Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/14382
標題: 非破壞檢測之波速量測法應用於火害混凝土波速與強度關係之探討
Application of the Stress-wave Methods to Evaluation of the Strength of Concrete After Fire Damage
作者: 劉建佑
Liu, Chien-Yu
關鍵字: Nondestructive Test
非破壞檢測
Stress-wave Methods
Fire-damaged
Rehydration
波速量測法
火害
再水化
出版社: 土木工程學系
摘要: 火災發生後在高溫的作用下,混凝土的強度會折減,將對混凝土結構物的安全產生相當大的影響。本論文主要目的為針對不同水灰比、溫度變化、高溫延時與火害後養護條件及材齡等變化參數,藉由非破壞檢測法之波速量測法,如超音波法、敲擊回音法頻譜領域、及時間領域等三種方法,建立火害混凝土抗壓強度與應力波速度之間的關係,探討利用應力波速度來評估火害混凝土抗壓強度之可行性。 根據試驗結果,受高溫500℃以下之混凝土強度折減較不明顯,而高溫作用後以水中養護條件之混凝土試體與空氣養護條件者比較,可發現其強度回復情況以受高溫600℃作用過後之混凝土有較佳之強度回復。利用前述三種波速量測法來量測火害後以不同養護條件養護之混凝土之應力波波速與殘餘抗壓強度間關係,可發現不同養護條件下之應力波波速與殘餘抗壓強度關係對應到不同曲線,此原因乃由於火害後混凝土受到再水化程度及孔隙與裂縫癒合的不同,造成應力波波速之回復較殘餘抗壓強度快。
The strength of concrete is reduced under the heat caused by a fire. The safety of a concrete construction will then be greatly influenced due to the fire damage. In this paper, the relationship between the residual strength of fire-damaged concrete and the residual speed of stress waves is set up, and the feasibility of evaluating residual strength of fire-damaged concrete with the residual speed of stress waves will also be discussed. In experiment, the wave speed in concrete is measured by the ultrasonic-echo method and the impact-echo method. The experimental specimens used in the studies have different parameters as follows: water to cement ratio (W/C), change of temperature, heat duration time as well as post-fire curing condition and ages. According to the result of experimental studies, the decrease in strength of concrete is not significant under heat temperature below 500 ℃. For concrete exposed to a high temperature of 600 ℃, the strength restoration of concrete cured in water is better than that of concrete in the air. In addition, the results show that the relation of the residual wave speed ratio and residual strength ratio varies with different curing conditions. The relationship between the residual wave speed ratio and residual strength ratio for each curing condition is well correlated. After establishing the relationship between the residual speed of stress waves and the residual strength of the fire-damaged concrete, the stress wave speed measurement can be used to evaluate the in-place strength of concrete after fire damage.
URI: http://hdl.handle.net/11455/14382
Appears in Collections:土木工程學系所

文件中的檔案:

取得全文請前往華藝線上圖書館



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.