宣威高速公路机制砂混凝土回弹测强试验研究

发布时间：2018-05-21 19:56

本文选题：机制砂混凝土 + 回弹法　；参考：《辽宁工程技术大学》2015年硕士论文

【摘要】：随着我国基础建设的发展和对环境保护的重视,现有的天然砂资源已不能满足工程需要,使用机制砂己成为今后的发展趋势。机制砂在生产过程中,不可避免地要产生一定数量的粒径小于75μm的石粉,这是机制砂与天然砂最明显的区别之一。与天然砂相比,机制砂还有级配较差,细度模数偏大,表面粗糙,颗粒尖锐有棱角等特点。因此,工程界普遍对采用机制砂来配制混凝土特别是高强度混凝土心存疑虑,对其性能更是缺乏了解,导致机制砂混凝土在一些重要构件和部位中的应用受阻。本文参考宣威高速公路机制砂混凝土科研课题研究,以编制宣威高速公路机制砂混凝土专用回弹测强曲线为目的,采用宣威高速公路混凝土工程使用的原材料进行试验,参考设计资料中给出的混凝土配比,分C30、C40、C50、C55和C60五个强度进行配合比试配和优化调整,同时每种强度混凝土配合比中均设计石粉含量为3%、5%、7%和10%用以对比。进行试块制作和养护,按照龄期进行回弹试验、碳化深度试验和抗压强度试验,分析试验数据,得出宣威高速公路工程机制砂混凝土专用回弹测强曲线,数据误差满足规范对专用测强曲线的要求,同时进行现场钻芯取样验证曲线,符合工程实际情况。将四种石粉含量试块的抗压强度数据进行对比分析,结果表明：在配制中等强度混凝土时可适当增加配合比中的石粉含量,石粉含量在7%左右时机制砂混凝土强度达到最高；在配制高等强度混凝土时要适当降低配合比中的石粉含量,石粉含量在3%左右时机制砂混凝土强度最高。即中等强度机制砂混凝土抗压强度随石粉含量的增加而增大,而高等强度机制砂混凝土的抗压强度随石粉含量的增加而降低。宣威高速公路机制砂混凝土工程回弹专用测强曲线的建立,填补了云南地区机制砂混凝土强度无损检测技术的空白,提高了机制砂混凝土回弹检测技术的精确度,对于云南地区推广使用机制砂混凝土起到了促进作用,但由于本次试验用混凝土原材料和配比的局限性,建立的回弹专用测强曲线仅限在宣威高速公路混凝土工程中使用。
[Abstract]:With the development of infrastructure construction and the importance of environmental protection, the existing natural sand resources can not meet the needs of engineering, the use of machine-made sand has become the development trend in the future. It is inevitable to produce a certain amount of stone powder with diameter less than 75 渭 m during the production of machine-made sand, which is one of the most obvious differences between machine-made sand and natural sand. Compared with the natural sand, the machined sand has the characteristics of poor gradation, larger fineness modulus, rough surface and sharp and angular grain. Therefore, engineering circles generally have doubts about the use of machine-made sand to prepare concrete, especially high-strength concrete, and lack of understanding of its performance, which results in the blocking of the application of machine-made sand concrete in some important components and parts. In this paper, referring to the scientific research of the mechanism sand concrete of Xuanwei Expressway, with the purpose of compiling the springback curve of the concrete of Xuanwei Expressway, the raw materials used in the concrete engineering of Xuanwei Expressway are used for the test. With reference to the concrete ratio given in the design data, the mixture ratio of C30C40C50C55 and C60 is tested and optimized. At the same time, the content of stone powder in each concrete mixture ratio is 3% and 10% respectively. The springback test, carbonation depth test and compressive strength test were carried out according to the age of the test block, and the test data were analyzed, and the springback strength curve for the mechanism sand concrete of Xuanwei Expressway Project was obtained. The data error meets the requirements of the specification for the special strength measurement curve, and the field core sampling is carried out to verify the curve, which is in line with the actual engineering situation. The data of compressive strength of four kinds of stone powder samples are compared and analyzed. The results show that the content of stone powder in mix ratio can be increased properly when the content of stone powder is about 7%, and the strength of machined sand concrete can reach the highest when the content of stone powder is about 7%. In the preparation of high strength concrete, the content of stone powder in mix ratio should be reduced appropriately, and the strength of machine-made sand concrete is the highest when the content of stone powder is about 3%. That is, the compressive strength of medium strength machined sand concrete increases with the increase of stone powder content, while the compressive strength of high strength machined sand concrete decreases with the increase of stone powder content. The establishment of the strength measurement curve for concrete resilience in Xuanwei Expressway filled the blank of non-destructive testing technology for the strength of machine-made sand concrete in Yunnan area, and improved the precision of springback detection technology of machine-made sand concrete. It can promote the popularization and use of machine-made sand concrete in Yunnan area, but due to the limitation of raw material and ratio of concrete used in this experiment, the strength measurement curve established for springback is only used in concrete engineering of Xuanwei Expressway.
【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U414

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