粉煤灰高性能混凝土的应用

The Application of Fly Ash on High Performance Concrete

粉煤灰在混凝土中的应用越来越广泛,但现行的规范一般限制掺量不超过25%,但混凝土抗氯离子渗透能力并不好,属普通混凝土,当粉煤灰的掺量超过30%以后,混凝土的抗氯离子的渗透能力逐步增强,掺量达到45%时,氯离子扩散系数降到2.04×10-12m2/s,其他性能也随之提高,使之成为高性能混凝土。随着粉煤灰掺量的提高,也增加了对工业废渣利用,减少固体废弃物的排放、保护环境有积极作用,同时还降低混凝土的成本。本文就粉煤灰高性能混凝土在杭州湾跨海大桥北航道桥的桩基、承台的混凝土配合比的设计、试配及施工中应用作介绍。

Fly ash is widely used in concrete nowadays.The dosage of fly ash is less than 25 percent in the actual code.However,the permeation capability of concrete resistance performance on chlorine ion is not so good.The permeation capability of concrete resistance performance on chlorine ion escalate with the increase of the dosage of fly ash over 30 percent in ordinary concrete.When the dosage of fly ash reaches 45 percent,the chloride diffusion coefficient decreases to 2.04×10^(-12)m^2/s.Other performances improve with it,and ordinary concrete turn into high performance concrete.The usage of the industrial waste slag increases accordingly with the increase of the dosage of fly ash,and the emission of solid waste material decreases accordingly.It can not only be helpful to protect the environment but also reduce the cost of concrete.The application of fly ash high performance concrete on the project of the Hangzhou Bay Span-sea Bridge was represented in this paper,including the designing of mixture ratio of concrete,the test matching and the constructing of the bridge pile foundation work.