共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
研究了不同品种熟料及细度,粉煤灰、矿渣粉及钢渣粉对复合水泥最早期强度的影响.研究表明:随熟料细度提高,水泥24h内最早期强度有明显提高.在化学组成及含量接近的情况下,熟料品种对水泥最早期强度影响不明 显.掺加粉煤灰、矿渣粉和钢渣粉等矿物掺合料后,复合水泥浆体最早期强度均有明显降低,但12h后复合水泥与纯硅酸盐水泥... 相似文献
3.
提高磷石膏基水泥早期性能的研究 总被引:3,自引:0,他引:3
通过磷石膏预处理和添加超细硅酸盐水泥熟料的方法,对提高磷石膏基水泥早期性能进行了研究,并通过XRD、SEM对其水化过程和机理进行了探讨。结果表明,磷石膏经钢渣预处理,或采用超细熟料粉作为碱性激发剂,均能显著改善磷石膏基水泥的早期强度和凝结特性,两种措施同时采用时,能制备出3d抗压强度超过10MPa,28d抗压强度达49MPa以上的磷石膏基水泥。钢渣固结或固化了磷石膏中缓凝的可溶性杂质,超细粉磨使熟料自身水化加快并同时促进了矿渣水化,是磷石膏基水泥早期水化性能提高的原因。 相似文献
4.
Sulphide-rich tailings from four Canadian mines were sampled (Mines A1, A2, B and C) to prepare several different paste backfill mixtures. The sulphur grade within these tailings samples range from 5 to 32 wt.%. The binders used were Portland-cement-based binders, fly-ash-based binders and slag-based binders with proportions ranging from 3 to 6 wt.%. The study was carried out in two stages. Stage I allowed us to understand the effects of binder type, binder proportion and tailings properties on compressive strength development of paste backfill during the course of curing time. It was pointed out that for high sulphide tailings, neither the slag-based binders nor the fly-ash-based binders were effective, whereas the sulphate-resistant-based binder (mix of Type I [TI] and Type V [TV] Portland cements) gave good long-term strength. However, the slag-based binders gave the best strength for low and medium sulphide-bearing tailings for which the Portland- and the fly-ash-based mixtures have a relatively low strength. Stage II allowed us to study the early stage strength acquisition of the various mixtures. It was found that the chemical composition of the mixing water plays a role on the mechanical behavior of certain cemented backfills. 相似文献
5.
6.
7.
Ladle slag fines consist mainly of γ-C2S, which does not show cementitious property in water, but can exhibit significant cementitious property in the presence of alkaline activators at room temperatures. This study deals with the hydraulic reactivity of ladle slag fines under autoclaving conditions. The results indicate that ladle slag fines cannot be used as cementing material alone because of the presence of free lime in ladle slag. The combination of a ladle slag fine and a siliceous material, such as silica flour (ground quartz), can eliminate the soundness problem and give very high strength. The introduction of a small amount of Portland cement or hydrated lime into ladle slag fine-silica flour system can increase strength significantly. Lime is more effective than Portland cement due to the presence of Al in Portland cement. The autoclaving temperature should be higher than 175 °C and the time for constant temperature does not need to be more than 4 h to achieve satisfactory strength. Finally, seven batches of experiments are designed to plot isostrength contours for ladle slag fine-cement-silica flour and ladle slag fine-hydrated lime-silica flour ternary systems. 相似文献
8.
9.
磷矿石、磷渣、磷尾矿在烧成高强度水泥熟料中的作用 总被引:4,自引:2,他引:2
利用磷渣、磷矿和磷尾渣并复合适宜的废渣或无机非金属矿配制了水泥熟料烧成助剂,利用这些助剂并适当调整配料方案在正常条件下烧成了高强熟料2对熟料进行了XRD,SEM和反光显微镜形貌分析及物理性能检验2结果表明:配制的烧成助剂利用磷废渣以及磷矿中某些元素的助熔作用和一些工业废渣的助熔作用,改善了水泥熟料易烧性2实验烧成的熟料中含有较多的C3S,同时使液相条件下形成的C3S亚微结构得到了改善,因而熟料具有较高强度2本研究配制的烧成助剂中挥发性组分很少,不会对环境污染和设备腐蚀带来明显影响,适宜于新型干法生产使用. 相似文献
10.
铜矿渣应用于水泥与混凝土中可降低炼铜企业成本,又有利于环境保护.介绍了铜矿渣的物理与化学性质,对铜矿渣在水泥和混凝土领域的研究进展进行了综述.铜矿渣可作为铁质原料配置生料,配置的生料易烧性好,并能改善熟料的岩相结构和力学性能;也可作为水泥熟料混合材,所制成的水泥具有早期水化放热低、后期强度发展高等优点.铜矿渣可作为细骨料应用于混凝土中,铜矿渣混凝土具有与普通混凝土相当的工作性、力学性能与耐久性能.铜矿渣和水泥熟料有相似的化学成分,可通过物理或化学方式激发铜矿渣的活性作为胶凝材料应用于混凝土中,与Ca(OH)2反应生成与水泥水化相似的水化产物.铜矿渣可降低混凝土的脆性系数,具有减脆的作用. 相似文献
11.
研究了利用混凝土产品吸收二氧化碳的可行性。混凝土的3个基本组分:水泥、细沙和骨料,都可被用来作为二氧化碳吸附物以实现储留最大化,另外,可利用高钙钢渣等工业废料生产混凝土骨料。研究发现波特兰水泥2h碳化后吸收14%二氧化碳,碳化后的材料的强度与7d传统养护的强度相当。钢包钢渣细粉能吸收4%~12%二氧化碳,能用来替代河沙。吹氧高炉钢渣对二氧化碳吸收的能力超过12%。由此制成的粗骨料其强度可与石灰岩相比。如果混凝土砌块由这3组分组成,一块20cm×20cm×20cm的标准砌块能吸收1.39kg二氧化碳。二氧化碳在混凝土中的储留是一项经济可行、直接减排的有效技术。 相似文献
12.
以铝酸盐水泥熟料、硅酸盐水泥熟料和粉煤灰为原料,探讨了掺加少量铝酸盐水泥熟料对硅酸盐水泥及粉煤灰硅酸盐水泥复合体系水化、凝结和硬化性能的影响。结果表明,在硅酸盐水泥及粉煤灰硅酸盐水泥中掺加铝酸盐水泥熟料,可以明显缩短水泥的初、终凝时间,但复合体系的需水量增加;掺加少量铝酸盐水泥熟料(≤3%)可明显提高硅酸盐水泥的早期强度,但后期强度(28d)有所降低;当铝酸盐水泥熟料的掺量达5%时,水泥的各龄期强度均明显降低。少量铝酸盐水泥熟料掺加到粉煤灰硅酸盐水泥中,复合体系的各龄期强度都明显提高,且早期强度的提高幅度较大。 相似文献
13.
14.
15.
16.
17.
研究了电石渣对硅酸盐水泥熟料形成动力学的影响,得到了熟料形成反应的活化能和动力学常数。研究表明,电石渣的掺入不利于硅酸盐水泥熟料的形成。 相似文献
18.
利用化学分析法、X射线衍射分析(XRD)、扫描电子显微镜(SEM)、热重分析(TG-DSC)等检测手段对电解锰渣、镁渣的化学组分、矿物组成、物化性能进行分析.根据分析结果,合理设计以锰渣、镁渣为原料制备硫铝酸盐水泥熟料的配比方案,并考察烧结温度对熟料性质的影响.在制备的水泥熟料中掺入一定量的石膏可制备出早强、快硬的硫铝酸盐水泥.在此过程中测定水化放热过程,并分析石膏掺量与水泥抗折和抗压强度的关系,确定最佳的石膏掺量.实验结果表明,电解锰渣、镁渣可以作为有价值的原料制备硫铝酸盐水泥熟料,两种废渣的掺比可分别达到21%,烧结过程的最佳温度为1260 ℃,保温时间为30 min,此时烧结出的试样的矿物相主要为C2S、C4A3S-.当石膏掺量为15%时,放出的水化总热最多,制备出的水泥力学性能最好,28 d的抗折强度为5.1 MPa,抗压强度为31.2 MPa,抗渗等级达到P6,烧制熟料和水化产物将锰渣和镁渣中的重金属有效的固化稳定,不易被浸出. 相似文献
19.
High strength can be obtained at early ages for precast concrete elements by the use of CEMI 52.5R cement (OPC) and thermal treatment (steam curing). To compensate for the announced withdrawal of CEM I cements because of high CO2 emissions during their production and the ecotax that this will imply, one attractive alternative is the use of composed cements resulting from the combination of clinker with mineral admixtures. In steam curing conditions, previous studies have shown an increase in the compressive strength at one day of age for mortars incorporating an OPC/blast furnace slag (GGBS)/metakaolin (MK) combination, in comparison with mortars incorporating OPC only. The present study investigates the connection between the compressive strength, at one day of age, of steam cured mortars made with various binders and the hydration of these binders. The progress of the hydration was characterised by means of XRD, thermal and microprobe analyses. The results indicate that the increase in compressive strength when MK is incorporated (OPC/MK or OPC/MK/GGBS) can be explained by an increase in the amount of C-S-H, C-A-H, C-A-S-H phases, a decrease in the amount of CH and a change in the chemical nature of the matrix (decrease in C/S ratio). The decrease in compressive strength of OPC/slag-based material can be explained by a reduction in the amount of hydrated phases (particularly C-S-H) and compactness.These are promising results for precast concrete manufacturers who are concerned about preserving the environment. 相似文献