粉煤灰在混凝土中应用的几个技术问题

Technical problems with applicatioa of flyash concrete

论述粉煤灰混凝土的碳化、钢筋腐蚀和耐久性问题和防患措施。

this is a feasiability study of using fly ash in Jiangsu, Zhejiang, Northeast and Northwest. The paper concentrates on carbonization of concrete, corrosion of reinforcements, and endurance. On one hand, adding fly ash into concrete has the demerits of less alkalinity of concrete, carbonization of concrete which will spoil the surface passivation film of reinforcements, electrochemistry of reinforcement surface which causes corrosion.On the other hand, it has the merits of good workability, compactness, resistance to filtration, high strength, less water needed, increase of strength with the increase of age. So, if the quantity of flyash is appropriate, the quantity of cement is controlled to reduce w/c ratio, grading is improved5 concrete is well mixed, placed, vibrated, and cured, the fly ash concrete is of no problem.