Study On The Performance Of Marine Cementitious Materials Under Simulated Ocean Splashing Conditions

The number of docks,ports,sea crossing bridge and undersea tunnel supporting for the regional trades are increasing with the development of the overseas and regional trades,but the characteristics of poor durability and low strength of the ordinary concrete will be highlighted when facing ocean and other extreme environments.Many large marine structures lost their local or overall ability in very short periods after completion when facing the extreme environments because of the lack of deep and accurate understanding of the behaviors of the marine materials.In view of this,this paper did some researches about viscosity,fluidity,anti-chloride penetration based on the study of composite cementitious material used in marine concrete in and abroad.The research mainly solved the problem of poor fluidity,insufficient later strength and high hydration heat of ordinary portland cement and explored the early ability of anti-chloride penetration of composite cementitious material used in marine concrete.The main contents of this paper are divided into the following sections:(1)Studying on the hydration heat of composite cementitious material used in marine concrete.The results show that the hydration heat of composite cementitious material used in marine concrete was significantly lower than that of ordinary portland cement with a drop of 70%.(2)Studying on the laws of viscosity and fluidity of composite cementitious material used in marine concret.Some experiments about the influence on the composite cementitious material used in marine concrete were done by changing the water cement ratio,amount and type of water reducing agent.Moreover,two indexes,viscosity and fluidity were used to evaluate the rheological and pumping properties of the material.The results show that the viscosity of composite cementitious material used in marine concrete was better than ordinary portland cement.(3)Studying on the mechanical property of composite cementitious material used in marine concrete.The results show that the initial strength of the composite cementitious material used in marine concrete was lower than the ordinary portland cement,but the later strength increased rapidly,and the strength of the ordinary portland cement was surpassed after 28d.(4)Using a corrosion device imitating the splash zone to study the ability of anti-chloride penetration of composite cementitious material used in marine concrete.Because of the large amount of mineral powder,fly ash and desulfurized gypsum mixed in,the early ability of anti-chloride penetration of composite cementitious material used in marine concrete was not as good as ordinary portland cement,then,as the admixture gradually participated in the hydration,it had a tendency of catching up at 56d.