不同冷卻再養護方式對混凝土承受高溫後殘餘強度及恢復狀況之影響

Abstract

混凝土承受高溫後會造成其抗壓強度很大的損失，進而影響結構物之安全。而高溫後混凝土若能給予適當的水分供給，會進行再水化作用使得部分強度恢復。 本研究擬就普通混凝土與高性能混凝土兩種材料，在加溫時承受不同目標溫度(200、400、600、800℃)、冷卻時以不同冷卻方式(自然冷卻、強制冷卻)、冷卻後再施予不同的再養護方式(空氣中養護、間歇性泡水養護、持續泡水養護)與不同再養護齡期(1、7、28、91天)下，對試體殘留強度之影響。探討不同冷卻再養護方式對混凝土承受高溫後殘餘強度及恢復狀況之影響。結果發現以間歇性泡水養護可得到最佳效果。

The compressive strength of concrete was lost significantly at high temperature, and might affect the safety of the structure. But partial recovery in strength may occur by appropriate re-curing. This study is aimed at the investigation of the strength recovery of Normal Strength Concrete and High Performance Concrete after suffering elevated temperature with different cooling method and re-curing method. This study is devoted to investigate the effects of re-curing method. The major experimental parameters include cooling method (natural cooling, forced cooling), re-curing method (air curing, intermittent water curing, sustained water curing), and curing time (1, 7, 28, 91 days). Result shows that intermittent water curing can get the best recovery strength.