DAMAGES OF REINFORCED CONCRETE UNDER SYNERGISTIC EFFECTS OF CYCLIC FREEZE-THAW, DEICING-SALT ATTACK, REBAR CORROSION AND BENDING LOAD
-
摘要: 采用自行研制的一套环境性能综合评估试验方法对钢筋混凝土试样成功地进行了冻融循环与除冰盐腐蚀协同作用(简称盐冻循环)、钢筋锈蚀与弯曲荷载协同作用下的失效试验。通过测量损伤演变过程中钢筋混凝土动弹性模量、钢筋应变和混凝土应变的变化,研究了盐冻循环、钢筋锈蚀与弯曲荷载协同作用下钢筋混凝土损伤失效的演变过程。结果表明,普通混凝土(C4 5 )和高强混凝土(C70 )在不同损伤因素协同作用下,损伤规律存在相似性,但损伤速率明显不同。相似性表现在:多因素协同作用下导致的损伤大于单因素损伤,特别是叠加上弯曲荷载后,混凝土动弹性模量下降速率大大增加,表明弯曲荷载对盐冻循环与钢锈协同作用下的钢筋混凝土的损伤有促进作用。在相同试验条件下,普通混凝土的损伤速率大于高强混凝土,表明普通混凝土的损伤阻力低于高强混凝土。另外,试验发现在给定的温差变化条件下,盐冻循环、钢锈与弯曲荷载协同作用导致钢筋混凝土中钢筋的应变幅值随着冻融循环次数的增加而逐渐增大。Abstract: The damage experiments of reinforced concrete samples under synergistic effects of cyclic freeze thaw, deicing salt attack, rebar corrosion and bending load were investigated using a comprehensive experimental method. Synergistic effects of these factors on the damage evolvement of the reinforced concrete was studied by measuring the change of dynamic modulus, rebar strain and concrete strain. Experimental results showed similar rule in damage evolvement,but different damage rate between the normal strength concrete (C45) and the high strength concrete (C70). The dynamic modulus of the reinforced concrete degraded with increasing effecting factors. Meanwhile, an interesting phenomenon is revealed that the amplitude of cyclic strains increase with the numbers of freeze thaw cycles within a fixed temperature difference.
-
Mehta P K, Burrows R W. Building Durable Structures in the 21st Century. Concrete International, 2001,23(3): 57 ~ 61; [2] Mehta P K. Durability-critical Issues for the Future. Concrete International, 1997, 19(7) :27 ~ 31; [3] Adam Neville. Consideration of Durability of Concrete Structures:Past,Present and Future. Materials and Structures,2001,34(3): 114 ~ 118; [4] 吴中伟,廉惠珍.高性能混凝土.北京:中国铁道出版社,1999.218 ~ 219; [5] Cerny R, Drchalova J, Rovnanikova P. The Effects of Thermal Load and Frost Cycles on the Water Transport in Two High-performance Concretes.Cement and Concrete Research, 2001, 31(8):1 129~ 1 136; [6] Li Chun Qing. Corrosion Initiation of Reinforcing Steel in Concrete under Natural Salt Spray and Service Loading-Results and Analysis. ACI Materials Journal, 2000, 97(6): 690 ~ 697; [7] Yoon Sanchun, Wang Kejin, Weiss W Jason, et al. Interaction between Loading, Corrosion, and Serviceability of Reinforced Concrete. ACI Materials Journal,2000,97(6): 637 ~ 643; [8] Sun W, Zhang Y M, Yan H D, et al. Damage and Damage Resistance of High Strength Concrete under the Action of Load and Freeze-Thaw Cycles. Cement and Concrete Research, 1999, 29(9):1 519 ~ 1 523; [9] Mu R, Miao C, Luo X, et al. Interaction between Loading, FreezeThaw Cycles, and Chloride Salt Attack of Concrete with and without Steel Fiber Reinforcement. Cement and Concrete Research, 2002, 32(7): 1061~1065; [10] 李金玉,林莉,曹建国,等.高浓度和应力状态下混凝土硫酸盐侵蚀性的研究.见:王媛俐,姚燕.重点工程混凝土耐久性的研究与工程应用.北京:中国建材工业出版社,2001; [11] 杨全兵,黄士元.受冻地区混凝土的盐冻破坏.公路,1998,42(8):25~28; [12] 朱蓓蓉,杨全兵,黄士元.除冰盐对混凝土化学侵蚀机理研究.低温建筑技术,2000,24(1):3~6; [13] ZhouYixia, CohenMD, DolchLWilliam. Effect of External Loads on the Frost-Resistant Properties of Mortar with and Without Silica Fume.ACI Materials Journal, 1994,91(6): 595 ~ 601; [14] 严安.在荷载与冻融双因素作用下混凝土的损伤过程:[硕士学位论文].南京:东南大学,1998; [15] 慕儒.冻融循环与外部弯曲荷载、盐溶液复合作用下混凝土的耐久性与寿命预测:[博士学位论文].南京:东南大学,2000; [16] ASTM C6661C666M - 03 Standard Test Method for Resistance of Concrete to Rapid Freezing and Thawing; [17] GB 50010-2002混凝土结构设计规范; [18] Lu X. Application of the Nernst-Einstein Equation to Concrete. Cement and Concrete Research, 1997, 27 (2): 293 ~ 301; [19] GBJ 82-85 普通混凝土长期性能和耐久性试验方法
点击查看大图
计量
- 文章访问数: 74
- HTML全文浏览量: 7
- PDF下载量: 100
- 被引次数: 0