Properties of self-compacting concretes made with binary,ternary, and quaternary cementitious blends of fly ash,blast furnace slag,and silica fume

Self-compacting concretes (SCCs) have brought a promising insight into the concrete industry to provide environmental impact and cost reduction. However, the use of ternary and especially quaternary cementitious blends of mineral admixtures have not found sufficient applications in the production of SCCs. For this purpose, an experimental study was conducted to investigate properties of SCCs with mineral admixtures. Moreover, durability based multi-objective optimization of the mixtures were performed to achieve an optimal concrete mixture proportioning. A total of 22 concrete mixtures were designed having a constant water/binder ratio of 0.44 and a total binder content of 450 kg/m³. The control mixture included only a Portland cement (PC) as the binder while the remaining mixtures incorporated binary, ternary, and quaternary cementitious blends of PC, fly ash (FA), ground granulated blast furnace slag (S), and silica fume (SF). Fresh properties of the SCCs were tested for slump flow diameter, slump flow time, L-box height ratio, and V-funnel flow time. Furthermore, the hardened properties of the concretes were tested for sorptivity, water permeability, chloride permeability, electrical resistivity, drying shrinkage, compressive strength, and ultrasonic pulse velocity. The results indicated that when the durability properties of the concretes were taken into account, the ternary use of S and SF provided the best performance.     

复合激发剂在矿渣-钢渣-粉煤灰三掺混凝土中的应用研究

采用自制的高效复合激发剂,研究了其对矿渣-钢渣-粉煤灰三掺混凝土工作性能和力学性能的影响。结果表明:复合激发剂的使用,对新拌混凝土的工作性能没有不利影响;复合激发剂对设计等级为C30混凝土抗压强度提高的效果明显,而对C50混凝土的作用效果则有所减弱,其原因在于单位体积混凝土中高水泥含量时,水泥对钢渣的水化在早期具有一定的抑制作用。     

双掺粉煤灰和粉状高炉矿渣的自密实混凝土流变性能的研究

研究了以水泥,粉煤灰和粉状高炉矿渣为胶凝材料的自密实混凝土的工作性参数和流变参数,并分析了它们之间的关系。结果表明,掺入10%粉煤灰和矿粉的自密实混凝土的扩展度和T50分别为625 mm和6.4 s,此时混凝土流动性最小。掺入粉煤灰和矿粉均能提高混凝土的扩展度、L仪充填比、屈服应力和塑性黏度,其中粉煤灰对混凝土体系流动性的提高更为显著。随着扩展度的升高,混凝土屈服应力呈下降趋势,而T50与塑性黏度则呈正向的变化关系。     

粉煤灰、矿渣复合硅酸盐水泥的研制

本文对粉煤灰和矿渣作混合材生产复合水泥采用不同的粉磨工艺进行对比,采用矿渣预粉磨工艺使复合水泥的早期强度明显提高,混合材总掺量达40％时,不加任何外加剂仍然能生产425R复合水泥。     

The use of ground blast furnace slag,chrome slag and corn stem ash mixture as a coating against corrosion

The ground blast furnace slag (GBFC), chrome slag (CS) and corn stem ash (CSA), produced following a number of processes, were mixed with pitch in different proportions in order to increase adherence. Iron plates were then coated with this mixture. The coated and uncoated plates were left to corrode in a NaCl solution (35 g/L NaCl). The potential differences of the specimens were measured after they were kept in the solution for a month by electrodes. The potential difference for the uncoated iron plates (iron plates without GBFC, CS and CSA) was approximately 0.501 V. For those coated with pitch, this value was 0.363 V. On the other hand, the potential difference of the coated iron electrodes was determined to be 0 V revealing the absence of corrosion after the NaCl solution treatment and the suitability for the use of the ground blast furnace slag, chrome slag and corn stem ash as coating materials.     

Durability of concrete incorporating non-ground blast furnace slag and bottom ash as fine aggregate

The paper presents investigation of how the usage of bottom ash (BA), granulated blast furnace slag (GBFS), and combination of both of these materials as fine aggregate in concrete affects the concrete durability. To assess durability characteristics of concrete, durability tests were conducted and the results were evaluated comparing with reference concrete. Three series concrete were produced. GBFS, BA and GBFS+BA are replaced the 3–7 mm-sized aggregate. Five test groups were constituted with the replacement percentages as 10%, 20%, 30%, 40% and 50% in each series. These by-products were used as non-ground form in the concrete. Durability properties of the concretes were compared in order to study the possible advantages of different replacement ratios. According to results, GBFS and BA affects some durability properties of concrete positively in case of it is used as fine aggregate. Resistance to high temperature and surface abrasion are positively affected properties. Capillarity, drying-wetting and freezing-thawing resistance of the concrete can be accepted to some extent. Properties of by-products and its replacement ratio are controlling the influence level and direction. Comparison of the SEM images and test results show that chemical and physical properties of GBFS and BA are the main factors affecting the concrete durability. It is concluded that it is possible to produce durable concrete by using GBFS and BA as fine aggregate.     

含钛高炉重渣的水热固化研究

将含钛高炉重渣与Ca(OH)2以9∶1的质量比混合,添加15%、2 mol/L的NaOH溶液,利用水热固化技术,低温(200℃)制备出抗折强度约15 MPa的建筑材料。结果表明,成型压力、固化温度、固化时间等因素对固化体强度的形成均有重要影响。水热过程中,生成的CSH和水化石榴石晶相是导致固化体强度提高的重要原因。水热固化技术为含钛高炉重渣的大规模综合利用提供了新的途径。     

利用水淬矿渣和粉煤灰制备免蒸砖的研究

以未处理的水淬矿渣为主要原料,掺入一定量粉煤灰、重矿渣等工业废料,加入少量水化活性激发材料制备免蒸砖.结果表明,用这种方法进行冶金渣的再生利用,解决了几种工业废渣的利用问题.制备的免蒸砖强度高,达到MU15及以上强度等级,干燥收缩小,抗冻、抗碳化等性能优良,满足JC 239-2001<粉煤灰砖>要求.     

Mix design and performance analysis of asphalt concretes with electric arc furnace slag

The paper presents the results of a laboratory study, aimed at verifying the possibility to use two particular typologies of electric arc furnace (EAF) steel slags, in substitution of the natural aggregates, in the composition of wearing course asphalt concrete for flexible pavements. The experimental research has been articulated in a preliminary study of the chemical, leaching, physical, and mechanical properties of the EAF steel slag, and in the following mix design and performance characterisation of the bituminous conglomerates, through gyratory compaction tests, permanent deformations tests, Stiffness Modulus tests at various temperatures, fatigue tests and indirect tensile strength tests. All the mixtures with EAF slag have satisfied the requisites for acceptance in the road sector technical standards, thus resulting as suitable for use in the construction of road infrastructures, moreover presenting higher mechanical characteristics than those of the corresponding asphalts with full natural aggregate.     

不锈钢渣和矿渣制备胶凝材料的试验研究

以不锈钢渣和矿渣为主要原料,配加脱硫石膏、粉煤灰、矿物激发剂制备胶凝材料,通过试验确定了原料的最佳质量配比:33％不锈钢渣、35％矿渣、5％脱硫石膏、5％粉煤灰、22％矿物激发剂,利用该配比制备的胶凝材料达到32.5级普通硅酸盐水泥的标准要求.同时,采用XRD分析了胶凝材料的矿相组成,采用扫描电镜对胶凝材料不同龄期水化产物的显微结构进行了分析.     

矿渣微晶玻璃研制

本文介绍烧结法矿渣微晶玻璃装饰材料的研制。配制原料以矿渣为主,掺入玻璃工业用普通原料以及玻璃析晶时产生矿物所需的成分,经混匀熔化成玻璃后,进行热处理成为均匀微晶结构的玻璃结晶材料。对半工业性试验产品进行了微观结构、外观微孔质量及产品性能分析,并与天然石材的主要性能指标进行了对比。     

粒化高炉矿渣粉在混凝土中的应用

从粒化高炉矿渣粉的基本概念出发,通过对照高价标准,对粒化高炉矿渣粉在混凝土中的作用原理进行了分析,提出了在实际混凝土中应用高炉矿渣粉应该注意的几个问题,以指导实践。     

高炉炉渣在建材工业中的应用

介绍了高炉炉渣在建材工业中的应用。     

水钢高炉重矿渣的应用研究

以贵州省六盘水市水钢高炉重矿渣为试验原料,分析了原料的化学成分、物相组成,并对高炉重矿渣集料的物化力学性能进行了试验研究。以100%高炉重矿渣集料为骨料可获得了C20高炉重矿渣混凝土和M10砂浆,其各项物理力学性能均符合规范要求,这为水钢重矿渣的开发利用提供了理论依据。     

镍渣矿渣免烧砖的试验研究

研究了镍渣矿渣比和水泥掺量对镍渣矿渣复合胶凝材料体系的影响,并在此基础上,辅以化学激发剂NS、CA,采用正交试验方法,研制开发新型镍渣矿渣基复合胶凝材料,最佳配比为:镍渣和矿渣的质量比5∶5,水泥、激发剂NS和CA分别占镍渣和矿渣总质量的20％、0.5％和2％,胶砂比1∶3,水胶比0.5,可制得符合MU25等级的免烧砖.     

钢渣矿渣复合粉在商品混凝土中的应用研究

本文研究了钢渣矿渣复合粉取代矿渣粉作为商品混凝土掺合料,对混凝土工作性和抗压强度的影响。试验结果表明:采用复合粉取代矿粉对混凝土的工作性和抗压强度无不利的影响,采用复合粉取代矿渣粉作为混凝土掺合料具有良好的经济社会效益。     

Microstructure and durability of mortars modified with medium active blast furnace slag

Mechanical characteristics and durability properties of blast furnace slag cement composites largely depend on the hydraulic activity of the slag. In this paper, a Granulated Blast Furnace Slag with a low reactivity index is used in modifying mortar composition. Microstructure and durability of mixes containing 0%, 30% and 50% of slag as substitution to OPC are respectively compared and analyzed. Water porosity, Mercury Intrusion Porosity and pore size distribution are studied after 28, 90 and 360 days of wet curing. A qualitative microstructure analysis of mortars is proposed with Scanning Electron Microscope (SEM). The durability of mortar is evaluated through capillary water absorption and chloride diffusion tests. The results indicate a finer porosity and lower water absorption for slag mortars at old ages (90 and 360 days). Moreover, lower chloride diffusion for 50% blast furnace slag substitution is observed.     

高钛高炉渣在混凝土材料中的应用

高钛高炉渣是攀钢公司炼铁后产生的特有矿渣,由于TiO2含量较高,矿渣的综合利用率低,近年来不断开发高钛矿渣在混凝土中的应用。从高钛矿渣的物理力学性能、高钛渣混凝土的配合比设计和使用性能等方面,对高钛矿渣混凝土的应用进行介绍。实践表明,高钛矿渣混凝土性能优良,综合经济指标好。     

钢渣-矿渣复合微粉的活性试验研究

研究了改变钢渣与矿渣微粉比例以及钢渣微粉比表面积对混合材的机械激发性能,同时考察了自行研制的KYH-8、KYH-9和KYH-10三种激发剂对复合微粉的化学激发,并通过X射线衍射(XRD)、偏光显微(PLM)和电子扫描电镜(SEM)对复合微粉材料进行了结构分析.试验结果表明,复合渣微粉中钢渣的比例越大,钢渣矿渣复合粉的活性越低;钢渣微粉比表面积在400～500m2/kg时,钢渣微粉细度增加,复合微粉活性有所提高;复合微粉在早期只是填充于水泥石之间,起填充剂的作用,后期逐渐水化;0.01 mol/L KYH-10激发剂对钢渣与矿渣微粉比例为3:2的复合微粉激发效果表现最佳,复合微粉7d活性指数达到85%以上,28 d活性指数可以达到104%.     

Residual compressive behaviour of pre-heated high-performance concrete with blast–furnace–slag

An experimental program was designed and carried out to study the residual compressive behaviour of high-performance concrete (HPC) with blast–furnace–slag (BFS) at elevated temperatures ranging from 20 to 800 °C. The residual cube compressive strength is examined and the relationship between the residual compressive strength and temperature is investigated based on the heated cube specimens (100×100×100 mm³) tested on a universal test machine. In addition, on the basis of the heated prism specimens (100×100×300 mm³) tested on an electro-hydromantic rigidity servo test machine, the complete stress–strain curves are obtained, and the effects of temperatures on the residual prism compressive strength, the strain, and the elastic modulus etc are analysed. An approximate formula for the stress–strain relationship of HPC–BFS after exposure to temperatures is proposed.