1995 Fiscal Year Final Research Report Summary
Study on exfoliation of finish mortal of external wall
Grant-in-Aid for General Scientific Research (C)
KUNIMOTO Kume Kagoshima University Fac.of Engineering, Architecture, Associate prof., 工学部, 助教授 (00041525)
ARIMA Fuyuki Kagoshima University Fac.of Engineering, Architecture, Research Assoc., 工学部, 助手 (60232071)
MITANI Isao Kagoshima University Fac.of Engineering, Architecture, Prof., 工学部, 教授 (70037935)
|Project Period (FY)
1994 – 1995
|exfoliation of finish mortar / elastic plate theory / thermal stress / shear adhesion strength / thermography / diagnosis for exfoliation / the thicker finish mortar / seasonal condition and orientation
Part I Analytical study on external wall with exfoliating finish mortal including effect fo thermal stress
High temperature gradients due to solar radiation cause thermal stress on the exposed surfaces of structure. On the external wall with exfoliating finish mortar plate and concrete wall, the capability of the buckling of the plate and the propagation of the exfoliation of the plate due to the thermal stress were investigated by using a simple elastic analysis. Based of the Analytical results, the main conclusions are ;
1) High temperature gradients between the exfoliating mortar plate and the concrete wall possibly cause the plte to buckle. Higher gradients in excess of those enough to buckle the plate cause wider gap between them.
2) A theoretical formula for the relation between t and the ratio L/h was proposed, where t=difference in temperature between mortar plate and concrete wall, L=length of shorter side of rectangular plate and h=plate thickness.
3) The existence of the exfolia
tion of the plate capably causes the nominal stress, which is generating the wider exfoliation, to propagate.
Part II Experimental study on the efficiency of thermographic diagnosis method for external R/C walls
The efficiency of thermographic diagnosis for external R/C walls with the thicker finish mortar depth was investigated. Each test specimen, which is a part of wall, has the artificial defect in the center of wall surface. The test parameters are wall depth of finish mortar (40,50and60mm), the thickness of defects (1and2mm), seasonal condition (summer, fall and winter)and the direction of outer wall (east, west and south).Based on the experimental results, the main conclusions are ;
1) The wall depth limit for thermographic diagnosis on walls with thicker depth is 60 mm.
2) The diagnosis in fall season is the most effective due to sun's altitude and flux of solar radiatio.
3) In case of summer-season diagnosis, the temperature rise more then 5ﾟC in duration of sunshine is required for the diagnosis. Less
Research Products (4 results)