepared successfully with a strength grade of CF90 and a flexural strength of more than 11.0 MPa.     

硅肥用量对水稻茎秆抗折力的影响研究

研究不同硅肥施用量对水稻茎秆抗折力的影响,为水稻生产中合理施用硅肥,提高水稻抗倒伏能力提供重要参考。本研究选用了3个抗倒伏能力有一定差异的品种（组合）为材料,分析了3个水平硅肥施用量对水稻灌浆期的3个基部节间抗折力和整株抗推力的影响。施用硅肥的处理比未施用硅肥的对照处理的茎秆节间抗折力有一定程度的提高,D2处理从总体上增加抗折力的幅度较大,不同的品种抗折力的提高有所不同,其中‘绿优1号’、‘汕优63’在Si 60 kg/hm²处理下茎秆抗折力最大,‘中优838’在Si 30 kg/hm²处理下抗折力最大;而整株抗推力的表现与节间抗折力有一定差异,从分析结果看,在Si 30 kg/hm²处理下整株抗推力最大,折合成单茎抗推力也较大,且在3个品种上表现基本一致。一般的中籼水稻品种在生产中可适量施用硅肥来提高水稻的抗倒伏能力,一般施纯Si 30 kg/hm²,施硅量不宜过大,可根据不同的品种作适当调整。     

黄泛平原土壤中有效态锰的分布及锰肥的增产效果

应用田间试验和室内分析相结合的方法探讨了黄泛平原土壤中锰的生物有效性，土壤中锰的赋存形态和锰肥的增产效果。结果显示，黄泛区土壤中活性锰的含量普遍较，８５．８０％农田土壤处于缺锰状态。潮土中的锰，４０％是以对植物无效的残态和晶形铁结合态存在，仅有０．０６％的锰是以植物可直接吸收利用的代换态存在的，还有４０％的锰以氧化物形态存在，虽然有效性较高，但需经还原转化。因此本区土壤施用锰肥具有一定的增产作用，     

ECC/钢筋混凝土叠合梁正截面受弯承载力试验与理论研究

为了探究ECC/高强钢筋混凝土叠合梁的正截面受弯特征，以及ECC层厚度对叠合梁整体受弯性能的影响，做了两组共5根梁试件的正截面受弯试验。发现与高强钢筋混凝土梁相比，叠合梁的承载力更高，相同荷载下的挠度值和最大裂缝宽度较小。在受弯全过程中其截面应变仍符合平截面假定，钢筋与ECC也可以实现协调变形，说明受拉区使用ECC可以使得高强钢筋的应力得到充分发挥。但ECC层厚度过大可能会使叠合梁发生脆性破坏。进一步地，在此研究的基础上，对已有ECC的本构模型进行简化，忽略其应力强化贡献，并运用叠加原理，提出一种用于计算ECC/钢筋混凝土叠合梁正截面受弯承载力的方法，将计算结果与试验结果及诸多文献结果进行比较，发现吻合度较高。     

A Study on Lightweight Aggregate Concrete with High Fluidity

In this paper, the influence of fly ash (FA), blast furnace slag (BS) and silica fume (SF) on the properties of lightweight aggregate concrete (LAC) with high fluidity were studied. Results show that in LAC the effects of composite additives are better than that of single additive. The slump of LAC with apparent density of 1 840 kg/m 3 could reach 267 mm and the spread 650 mm. The 28d strength is 28.8 MPa for LAC with 20% ground FA and 20% BS as additives and the shale ceramsite with bulk density of 503 kg/m 3 and crushing strength 3.1 MPa was used as aggregate. Physical properties of lightweight aggregate have significant effects on durability of the flowing LAC.     

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.     

A Study Raising the Grade of Silico-titanium Ferroalloy

It is studied in this paper that the influences of various factors,such as the smelting temperature,the basicity of the slag,and the quantity of reductant on the titanium content of alloy,silicon content of alloy,TiO2 content of the remaining slag and the titanium recovery in smelting silico-itanium ferroalloy using silicoaluminium ferroalloy as reductant.With this study,the optimum techn ological parameters are obtained of raising the titanium content of alloy and re-$$$ucing the silicon content of alloy. The stable experiments in laboratory and factory using this opti-mum technological parameters are conducted.     

Expansion Characeriscs of Fluidized Bed Combustion Ashes Under Auoclaved Curing

Containing more SO3 and f-CaO, the fluidized bed combustion (FBC) ash and slag is easier to be in greater volume expansion when it is cured in the normal temperature. The linear expansion rates and the strength development of two FBC ashes and one FBC slag in autoclaved curing and normal curing are studied, and the hydrated products are also analyzed by X-ray diffraction (XRD) and SEM. It is shown that the expansion of FBC ashes is significantly inhibited by autoclaved curing. Also, there is no gypsum and ettringite but some tobermorite in the hydrated products which become richer and better crystallization,resuleing in the significant increase of the sevength.     

硅肥对高粱产量、光合速率以及抗折力影响的研究

通过不同时期喷施硅肥,研究硅肥对高粱产量、光合速率及抗折力的影响,为硅肥在高粱上的推广应用提供科学依据。试验选用"归来"牌液体硅肥,采取随机区组设计,共设3个处理,每个处理3次重复。研究结果表明:喷施硅肥具有提高高粱净光合速率、叶绿素含量的作用,可以降低重心高度提高茎秆抗折力,提高高粱籽粒中淀粉、蛋白质、脂肪含量,其中以高粱10片叶时期喷施硅肥效果最好。