冻融循环作用下纳米混凝土的抗硝酸盐侵蚀性能  

Nitrate corrosion resistance of concrete with nano-particles under freeze-thaw cycles

作　　者：张茂花[1] 韩玥 田泽农 崔继印 刘大志 许荣华 ZHANG Maohua;HAN Yue;TIAN Zenong;CUI Jiyin;LIU Dazhi;XU Ronghua(School of Civil Engineering,Northeast Forestry University,Harbin 150006,China)

机构地区：[1]东北林业大学土木工程学院,黑龙江哈尔滨150006

出　　处：《混凝土》2022年第9期29-33,共5页Concrete

基　　金：国家自然科学基金面上项目(52078109)。

摘　　要：海港码头处的混凝土处在多因素侵蚀的环境,混凝土容易受到冰冻以及硝酸盐共同侵蚀作用的影响,导致海工混凝土耐久性不足。为研究纳米材料对海工混凝土抗硝酸盐盐冻性能的影响,在普通混凝土中加入不同掺量的纳米Al_(2)O_(3),进行混凝土抗硝酸盐侵蚀和抗冻性共同作用试验,以相对动弹性模量、质量损失率和不同深度下混凝土中NO_(3)^(-)含量作为测试指标来评价二者共同作用下纳米混凝土的耐久性,并分析其微观结构。结果表明:在二者共同作用下,纳米混凝土的相对动弹性模量明显提高、质量损失率明显降低;相同冻融循环次数下,不同深度处纳米混凝土的NO_(3)^(-)含量均低于普通混凝土;微观试验表明,纳米Al_(2)O_(3)能够优化孔隙结构、减少裂缝生成,因此在混凝土中添加纳米Al_(2)O_(3)能够显著改善海工混凝土的抗硝酸盐盐冻性能,使海工混凝土的耐久性得到有效地提高。The concrete at harbor wharf is in the environment of multi-factor erosion,and the concrete is susceptible to the combined erosion of freezing and nitrate,which leads to the lack of durability of marine concrete.In order to study the effect of nano-particles on the anti-nitrate freezing performance of marine concrete,different amounts of nano-Al_(2)O_(3) were added into ordinary concrete and the test of freeze-thaw cycles and nitrate erosion are carried out.The durability concrete with nano-particles under the combined action of the two was evaluated by using the relative dynamic elastic modulus,mass loss rate and NO_(3)^(-)contents in concrete at different depths as test indices.SEM were used to analyze the microstructure.The experimental results show that the relative dynamic elastic modulus of concrete with nano-particles increases obviously and the mass loss rate decreases obviously for the case of the combined action of the freeze-thaw cycles and nitrate erosion.Under the same number of freeze-thaw cycles,the NO_(3)^(-) content of concrete with nano-particles at different depths was lower than that of ordinary concrete.Microscopic tests show that nano-Al_(2)O_(3) can optimize the pore structure and reduce the formation of cracks.Therefore,adding nano-Al_(2)O_(3) into concrete can significantly improve the anti-nitrate freezing performance of marine concrete,which effectively improves the durability of marine concrete.

关 键 词：海工混凝土 纳米AL2O3 冻融循环 硝酸盐侵蚀 微观试验 

分 类 号：TU528.01[建筑科学—建筑技术科学]