聚丙烯纤维和氧化镁在面板混凝土中的应用

Application of admixing technology of polyacrylic fiber and Magnesia in face slab concrete of Hongjiadu hydropower station

洪家渡水电站面板堆石坝属200m级高面板坝,面板混凝土的防裂技术是一个重要的研究课题。洪家渡大坝面板混凝土配合比设计的基本思路是在满足设计要求的强度、耐久性及良好的施工和易性的前提下,重点考虑其抗渗防裂问题。经过大量的试验论证之后,采用了在混凝土中掺加聚丙烯纤维和轻烧氧化镁的方法。已完工的一期面板到目前为止仅发现10条小于0.2mm的细微裂缝,大大低于同类坝型的水平。聚丙烯纤维和轻烧氧化镁双掺技术的应用,在面板混凝土的防裂中发挥了明显的作用。

Hongjiadu concrete face rockfill dam belongs to a kind of dams with their height of 200 m, so crack control technology for the dam's concrete facing slabs becomes an important research subject. The basic design consideration of the mix proportion of facing slab concrete for the rockfill dam was to put stress on the seepage prevention and crack control of concrete on condition of meeting stipulated design strength, durability and workability of concrete. Through extensive experimental demonstration, polyacrylic fiber and lightly sintered magnesia were added in concrete for crack control. Up to now, only 10 cracks have been found in the completed stage I concrete facing slabs, with their crack width less than 0.2 mm. The number of cracks are far less than that of other similar dams. The application of the technology of adding both polyacrylic fiber and lightly sintered magnesia in concrete played a remarkable role in crack control of concrete facing slabs.