基于碳化数值模拟的桥梁混凝土构件耐久性设计
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摘要
现有混凝土桥梁耐久性规范和指南中,对精细化的耐久性设计还未有明确的规定,在面对桥梁混凝土构件转角区域的二维侵蚀情况时,存在一定的局限性。为解决这一问题,基于碳化作用的数值模拟工具,开展了二维的碳化过程计算。依托于工程实际中存在的构件二维侵蚀情况,对6个截面进行了数值模拟计算,通过对比钢筋实际分布情况与碳化锋面发展情况,给出了钢筋锈蚀可能性的判断标准;对钢筋锈蚀不利截面开展了深入分析,采用数值模拟工具计算了寿命周期内不利截面的碳化情况,基于计算结果制定了对应的管理养护策略。
In the current durability design standards and guidelines for concrete bridges, specifications on refined design method is not yet introduced.When the two-dimensional ingress happened in the corner areas of the concrete components,the durability assessment is limited with the codes.In order to answer this question,a two-dimensional carbonation numerical calculation is presented in this paper.Carbonation processes of 6 two-dimensional sections picked from the girder and pillars of the example bridge are simulated.By comparing the actual arrangement of the rebar in concrete and the carbonization front,the probability of rebar corrosion is indicated for different sections.For the section with highest risk of rebar corrosion,the development of the carbonization front is presented in the service life time.Management and maintenance strategies are formulated on the base of the life-time calculation results.
In the current durability design standards and guidelines for concrete bridges, specifications on refined design method is not yet introduced.When the two-dimensional ingress happened in the corner areas of the concrete components,the durability assessment is limited with the codes.In order to answer this question,a two-dimensional carbonation numerical calculation is presented in this paper.Carbonation processes of 6 two-dimensional sections picked from the girder and pillars of the example bridge are simulated.By comparing the actual arrangement of the rebar in concrete and the carbonization front,the probability of rebar corrosion is indicated for different sections.For the section with highest risk of rebar corrosion,the development of the carbonization front is presented in the service life time.Management and maintenance strategies are formulated on the base of the life-time calculation results.
引文
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[5]屈文俊,郭猛.混凝土截面角区双向碳化的计算模型与试验研究[J].工业建筑,2005,35(S1):687-690.
[6]MEIER S A,PETER M A,MUNTEAN A,et al.Dynamics of the internal reaction layer arising during carbonation of concrete[J].Chemical Engineering Science,2007,62(4):1125-1137.
[7]PAPADAKIS V G,FARDIS M N,VAYENAS C G.Effect of composition,environmental factors and cementlime mortar coating on concrete carbonation[J].Materials&Structures, 1992,25(5):293-304.
[8]牛荻涛,陈立亭,张成中.混凝土中气体扩散系数的计算模型[J].西安建筑科技大学学报(自然科学版),2007,39(6):741-745.
[2]张誉,蒋利学.基于碳化机理的混凝土碳化深度实用数学模型[J].工业建筑,1998,28(1):16-19.
[3]CEBFIB.Model Code 2010-Final Draft[S].Lausanne:International Federation for Structural Concrete(fib),2012.
[4]JAPAN SOCIETY OF CIVIL ENGINEERING.JSCE Guidelines for Concrete No.15:Standard Specifications for Concrete Structures-Design[S].Tokyo:Subcommittee on English Version of Standard Specifications for Concrete Structures,2007.
[5]屈文俊,郭猛.混凝土截面角区双向碳化的计算模型与试验研究[J].工业建筑,2005,35(S1):687-690.
[6]MEIER S A,PETER M A,MUNTEAN A,et al.Dynamics of the internal reaction layer arising during carbonation of concrete[J].Chemical Engineering Science,2007,62(4):1125-1137.
[7]PAPADAKIS V G,FARDIS M N,VAYENAS C G.Effect of composition,environmental factors and cementlime mortar coating on concrete carbonation[J].Materials&Structures, 1992,25(5):293-304.
[8]牛荻涛,陈立亭,张成中.混凝土中气体扩散系数的计算模型[J].西安建筑科技大学学报(自然科学版),2007,39(6):741-745.