高性能再生混凝土自生收缩影响因素试验研究

发布时间：2018-07-12 10:54

本文选题：高性能再生混凝土 + 再生粗骨料　；参考：《福州大学》2014年硕士论文

【摘要】：随着经济发展,巨大的混凝土生产量使资源、能源、环境以及相关的社会问题越发突出,可持续发展和环境保护战略迫切需要有效合理地利用废弃混凝土,再生混凝土也因此应运而生。近年来国内外开展了大量关于再生混凝土技术的研究,但仍存在许多问题。鉴于此,本文主要针对高性能再生混凝的自生收缩影响因素进行研究。1、通过粗骨料基本性能的研究,分析再生粗骨料与天然粗骨料的差别。试验结果表明与天然粗骨料相比,再生粗骨料性能较差,具体表现为骨料较粗、表观密度较低、堆积密度较小、孔隙率较大、吸水率较高以及压碎指标大。2、参照普通混凝土高性能化的方法,以混凝土工作性能为标准,控制其坍落度在180-220mm,采用净浆裹石工艺,配制C30强度等级的高性能再生混凝土。试验结果表明再生粗骨料使混凝土工作性能变差,单掺粉煤灰以及复掺粉煤和矿渣可以改善再生混凝土工作性能。3、通过混凝土基本力学性能试验,分析再生粗骨料、粉煤灰掺量、粉煤灰和矿渣复掺量对高性能再生混凝土力学性能的影响。试验结果表明：加入再生粗骨料使混凝土的立方体抗压强度、弹性模量降低；随着粉煤灰掺量、粉煤灰和矿渣复掺量增加,混凝土力学性能下降,但是复掺粉煤灰和矿渣的混凝土力学性能下降程度较小。4、通过混凝土自生收缩试验,分析再生粗骨料、粉煤灰掺量、复掺粉煤灰和矿渣量对高性能再生混凝土自生收缩性能的影响,并分析高性能再生混凝土同普通混凝土、高性能混凝土、自密实混凝土自生收缩的区别。试验结果表明,再生粗骨料对控制自生收缩不利,单掺粉煤灰可有效改善自生收缩,复掺粉煤灰和矿渣相比单掺粉煤灰更有利于控制自生收缩,高性能再生混凝土的自生收缩发展规律同普通混凝土、高性能混凝土、自密实混凝土一致,但自生收缩值较大。5、分析比较几个常用的自生收缩计算模型与本文试验值的区别,选取较适用的模型作为基准模型,结合本文自生收缩试验结果提出修正参数,建立适用于高性能再生混凝土的自生收缩预测模型。
[Abstract]:With the development of economy, the huge concrete production has made the resources, energy, environment and related social problems more prominent. Sustainable development and environmental protection strategies urgently need to make effective and rational use of abandoned concrete, Recycled concrete also arises at the historic moment. In recent years, a lot of research on recycled concrete technology has been carried out at home and abroad, but there are still many problems. In view of this, this paper mainly focuses on the factors affecting the autogenous shrinkage of high performance regenerated coagulant. 1. Through the study of the basic properties of coarse aggregate, the difference between regenerated coarse aggregate and natural coarse aggregate is analyzed. The experimental results show that the properties of regenerated coarse aggregate are worse than that of natural coarse aggregate, which are characterized by coarse aggregate, low apparent density, low stacking density and high porosity. According to the method of high performance of ordinary concrete, the slump of concrete is controlled in 180-220 mm, and the C30 strength grade high performance recycled concrete is prepared by using the technology of clean paste and stone wrapping, referring to the method of high performance of ordinary concrete, taking the working performance of concrete as the standard and controlling its slump in 180-220 mm. The test results show that the recycled coarse aggregate makes the working performance of concrete worse, and the working performance of recycled concrete can be improved by adding fly ash, coals and slag. The basic mechanical properties of recycled concrete are analyzed through the tests of the basic mechanical properties of recycled aggregate. The effect of fly ash content, fly ash and slag content on mechanical properties of high performance recycled concrete. The experimental results show that the cube compressive strength and elastic modulus of concrete are decreased by adding recycled coarse aggregate, and the mechanical properties of concrete decrease with the increase of fly ash and slag content. However, the mechanical properties of concrete mixed with fly ash and slag decreased slightly. 4. Through the test of autogenous shrinkage of concrete, the recycled coarse aggregate and the content of fly ash were analyzed. The effect of the amount of fly ash and slag on the autogenous shrinkage of high performance recycled concrete is analyzed, and the difference between high performance recycled concrete and ordinary concrete, high performance concrete and self compacting concrete is analyzed. The test results show that regenerated coarse aggregate is unfavorable to control the autogenous shrinkage, and the addition of fly ash can effectively improve the autogenous shrinkage, and the addition of fly ash and slag is more favorable to control the autogenous shrinkage than the single addition of fly ash. The development law of autogenous shrinkage of high performance recycled concrete is consistent with that of ordinary concrete, high performance concrete and self compacting concrete, but the value of autogenous shrinkage is larger. 5. The differences between several commonly used calculation models of autogenous shrinkage and the experimental values in this paper are analyzed and compared. Taking the more suitable model as the benchmark model and combining with the results of the autogenous shrinkage test in this paper, the modified parameters are proposed, and the prediction model of the autogenous shrinkage suitable for high performance recycled concrete is established.
【学位授予单位】：福州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528

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