基于最大密实度的混凝土配合比优化方法及其性能研究

发布时间：2018-02-01 13:35

本文关键词： 混凝土密实度颗粒堆积 CIPM模型浆体体积富余系数配合比优化　出处：《烟台大学》2017年硕士论文　论文类型：学位论文

【摘要】：高性能化和绿色化已然成为当今混凝土发展的大方向,粉煤灰、矿粉等矿物掺合料和再生粗、细骨料等材料的应用日益广泛,导致混凝土已从传统4组分发展成为更多组分混合材料。传统混凝土配合比设计方法适应能力越来越差,这是由于在传统的配合比设计方法中大多参数均采用经验表格的方式确定,主观性很强,须根据经验不断试配、调整,这样混凝土性能将无法保证。对于混合材料而言,改善其性能的最直接和最根本的方式就是尽力提高混合体的密实度,实现均匀、无空隙的整体。目前也逐渐发展了基于混凝土最大密实度的配合比设计方法,但仍存在考虑角度单一、仅实现骨料体系最大密实度、实际应用较难等问题。为了从胶凝材料体系、骨料体系和浆骨比三个角度实现混凝土密实度最大化设计,本文通过试验研究了胶凝材料体系密实度与矿物掺量间关系和修正了CIPM颗粒体系密实度计算模型中相互作用系数,提出了基于骨料体系密实度的浆体体积富余系数并试验分析其与混凝土工作性和强度间相关性;在此基础上提出基于浆体体积富余系数的配合比优化设计方法。本文主要研究内容具体如下:(1)分析和总结现有配合比设计理论和优化方法的基础上,结合绝对体积法和密实度概念提出浆体体积富余系数,它能够很好的从理论上描述单位体积混凝土内骨料和浆体体积间平衡问题,减少混凝土配合比设计中经验取值现象,实现配合比的理论化设计。(2)为了实现胶凝材料密实度最大,采用试验和TOUFAR模型计算分析粉煤灰或矿粉与水泥二元复合和粉煤灰、矿粉、水泥三元复合时矿物掺量对体系密实度的影响规律,并进一步分析空隙体积和胶凝材料需水量与矿物掺量间关系。分析结果表明,在二元复合时,矿物掺量的增加均降低体系密实度;而在三元复合时胶凝材料密实度明显好于二元复合体系,并且在粉煤灰和矿粉掺量分别在20%和25%时达到稳定。(3)为了计算骨料体系密实度,并寻找密实度最大时粗、细骨料混合情况,研究分析CIPM颗粒堆积体系密实度计算模型,试验发现,其计算值与实测值相差较大,且均小于实测值。以混凝土中粉体颗粒为试验材料,通过实测值与计算值误差分析的方法,通过最小二乘误差控制,采用反演分析方法得出修正后的相互作用系数(28)6.1LeC、(28)8.0W eC,试验验证该参数值的可靠性,并可用于计算骨料体系密实度。(4)在胶凝材料体系和骨料体系密实度均得以解决的基础上,为了应用浆体体积富余系数优化拌合后混凝土所含浆体体积,首先试验分析富余系数对混凝土强度和工作性的影响规律,试验结果表明:对水胶比不同混凝土而言,随着系数值的增加,混凝土坍落度和抗压强度均呈现先逐渐提高达到最高点后缓慢下降现象,且坍落度变化范围更大。进一步以二者为控制指标,确定浆体体积富余系数的最优值,对于C30和C40强度等级混凝土系数的最优值分别为1.251和1.624。(5)在此基础上,结合配合比设计理论中绝对体积法和Bolomey混凝土强度计算公式,提出基于浆体体积富余系数的配合比优化设计方法,并详细说明其计算过程。
[Abstract]:High performance and green has become the development direction of concrete, fly ash, slag and other mineral admixtures and recycled coarse and fine aggregate and other materials used more widely, leading to the concrete from the traditional 4 components become more components of mixed materials. The traditional concrete mix proportion design method of the ability to adapt to more and more poor, this is because in the traditional mix design method in most parameters are used to determine the way the experience form, with very strong subjectivity, according to the experience of continuous test, adjustment, so the concrete performance will not be guaranteed. For the mixed material, improve the performance of the most direct and most fundamental way is to improve the density of degree of mixture uniformity, overall void free. At present has gradually developed the design method of concrete mix ratio based on the maximum density, but there are still considered a single point of view, only aggregate body Department of maximum density, the actual application difficult problem. In order to system of cementitious material, aggregate slurry system and bone than the three angles to realize the maximum compactness of concrete design, this article through the tests of cementitious materials density and mineral content and the relationship between the interaction coefficient calculation model in a fixed CIPM the particle density of the system, put forward the system of aggregate density slurry volume and the surplus coefficient test analysis with the workability and strength of concrete based on correlation; on this basis with the surplus coefficient of paste volume ratio based on optimization design method in this paper. The main research contents are as follows: (1) analysis and summary of the existing mix the basic design theory and optimization method, combined with the absolute volume method and the compactness of the concept of paste volume surplus coefficient, it can be very good in theory to describe the unit volume of concrete in bone Material and paste volume balance problem, reduce the concrete mix proportion design experience value phenomenon, with the theory of design than. (2) in order to achieve maximum cementitious material density, the model test and TOUFAR calculation and analysis of fly ash or slag cement and two element composite fly ash and slag, influence law system compactness of cement composite mineral admixture is three yuan, and further analysis of the void volume and cementitious material requirement and mineral content. The relationship between the analysis results show that the two yuan in the composite, the increase of mineral admixture content decreased the density of the system; and in the three element composite cementitious materials were dense in the two element composite system, and in the fly ash and slag content respectively in 20% and 25% reached. (3) in order to calculate the aggregate density of the system, and find the maximum density of coarse and fine aggregate mixture, the research and analysis of CIPM particles The calculation model, the density of the system test shows that the calculation value of difference with the measured values, which are less than the measured value. The concrete powder particles as test material, through the measured and calculated values of the error analysis method, controlled by the least square error, using inverse analysis method of the interaction coefficient after correction (28) 6.1LeC, 8.0W (28) eC, test and verify the reliability of the parameter value, and can be used to calculate the aggregate density of the system. (4) on the basis of cementitious materials and aggregate density of the system are solved, in order to apply the paste volume surplus coefficient optimization after mixing concrete containing slurry volume, analysis of surplus the coefficient of influence on concrete strength and workability of the first test, test results show that the ratio of different water cement concrete, with the increase of coefficient, concrete slump and compressive strength increased first and gradually improve The phenomenon reached the highest point and then decreased slowly, and the slump of large change. Further to two as control index, to determine the optimal paste volume surplus coefficient values for the optimization of C30 and C40 concrete coefficient values were 1.251 and 1.624. (5) on the basis of this, combined with the design theory of absolute volume method and Bolomey concrete strength calculation formula, the optimization method is proposed with the ratio of mortar volume based on the surplus coefficient, and a detailed description of the calculation process.

【学位授予单位】：烟台大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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