全再生骨料混凝土高性能化及再循环研究

发布时间：2019-05-21 07:54

【摘要】：随着“绿色混凝土”概念的提出,再生混凝土受到越来越多的关注。但由于再生骨料特性上的不足,导致所制备出的再生混凝土性能不佳,因此,研究如何制备出特性良好的再生骨料及提高再生混凝土的各方面性能具有重要的意义。本文研究了全再生骨料混凝土高性能化的主要途径,研究了粉煤灰和矿粉单、复掺对全再生骨料混凝土的基本性能的影响,同时探讨了全再生骨料混凝土多次循环利用的可能性。结果表明： 1、将简单破碎得到的再生骨料经过机械强化处理,可有效提高再生骨料品质,吸水率、表观密度、堆积密度、压碎指标以及颗粒级配等各方面性能均得到一定的改善。 2、在相同配合比的情况下,全再生骨料混凝土抗压强度、抗氯离子渗透性能略低于普通混凝土,掺入矿物掺合料可提高全再生骨料混凝土的抗压强度和抗氯离子渗透性能；矿物掺合料的形态效应、微集料效应和火山灰效应是改善全再生骨料混凝土性能的主要因素。 3、单掺粉煤灰、矿粉均降低全再生骨料混凝土的7d抗压强度,相同掺量时,掺有粉煤灰的全再生骨料混凝土早期强度下降更为明显；在掺量小于40%时,粉煤灰、矿粉的掺入能提高全再生骨料混凝土的90d抗压强度,且掺量越大,提高越明显；复掺粉煤灰和矿粉的效果要优于单掺同等掺量的粉煤灰或者矿粉。 4、当复掺总量一定时,粉煤灰与矿粉掺入的不同比例(1：3、1：1、3：1)对全再生骨料混凝土7d抗压强度有一定影响,表现为粉煤灰含量高的再生混凝土的7d抗压强度较高,但对全再生骨料混凝土90d抗压强度影响不大。 5、全再生骨料混凝土的抗氯离子渗透性能同样受到粉煤灰和矿粉掺量的影响,掺量越大,抗氯离子渗透性能提高越明显,但对全再生骨料混凝土的抗碳化性能起到反作用,综合考虑抗压强度、抗氯离子渗透性能及抗碳化性能,建议高性能化方案选择复掺粉煤灰和矿粉,且掺量均为20%。 6、火山灰效应数值分析能够将矿物掺合料对全再生骨料混凝土强度的贡献值量化,准确地反映出不同矿物掺合料在全再生骨料混凝土的不同龄期对其各项性能的影响规律,且和分析试验实测值所得的结论一致。7、灰色关联度分析能定量描述出粉煤灰、矿粉对全再生骨料混凝土性能影响的动态过程,通过关联度比较得知矿物掺合料的总掺量是各项性能的最大影响因子,而抗压强度的次级影响因子为矿粉掺量,抗氯离子渗透性能的次级影响因子为粉煤灰掺量。 8、矿物掺合料可以大幅降低全再生骨料混凝土中孔径为100-1000nm之间的孔体积百分数,细化再生混凝土孔隙,提高其密实性。 9、二次全再生混凝土较一次全再生混凝土在抗压强度和抗氯离子渗透性方面性能均有一定程度下降,抗压强度下降幅度约为15%,电通量上升幅度在10%～30%之间,在不改变配合比的情况下再生混凝土的再循环的次数是有限的。
[Abstract]:With the introduction of the "green concrete" concept, more and more attention has been paid to the recycled concrete. However, it is of great significance to study how to prepare regenerated aggregates with good characteristics and to improve the performance of recycled concrete because of the insufficient properties of recycled aggregate. In this paper, the main ways of high-performance of full-regenerative aggregate concrete are studied, and the effect of fly ash and mineral powder single and complex admixture on the basic properties of fully-regenerated aggregate concrete is studied, and the possibility of multi-cycle utilization of fully-regenerated aggregate concrete is also discussed. The results show that: 1. The regenerated aggregate obtained by simple crushing is subjected to mechanical strengthening treatment, and the quality of the recycled aggregate, the water absorption, the apparent density, the packing density, the crushing index and the particle grading can be effectively improved good.2. In the case of the same matching ratio, the compressive strength of the full-regenerative aggregate concrete and the anti-chloride ion permeability are slightly lower than that of the common concrete, and the addition of the mineral admixture can improve the compressive strength and the chloride-ion permeability property of the fully-regenerated aggregate concrete, and the shape of the mineral admixture The effect of the state, the effect of the micro-aggregate and the pozzolanic effect are the main factors to improve the performance of the full-regenerative aggregate concrete. For the factors,3, the single-mixed fly ash and the mineral powder reduce the 7-d compressive strength of the fully-regenerated aggregate concrete, and the early strength of the fully-regenerated aggregate concrete mixed with the fly ash is more obvious when the same amount is used, and the content is less than 40%. When the fly ash and the mineral powder are mixed, the 90-d compression strength of the fully-regenerated aggregate concrete can be improved, the larger the mixing amount is, the more obvious the improvement is; the effect of the complex-doped fly ash and the mineral powder is better than that of the coal powder with the same mixing amount The different ratio of fly ash to mineral powder (1:3,1:1,3:1) has a certain effect on the compressive strength of the total recycled aggregate concrete 7d when the total amount of the complex admixture is certain, and is shown as 7 of the recycled concrete with high content of fly ash. D. The compressive strength is high, but it is resistant to the total recycled aggregate concrete 90d. The effect of the anti-chloride ion permeability of the fully-regenerated aggregate concrete is also affected by the fly ash and the content of the mineral powder. The higher the mixing amount, the more obvious the penetration resistance of the anti-chloride ion, but the anti-carbonization property of the fully-regenerated aggregate concrete and considering the compressive strength, the anti-chloride ion permeability and the anti-carbonization performance, the high-performance scheme is recommended to select the composite fly ash and the mineral powder, And the numerical analysis of the pozzolanic effect can quantify the contribution of the mineral admixture to the strength of the full-regenerative aggregate concrete, and accurately reflect the different age of the different mineral admixture in the full-regenerative aggregate concrete. The influence of fly ash and mineral powder on the performance of the fully-regenerated aggregate concrete is analyzed and the dynamic process of the effect of the fly ash and the mineral powder on the performance of the fully-regenerated aggregate concrete can be quantitatively described, and the total content of the mineral admixture is obtained through the comparison of the degree of association. The maximum impact factor of each performance, and the secondary effect factor of the compressive strength is the content of the mineral powder and the secondary effect of the chloride ion penetration. the level influence factor is the fly ash content.8, the mineral admixture can greatly reduce the volume percentage of the pore between 100 and 1000nm in the fully-regenerated aggregate concrete, The porosity of the raw concrete is improved, and the compactness of the secondary fully-regenerated concrete is improved.9. The performance of the secondary fully-regenerated concrete is reduced to a certain extent in terms of the compressive strength and the chloride-ion permeability, and the decrease of the compressive strength is about 15%. the rising range of the quantity is between 10% and 30%, and the ratio of the matching ratio is not changed,
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528.041

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