|
Title |
Evaluation for Mechanical Properties of High Strength Concrete at High Temperature by Stressed Test and Unstressed Test
|
|
Authors |
김규용 ; 김영선 ; 이태규 ; 박찬규 ; 이승훈 |
|
Keywords |
고온에서 고강도콘크리트의 특성 ; 설계하중 사전재하시험 ; 설계하중 사전재하 잔존강도시험 ; 열전달방식 ; 열팽창 변형 properties of high strength concrete at high temperature ; stressed test ; stressed residual test ; heat transfer method ; thermal strain |
|
Abstract |
Recently, the effects of high temperature on compressive strength, elastic modulus and strain at peak stress of high strength concrete were experimentally investigated. The present study is aimed to study the effect of elevated temperatures ranging from 20 to 700 on the material mechanical properties of high strength concrete of 40, 60, 80 MPa grade. In this study, the types of test were the stressed test and stressed residual test that the specimens are subjected to a 25% of ultimate compressive strength at room temperature and sustained during heating and when target temperature is reached, the specimens are loaded to failure. And another specimens are loaded to failure after 24 hour cooling time. Tests were conducted at various temperatures (20~700oC) for concretes made with W/B ratios 46%, 32% and 25%. Test results showed that the relative values of compressive strength and elastic modulus decreased with increasing compressive strength grade of specimen and the axial strain at peak stress were influenced by the load before heating. Thermal strain of concrete at high temperature was affected by the preload level as well as the compressive strength. Finally, model equation for compressive strength and elastic modulus of heated high strength concrete proposed by result of this study.
|