Study On Properties Of Underwater Aluminate Cement-based Materials

With the development of modern society,land resources have been far from meeting the needs of human development,and human development strategy is advancing to the vast ocean.There are many underwater projects in marine civil engineering and harbor civil engineering.The traditional underwater sealing material based on ordinary Portland cement has the defect of easy segregation and delamination.Therefore,it is imperative to develop a kind of sealing pouring material that is in line with modern,and rapidly hardens underwater with high strength.In order to provide the basis for the preparation of the fast hardening,early strength,easy construction of underwater materials,through the ordinary Portland cement-aluminate cement-dihydrate gypsum ternary cementitious system and high corrosion resistance aluminate cement system to carry out a systematic underwater test research.Firstly,two preparation methods of adding non-dispersing agent underwater and pouring with controlled setting time were determined.Secondly,the influence of the three admixtures on the properties of aluminate cement base was studied by adding non-dispersing agent underwater,redispersible latex,retarder and other admixtures.Finally,the effects of different casting time on the properties of aluminate cement-based material were studied.The test mainly tested the setting time,fluidity,anti-dispersion and mechanical properties of the aluminate cement-based materials.Finally,the composition and morphology of the hydration products were tested by X-ray diffraction analyzer and scanning electron microscope.Research shows:(1)The double mixing of tartaric acid and sodium gluconate can effectively solve the problem that the fluidity of ternary aluminate cement-based material loses too fast for 30 min.The mixing of sodium gluconate will cause the high corrosion resistance aluminate cement-based material to lose its cementability during curing.(2)The mixing of non-dispersing agent underwater and dispersible rubber powder will have a negative effect on the mechanical properties of the test block,reduce the fluidity of the slurry,but increase the anti-dispersion ability of the slurry.The dispersion resistance of aluminate cement was better than that of redispersible latex powder,but it had more adverse effects on the mechanical properties of test block.(3)The strength of aluminate cement-based subsea forming test block increases first and then decreases with the increase of the content of subsea anti-dispersant or re-dispersible latex powder.When the ratio of water to glue is 0.3and the content of re-dispersible latex powder is 0.2%,the mechanical properties and anti-dispersive properties are the best.When the water-cement ratio is 0.3,the optimal content of underwater dispersant for ternary aluminate cement-based materials is 1.0% and that for high-corrosion aluminate cement-based materials is0.8%.(4)When aluminate cement based material initial setting time control at about 3 h,mixed with water dispersant of aluminate cement base material under optimum pouring time is completed immediately stir casting,and adding to disperse latex powder net aluminate cement paste and mortar material optimum pouring time of 90 min,adding to disperse latex powder of aluminate cement concrete material optimum pouring time for 60 min.(5)The slump protector can effectively delay the optimal pouring time and slightly increase the compressive strength and water-land strength ratio of the underwater molding test block.