基于双K断裂模型的海水对混凝土断裂性能的影响研究
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摘要
基于双K断裂模型,通过三点弯曲试验研究了海水养护、海水搅拌对混凝土断裂性能的影响。试验结果表明:海水拌制明显降低了混凝土的起裂荷载及峰值荷载,对混凝土的起裂断裂韧度KIcini及失稳韧度KIcun也均有降低作用,降幅最大分别达到52.6%和25.6%;海水养护对双K断裂参数影响相对较小,起裂断裂韧度及失稳韧度降幅范围分别为3.2%~23.4%、12.7%~20.8%。此外在海水影响下,计算得到的断裂能有较明显的降低,降幅范围在14.5%~28.1%。海水对混凝土立方体抗压强度影响较小。
Based on the double-K model,the effect of seawater curing and seawater agitation on the fracture properties of concrete was studied by three-point bending test in this paper. The test results show that:Seawater mixing reduces significantly the initiation load and peak load of concrete,and also reduces the initiation fracture toughness and instability fracture toughness of concrete. The maxima of decreasingare 52.6% and 25.6% respectively. The effect of seawater maintenance on the fracture parameters of double-K is relatively small,and the ranges of fracture toughness and instability toughness are 3.2%~23.4% and 12.7%~20.8%,respectively. In addition,under the influence of seawater,the calculated fracture energy is obviously reduced,and the range of decrease is 14.5%~28.1%.The effect of seawater on the compressive strength of concrete cubes is fairly minor.
Based on the double-K model,the effect of seawater curing and seawater agitation on the fracture properties of concrete was studied by three-point bending test in this paper. The test results show that:Seawater mixing reduces significantly the initiation load and peak load of concrete,and also reduces the initiation fracture toughness and instability fracture toughness of concrete. The maxima of decreasingare 52.6% and 25.6% respectively. The effect of seawater maintenance on the fracture parameters of double-K is relatively small,and the ranges of fracture toughness and instability toughness are 3.2%~23.4% and 12.7%~20.8%,respectively. In addition,under the influence of seawater,the calculated fracture energy is obviously reduced,and the range of decrease is 14.5%~28.1%.The effect of seawater on the compressive strength of concrete cubes is fairly minor.
引文
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[7]JCI-S-001-2003,Method of test for fracture energy of concrete by use of notched beam[S].
[2]徐世烺.我国混凝土断裂力学发展三十年[J]水利学报2014,45(Z):1-9.
[3]朱榆.混凝土断裂及阻裂理论的研究[D].大连:大连理工大学,2009.
[4]XU S L,REINHARD H W.Determination of double-K criterionforcrackpropagationinquasibrittlefracture Part II:Analytical evaluating and practical measuring methodsforthreepointbendingnotchedbeams[J].International Journal of Fracture,1999(98):151-177.
[5]徐世烺.混凝土断裂力学[M].北京:科学出版社,2011.
[6]BAZANT Z P,KIM J K,PFEIFFER P A.Determination of fracture properties from size effect tests[J].Journal of Structural Engineering,1986(112):289-307.
[7]JCI-S-001-2003,Method of test for fracture energy of concrete by use of notched beam[S].