顶棚抹灰脱落处理（Treatment of ceiling plastering）.docVIP

顶棚抹灰脱落处理（Treatment of ceiling plastering） 1 project overview A 6 storey commercial building, concrete frame integral floor (roof) cover structure. The structure of C25 concrete, forming multi-layer laminated wood template, waste oil emulsion release agent. Second, three for the laundry, clean vegetable business buildings, structural elements in a humid atmosphere. To prevent dew condensation harm, concrete slab roof surface layer of thick 20mm 1:3 cement mortar plastering, two white paint. 42.5R ordinary portland cement mortar with cement and the local quality of river sand (sand). Plastering construction time in mid March, and then the terrazzo floor surface construction. At the time of the accident has been completed two to four terrazzo tiling, but not for the door window frame installation. 2 accident phenomenon The ceiling plastering layer in the construction within 1 weeks after the common cracking, irregular crack width ranging from 0.2 ~ 0.6mm, the crack spacing is about 40 ~ 60cm, and there is a long crack. Less than 1 months after the construction, there is a large area of hollowing, shedding. Detachment with a small hammer tap, plastering layer can fall off. The abscission zone edge with the finger can be stripped at the grassroots level. Off the cement mortar layer and the structure with the surface smooth, no other abnormal. The floor height is 4m, plastering massive exfoliation fortunately injuring personnel. 3 Analysis of the cause of the accident 3.1 eliminate factors Before plastering, convex and concave surface of the cast-in-place concrete ceiling has filled or chisel to avoid shrinkage cracking caused by local plastering too thick. Through the observation and analysis of cracks in the wall and there were no transfer of concrete slab, main structure parts, cracks appear only in plaster layer, and no certain rules, therefore, can eliminate cracking caused by ground subsidence, structural deformation, deflection, dislocation etc.. The mixture ratio