住宅剪力墙混凝土表面点状爆裂的原因分析

ANALYSIS ON CAUSE OF PUNCTUATE BURSTS ON CONCRETE SURFACE OF RESIDENTIAL BUILDING SHEAR WALLS

针对某住宅部分剪力墙混凝土出现点状爆裂现象,采用XRF、XRD、DSC-TG,SEM和EDS等方法分析爆裂中心物质,并与未爆裂部位的硬化水泥浆体进行对比,对爆裂构件进行了钻芯法强度试验和沸煮试验,结果表明胶凝材料f-CaO超限造成点状爆裂的可能性极小;点状爆裂的原因为混凝土中混入过烧生石灰,过烧石灰表层破坏后剪力墙浅部CaO与水作用生成Ca(OH)_(2),同时体积膨胀;发生爆裂构件后期存在继续产生体积稳定性不良的可能。

Punctuate bursts happened on concrete surface of a residential building shear walls,and the core materials were analyzed by XRD,DSC-TG,SEM and EDS and compared with hardened cement paste(HCP)at the site without bursting,and the core drilling strength test and boiling test were carried out for the burst components.The results show the possibility of punctuate burst caused by f-CaO overrun is very small,the reason of the punctuate burst is that concrete is mixed with over-burnt quicklime,after surface of over-burnt quicklime is destroyed,CaO in the shallow part of the shear wall reacts with water to form Ca(OH)_(2),and the volume expands at the same time;and it is possible that the volume stability of the cracked component will be poor in the later stage.