机制砂特性对混凝土性能的影响研究
发布时间：2018-07-20 14:52
【摘要】：随着建筑业的高速发展，混凝土用量越来越大，天然砂资源也将越来越紧张，许多地方因乱采、乱挖已造成严重的环境污染问题，应用机制砂部分或者全部替代天然砂作为混凝土细集料的趋势明显。但是，生产工艺对机制砂特性产生重要的影响，机制砂特性与机制砂混凝土性能密切相关，通过测试混凝土性能来揭示机制砂特性对混凝土的影响规律。研究了机制砂中石粉含量、MB值对混凝土的工作性、力学性、早期抗裂、干燥收缩、抗氯离子渗透性能、抗硫酸盐侵蚀性能的影响规律；利用数字图像处理技术研究了机制表面粒形的评价方法以及其对混凝土性能的影响规律；结合机制砂特性，利用软件优化机制砂混凝土配合比，为推广机制砂在混凝土中的应用提供理论基础和参考价值。揭示的主要影响规律和研究结果如下： 1)研究了机制砂中石粉含量对混凝土性能的影响,结果显示，适量的石粉能够提高混凝土的工作性能和抗压强度，在本试验条件下，当石粉含量在3%~20%时，对于C30、C40和C60混凝土，当石粉含量在15%、10%和5%时拌合物具有最好的工作性；当石粉含量在20%、10%和8%时机制砂混凝土28天抗压强度达到最大值。 2)机制砂中适量的石粉能够机制砂的混凝土的抗硫酸盐侵蚀性能，对抗氯离子渗透性能不利，当机制砂中石粉含量在8%~10%范围内时，混凝土的干缩增长最快。 3)研究了机制砂MB值的影响因素，泥粉含量、种类以及细度对机制砂MB影响较大，相比较于岩土，黏土类的泥粉对MB值的影响更大。泥粉含量和MB值的相关系数R2=0.991；在等含量的条件下，机制砂MB值都是随着泥粉或者石粉的细度增加而增加。 4)机制砂混凝土的工作性能随MB值的增加而减小，抗压强度都是随着机制砂MB增大呈先增大后减小的趋势，当泥粉含量从0%增加到5%时，MB值从0.3增加到4.65；混凝土塑性开裂随着MB值的增大而增大，抗氯离子渗透性能随着MB值的增大而降低，在本试验条件下，MB值从0.3增加到4.65时，C60混凝土抗氯离子渗透等级从Q-Ⅳ下降到Q-Ⅲ。 5)利用MATLAB和IPP软件的数字图像处理技术可对机制砂表面粒形进行评价，，并以二维圆度和三维球度作为评价指标，圆度和球度与水泥胶砂流动度的相关系数分别为R2=0.717和R2=0.689，球度和间隙率的相关性R2=0.908；圆度和流动时间的相关性R2=0.71。机制砂表面粒形对混凝土的工作性能影响较大，对混凝土力学性能影响较小。 6)结合机制砂石粉含量、MB值，利用MATLAB软件优化函数，编制优化程序优化C30机制砂混凝土配合比，优化前后的C30混凝土基本工作性和力学性能相当，在保证混凝土的基本工作性能和力学性能条件下，提高经济效应。
[Abstract]:With the rapid development of the construction industry, the quantity of concrete is increasing, and the natural sand resources will be more and more tight. Because of random mining and digging in many places, serious environmental pollution problems have been caused. The tendency of using machine-made sand to replace natural sand as concrete fine aggregate is obvious. However, the production process has an important effect on the characteristics of the machine-made sand, and the characteristics of the machine-made sand are closely related to the properties of the machine-made sand concrete. The effects of the characteristics of the machine-made sand on the concrete are revealed by testing the properties of the concrete. The effects of rock powder content MB value on the workability, mechanical properties, early crack resistance, drying shrinkage, chloride ion penetration resistance and sulfate erosion resistance of concrete were studied. The evaluation method of mechanism surface grain shape and its influence on concrete performance are studied by using digital image processing technology, and the software is used to optimize the mix ratio of mechanism sand concrete, combining with the characteristics of mechanism sand. It provides theoretical basis and reference value for popularizing the application of machine-made sand in concrete. The main results are as follows: 1) the effect of stone powder content in machine-made sand on concrete performance is studied. The results show that proper amount of stone powder can improve the working performance and compressive strength of concrete. Under this condition, when the content of stone powder is 3 ~ 20, the mixture has the best workability for C30% C40 and C60 concrete, and when the content of stone powder is 15% or 10% and 5%, the mixture has the best workability. When the content of stone powder is 20% and 8%, the compressive strength of concrete made of machine-made sand reaches the maximum value in 28 days. 2) the concrete with proper amount of stone powder in machine-made sand can resist sulfate erosion, which is unfavorable to the permeability of chloride ion. When the content of stone powder in machined sand is in the range of 8% or 10%, the dry shrinkage of concrete increases fastest. 3) the influencing factors of MB value of machined sand are studied. The content, type and fineness of clay have great influence on MB of machined sand, compared with rock and soil. Clay silt has a greater effect on MB value. Under the condition of equal content, the MB value of machined sand increases with the increase of fineness of mud or stone powder. 4) the working performance of machine-made sand concrete decreases with the increase of MB value. The compressive strength increased first and then decreased with the increase of the MB of machine-made sand. When the content of mud powder increased from 0% to 5%, the compressive strength increased from 0.3 to 4.65, and the plastic cracking of concrete increased with the increase of MB value. The resistance to chloride ion penetration decreased with the increase of MB value. Under this test condition, when the value of MB is increased from 0.3 to 4.65, the resistance to chloride ion permeation of concrete can be reduced from Q- 鈪
本文编号：2133889
[Abstract]:With the rapid development of the construction industry, the quantity of concrete is increasing, and the natural sand resources will be more and more tight. Because of random mining and digging in many places, serious environmental pollution problems have been caused. The tendency of using machine-made sand to replace natural sand as concrete fine aggregate is obvious. However, the production process has an important effect on the characteristics of the machine-made sand, and the characteristics of the machine-made sand are closely related to the properties of the machine-made sand concrete. The effects of the characteristics of the machine-made sand on the concrete are revealed by testing the properties of the concrete. The effects of rock powder content MB value on the workability, mechanical properties, early crack resistance, drying shrinkage, chloride ion penetration resistance and sulfate erosion resistance of concrete were studied. The evaluation method of mechanism surface grain shape and its influence on concrete performance are studied by using digital image processing technology, and the software is used to optimize the mix ratio of mechanism sand concrete, combining with the characteristics of mechanism sand. It provides theoretical basis and reference value for popularizing the application of machine-made sand in concrete. The main results are as follows: 1) the effect of stone powder content in machine-made sand on concrete performance is studied. The results show that proper amount of stone powder can improve the working performance and compressive strength of concrete. Under this condition, when the content of stone powder is 3 ~ 20, the mixture has the best workability for C30% C40 and C60 concrete, and when the content of stone powder is 15% or 10% and 5%, the mixture has the best workability. When the content of stone powder is 20% and 8%, the compressive strength of concrete made of machine-made sand reaches the maximum value in 28 days. 2) the concrete with proper amount of stone powder in machine-made sand can resist sulfate erosion, which is unfavorable to the permeability of chloride ion. When the content of stone powder in machined sand is in the range of 8% or 10%, the dry shrinkage of concrete increases fastest. 3) the influencing factors of MB value of machined sand are studied. The content, type and fineness of clay have great influence on MB of machined sand, compared with rock and soil. Clay silt has a greater effect on MB value. Under the condition of equal content, the MB value of machined sand increases with the increase of fineness of mud or stone powder. 4) the working performance of machine-made sand concrete decreases with the increase of MB value. The compressive strength increased first and then decreased with the increase of the MB of machine-made sand. When the content of mud powder increased from 0% to 5%, the compressive strength increased from 0.3 to 4.65, and the plastic cracking of concrete increased with the increase of MB value. The resistance to chloride ion penetration decreased with the increase of MB value. Under this test condition, when the value of MB is increased from 0.3 to 4.65, the resistance to chloride ion permeation of concrete can be reduced from Q- 鈪
本文编号：2133889
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