镁基海水海砂混凝土技术研究

Research on magnesium-based seawater sea sand concrete technology

镁基海水海砂混凝土以海砂为唯一骨料,以原状海水为拌合水,具有较高强度。硫氧镁水泥MOS含量为16%时,28d抗压强度达59MPa以上、抗折强度达10MPa以上;含量增至20%时,28d抗压强度达72MPa以上、抗折强度达16MPa以上。试验证明,使用较少的镁基胶凝材料即可使海水海砂混凝土达到较高强度,满足多种建材产品的强度要求。同样,氯氧镁水泥MOC含量为25%时,7d抗压强度达68MPa以上,28d抗压强度达94MPa以上。海水拌合海砂混凝土以镁基胶凝材料通过改性剂及掺合料控制海砂中游离氯离子的含量,克服硫酸盐硫酸根离子与混凝土孔隙中的钙离子发生反应,提高混凝土材料的强度和耐久性。以原状海水代替淡水直接拌合,就地取材,以盐治盐,施工成本低廉,经济优势明显。

Magnesium-based seawater sea sand concrete has high strength,and uses sea sand as the sole aggregate and undisturbed seawater as the mixing water.When the content of magnesium oxysulfate cement(MOS)is 16%,the compressive strength of 28-day is above 59MPa and the flexural strength is above 10MPa.When MOS is increased to 20%,the compressive strength of 28-day is above 72MPa and the flexural strength is above 16MPa.The experiment results show that the use of less magnesium-based cementitious materials can make seawater sea sand concrete achieve higher strength,which can meet the strength requirements of various building materials.Similarly,when the content of magnesium oxychloride cement(MOC)is 25%,the compressive strength of only 7-day is over 68MPa and the compressive strength of 28-day is over 94MPa.Seawater-mixed sea sand concrete uses magnesium-based cementitious materials to control the content of free chloride ions in sea sand through modifiers and admixtures,overcome the reaction of sulfate ions with calcium ions in the concrete pores,and improve the strength and durability of concrete materials.The undisturbed seawater is used to replace fresh water for direct mixing and the local materials are utilized,which makes the construction cost low and has obvious economic advantages.