Studies On Proporties Of Cemented Sand And Gravel Material In Cold Area

The Cemented Sand and Gravel(CSG) Dam is a new dam type which combinates the advantages of Concrete Faced Rockfill(CFR) Dam and Roller Compacted Concrete(RCC). It has characteristics such as using less cement content, local materials, low quality demand for aggregate, and so on. There are some practical results of CSG technology in China and abroad. Lower cement content, smaller slump and less compactness all results in poor freeze-thaw resistance. So the freezing resistance is a major problem of CSG. To promote the CSG technology in cold areas, it’s quite important to improve the freezing resistance problem of CSG.Firstly, the orthogonal experiment was to study the optimal mix proportion of lean CSG. And the main factors affecting the compressive strength of lean CSG’ were pointed out.Next, to improve the freezing resistance of lean CSG, and considering that it’s difficult for the ordinary entraining agent to work in RCC, this paper presented a new way to improve the freezing resistance of the lean CSG by adding the lightweight particles. The lightweight particles mainly are pottery sand, EPS grain and rubber powder with different size becauselightweight particle used as air-entraining agent. can make the CSG construction convenient.This paper studied the effects of kinds and content of lightweight particles on the compressive strength and freezing resistance of the low workability mortar. The result shows that adding lightweight particles can improve freezing resistance of low workability mortar. And the optimal content of the lightweight particles was determined.Then, this paper studied the effects of the durability oflean CSG by adding the ordinary entraining agent called AOS and the lightweight particles. The results shows that adding AOS entraining agent can improve freezing resistance of the lean CSG. A treatment for adding AOS into ean CSG was adopted to form micro pore in paste-poor CSG. Adding lightweight particles in lean CSG can also improve its freezing resistance. Adding AOS entraining agent and lightweight particles can affect the anti-permeability and drying shrinkage of CSG even its effects is little.Finally, the CSG with binder contents over 150kg/m3 called rich CSG. The only difference between rich CSG and lean CSG is the binder contents. Increasing the content of binder material can improve the properties of lean CSG and rich CSG in freezing resistance, anti-permeability and drying shrinkage.