發(fā)布時間：2018-10-26 07:21

【摘要】：我國的水利工程主要集中在西部地區(qū)，這些地區(qū)地質條件復雜、冬季溫度低以及水利工程水頭高、體積大等原因，就對水利工程中所用的水工混凝土的抗?jié)B性、抗凍性、以及變形等耐久性有了更高的要求。其中面板土石壩中的面板混凝土由于其厚度與其他兩個方向的差別比較大對混凝土提出了更高的要求。國內外的很多研究表明，，在水工混凝土中加入纖維能夠起到提高水工混凝土耐久性的作用，因此研究纖維對水工混凝土耐久性的影響有著積極的意義。 纖維素纖維是新一代高新技術材料，具有彈性模量高、易分散，與混凝土粘結性好等優(yōu)點。適用于路面橋面、襯里護壁、地坪等工程部位,近幾年在我國市政、公路、橋隧、地鐵和薄壁結構、建筑工程、尤其在客運專線中已有較多應用，但在水利工程中應用較少見于報道。本課題首次在堆石壩的面板混凝土中加入纖維素纖維來提高水工混凝土的耐久性。 本文通過系統(tǒng)的試驗對纖維素纖維水工混凝土的耐久性進行了研究，對摻入不同纖維素纖維摻量和未摻纖維素纖維的水工混凝土的基本力學性能、抗?jié)B性能、抗凍性能、絕熱溫升性能、自生體積變形性能以及干縮性能進行對比試驗，對纖維素纖維的增強作用效果、評價方法、作用機理進行分析，選擇最佳的纖維素纖維摻量，為纖維素纖維在水利工程中的應用提供依據(jù)。 研究結果表明：水工混凝土中纖維素纖維摻量在0～1.5kg/m3低摻量時，對水工混凝土的抗壓強度沒有影響；能增強水工混凝土的劈裂抗拉強度、抗?jié)B性能、抗凍性能；減少水工混凝土的干縮變形、自生體積變形；但是摻入纖維素纖維會增加水工混凝土的絕熱溫升，影響水工混凝土的耐久性。在0～1.5kg/m3低摻量范圍內隨著纖維素纖維摻量的增加，水工混凝土抗拉強度逐漸變大，水工混凝土的抗?jié)B性能和抗凍性能也隨著提高，水工混凝土的自生體積變形以及干縮變形逐漸減小，而水工混凝土的絕熱溫升隨著摻量的增加而變大。綜合以上試驗結果，纖維素纖維的最佳摻量為1.2kg/m3。為了改善纖維素纖維水工混凝土的絕熱溫升性能，又在在纖維素纖維水工混凝土中加入了WHDF增密劑。纖維素纖維和增強密實劑混摻入水工混凝土后，和單獨摻入纖維素纖維相比，能減少水工混凝土的絕熱溫升，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.
【學位授予單位】：青海大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TV431

【共引文獻】

相關期刊論文 前1條

1 呂進;林磊;;新型端勾型鋼纖維對混凝土性能的提升[J];新型建筑材料;2014年02期

本文編號：2294988