共查询到19条相似文献,搜索用时 515 毫秒
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水泥生产一般经历生料制备、熟料煅烧与水泥粉磨3个步骤。针对粉磨中出现的"团聚"现象,水泥助磨剂成为当前水泥行业的应用主流。通过采用正交试验的方法对选出3种助磨效果较好的单组分助磨剂进行助磨组分的优化设计,配制出复合型水泥助磨剂。结果表明:TEA、GQA、JDC掺量为0.01%、0.02%与0.03%是最优配比,复合型水泥助磨剂使水泥两阶段的(3d与28d)抗压强度分别提高了14.5%与10.2%,有促进水泥水化、提高水泥早期与后期抗压强度的作用。 相似文献
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采用新型改性醇胺制备了一种助磨剂,在标准实验室小磨实验条件下,采用三乙醇胺(TEA)制备的助磨剂为对比样品,对比了不同醇胺掺量制备的助磨剂助磨效果、对水泥的粉磨性能及水泥抗压强度的影响。结果表明,新型改性醇胺助磨剂助磨效果与TEA助磨剂基本一致,随着掺量的提高,二者助磨效果均明显提高,而新型改性醇胺助磨效果及水泥抗压强度改善效果更优。在工业应用中,改性醇胺助磨剂在水泥助磨、提产、改善工作性能(凝结时间和需水量)和力学性能方面均有显著作用,可提高水泥磨机产量13%以上,水泥3d强度提高3MPa以上,28d强度提高4MPa以上,使用改性醇胺助磨剂的水泥在混凝土应用中工作性能佳,强度更高。 相似文献
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高强度混凝土的研究及其在红水河铁路斜拉桥中的应用 总被引:1,自引:0,他引:1
本文介绍用高效能减水剂配制高强度混凝上的试验成果。试验查明减水剂品种、水泥品种、矿物组成和细度、水泥用量、水灰比、骨料质地和粒状的影响。提出FDN 三乙醇胺残渣的复合制剂——FDN(R)。FDN(R)具有缓凝特性,其早期和后期强度达到或超过FDN的效果。掺FDN(R)剂的塑性高强度混凝土的物理力学基本性能(抗压、抗拉和抗折强度,静弹性模量,泊桑比,受压疲劳强度等)都达到普通混凝土设计规范定值,徐变系数比普通混凝土显著地减小。文章还介绍了掺FDN(R)塑性600公斤力/厘米~2混凝土在红水河48 96 48(米)预应力混凝土铁路斜拉桥中应用实例。 相似文献
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随着水泥混凝土需求量的剧增,有效利用各种固体废弃物作为矿物掺合料受到更多关注。矿渣、粉煤灰具有很高的潜在活性,可以作为矿物掺合料取代水泥。然而,在某些地方矿渣和粉煤灰都比较缺乏,而且价格较贵,因此,与其他天然矿粉复合使用已经成为目前矿物掺合料的使用趋势,这样不仅可以改善矿物掺合料的性能,而且可以最大程度的降低成本。通过单因素法的试验方法和水泥胶砂试验,研究了粉煤灰、页岩、石粉、石膏和矿渣复合使用后对水泥胶砂试块力学性能的影响,由此确定出了用这五种矿物配制复合矿物掺合料的最佳配合比。并在此基础上研究了助磨剂对矿物掺合料易磨性以及力学性能的影响。试验结果表明:采用最佳配合比的矿物掺合料取代30%水泥制作的试块,其3、7、28 d抗折、抗压强度均与基准试块相持平,因此,相比较于单一使用复合矿物掺合料可以达到更好的效果。 相似文献
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本文依据水泥煅烧原理,分析了立窑熟料质量低、易粉化等问题的原因,并提出了对立窑腰风管的开设位置,风量、风速、开闭状态进行改革的设想和方法,使立窑腰风不仅具有纠正偏火的功用,还能改善熟料矿物组成,提高水泥熟料质量,有效地抑制粉化现象等,还有一定的节能降耗作用。 相似文献
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以木炭模拟研究了残余碳对掺萘系减水剂水泥浆体流变性的影响,测试了水泥颗粒对萘系减水剂的吸附量以及浆体的流动度、Marsh时间、饱和掺量、表观黏度及剪切应力,同时观察了浆体絮凝情况.结果表明:随着残余碳含量的增加,萘系减水剂的表观吸附量逐渐增大;掺萘系减水剂水泥浆体的流动性随着残余碳含量的增加而下降,表现为浆体流动度下降、Marsh时间增大、饱和掺量增大、分散性下降、浆体絮凝结构数量及强度增大、剪切应力及表观黏度增大;浆体流动性与萘系减水剂的表观吸附量存在反向对应关系. 相似文献
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活化磺化麦草碱木质素高效减水剂性能的研究 总被引:1,自引:0,他引:1
以麦草碱木质素为原料,通过活化、磺化、缩合制备高效减水剂GSAL,研究其对水泥和混凝土性能的影响,并探讨了GSAL的减水作用机理。结果表明,水灰比为0.32,掺0.6%GSAL的水泥净浆流动度为248 mm,比掺奈系减水剂FDN的水泥净浆流动度大30 mm,水泥净浆流动度120 min后仅损失17.3%,水泥净浆的终凝时间延长2~3 h,混凝土减水率达24.5%,比FDN高3.7%,GSAL使混凝土3 d、28 d抗压强度比分别达到178%和154%,比掺FDN分别提高36%和33%。通过表面物化性能研究表明,GSAL对水泥的减水分散作用主要是由于其对水泥颗粒具有良好的润湿作用、适当的气泡润滑作用以及在水泥颗粒表面形成了较强的静电斥力。 相似文献
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This paper investigates the viability of using beet molasses as a grinding aid for blended cements with high volumes of mineral admixtures. Different ratios of beet molasses (0.01–0.05% by weight of cement) were added into a blended cement containing 41% of fly ash and GBFS. The influence of beet molasses on performances of blended cement was studied by comparing with one commercially available, triethanolamine-based grinding aid (TA). The results show that when comparing with the blank cement mixture, the cement containing 0.02–0.03% molasses shows a higher compressive strength at 3 days and 28 days, even exceeding the TA mixture. The improved microstructure of the molasses modified cement paste was also demonstrated by the pore structure and SEM measurements. These improvements are attributed to the better particle size distribution induced by the addition of molasses, indicating the potential application of beet molasses as a good grinding aid. 相似文献
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通过调整Na2SO4,K2SO4,Na2CO3及K2CO3溶液浓度来改变水泥浆体中可溶性碱含量,研究可溶性碱对萘系减水剂吸附-分散性的影响.结果表明:碱金属盐对萘系减水剂分散性的影响存在最佳掺量区间,这一掺量区间与萘系减水剂掺量及碱金属盐种类相关.当萘系减水剂掺量较小时,较低掺量的碱金属盐即可调整水泥浆体表面张力,改善浆体流变性;当萘系减水剂掺量较大时,较高掺量的碱金属盐才可调整水泥浆体表面张力,改善浆体流变性.碱金属盐掺量过高时,水泥浆体流变性下降,表观黏度增加.碱金属硫酸盐除了存在碱金属离子对萘系减水剂双电层的压缩和破坏作用,还存在硫酸根离子对萘系减水剂的竞争吸附作用,因而使萘系减水剂在水泥颗粒表面的平衡吸附量下降程度更大. 相似文献
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Wunchock Kroehong Theerawat Sinsiri Chai Jaturapitakkul Prinya Chindaprasirt 《Construction and Building Materials》2011,25(11):4095-4104
This paper presents the effect of palm oil fuel ash fineness on the microstructure of blended cement paste. Palm oil fuel ash (POFA) was ground to two different finenesses. Coarse and high fineness palm oil fuel ash, with median particle sizes of 15.6 and 2.1 μm, respectively, were used to replace ordinary Portland cement (OPC) at 0%, 20% and 40% by binder weight. A water to binder (W/B) ratio of 0.35 was used for all blended cement pastes. The amorphous ground palm oil fuel ash was characterized by the Rietveld method. The compressive strength, thermogravimetric analysis and pore size distribution of the blended cement pastes were investigated. The test results indicate that the ground palm oil fuel ash was an amorphous silica material. The compressive strengths of the blended cement pastes containing coarse POFA were as high as that of OPC cement paste. Blended cement paste with high fineness POFA had a higher compressive strength than that with coarse POFA. The blended cement pastes containing 20% of POFA with high fineness had the lowest total porosity. The Ca(OH)2 contents of blended cement paste containing POFA decreased with increasing replacement of POFA and were lower than those of the OPC cement paste. In addition, the POFA fineness had an effect on the reduction rate of Ca(OH)2. Furthermore, the critical pore size and average pore size of blended cement paste containing POFA were lower than those of the OPC cement paste. The incorporation of high fineness POFA decreased the critical pore size and the average pore size of blended cement paste as compared to that with coarse POFA. 相似文献
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