大坝混凝土水泥选用的几个问题

Selection of Cement for Dam Concrete

文章讨论了大坝混凝土水泥品种和供应方式的选择及低热微膨胀水泥的使用。认为：由于工地上已普遍掺用粉煤灰，对大坝混凝土水泥品种的限制可以放宽，要求可以降低，不一定非要采用大坝水泥和矿渣大坝水泥，水泥的供应方式，应尽量少用或不用袋装，多用散装，向远离水泥厂的大坝工地供应水泥熟料，在工地设粉磨站磨成水泥，比采用散装水泥更优越、更经济。目前试用的底热微膨胀水泥，最适用于完全受约束的工程部位，用于大坝基础约束部位，对防裂有一定作用，但作用不大，用于大坝非约束区，对防裂无益且有害。

Selection of cement classification and supply way for dam concrete and application of low-heat,mi-cro-dilated cement are discussed.Because fly ash is normally used in the site,limilations and requireTnents forcement classification of dam concrete will be less.Therefore,dam concrete and slag dam concrete is not inve-vitably used.Buck cement is used instead of bagged cement.Cement clinker is supplied to dam site far awayfrom cement plant and grinded into cement in grinding plant in site. In this way,cement is gained more cheaper than buck cement.Low-heat, micro-dilated cement which are presently used is best fitted to be used incompletely restrained location,when the cement is used in restrained location at dam foundation,it has a cer-tain effect to prevent cracking,but is not obvious. When the cement is used in nonrestrained Iocation of dam,it is harmful to prevent cracking.