锈蚀钢筋与混凝土粘结应力模型研究

研究了混凝土保护层胀裂时及胀裂前锈蚀对无横向约束光圆钢筋混凝土试件粘结性能的影响机理。应用弹性力学理论,建立了锈胀力计算模型,推导出了保护层胀裂时刻钢筋锈蚀深度的计算表达式;结合已有研究成果,建立了钢筋表面摩擦系数计算公式;在综合考虑锈胀力作用及钢筋表面状况变化对粘结强度影响的基础上,提出了光圆钢筋粘结应力计算模型,并通过多个试验结果对理论模型进行了验证,结果表明计算值与试验值吻合良好,从而定量阐明了保护层锈胀裂前光圆钢筋粘结应力随锈胀力增长及钢筋表面摩擦系数增大而增长的内在机理。

Bond strength modeling for corroded reinforcing bar in concrete

The effect of corrosion on the bond between concrete and plain bar reinforcement without stirrups is studied during cover cracking and before cover cracking.A new analytical model of splitting stresses is formulated based on mechanics of elasticity.Then the critical attack penetration depth of reinforcing bar at the time of cover cracking was calculated.Based on the existing research fruits,an explicit function expression for the friction factor between steel bar and concrete was provided.With the effects of deterioration of bar surface and increase of splitting stresses on bond strength taken into consideration,a model was proposed to calculate the bond strength during cover cracking and before cover cracking.The theoretical results were compared with experimental results,showing good agreement.The mechanism of increase in bond strength was analyzed quantitatively from the increase of both friction factor and splitting stresses.