摘要
处于滨海大气区的钢筋混凝土结构容易受到氯离子、硫酸根离子等有害离子的侵害,导致结构服役寿命缩短。通过低场核磁等试验研究了蒸养、标养混凝土的孔径分布,揭示了氯离子、硫酸根离子对蒸养混凝土的侵蚀演变规律。结果表明,相比于标养混凝土,蒸养混凝土的无害孔含量降低,有害孔和多害孔含量增大,导致具有更高水化程度蒸养混凝土的抗压强度低于标养混凝土抗压强度。掺入一定量的矿粉可以显著提高蒸养混凝土抗氯离子侵蚀能力,氯离子结合能力越大,氯离子扩散系数越小,表层氯离子浓度越低。当矿粉掺量为25%时,蒸养混凝土的氯离子扩散系数较低,说明矿粉的二次水化作用优化孔径效果达到最佳;随着矿粉掺量的增加硫酸根离子反应系数逐渐降低,当矿粉掺量为50%时,由于混凝土中的钙相物质含量最低,导致硫酸根离子的反应系数最小。
Reinforced concrete structures located in coastal atmospheric areas are susceptible to harmful ions such as chloride ions and sulfate ions,resulting in a shortened service life of the structure.The pore size distribution of steam-cured and standard-cured concrete was studied through low-field nuclear magnetic resonance experiments,revealing the corrosion evolution law of chloride ions and sulfate ions on steam-cured concrete.The results indicate that compared to standard cured concrete,the harmless pore content of steam-cured concrete decreases,while the harmful and multi-harmful pore content increases,resulting in a higher degree of hydration.The compressive strength of steam-cured concrete is lower than that of standard-cured concrete.Adding a certain amount of mineral powder can significantly improve the resistance of steam-cured concrete to chloride ion corrosion.The greater the chloride ion binding ability,the smaller the chloride ion diffusion coefficient,and the lower the surface chloride ion concentration.When the content of mineral powder is 25%,the chloride ion diffusion coefficient of steam-cured concrete is low,indicating that the optimal pore size effect of the secondary hydration of mineral powder is achieved;As the amount of mineral powder increases,the reaction coefficient of sulfate ions gradually decreases.When the amount of mineral powder is 50%,the reaction coefficient of sulfate ions is the lowest due to the lowest content of calcium phase substances in concrete.
作者
董升圆
王秀林
周建国
隋晓萌
李涛
田砾
DONG Shengyuan;WANG Xiulin;ZHOU Jianguo;SUI Xiaomeng;LI Tao;TIAN Li(School of Civil Engineering,Qingdao University of Technology,Qingdao,Shandong 266033,China;Jinan Tongda Highway Engineering Co.,Ltd.,Jinan,Shandong 250200,China;Shandong Road and Bridge Group Co.Ltd.,Qingdao,Shandong 266033,China;China Construction Port Group Ltd.,Qingdao,Shandong 266011,China)
出处
《河北工程大学学报（自然科学版）》
CAS
2023年第4期25-31,共7页
Journal of Hebei University of Engineering:Natural Science Edition
基金
国家自然科学基金资助项目(52278263)。
关键词
大气区
蒸养混凝土
孔结构
氯离子传输
硫酸根离子侵蚀
atmosphere zone
steam cured concrete
pore structure
chloride penetration
sulfate at-
