基于比强度的高强高性能混凝土配合比优化设计

发布时间：2019-07-05 16:26

【摘要】：随着经济的发展和材料科学的进步,混凝土凭着其不可取代的优越性,已成为当今世界用量最大的人造材料,是土木建筑工程用材的主体。为了适应现代土木建筑工程的(超)高层化、(超)大跨化、(超)耐久化、重载化、抗震防灾和承受恶劣环境条件的要求或需要,混凝土正朝着“绿色”、“(超)高强高性能”和“可持续”的方向发展。目前,除了混凝土的四大组分—水泥、水、砂和石之外,在混凝土中掺入活性矿物掺合料和高效减水剂及其它外加剂制备高强高性能混凝土已经成为最常用的通用技术途径,以往的混凝土配合比设计方法却已不再适用。因此,对高强高性能混凝土的配合比设计方法的研究具有重要的学术意义、广泛的工程应用价值。确定高强高性能混凝土的配合比时,不仅要考虑实际工程对其的各种性能要求,还要考虑材料的选择、材料相互之间的相容性或协同性及其最优配置。本论文结合国家自然科学基金项目—型钢混凝土组合结构的材料-结构一体化多目标优化设计理论与方法研究(50978218),着眼于原材料本身,采用试验和理论相结合的方法,融入优化概念,不仅研究了聚羧酸系高性能减水剂用于混凝土时与水泥的相容性评价,还研究了集料尺寸及其级配、粉煤灰和硅灰对混凝土性能的影响并进行机理分析,建立其与混凝土强度之间的数学模型,最终形成一套基于比强度的高强高性能混凝土配合比优化设计方法。主要进行的研究有：1.增加表征水泥与减水剂相容性的参数或指标—凝结时间和泌水率,基于Matlab平台建立隶属度,打破基准减水剂的局限,建立模糊评判模型对聚羧酸系高性能减水剂与水泥的相容性进行综合性评价。2.通过研究集料的品质及性能对混凝土性能的影响,建立了一套基于Bolomey等式的集料连续级配最佳组合的数值求法；建立了砂石颗粒基于级配的平均粒径计算公式,通过试验和理论研究得出水泥砂浆浆体体积与集料平均粒径之间存在着一定的相关性,并明确给出它们之间的函数关系,利用该关系可以进行满足不同和易性要求的混凝土配合比的定量调整。3.基于试验,研究了粉煤灰、硅灰对混凝土性能的影响并进行机理分析,提出并确定了等效水胶比的数学模型；提出并建立了单掺或双掺硅灰和(或)粉煤灰的活性指标评价模型,建立了其随掺量(之比)的一般变化规律的数学模型和混凝土强度绝对值的预测模型。4. 经过对普遍采用的不同混凝土配合比设计方法的考察,取长补短,基于各原材料对混凝土性能影响的研究,建立了一套基于比强度、适用于高强高性能混凝土配合比的优化设计方法
[Abstract]:With the development of economy and the progress of material science, concrete has become the most widely used artificial material in the world and the main body of civil engineering materials because of its irreplaceable advantages. In order to meet the requirements or needs of (super) high-rise, (super) long-span, (super) durability, heavy load, seismic and disaster prevention and bearing harsh environmental conditions, concrete is developing in the direction of "green", "super high strength and high performance" and "sustainable". At present, in addition to the four components of concrete-cement, water, sand and stone, the preparation of high strength and high performance concrete by adding active mineral admixture, superplasticizer and other admixtures has become the most commonly used technical way, but the previous concrete mix proportion design method is no longer applicable. Therefore, the research on the mix proportion design method of high strength and high performance concrete has important academic significance and extensive engineering application value. When determining the mix proportion of high strength and high performance concrete, we should not only consider all kinds of performance requirements of practical engineering, but also consider the selection of materials, the compatibility or synergy of materials with each other and their optimal configuration. Based on the research on the theory and method of material-structure integration multi-objective optimization design of steel reinforced concrete composite structure project of National Natural Science Foundation of China (50978218), this paper focuses on the raw material itself, adopts the method of combining test and theory, and integrates the optimization concept. It not only studies the compatibility evaluation of polycarboxylic acid series high performance water reducer when it is used in concrete, but also studies the aggregate size and its gradation. The influence of fly ash and silica fume on the performance of concrete is analyzed and the mathematical model between fly ash and silica fume and concrete strength is established. Finally, a set of high strength and high performance concrete mix proportion optimization design method based on specific strength is formed. The main studies carried out are as follows: 1. By adding the parameters or indexes to characterize the compatibility of cement and water reducer-setting time and bleeding rate, the membership degree is established based on Matlab platform, the limitation of reference water reducer is broken, and the fuzzy evaluation model is established to comprehensively evaluate the compatibility of polycarboxylic acid series high performance water reducer with cement. 2. By studying the influence of aggregate quality and performance on concrete performance, a set of numerical method for calculating the optimal combination of aggregate continuous gradation based on Bolomey equation is established. The formula for calculating the average particle size of sand and stone particles based on gradation is established. Through experimental and theoretical research, it is concluded that there is a certain correlation between the volume of cement mortar paste and the average particle size of aggregate, and the functional relationship between them is clearly given, which can be used to quantitatively adjust the mix proportion of concrete to meet different and easy requirements. Based on the test, the influence of fly ash and silica fume on the performance of concrete is studied and the mechanism analysis is carried out, and the mathematical model of equivalent water-glue ratio is put forward and determined, and the evaluation model of activity index of single or double mixed silica fume and / or fly ash is put forward and established, and the mathematical model of its general variation with the ratio of silica fume and / or fly ash and the prediction model of absolute value of concrete strength are established. Based on the study of the influence of each raw material on the performance of concrete, a set of optimal design method based on specific strength, which is suitable for high strength and high performance concrete, is established through the investigation of different concrete mix proportion design methods which are widely used in high strength and high performance concrete.
【学位授予单位】：西安建筑科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU528

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