纤维素纤维水工混凝土耐久性性能试验研究
发布时间：2018-10-26 07:21
【摘要】：我国的水利工程主要集中在西部地区，这些地区地质条件复杂、冬季温度低以及水利工程水头高、体积大等原因，就对水利工程中所用的水工混凝土的抗渗性、抗冻性、以及变形等耐久性有了更高的要求。其中面板土石坝中的面板混凝土由于其厚度与其他两个方向的差别比较大对混凝土提出了更高的要求。国内外的很多研究表明，，在水工混凝土中加入纤维能够起到提高水工混凝土耐久性的作用，因此研究纤维对水工混凝土耐久性的影响有着积极的意义。 纤维素纤维是新一代高新技术材料，具有弹性模量高、易分散，与混凝土粘结性好等优点。适用于路面桥面、衬里护壁、地坪等工程部位,近几年在我国市政、公路、桥隧、地铁和薄壁结构、建筑工程、尤其在客运专线中已有较多应用，但在水利工程中应用较少见于报道。本课题首次在堆石坝的面板混凝土中加入纤维素纤维来提高水工混凝土的耐久性。 本文通过系统的试验对纤维素纤维水工混凝土的耐久性进行了研究，对掺入不同纤维素纤维掺量和未掺纤维素纤维的水工混凝土的基本力学性能、抗渗性能、抗冻性能、绝热温升性能、自生体积变形性能以及干缩性能进行对比试验，对纤维素纤维的增强作用效果、评价方法、作用机理进行分析，选择最佳的纤维素纤维掺量，为纤维素纤维在水利工程中的应用提供依据。 研究结果表明：水工混凝土中纤维素纤维掺量在0～1.5kg/m3低掺量时，对水工混凝土的抗压强度没有影响；能增强水工混凝土的劈裂抗拉强度、抗渗性能、抗冻性能；减少水工混凝土的干缩变形、自生体积变形；但是掺入纤维素纤维会增加水工混凝土的绝热温升，影响水工混凝土的耐久性。在0～1.5kg/m3低掺量范围内随着纤维素纤维掺量的增加，水工混凝土抗拉强度逐渐变大，水工混凝土的抗渗性能和抗冻性能也随着提高，水工混凝土的自生体积变形以及干缩变形逐渐减小，而水工混凝土的绝热温升随着掺量的增加而变大。综合以上试验结果，纤维素纤维的最佳掺量为1.2kg/m3。为了改善纤维素纤维水工混凝土的绝热温升性能，又在在纤维素纤维水工混凝土中加入了WHDF增密剂。纤维素纤维和增强密实剂混掺入水工混凝土后，和单独掺入纤维素纤维相比，能减少水工混凝土的绝热温升，提高了水工混凝土的耐久性。
[Abstract]:Water conservancy projects in China are mainly concentrated in the western region. These areas have complex geological conditions, low temperature in winter, high water head and large volume of water conservancy projects, so that the impermeability and frost resistance of hydraulic concrete used in water conservancy projects can be improved. As well as deformation and other durability has higher requirements. Because of the difference between the thickness and the other two directions, the concrete slab in the concrete face rockfill dam has put forward a higher demand for the concrete. Many studies at home and abroad show that adding fiber to hydraulic concrete can improve the durability of hydraulic concrete, so it is of positive significance to study the effect of fiber on the durability of hydraulic concrete. Cellulose fiber is a new high-tech material with high elastic modulus, easy dispersion and good bond with concrete. In recent years, it has been widely used in municipal, highway, bridge and tunnel, subway and thin-walled structures in China, especially in passenger dedicated lines. But its application in water conservancy engineering is seldom reported. In order to improve the durability of hydraulic concrete, cellulose fiber is added to face concrete of rockfill dam for the first time. In this paper, the durability of cellulose fiber hydraulic concrete is studied by systematic test. The basic mechanical properties, impermeability and frost resistance of hydraulic concrete with different fiber content and without cellulose fiber are studied. The performance of adiabatic temperature rise, autogenous volume deformation and dry shrinkage of cellulose fiber were compared. The reinforcement effect, evaluation method and mechanism of cellulose fiber were analyzed, and the optimum amount of cellulose fiber was selected. It provides the basis for the application of cellulose fiber in water conservancy engineering. The results show that when the content of cellulose fiber in hydraulic concrete is low in 0~1.5kg/m3, it has no effect on the compressive strength of hydraulic concrete, and can enhance the splitting tensile strength, permeability resistance and freezing resistance of hydraulic concrete. The dry shrinkage deformation and autogenous volume deformation of hydraulic concrete are reduced, but the adiabatic temperature rise of hydraulic concrete is increased by adding cellulose fiber, and the durability of hydraulic concrete is affected. In the range of low content of 0~1.5kg/m3, the tensile strength of hydraulic concrete increases with the increase of cellulose fiber content, and the impermeability and freezing resistance of hydraulic concrete also increase with the increase of fiber content. The autogenous volume deformation and dry shrinkage deformation of hydraulic concrete decrease gradually, while the adiabatic temperature rise of hydraulic concrete increases with the increase of the content. Based on the above experimental results, the optimum content of cellulose fiber is 1.2 kg / m ~ (3). In order to improve the adiabatic temperature rise performance of cellulose fiber hydraulic concrete, WHDF densifier was added to cellulose fiber hydraulic concrete. When cellulose fiber and reinforcing compacting agent are mixed in hydraulic concrete, the adiabatic temperature rise of hydraulic concrete can be reduced and the durability of hydraulic concrete can be improved compared with the addition of cellulose fiber alone.
【学位授予单位】：青海大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV431
本文编号：2294988
[Abstract]:Water conservancy projects in China are mainly concentrated in the western region. These areas have complex geological conditions, low temperature in winter, high water head and large volume of water conservancy projects, so that the impermeability and frost resistance of hydraulic concrete used in water conservancy projects can be improved. As well as deformation and other durability has higher requirements. Because of the difference between the thickness and the other two directions, the concrete slab in the concrete face rockfill dam has put forward a higher demand for the concrete. Many studies at home and abroad show that adding fiber to hydraulic concrete can improve the durability of hydraulic concrete, so it is of positive significance to study the effect of fiber on the durability of hydraulic concrete. Cellulose fiber is a new high-tech material with high elastic modulus, easy dispersion and good bond with concrete. In recent years, it has been widely used in municipal, highway, bridge and tunnel, subway and thin-walled structures in China, especially in passenger dedicated lines. But its application in water conservancy engineering is seldom reported. In order to improve the durability of hydraulic concrete, cellulose fiber is added to face concrete of rockfill dam for the first time. In this paper, the durability of cellulose fiber hydraulic concrete is studied by systematic test. The basic mechanical properties, impermeability and frost resistance of hydraulic concrete with different fiber content and without cellulose fiber are studied. The performance of adiabatic temperature rise, autogenous volume deformation and dry shrinkage of cellulose fiber were compared. The reinforcement effect, evaluation method and mechanism of cellulose fiber were analyzed, and the optimum amount of cellulose fiber was selected. It provides the basis for the application of cellulose fiber in water conservancy engineering. The results show that when the content of cellulose fiber in hydraulic concrete is low in 0~1.5kg/m3, it has no effect on the compressive strength of hydraulic concrete, and can enhance the splitting tensile strength, permeability resistance and freezing resistance of hydraulic concrete. The dry shrinkage deformation and autogenous volume deformation of hydraulic concrete are reduced, but the adiabatic temperature rise of hydraulic concrete is increased by adding cellulose fiber, and the durability of hydraulic concrete is affected. In the range of low content of 0~1.5kg/m3, the tensile strength of hydraulic concrete increases with the increase of cellulose fiber content, and the impermeability and freezing resistance of hydraulic concrete also increase with the increase of fiber content. The autogenous volume deformation and dry shrinkage deformation of hydraulic concrete decrease gradually, while the adiabatic temperature rise of hydraulic concrete increases with the increase of the content. Based on the above experimental results, the optimum content of cellulose fiber is 1.2 kg / m ~ (3). In order to improve the adiabatic temperature rise performance of cellulose fiber hydraulic concrete, WHDF densifier was added to cellulose fiber hydraulic concrete. When cellulose fiber and reinforcing compacting agent are mixed in hydraulic concrete, the adiabatic temperature rise of hydraulic concrete can be reduced and the durability of hydraulic concrete can be improved compared with the addition of cellulose fiber alone.
【学位授予单位】：青海大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV431
【共引文献】
相关期刊论文 前1条
1 吕进;林磊;;新型端勾型钢纤维对混凝土性能的提升[J];新型建筑材料;2014年02期
本文编号：2294988
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