共查询到20条相似文献,搜索用时 218 毫秒
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研究了经破碎后不同再生集料种类、掺入量、粉煤灰掺量三种因素对再生细石混凝土强度的影响。结果表明,混凝土再生集料所配制的C20再生细石混凝土的早期、后期强度可与天然细石混凝土强度相当,本试验条件下,混凝土再生集料取代率在60%时,试件的7d和28d抗压强度甚至比天然细石混凝土更高;砂浆再生集料和碎砖再生集料配制的再生细石混凝土的早期、后期强度均低于天然细石混凝土强度,且随着砂浆再生集料、碎砖再生集料取代率的增加而明显下降;掺有粉煤灰的再生细石混凝土掺量在20%以内时28d的抗压强度略高于未掺粉煤灰的再生细石混凝土强度。 相似文献
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橡胶集料混凝土氯离子渗透性试验研究 总被引:11,自引:0,他引:11
将废旧汽车轮胎经过处理后得到的橡胶细颗粒取代部分骨料配制成橡胶集料混凝土。采用ASTMC1202-97法对5组不同橡胶掺量的混凝土进行抗氯离子渗透性研究,结果表明。橡胶集料混凝土具有很低的氨离子渗透性。28d电量值均小于1000C,且导电量随橡胶掺量增加而减少。 相似文献
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橡胶集料对混凝土抗压强度的降低效应 总被引:2,自引:0,他引:2
研究了振捣密实混凝土和自密实混凝土抗压强度随(废旧轮胎)橡胶集料体积分数的变化规律,分析了橡胶集料对混凝土抗压强度的降低效应,建立了混凝土抗压强度降低率与橡胶集料体积分数之间的经验关系式.结果表明:橡胶集料的掺加导致了混凝土抗压强度降低,橡胶集料体积分数越大,混凝土抗压强度降低越多;橡胶集料体积分数相同时,振捣密实混凝土抗压强度降低率比自密实混凝土抗压强度降低率稍大;一定体积分数橡胶集料对混凝土抗压强度的降低效应与相同体积分数气孔的降低效应相当;建议混凝土中每增加1%体积分数的橡胶集料,混凝土抗压强度降低率按4.5%计算. 相似文献
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研究了经过化学螯合稳定化处理后的城市生活垃圾焚烧飞灰(CFA)对水泥浆体凝结时间、抗压强度、电阻率和水化产物的影响规律。结果表明,掺入CFA后,水泥浆体的凝结时间缩短,在3 d和28 d龄期时生成了水化产物Friedel盐,且水泥浆体的液相离子浓度增大,电阻率减小;当CFA掺量为5%时,硬化水泥浆体7 d龄期内的抗压强度提高,但28 d抗压强度降低;当CFA掺量从10%增大到60%时,硬化水泥浆体的抗压强度均小于空白组,并逐渐降低。 相似文献
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采用煤矸石炉渣等量替代天然细集料,制备了掺煤矸石炉渣的水泥混凝土.结果表明:在混凝土中用一定量的煤矸石炉渣替代天然砂,可配制出强度等级为50MPa以上的混凝土,其28d抗压强度和耐久性能均高于同配合比的基准混凝土;随着煤矸石炉渣掺量的增加,混凝土坍落度降低;掺煤矸石炉渣水泥混凝土的体积安定性满足国家标准. 相似文献
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用经过破碎和磁选处理的钢渣废料作细集料替代天然砂,与水泥浆和碎石配制成混凝土。在流动性一致原则下,研究了粉煤灰和矿粉按不同比例替代水泥后对钢渣砂混凝土的力学性能及水热养护制度下膨胀性能的影响规律。结果表明:随着矿粉和粉煤灰掺量的增加,混凝土7d和28d的强度不断减小;在两种掺合料同掺量下,掺矿粉的钢渣砂混凝土的强度略高于掺加粉煤灰的;但掺加粉煤灰能降低钢渣砂混凝土的膨胀率,改善钢渣砂混凝土的体积稳定性。 相似文献
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选用聚羧酸减水剂加到水泥净浆中,利用测定水泥、黏土和石粉的吸水性,同时,通过对水泥净浆流动度和抗压强度等性能的研究,探讨黏土和石粉含量(0、0.5%、1%、2%、4%、8%)对掺聚羧酸减水剂的净浆性能影响规律。结果表明:掺减水剂的浆体,随含泥量的增大,其流动度与7、28 d抗压强度均降低。掺减水剂的浆体,随石粉含量的增加,其流动度变化不大;含量小于4%时,试块7、28 d抗压强度基本不变,甚至增大。黏土和石粉同时取代水泥时,其含量小于2%时,对掺聚羧酸减水剂的净浆7、28 d抗压强度影响不大;但当含量超过0.5%,掺聚羧酸的净浆流动度明显下降。 相似文献
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Tung-Chai Ling 《Construction and Building Materials》2011,25(11):4303-4306
The influence of rubber content within the range of 5–50% as the replacement for sand volume and water/cement (w/c) ratio (0.45–0.55) on the density and compressive strength of concrete blocks was investigated. All the mixtures were proportioned with a fixed aggregate/cement ratio of 5.6. A total of 50% of the total aggregate was fine aggregate. Based on the experimental results, the density and strength reduction factors for rubberized concrete blocks were calculated by considering the dependent factors of rubber content and w/c ratio. Linear and logarithm equations derived, based on the results from experimental work are proposed to predict the density and compressive strength of rubberized concrete blocks. 相似文献
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基于建筑废弃物资源化利用的发展理念,制备了包浆再生骨料混凝土,试验研究了应用不同处理方法的再生骨料对该混凝土材料的抗折强度、抗压强度和收缩性能的影响规律,建立了收缩模型,并运用秩和检验方法检验了其显著性;采用扫描电镜图像分析(SEM)研究了混凝土界面过渡区的结构。试验结果表明:包裹用水泥浆中胶粉和硅粉协同作用可以明显改善包浆再生骨料混凝土界面过渡区的结构,提高抗压强度和抗折强度;再生骨料包浆3 d拌制的混凝土强度较高,收缩最大,包浆28 d拌制使得混凝土收缩最小;硅粉对包浆再生骨料混凝土35 d之前的收缩抑制效应明显,35 d之后胶粉抑制效应显著;包浆再生骨料混凝土收缩率与龄期满足指数函数关系,且在水平α=0.01下其相关关系显著。 相似文献
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《Construction and Building Materials》2010,24(9):1754-1760
A completely random experimental design has been used to simultaneously optimize process variables and cementitious mixture components for rubberized concrete. In this study the concrete is composed of only three mixture components, cement, aggregate (including fine and coarse) and water, and two process variables, size of rubber (chips of waste truck tires) and percentage rubber that replaced the aggregate in concrete, were varied. The calculations of regression and residual ANOVA sums of squares for regression and lack of fit are illustrated. These values are shown to be useful for model development. Two different models were evaluated. The bilinear–linear model has no lack of fit and is preferred. The significant terms in this model are capable of describing how the process response surfaces change as mixture level conditions are varied. Optimum condition in the rubberized concrete, considering the level of the variable studied is: 2.4 mm size of rubber, 2.5% rubber that replaced the aggregate, 16% of cement, 76% of aggregate and 8% of water. The optimum mixture conditions with 2.5% of rubber show a concrete value of compressive strength above 20 MPa, can generate concrete suitable for use in structures as well as pavement, curbs, walls and other applications in civil engineering. 相似文献
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