共查询到17条相似文献,搜索用时 109 毫秒
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总结了各种矿物掺合料对减水剂作用效果影响方面的最新研究进展。结果表明:硅灰、沸石粉、偏高岭土、煤矸石等会降低减水剂的塑化效果;优质粉煤灰和矿渣粉与减水剂同时使用,可以增加浆体的流动度、减少流动度损失、增加黏聚性、减少泌水,改善减水剂的作用效果;同时掺加粉煤灰、矿渣粉与高效减水剂的浆体,其流变性能要优于高效减水剂与单一掺合料复合掺加的浆体;根据超叠加理论,应把几种矿物掺合料复合在一起掺加到混凝土拌合物中,利用不同粒径掺合料互相紧密填充的物理效应,达到取长补短的目的。并对各种矿物掺合料影响减水剂作用效果的机理进行了阐述。 相似文献
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高活性粉煤灰混合材(简称HFA)活性明显优于水淬矿渣、沸石、液态渣、沸腾炉渣等混合材。在水淬矿渣价格高、供不应求的今天,该产品的问世,对水泥生产企业有重要意义。 相似文献
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减水剂对阿利特-硫铝酸盐水泥适应性的研究 总被引:1,自引:0,他引:1
研究了高效减水剂对阿利特-硫铝酸盐水泥的饱和点、水泥浆体的流动度及流动度经时损失的影响。结果表明,对于阿利特-硫铝酸盐水泥,萘磺酸盐高效减水剂的饱和点掺量明显高于聚羧酸盐和氨基磺酸盐高效减水剂;不同高效减水剂对阿利特-硫铝酸盐水泥浆体的流动度及流动度经时损失的作用效果亦不同,聚羧酸盐高效减水剂最好,氨基磺酸盐次之,萘磺酸盐较差;阿利特-硫铝酸盐水泥中掺加矿物掺合料可以改善其与减水剂的适应性,矿物掺合料掺量越大,水泥净浆的流动度越大,流动度经时损失越小,矿渣粉的作用效果优于粉煤灰。 相似文献
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采用25 mm平行板式流变仪对水胶比为0.29的单掺粉煤灰(FA)、单掺矿渣(SG)以及粉煤灰和矿渣复掺的水泥基胶凝材料浆体进行了流变性能测试,基于H-B流变模型,并采用Matlab软件编程对试验数据进行了拟合.试验结果表明:单掺粉煤灰的水泥基胶凝材料浆体呈现先剪切增稠后剪切变稀行为,而单掺矿渣的水泥基胶凝材料浆体呈现先剪切变稀后剪切增稠行为;粉煤灰与矿渣复掺后粉煤灰对水泥基胶凝材料浆体流变性能的影响比矿渣的影响更大.同时得出了粉煤灰、矿渣单掺时以及粉煤灰与矿渣复掺时不同掺量条件下水泥基胶凝材料浆体的表征参数值.研究结果还表明:FA∶ SG为1∶1复掺等量取代水泥30%组成的水泥基胶凝材料浆体,其屈服应力值较小,而粘度相对较大,为绿色生态混凝土目标孔隙率的实现奠定了理论基础. 相似文献
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碱—粉煤灰—矿渣基胶凝材料的研究 总被引:2,自引:2,他引:2
在碱-矿渣系统中加入酸性粉煤灰,构成碱-粉煤灰-矿渣系统。实验室条件下,研究了水玻璃模数和掺量,硅酸盐水泥熟料、沸石、减水剂对酸性粉煤灰掺量为50%的碱-粉煤灰-矿渣胶凝材料强度的影响规律,同时在试验参数下,对该系统的凝结时间进行了测定。结果表明,以上各加入物对碱-粉煤灰-矿渣胶凝材料的强度均有较大影响;实验参数下,该材料并不发生急凝,凝结时间可以满足施工要求。 相似文献
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利用电炉氧化钢渣制备混凝土矿物掺合料的研究 总被引:1,自引:0,他引:1
研究了磨细电炉氧化钢渣对水泥标准稠度需水量、水泥净浆流动度以及混凝土抗压强度、抗渗性、抗冻性、抗碳化等性能指标的影响.研究结果表明,磨细钢渣具有令人满意的减水效果且与混凝土减水剂有较好的适应性;适量磨细钢渣掺入混凝土中对混凝土抗压强度以及耐久性能影响不大;将磨细钢渣与磨细粉煤灰或矿渣混掺可以发挥复合效应,提高掺合料的活性,改善混凝土的性能. 相似文献
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M.L. Allan 《Cement and Concrete Research》1997,27(12):1875-1884
The rheology of grouts containing latex was investigated. The two latex additives used were carboxylated styrene-butadiene and acrylic. The influences of superplasticizer, fly ash, and blast furnace slag on the rheology of latex-modified grouts were addressed. Shear stress-shear rate curves were determined for a variety of mix proportions. The time-dependent behaviour of selected grouts was also studied. It was determined that the yield stress and apparent viscosity are influenced by latex content and that the grouts are shear thinning at low water/cement ratios. Latex imparts stability and thixotropy in grouts. Partial replacement of cement with either fly ash or slag diminishes the effect of latex on rheology. 相似文献
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The influence of various fly ashes on the fluidity of fly ash-cement paste with superplasticizer was investigated in connection with the amounts of superplasticizer adsorbed on fly ashes, the change of ζ-potential and the physical properties of fly ashes. Fly ash indicates a high negative ζ-potential, and by adding superplasticizer, an even higher negative ζ-potential is indicated. However, the fluidity of fly ash paste is not improved by addition of superplasticizer as much as in the case of cement. The fluidity of fly ash-cement paste mixed with superplasticizer is influenced by the kinds of fly ashes. The bulk specific gravity of fly ash may be an index for judging the influence of fly ash on the fluidity of fly ash-cement paste. 相似文献
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碱-磷渣-粉煤灰胶凝材料的性能与硬化浆体结构 总被引:2,自引:1,他引:2
为充分利用磷渣和粉煤灰两种工业废渣生产高性能胶凝材料,研究了不同磷渣/粉煤灰配合比的碱-磷渣-粉煤灰胶凝材料性能,并用扫描电子显微镜和压汞仪分析了硬化浆体的细观结构和孔结构.结果表明:碱-磷渣-粉煤灰胶凝材料的凝结时间正常,在粉煤灰掺量为0~30 %(质量分数)范围内,随粉煤灰的掺量的增加,碱-磷渣-粉煤灰胶凝材料的凝结时间略有延长.与普通硅酸盐水泥相比,碱-磷渣胶凝材料的抗压强度较高,其3d和28d抗压强度分别可达到30.9MPa和98.8MPa,但其抗折强度相对较低.掺加粉煤灰后碱胶凝材料的抗压强度降低,而抗折强度提高.碱-磷渣-粉煤灰胶凝材料的耐蚀性和抗冻性能均显著优于硅酸盐水泥,其干缩比硅酸盐水泥的大.用部分粉煤灰取代磷渣粉可一定程度减小干缩.碱-磷渣-粉煤灰胶凝材料硬化浆体的结构非常致密,其孔隙率和平均孔径均小于普通硅酸盐水泥硬化浆体. 相似文献
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The rheological properties of cementitious materials containing fine particles, such as mineral admixtures (MA), were investigated using a Rotovisco RT 20 rheometer (Haake) with a cylindrical spindle. The mineral admixtures were finely ground blast furnace slag, fly ash and silica fume. The cementitious materials were designed as one, two and three components systems by replacement of ordinary portland cement (OPC) with these mineral admixtures. The rheological properties of one-component system (OPC) were improved with increasing the dosage of PNS-based superplasticizer. For two-components systems, yield stress and plastic viscosity decreased with replacing OPC with blast furnace slag (BFS) and fly ash (FA). In the case of OPC-silica fume (SF) system, yield stress and plastic viscosity steeply increased with increasing SF. For three components systems, both OPC-BFS-SF and OPC-FA-SF systems, the rheological properties improved, compared with the sample with SF. In the two and three components systems, the rheological properties of samples containing BFS improved much more than with FA replacement alone. 相似文献
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粉煤灰因其主要成分为二氧化硅、三氧化二铝常被用来当作合成沸石的原材料,合成的沸石类型主要有X型、Y型、A型、ZSM-5型等,相关合成技术也已非常成熟。水淬渣是高炉炼铁水淬急冷产生的高炉渣,对其主要利用方式是作为水泥、路基材料,均属低附加值利用。通过碱熔水热法利用水淬渣、粉煤灰混合原料合成4A型沸石。初步探究硅铝物质的量比(简称硅铝比)、熔融温度、熔融时间、晶化时间对制备的沸石样品品质造成的影响,得到最佳制备条件:硅铝比为1.0、碱灰质量比为1.5、碱熔时间为1 h、碱熔温度为600 ℃、老化时间为12 h、灰水质量比为1∶5、晶化温度为90 ℃、晶化时间为16 h。对合成的沸石进行X射线衍射(XRD)、X射线荧光光谱(XRF)、扫描电镜(SEM)、红外光谱(FT-IR)等表征,结果表明利用水淬渣、粉煤灰合成的4A型沸石各方面性能良好,具有超高的工业化生产价值。 相似文献