对比水泥对粒化高炉矿渣粉性能检测结果的影响研究

采用不同的对比水泥对矿渣粉的活性指数、流动度比和凝结时间比等物理性能进行了测定,研究了对比水泥的抗压强度、比表面积、碱含量以及混合材的种类和掺量对矿渣粉性能检测结果的影响规律,并探讨了粒化高炉矿渣粉对比水泥技术指标的适宜范围。结果表明,对比水泥的混合材掺量、碱含量、比表面积、凝结时间和抗压强度对矿渣粉的活性指数、流动度比以及凝结时间比等指标检测结果影响显著;本试验研究建议将GB/T 18046-2008标准中对比水泥的比表面积修改为"350~400m~2/kg",同时增加3d抗压强度为"25~35MPa",更符合矿渣粉物理性能检测的需要。     

高细石灰石粉与矿渣粉复合配制高强水泥试验研究

按正交试验方法设计了不同比例高细石灰石粉、矿渣粉和粉煤灰掺入到P.Ⅰ42.5R硅酸盐水泥中的多组样品,使用RRSB线性回归得到样品的颗粒群分布,并检验样品的物理性能。结果表明,高细石灰石粉和矿渣粉可以明显改善水泥的粒度分布,增加水泥细微颗粒含量,显著提高水泥早期、后期和长期强度。将60%的P.Ⅰ42.5R硅酸盐水泥、6%的高细石灰石粉、30%矿渣粉和4%粉煤灰混合可以配制3d、28d和90d抗压强度分别为38.5MPa、71.2MPa和76.5MPa的高强水泥,与P.Ⅰ42.5R硅酸盐水泥比较,3d、28d和90d抗压强度分别提高约7MPa、10MPa和13MPa。     

球磨和立磨矿渣粉对矿渣水泥性能的影响研究

通过激光粒度分析仪(LPS)分析球磨和立磨粉磨的矿渣粉粒度,并用旋转黏度计测定矿渣水泥流变性能及胶砂强度。结果表明:球磨机加工的矿渣粉比立磨加工的矿渣粉颗粒粒度分布宽、细颗粒含量高;矿渣粉比表面积相近时,2种矿渣水泥的流变性能相差不大,球磨矿渣水泥的强度比立磨的稍好。     

矿渣-钢渣复合水泥的性能研究

试验利用矿渣和钢渣作为配制复合水泥的辅助性胶凝材料,研究了矿渣、钢渣细度和复合比例对复合水泥强度的影响,并从颗粒堆积和复合胶凝效应的角度探讨了矿渣-钢渣在复合水泥中的作用机理。试验结果表明：在矿渣与钢渣组成的复合体系中,矿渣细度决定了复合水泥的强度,矿渣越细,复合水泥强度越高;在辅助性胶凝材料掺量一定的情况下,矿渣占的比例越高,复合水泥的强度越高;在适宜的复合比例下,用矿渣和钢渣混合配制的复合水泥28d抗压强度高于纯水泥的28d抗压强度。     

磨细矿渣高性能混凝土的试验研究

通过试验,研究了磨细矿渣和水泥用量以及材料配比对混凝土性能的影响。试验结果表明:水胶比是影响矿渣高性能混凝土强度的主要因素;矿渣等量取代水泥有一最佳值;硅粉和减水剂对矿渣高性能混凝土 28d抗压强度影响有一个较优掺量范围。     

分别粉磨对矿渣水泥颗粒分布以及性能的影响

本文从矿渣和熟料的易磨性和粉磨动力学方面,解释了共同粉磨和分别粉磨的矿渣水泥颗粒分布产生差异的原因,总结并分析了两种不同工艺对矿渣水泥和混凝土性能的影响。     

矿渣微粉粒度分布对水泥性能的影响

利用灰色关联分析方法,研究了矿渣微粉的粒度分布对矿渣水泥性能的影响。研究结果表明:0~5μm、5~11μm的矿渣微粉颗粒分别对3 d、28 d强度有显著影响;0~23μm的矿渣粉颗粒对3 d,28 d强度起增进作用;水泥强度随23μm的矿渣微粉颗粒含量增大而降低。因此,可以通过优化矿渣微粉的粒度分布来改善水泥性能。     

矿渣-水泥胶凝体系颗粒群匹配与其活性的关系研究

将矿渣粉磨后,以不同的比例与一定细度的水泥混合,配成一系列的矿渣-水泥胶凝粉体。以Fuller曲线得到的粉体颗粒群分布作为矿渣-水泥胶凝粉体的最佳紧密堆积颗粒群分布。利用水泥与矿渣激光粒度检测结果来计算矿渣-水泥胶凝粉体的颗粒群分布,运用灰色关联分析方法计算矿渣-水泥胶凝粉体与最紧密颗粒群堆积颗粒群分布的关联度,同时测定不同矿渣掺量下矿渣-水泥胶凝体系的不同龄期的活性指数。结果表明:矿渣-水泥胶凝粉体的实际颗粒群分布与最紧密堆积颗粒群分布关联度最高时,该胶凝体系的28d矿渣活性指数最为理想。     

水胶比矿渣粉对混凝土力学性能影响的试验及机理研究

以不同配比的水胶比和矿渣粉掺量为影响因素,配制混凝土试件进行抗压强度正交试验,深入系统的研究其对高性能混凝土力学性能的影响。在此基础上,通过电镜观测,从微观机理角度对宏观性能进行分析解释。研究表明,混凝土的抗压强度均随着水化龄期的延长而增大。水化早期,掺有矿渣粉的高性能混凝土强度都较低;水化后期,矿渣粉活性效应发挥显著。在水胶比不变时,随着矿渣粉掺量的增加混凝土的强度是在逐渐降低的。使用42．5R普通水泥,控制水胶比在0．40—0．20,掺加矿渣粉,可配制出C45～C65的高性能混凝土。微观机理研究显示矿渣粉的存在使混凝土中孔隙减少,孔径变小,结构变密实,起到了很好的填充和微集料作用。     

不同比表面积球磨矿渣粉对水泥性能的影响

借助粒度分布仪,分析了球磨矿渣在不同比表面积情况下的粒度分布,研究结果表明：随着比表面积的增大,球磨矿渣粉的细颗粒明显增多,n值增大,即随着比表面积的增加,粒度分布越来越宽。研究同时指出：矿渣粉比表面积的变化对矿渣水泥的标准稠度用水量影响不大;比表面积的增加,有利于提高矿渣水泥的强度,但对其流变性的影响没有特定的规律。     

硅酸盐水泥对钢渣活性激发的性能研究

试验研究了在硅酸盐水泥体系中通过碱性激发提高钢渣水化活性的方法.研究表明,钢渣掺入量<30%时,硅酸盐水泥对钢渣的活性激发效果最好;复掺矿渣对钢渣活性的激发效果优于粉煤灰,即使掺量为30%时,其早期强度也与相应龄期普通硅酸盐水泥强度持平,而后期强度逐渐超过纯水泥的强度;在普通硅酸盐水泥体系中掺入钢渣可以改善其硬化浆体的性能.     

The effect of particle size distribution on the properties of blended cements incorporating GGBFS and natural pozzolan (NP)

This paper investigates the effect of particle size distribution on the properties of blended cements incorporating ground granulated blast-furnace slag (GGBFS) and natural pozzolan (NP). Pure Portland cement (PPC), NP and GGBFS were used to obtain blended cements that contain 10, 20, 30% additives. The cements were produced by intergrinding and separate grinding and then blending. Each group had two different Blaine fineness of 280 m²/g and 480 m²/g. According to the particle size distribution (PSD) curves, 46% of the coarser specimens and 69% of the finer specimens passed through the 20 μm sieve. It was observed that the separately ground specimens were relatively finer than the interground ones and had higher compressive strength and sulfate resistance. The separately ground coarser specimens had the lowest heat of hydration. The separately ground finer specimens, which had the highest compressive strength and sulfate resistance, had the highest percent passing for each sieve size. For these specimens 34, 69, 81 and 99% passed through 5, 20, 30 and 55 μm sieves, respectively. For the interground specimens, which had the same fineness, the respective values for the same sieves were 32, 68, 75 and 94%.     

Utilization of fly ash and ground granulated blast furnace slag as an alternative silica source in reactive powder concrete

Reactive powder concrete (RPC) is an ultra high strength cement-based material. Cement and silica fume (SF) content of RPC are generally rather high compared to the conventional concrete. The aim of this study is to decrease the cement and SF content of RPC using with fly ash (FA) and/or ground granulated blast furnace slag (GGBFS). The effect of these mineral admixtures on compressive strength of RPC has been investigated under autoclave curing. In the first stage, the effect of autoclave time and SF content on compressive strength was determined. In the second stage, SF was gradually decreased and cement was replaced with FA and/or GGBFS at different proportions. The microstructure was investigated by scanning electron microscope (SEM). Test results indicate that, the utilization of FA and/or GGBFS in RPC is possible without significant mechanical performance loss. SEM micrographs revealed the tobermorite having different morphology.     

高性能矿渣基复合掺合料的研究

矿渣粉较高的价格以及大掺量矿渣混凝土的泌水一直是其在建筑工程中大规模应用的主要障碍.本研究选用转炉钢渣粉、石灰石粉和粉煤灰作为矿渣基掺合料的辅助原料,重点考察了掺合料组成与性能之间的关系.结果表明:转炉钢渣粉具有减水增密和抵抗泌水的突出功效.石灰石粉具有一定的早强作用.粉煤灰对胶砂流动度和强度发展有不良影响,但混凝土试验结果与之有所不同.当复合10%～20%转炉钢渣的矿渣基掺合料在混凝土中的掺量高达50%时,其新拌混凝土流动性和稳定性俱佳,28d抗压强度稍优于纯矿渣粉,而生产成本可降低30%以上.实现矿渣基复合掺合料在低成本前提下高性能化的关键在于掺合料在颗粒级配上的优化以及它们对水化进程的协同促进作用.     

适于配制高性能混凝土的硅酸盐水泥及其胶凝材料的最佳颗粒级配

根据国内外学者关于硅酸盐水泥及其胶凝材料最佳颗粒级配的论述,进一步探讨其颗粒分布,理顺和阐明硅酸盐水泥最佳颗粒级配与胶凝材料最佳颗粒级配之间的关系和不同点,从而为配制高性能混凝土提供在硅酸盐水泥及其胶凝材料颗粒级配方面的一些理论根据。     

Hydration and properties of novel blended cements based on cement kiln dust and blast furnace slag

The aim of the present paper is to address the key technical issues pertaining to the utilization of cement kiln dust (CKD) as an activator for ground granulated blast furnace slag (GGBFS) to create nonconventional cementitious binders for concrete. The relatively high alkaline content of CKD is the predominant factor preventing its recycling in cement manufacture. However, it was observed that depending on the water-soluble alkali and sulfate compounds, CKD could provide the environment necessary to activate latent hydraulic materials such as GGBFS. Binary blends containing slag and CKDs from different sources were characterized and compared in terms of the rates of heat evolution and strength development, hydration products, and time of initial setting. A study of the effects of the influencing factors in terms of soluble alkali content, particle size, and free lime content was undertaken. The results confirm the dependence of the dissolution rate of slag on the alkalinity of the reacting system, and the importance of the optimum lime content on the rate of strength gain.     

Effect of material characteristics on the properties of blended cements containing high volumes of natural pozzolans

The effect of three different natural pozzolans from Turkish deposits on the properties of blended cements produced by intergrinding cement clinker with a high volume of natural pozzolan (55 wt.% of the cementitious material) was investigated. The particle size distribution of blended cements, setting time, heat of hydration, and compressive strength of blended cement mortars were determined. Experimental results showed that the hardness of the pozzolanic material strongly influenced the particle size distribution and the related properties of the blended cements by affecting the fineness of the components of the blended product. The early strength of the mortars was strongly affected by the particle size distribution of blended cements, whereas the strength development performance of the mortars was more related to the pozzolanic activity of the natural pozzolan present in the blended cement.     

水泥助磨剂性能测定方法的试验研究

研究了三种高效助磨剂对普通硅酸盐水泥性能的影响。结果表明：不同助磨剂对水泥颗粒的粒径分布、筛余、流动性，尤其是对粒径3～32μm颗粒的含量以及水泥各龄期强度都有不同的影响。而对由透气法测得的勃氏比表面积无明显影响。水泥助磨剂的性能可用磨制的水泥的颗粒组成、45μm筛余、流动性、强度来表征或评价。而勃氏比表面积不适宜用来表征助磨效果。同时对助磨剂作用微观机理也进行了探讨。     

胶凝组分粒度特性对水泥性能影响的研究评述

介绍了具有胶凝活性的粉煤灰、矿渣、纳米材料的颗粒特性对水泥性能影响的研究,包括颗粒级配区间的优化、颗粒尺寸分布模型以及矿物掺合料的作用机理.细度对水泥强度的贡献很大,特别是在水化初期;目前大多研究中的紧密堆积模型采用fuller分布,可改善浆体的结构;高活性胶凝颗粒、水泥颗粒和低活性胶凝颗粒分别取代细、中和粗颗粒区间,可优化区间提高整体性能.最后对目前国内外研究成果的总结分析,展望了胶凝组分粒度特性的未来研究方向.     

水泥粉磨工艺对混凝土性能的影响

分别检测了球磨机圈流粉磨工艺和辊压机-球磨机联合粉磨工艺生产的不同强度等级水泥的物理性能及与外加剂的适应性，并将各水泥样配制成混凝土，测试相应混凝土的性能。试验发现，强度高的水泥所配制混凝土的强度不一定高，水泥需水性对混凝土强度的影响甚至超过了水泥强度对它的影响；圈流磨的水泥所配混凝土的强度较高。试验检测了圈流磨及联合粉磨生产的水泥的颗粒组成，分析了联合粉磨的水泥需水性大的原因，找到了控制联合粉磨工艺水泥需水性的工艺指标。