共查询到19条相似文献,搜索用时 180 毫秒
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将秸秆纤维按不同比例掺入污泥中,分别将各组试样添加相同剂量的生石灰和水泥,充分搅拌混合制样并养护,对试样开展无侧限抗压强度试验和直剪试验,研究秸秆纤维材料对污泥固化体抗压强度和抗剪强度的作用。试验确定了污泥固化体无侧限抗压强度与秸秆纤维材料掺入比例的关系曲线,试验测得了,试样在养护5 d、10 d、20 d、30 d时,0、1%、3%秸秆纤维含量的污泥固化体的无侧限抗压强度值。结果显示:由于秸秆纤维的掺入,污泥固化体的无侧限抗压强度均呈增大趋势,且随着秸秆纤维的含量增大而增大;试验测得了污泥固化体的直剪试验的抗剪强度。试验显示,污泥固化体中掺入秸秆纤维,提高了其抗剪强度,且由污泥固化体的抗剪强度与秸秆纤维含量的关系曲线可知,在一定范围内,秸秆纤维的含量与污泥固化体的抗剪强度成正比例增长。 相似文献
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为探明水化硅酸钙(CSH)凝胶-蒙脱石界面能对水泥固化蒙脱土无侧限抗压强度的影响,通过分子动力学模拟方法对蒙脱石和CSH结合界面区能量进行定量计算,并结合灰色关联度分析和X射线衍射(XRD)表征,讨论模型的正确性和偏差来源。研究表明:CSH-蒙脱石界面能由范德华力、氢键能与静电作用组成;CSH-蒙脱石界面能与水泥固化蒙脱土无侧限抗压强度具有较好的相关性,界面能随着水分子数增加而降低,随着蒙脱石层数增多而先减小后增大;通过调整水胶比及胶土比可使CSH-蒙脱石界面处斥力达到最大或引力达到最小,进而控制水泥固化蒙脱土无侧限抗压强度性能达到最优。 相似文献
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为了解决重金属铬污染带来的土壤及地下水污染问题,以沈阳铬渣堆场污染土为研究对象,进行水泥固化重金属铬污染土中Cr(VI)和Cr(Ⅲ)试验研究,测定了水泥掺量、养护龄期、铬不同含量及价态对固化土体的无侧限抗压强度及淋滤特性影响.结果表明,水泥是Cr(VI)和Cr(Ⅲ)污染土的有效固化剂,水泥掺量以20%为宜;Cr(VI)和Cr(Ⅲ)对固化土强度都具有弱化效应,Cr(Ⅲ)弱化效应更明显;SEM图从微观上解释了水泥固化铬污染土强度的变化,该变化与无侧限抗压强度试验结果一致. 相似文献
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流态固化土是近年来为提高市政、建筑工程狭窄空间回填质量而发展的一种新材料。本文采用钢渣粉、CFB脱硫灰、稻壳灰等多种低品质固废作为无熟料胶凝材料制备流态固化土,并对流态固化土的无侧限抗压强度、干燥收缩性能、重金属浸出性能、微观结构等开展相关试验。研究表明:采用无熟料胶凝材料制备的流态固化土,其拌合物流动扩展度和无侧限抗压强度可满足一般填筑工程的要求,硬化体的干燥收缩值明显低于同掺量的水泥固化土,且无重金属浸出毒性超标的风险;在多种固废协同作用下,土颗粒聚集成团,孔隙明显减小,絮状的凝胶与针棒状的钙矾石晶体相互交织,附着在土颗粒表面,联结土颗粒,使得固化土的强度显著提高。 相似文献
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将粉煤灰和聚丙烯纤维按不同比例掺入污泥中,并将所有试样加入相同比例的水泥,养护数天后,对试样开展无侧限抗压强度试验,研究粉煤灰、聚丙烯纤维材料对污泥固化的作用。试验确定了无侧限抗压强度与养护天数、材料掺入比例的关系曲线。试验测得:试样在养护5 d、10 d、20 d、30 d时,5%、10%、15%粉煤灰聚丙烯纤维含量的混合物的无侧限抗压强度值。试验结果显示,由于粉煤灰、聚丙烯纤维的掺入,混合物的无侧限抗压强度均呈增大趋势,且随着粉煤灰、聚丙烯纤维的含量增大而增大;当养护天数增加时,混合物的无侧限抗压强度也随之增大,若继续增大养护天数,混合物的无侧限抗压强度值将会趋于稳定。 相似文献
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为了研究水泥复合土在建筑垃圾处理中发挥的作用,设计了不同废弃混凝土颗粒掺入比,不同的水泥掺入比,制作了掺入无筛分废弃混凝土颗粒的水泥复合土试件,进行了无侧限抗压强度试验,研究了不同龄期下水泥复合土的无侧限抗压强度变化规律,运用SPSS软件建立了无侧限抗压强度的多元线性回归分析模型.试验结果表明,废弃混凝土颗粒掺量存在适宜区间,适宜区间随着水泥掺量的增加而向数轴右侧移动;加入过低掺量的废弃混凝土颗粒会降低水泥复合土的抗压强度,随着废弃混凝土颗粒掺量增加,废弃混凝土颗粒形成骨架支撑,使抗压强度上升;当掺入废弃混凝土颗粒超过适量值后,抗压强度反而降低;水泥复合土强度后期增长潜力大,在28~60 d龄期区间可维持0.14 MPa/d的高速增长.其研究成果可为水泥土拓展新的应用方向,提供有效解决废弃混凝土堆放问题的新思路和研究数据. 相似文献
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Asskar Janalizadeh Choobbasti Mobina Taslimi Paein Afrakoti 《Journal of Adhesion Science and Technology》2019,33(8):791-807
This paper attempted to show the application of particle swarm optimization in the prediction of the compressive strength of cement sandy soil from the curing period, porosity of sample and percentage of cement. The results of the study show that the unconfined compressive strength of the cement stabilized sandy soil increases with an increasing cement content curing time period. Moreover the compressive strength decreases with an increasing porosity. The compressive strength improvement due to cement treatment has a larger increase in samples with less porosity. In addition, particle swarm optimization algorithm is and accurate technique in estimation of compressive strength of cement stabilized sandy soil. In order to compare of existing correlations, a total number of 100 unconfined compressive tests and 15 scanning electron microscope tests have been conducted on cemented Babolsar sand. It can be concluded that compared to existing correlations models, particle swarm optimization algorithm models give more reliable prediction about compressive strength of cement satblized sandy soil. Moreover, the sensitivity analysis of the polynomial model shows that cement content and porosity have significant impact on predicting unconfined compressive strength. 相似文献
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水泥粉体流动性与其储存、输送、给料、混合等操作密切相关。通过休止角、内摩擦角、粘聚力和无侧限抗压强度测试方法,研究了含水率对水泥粉体流动性的影响,对比了水泥粉体与砂浆、钢、涂料、防腐卷材四种壁面材料的壁摩擦角和附着力。结果表明:随着水泥粉体含水率增加,休止角、粘聚力和无侧限抗压强度增加,水泥粉体流动性变差。松散堆积水泥粉体随着放置时间增加,由于水泥水化引起颗粒尺寸增加造成流动性变好。固结应力增加,无侧限抗压强度明显增大,导致水泥粉体流动性变差。水泥粉体在不同壁面材料的粘聚力均随着含水率的增加而增大,在水泥库内表面涂覆涂料和防腐卷材均可以起到降低水泥粉体与壁面的摩擦力和附着力的作用。 相似文献
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将钢渣、矿渣微粉与废弃混凝土碎料混拌制备钢渣-杂填土基层,并对其性能开展研究。体积安定性试验表明,矿渣微粉具有明显抑胀作用,掺入50%(质量分数,下同)钢渣、50%杂填土以及外掺钢渣质量30%矿渣微粉的试件的10 d高温水浴膨胀率仅为1.32%,而未掺矿渣微粉的试件3~5 d膨胀率均超过2%限值。7 d无侧限抗压强度和28 d劈裂强度正交试验表明:7 d无侧限抗压强度、28 d劈裂强度影响因素大小顺序为钢渣、水泥掺量、混凝土碎料占比、土壤固化剂;各组试件中7 d无侧限抗压强度、28 d劈裂强度最大值分别为12.41 MPa、2.24 MPa;钢渣-杂填土基层最佳配比为50%钢渣、50%杂填土(m(混凝土碎料)∶m(素土)=6∶4),外掺钢渣质量40%的矿渣微粉、5%水泥、0.018%固化剂,此时试件具有良好的水稳定性。强度影响因素试验表明,矿渣微粉对试件强度的增幅影响最大。X射线衍射及扫描电子显微镜分析表明,在矿渣微粉和土壤固化剂的作用下,钢渣中f-CaO被有效消解,团聚体与混凝土碎料、钢渣颗粒的密实包裹阻止了内部水分的挥发和外部自由水的侵入,既保证了钢渣-杂填土基层的强度,又有效抑制了膨胀。 相似文献
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通过开展一系列劈裂强度测试、无侧限抗压强度测试和弯拉强度测试,研究了玄武岩短切纤维对水泥稳定多孔玄武岩碎石力学性能的增强作用。龄期为7 d的混合料劈裂试验表明,玄武岩短切纤维对水泥稳定多孔玄武岩碎石的劈裂强度具有显著的增强效果,其中长度为18 mm的纤维对混合料劈裂强度的增强效果优于12 mm、24 mm的纤维。掺加长度18 mm玄武岩纤维的水泥稳定多孔玄武岩碎石,其劈裂强度、无侧限抗压强度、弯拉强度等随着纤维掺量增加先增大后减小;当掺量为碎石质量的0.10%时,纤维对混合料各项力学性能的增强效果最好;随着养护龄期的延长,混合料力学性能不断提升。研究表明掺加玄武岩短切纤维可提高水泥稳定多孔玄武岩碎石的路用性能。 相似文献
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This research evaluated the use of sewage sludge and refuse incineration bottom ash to replace calcium sulfoaluminate cement(CS(_)A) in making controlled low-strength material(CLSM).Various properties of CLSM mixtures were characterized in terms of unconfined compressive strength,microstructure and leachability.It was found that the strength of tested CLSM mixtures ranged from 3.6 to 9.0 MPa,over the upper excavatable limit of 2.1 MPa.The micro-structural analysis revealed that sewage sludge and bottom ash were crystallochemically in-corporated within CLSM systems by forming the needle-like ettringite(C3A?3CS(_)?H32) with exiguous tubers via the typical Pozzolanic Reaction,leading to a dense and low-porosity microstructure.Furthermore,the toxicity charac-teristic leaching procedure evidenced that the cumulative leachable metals in the leachate were much below the regulatory thresholds.The potential for using sewage sludge and bottom ash in CLSM making was thus confirmed. 相似文献
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When the geotechnical engineering projects have to be built on weak soils, problems related to bearing capacity and settlement arise. Chemical stabilization of soil using cement is a popular and effective technique that can significantly improve workability and shear strength of soil. However, very limited studies have been conducted to reveal the effect of silica fume on the engineering properties of cement-stabilized sandy soil. For this purpose, in the present study, a series of laboratory tests including standard Proctor compaction, unconfined compression and ultrasonic pulse velocity tests were carried out on sand-cement-silica fume samples. Moreover, it has been attempted to investigate the relation between ultrasonic pulse velocity and unconfined compressive strength of cemented sand containing silica fume. The cement contents were 3, 5 and 7% and silica fume contents were 0, 0.25, 0.5 and 1% by weight of dry sand. The cylindrical specimens were prepared and cured for 3, 7, 14, 28, 42 and 56?days and tested. The results show that inclusion of silica fume to cemented sand increases maximum dry unit weight, unconfined compressive strength and ultrasonic pulse velocity while decreases optimum moisture content. In addition, according to the obtained results, acceptable correlations exist between ultrasonic pulse velocity, unconfined compressive strength and stiffness. 相似文献
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活性炭对医疗垃圾焚烧飞灰水泥固化的影响 总被引:5,自引:0,他引:5
对医疗垃圾焚烧飞灰(FA)及其灼烧灰(IFA)进行水泥固化实验研究,考察了飞灰中活性炭对水泥固化体凝结时间、抗压强度、重金属浸出毒性等的影响. 结果表明,掺60% FA的水泥固化体终凝时间长达63 h,超出48 h的限值,相同IFA配比下水泥固化体终凝时间低于该值; 掺40%和60% FA的水泥固化体7 d的抗压强分别仅为0.187和0.16 MPa,低于0.2 MPa的标准,但2种IFA配比下水泥固化体的抗压强度均达标;掺40%和60% FA的水泥固化体中Pb的渗沥浓度分别为5.634和6.032 mg/L,均超过5 mg/L的限值,而掺60% IFA的水泥固化体Pb渗沥浓度超过限值. 结果证实医疗垃圾焚烧飞灰中活性炭是导致水泥固化体凝结时间延长、抗压强度降低、重金属渗沥浓度升高的主要原因. 相似文献