火害對高溫高壓蒸氣養護的TAICON握裹力影響之研究

Abstract

本研究之主要目的在探討經過高溫高壓蒸汽養護的TAICON和一般標準養護之TAICON在各種火害溫度作用後，對於握裹強度的影響，以期能夠對蒸氣養護有更通盤的了解。 經本研究結果顯示，高溫高壓蒸氣養護的方式，對於鋼筋混凝土的握裹強度、混凝土的抗壓強度與劈裂強度都有顯著的提昇；而火害後，所有試體的抗壓強度及握裹強度均隨火害溫度的增加而遞減。但經高溫高壓蒸氣養護後，其抗壓強度與握裹強度在火害溫度750℃以下時，強度折損較一般標準養護為小。 經由SEM觀察混凝土的微觀，並未發現因鋼筋與混凝土受熱膨脹所引起的裂縫，經高溫高壓蒸氣養護後，與鋼筋接觸面的混凝土其結構亦明顯比一般標準養護組緻密。 當火害溫度越高時，微觀結構則呈現較多的孔隙，且水化產物也因火害而分解導致強度的降低。

The major aim of this study is to explore the different effects that fire-damage has on the bond strength of TAICON treated with high temperature and high pressure steam and normally treated TAICON, in the hope that it will bring a deeper understanding of steam treatment. The results of this study show that high temperature and high pressure treatment clearly increases the bond strength between rebars and cement, and the pressure strength and cleavage strength of cement. After fire damage, the pressure strength and bond strength of all specimen is reduced as the heat of the fire is increased. After high temperature and high pressure treatment, however, the decrease in pressure and bond strength below 750□ C is lower than for normal treatment. SEM test micro observations do not reveal cracks due to rebar or cement thermal expansion. After high temperature and high pressure treatment, the structure of the cement at the interface between cement and rebar is clearly finer than normally treated specimen. The higher the temperature of the fire, the more the crevices that appear in the microscopic structure. Hydrated products also dissolve as a result of fire damage, leading to a fall in strength.