【作者】 陈刚；

【导师】 杨文萃；

【作者基本信息】 哈尔滨工业大学 ， 交通运输工程（专业学位）， 2018， 硕士

【摘要】 硫酸盐侵蚀是造成混凝土结构破坏的主要原因之一。吸水树脂作为内养护材料,在混凝土中发挥内养护作用的同时可以引入部分封闭孔隙并改善混凝土内部孔结构。结合这些特点,本文研究了掺吸水树脂混凝土在溶液中的抗侵蚀性能。试验通过改变SAP种类、掺量、粒径来研究掺SAP对混凝土力学性能的影响。研究在不同溶液中,随干湿循环次数增加混凝土抗折强度、抗压强度变化,通过质量变化、相对动弹性模量变化对其性能进行评价,利用MIP、XRD分析混凝土微观结构的改变。同时比较了干湿-冻融循环交替与干湿循环加速侵蚀破坏特点。研究表明,干掺SAP可以提高混凝土3d、7d、28d抗压强度。抗压强度变化随SAP粒径增加而减小,随SAP掺量增加表现为先增加后减小。确定干掺SAP最佳掺量为0.2%、最佳粒径为45μm⁵8μm;干掺SAP2对混凝土抗压强度的提高略优于掺SAP1混凝土;SAP掺量越多、粒径越小,对混凝土在水中干湿循环破坏抵抗能力越强;5%Na₂SO₄溶液中,SAP掺量越多、粒径越大,在干湿循环后期混凝土的抗折强度、抗压强度越高;干湿-冻融循环交替较干湿循环能够显著地加速混凝土在5%Na₂SO₄溶液中性能劣化,并且前者试件表面破坏更加严重;干湿循环条件下,混凝土在多离子侵蚀溶液中劣化程度为5%MgSO₄溶液最严重,5%MgSO₄+3.5%NaCl溶液次之,5%Na₂SO₄+3.5%Na Cl溶液中最好,并且掺加SAP能够有效延缓溶液中试件劣化。更多还原

【Abstract】 Sulfate attack is one of the major causes of structural damage to concrete.The super absorbent polymer is used as the inner curing material playing a role of internal curing in the concrete while introducing some closed pores and improving the internal pore structure of the concrete.Combining these characteristics,the anti-erosion properties of concrete with super absorbent polymer in solution are studied in this paper.The impact on the mechanical properties of the concrete with SAP was investigated by changing the SAP types,dosage,particle size.In different solutions,testing the flexural and compressive strength of concrete changed with the dry-wet cycles.Durability was evaluated by the changes of mass and relative dynamic elastic moduli,and the changes in the microstructure of the concrete were analyzed using MIP and XRD.At the same time,the characteristics of accelerated erosion and damage of dry-wet freeze-thaw alternate cycle and dry-wet cycle were compared.Studies have shown that dry added SAP can improve the compressive strength of concrete 3d,7d,28 d.The compressive strength decreases with the increased particle size of SAP.The compressive strength increases firstly and then decreases with increasing dosage of SAP.It was determined that the optimum dry added SAP dosage was 0.2%and the optimal particle size was 45μm⁵8μm.The dry added SAP2 slightly improved the compressive strength of the concrete compared to the SAP1.Adding SAP with more dosage and smaller particle size,the damage of concrete suffered by dry-wet cycle in water is lighter.In 5%Na₂SO₄ solution,adding SAP with more dosage and larger particle size can maintain the concrete with higher mechanical properties at the later stage of the dry-wet cycle.Dry-wet freeze-thaw alternate cycle can significantly accelerate the deterioration of the concrete in 5%Na₂SO₄ solution compared with the deterioration in dry-wet cycle.The damage of specimen surface is more serious in former cycle.Under dry-wet cycle conditions,the degree of deterioration of concrete in multi-ion-erosion solution is 5%Mg SO₄solution>5%Mg SO₄+3.5%Na Cl solution>5%Na₂SO₄+3.5%NaCl solution.With SAP added,the deterioration of the concrete could be effectively delayed in the 5%Na₂SO₄+3.5%NaCl solution.更多还原