绿色生态混凝土配合比优化设计研究

发布时间：2018-04-21 15:06

本文选题：绿色生态混凝土 + 流变性能　；参考：《中南林业科技大学》2015年硕士论文

【摘要】：绿色生态混凝土是一种性能介于普通混凝土和耕植土之间并具有及时调节生态平衡、美化环境景观、实现人类与自然的协调的一种新型混凝土材料,也是我国建设资源节约型、环境友好型社会发展的必然要求。本文基于材料科学、生态学、植物学等基础理论,借鉴传统普通混凝土配合比设计方法的思想,以水泥基胶凝材料净浆流变参数的优选为切入点,深入探讨了水胶比、材料组成及其掺量、高效减水剂等因素对绿色生态混凝土性能的影响规律；运用MATLAB软件编程建立了原材料与其性能之间的相互关系；然后利用序列二次规划法和MATLAB优化工具箱,对绿色生态混凝土配合比设计的数学模型进行了优化求解。主要研究结论如下：(1)单掺粉煤灰(FA)掺量在20%,-40%范围内变化时,随着剪切速率增大,水泥基胶凝材料浆体呈现先剪切增稠后剪切变稀行为,且剪切增稠程度和剪切变稀程度均随粉煤灰掺量增大而先降低后升高；单掺矿渣(SG)掺量在20%-40%范围内变化时,随着剪切速率增大,浆体呈现先剪切变稀后剪切增稠行为,随着矿渣掺量增大,剪切变稀程度逐渐升高,剪切增稠程度逐渐降低。(2)双掺粉煤灰和矿渣的总掺量为30%、掺加比例在1：2～2：1范围变化时,随着剪切速率增大,浆体呈现先剪切增稠后剪切变稀行为,流变曲线的趋势与单掺粉煤灰时的流变曲线趋势类似,这表明粉煤灰对水泥基胶凝材料净浆流变性能的影响比矿渣大得多；但是与单掺粉煤灰不一样的是,随着复掺粉煤灰掺量增加、矿渣掺量减少,浆体的剪切增稠程度和剪切变稀程度均逐渐降低。(3)基于Herschel-Bulkley模型,在水胶比为0.29的条件下,优选出使胶凝材料体系符合绿色生态混凝土胶凝材料净浆流变特性要求(即屈服应力值相对较小而粘度适中)的掺合料组合：粉煤灰与矿渣复掺且掺加比例为1：1或1：2。(4)基于泰勒公式,建立了粗骨料粒径范围为16.0-19.0mm和19.0-26.5mm时绿色生态混凝土的材料(水胶比、胶凝材料用量及组成、高效减水剂)与其性能(抗压强度及孔隙率)的相互关系。(5)根据序列二次规划法,基于MATLAB工具箱,以绿色生态混凝土28d抗压强度、孔隙率为控制目标,在原材料用量的最佳取值范围内,得出了粗骨料粒径范围为16.0-19.0mm和19.0-26.5mm时的绿色生态混凝土最优配合比。(6)在水胶比为0.29条件下,选用粒径范围为19.0-26.5mm的粗骨料,优化配制的混凝土28d抗压强度可达9.1MPa,有效孔隙率可达27.8%,在其上播种狗牙根草种,成功配制出了绿色生态混凝土。
[Abstract]:Green ecological concrete is a kind of new concrete material whose performance is between ordinary concrete and tillage soil, which can adjust the ecological balance timely, beautify the environment landscape, realize the coordination between human beings and nature, and is also a kind of construction resource saving type in our country. Environment-friendly social development of the inevitable requirements. Based on the basic theories of material science, ecology and botany, and drawing lessons from the traditional design method of ordinary concrete mixture ratio, this paper takes the optimum selection of rheological parameters of cement based cementitious material as the starting point, and probes into the water-binder ratio. The effects of material composition and its content, high efficiency water reducer on the performance of green ecological concrete are studied. The relationship between raw materials and their properties is established by using MATLAB software, and then the sequential quadratic programming method and MATLAB optimization toolbox are used. The mathematical model of mix proportion design of green ecological concrete is solved optimally. The main conclusions are as follows: (1) when the content of fly ash + FAA) varies from 20% to 40%, with the increase of shear rate, the cement based cement paste exhibits shear thickening and then shearing thinning behavior. The shear thickening degree and shear thinning degree decreased first and then increased with the increase of fly ash content, and when the content of SGG increased in the range of 20-40%, with the increase of shear rate, the slurry showed shear thinning and then shearing thickening behavior. With the increase of slag content, the shear thinning degree increases gradually, and the shear thickening degree decreases gradually. The total content of fly ash and slag mixed with fly ash and slag is 300.When the addition ratio varies from 1: 2 to 2: 1, the shear rate increases with the increase of shear rate. The slurry shows shear thickening and then shearing thinning behavior, and the trend of rheological curve is similar to that of single fly ash, which indicates that the influence of fly ash on the rheological properties of cement based cement paste is much greater than that of slag. But different from single fly ash, with the increase of fly ash content, slag content decreases, the shear thickening degree and shear thinning degree of slurry decrease gradually.) based on Herschel-Bulkley model, under the condition of water-binder ratio 0.29, The optimal selection of the binder system meets the requirements for the rheological properties of green ecological concrete cement paste (that is, the yield stress is relatively small and the viscosity is moderate): the mixture of fly ash and slag is mixed with the ratio of 1:1 Or 1: 2. 4) based on Taylor's formula, In this paper, the relationship between the material (water-binder ratio, amount and composition of cementitious material, and superplasticizer) and its properties (compressive strength and porosity) of green ecological concrete with coarse aggregate particle size range of 16.0-19.0mm and 19.0-26.5mm is established according to the sequential quadratic programming method. Based on MATLAB toolbox, the green ecological concrete is controlled by 28d compressive strength and porosity in the optimum range of raw material dosage. The optimum mix ratio of green ecological concrete with 16.0-19.0mm and 19.0-26.5mm is obtained. When the water-binder ratio is 0.29, the coarse aggregate with the diameter of 19.0-26.5mm is selected. The compressive strength and effective porosity of the optimized concrete can reach 9.1 MPA and 27.8% respectively. The green ecological concrete is prepared successfully.
【学位授予单位】：中南林业科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

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