钢筋混凝土文物建筑的病害检测技术应用——以浙江省宁波鼓楼为例

Application of disease detection technology of reinforced concrete historical buildings——Taking Ningbo Drum Tower for example

混凝土碳化是工程中常见的问题,结合宁波鼓楼工程实例,介绍碳化的无损检测方法,即选取用于混凝土的碳化深度检测的原位酚酞测试技术,混凝土表面回弹强度检测技术,以及用于检测钢筋锈蚀程度的电化学技术和X衍射仪混凝土成分分析技术。根据现场勘测和取样采集到的技术数据,宁波鼓楼的混凝土成分主要含CaCO_3、SiO_2等成分,与普通碳化混凝土成分相似,没有检测到氯离子等其他特殊成分。鼓楼瞭望台梁和板碳化严重,碳化深度已达钢筋位置,板内钢筋锈蚀概率大于90%。同时,混凝土表面回弹强度检测显示,其警钟台的柱和瞭望台梁底推定强度只有14 MPa左右。上述结果说明,本课题组选取的检测技术能够在一定程度上对钢筋混凝土文物建筑的病害进行定性的分析,但是需要补充其他微损的实验室分析技术参数进行量化分析。

In response to concrete carbonization,a common problem in engineering,the nondestructive testing methods of carbonization is introduced in this article.With Ningbo Drum Tower as an engineering example,it applies the on-site phenolphthalein test for carbonation depth of concrete,the concrete snapping back test,the electrochemical technique for steelcorrosion degree and the technique for concrete composition analysis by X-ray diffraction.Based on the technical data obtained by the on-site investigations and sampling,the main compositions in the concrete of Ningbo Drum Tower are CaCO_3 and SiO_2,which are similar to ordinary concrete,with no chloride ions detected.The beams and the slabs of the observatory are seriously carbonated,reaching deep to the steel level,with the steel corrosion probability of slabs more than 90%.Meanwhile,the concrete snapping back test indicates the deducted concrete strength of columns of the alarm clock stand and beam bottoms of the observatory is only around 14 MPa.The detection techniques applied by this study can partly provide qualitative diagnostic analysis for diseases of historic buildings of reinforced concrete structure.However,other small-invasive laboratory technical parameters should be complemented for quantitative analysis.