Study On Durability Properties Of Non-dispersible Underwater Concrete In The Sea-water

With the decrease of land space resources and the increase ocean engineering,non-dispe-rsible underwater concrete in the sea water environment has been widely used in practical engineering,which is different from normal concrete.Non-dispersion underwater concrete generally was eroded by all kinds of salts,compared with the fresh water environment,the non-dispersible underwater concrete damage in the sea water environment is more serious.In this paper,there is an experimental study to improve durability properties of non-dispersible underwater concrete in the sea water environment.In this paper,According to the selection of raw materials,additive(non-dispersible agent,poly carboxylic acid and high efficiency water reducing agent,cementitious capillary crystalline waterproofing agent)and mineral admixture,(silica fume,fly ash and ground granulated blast furnace slag and zeolite powder)and test code for non-dispersible underwater concrete.we design 11 groups mix proportions of non-dispersible underwater concrete,which are designed according to C40 and are made in two conditions:on the land and in water.To test slumb and extension of the fresh non-dispersible underwater concrete mixture.After maintenance to the test age,we test strength to find the best dosage of mineral admixture for non-dispersible Underwater concrete.And On this basis,we study on durability(Test Method for resistance of concrete to freezing and thawing;Test method for resistance of concrete to water penetration;Test method for resistance of concrete to chloride penetration)of non-dispersible underwater concrete.Especially cementitious capillary crystalline waterproof-ing agent have a positive effect on resistance of concrete to water penetration and dry-wet alternation of non-dispersion underwater concrete effect on resistance of concrete to chloride penetration and resistance of concrete to freezing and thawing.Experimental results show that part of the cement slurry were are taken away by water,when non-dispersible underwater concrete were casting molding in the sea water environment,on this account(1)The long-term(28d and 56d)strength of non-dispersible underwater concrete which is molded in water are 60%to 80%of strength of non-dispersible underwater concrete which is molded on the land,The performance of concrete(Resistance of concrete to freezing and thawing;resistance of concrete to water penetration;and resistance of concrete to chloride penetration),which is molded in water is lower that is molded in fresh water.(2)Adding cementitious capillary crystalline waterproofing agent and mineral admixture concrete performance that are resistance of concrete to water penetration and resistance of concrete to chloride penetration are better than adding nothing concrete performance.(3)The concrete of forming in water,the concrete early(3d and7d)strength of curing in sea water is higher than the concrete early strength of curing in fresh water,but the concrete long-term(28d and 56d)strength of curing in sea water is lower than the concrete long-term strength of curing in fresh water.Conclusions:To compare with adding nothing concrete,adding silica fume can improve non-dispersion underwater concrete strength,the biggest can be increased by 27.1%;and can significantly improve resistance of concrete to freezing and thawing.(2)Resistance of concrete to water penetration of adding cementitious capillary crystalline waterproofing agent concrete is 6.32 times as many as resistance of concrete to water penetration of adding nothing,To contrast with adding nothing concrete,Adding cementitious capillary crystalline waterproofing agent can improve resistance to chloride ion permeability,the biggest can be increased by 69.1%.