箱梁先张法施工技术和外观质量通病预防措施

Pretension Prefabrication Construction Technology of Box Girder and Appearance Quality Problem Prevention Measures

结合沙特麦加轻轨上部穿越公路的桥梁项目,对先张法预制技术进行详细介绍,另外针对箱梁的施工过程中箱梁表面容易产生气泡、色差、水波纹、蜂窝、裂纹等一系列质量通病,分析其原因与混凝土自身配合比及施工方式有关,通过从混凝土配合比、箱梁模板、脱模剂和混凝土浇筑振捣方式优化等入手,确保模板光滑,合理搭配骨料级配,选择优质外加剂和优质水泥,规范现场布料,从而有效避免气泡、裂纹产生,确保箱梁内实外美。

Combined with the bridge project of the upper part of the light rail crossing the highway in Mecca,Saudi Arabia,the pretension prefabrication technology is introduced in detail.In addition,aiming at a series of common quality problems such as bubbles,color difference,water ripple,honeycomb and cracks on the surface of the box girder during the construction of the box girder,it is analyzed that the causes of the common quality problems are related to the concrete mix proportion and construction method.Starting with the optimization of concrete mix proportion,box girder formwork,release agent and concrete pouring and vibration mode,we can ensure the smoothness of formwork,reasonably match the aggregate gradation,select high-quality admixture and high-quality cement,and standardize the on-site distribution,so as to effectively avoid bubbles and cracks and ensure the reality and beauty of box girder.