The Study On Slump Loss Of The Concrete With High-Rang Water-Reducing Agent

As commercial concrete is arisen, people pay much attention to make concrete fluidized; and it's to say the concrete must keep a high slump after long-playing transportation and halt. Not only does slump loss influence the effect, it constrains the transportation distance and pumping height and distance but also, and these will make the construction harder. And if slump loss is too much, it will be difficult to cast, and these will be such defects as honeycombs and pothotes, and they will reduce the quality of construction. In recent ten years, scientists and engineers have being researching the admixture that can control the slump loss effectively. Such methods as compounding retardants, compounding water-reducing agents(which has various the extent of condensation ), changing the ways of addition and retardarce method, are used to impolder new water-reducing agent and construction method to salve slump loss, but it can not work drastically.Based on quite a few literatures, the paper discusses the method to researching slump loss; researches the mechanism of slump loss and compares several measures which are used to control slump loss. It's believed that retardarce method can constrain the slump loss of fresh concrete effectively and have no bad influence on the early strength of concrete.The new type of high effective water-reducing agent we developed based on Naphthalin series has characteristic of retardarce. It can reduce slump loss through its slow solution. The new high effective water-reducing agent Act-FDN has characteristic of reactivity, it can't dissolve in water but do in alklia. In the concrete, it decompounds slowly and gives out sulfonate group which has dispersity, this can make the high effective water-reducing agent available for a long time, therefore it can reduce slump loss. Act-FDN varies from common water-retaining plasticizers and complex water reducers; it doesn't contain compound retardants and has no bad influence on the early strength of concrete. Though Act-FDN is not the best admixture used to reduce slump loss, it's still a practicable method, for its obvious effect, stable production technology and low cost.