Effect of temperature gradient on transient thermal creep of heated and stressed concrete in transient state tests

作     者：Fan, Kunjie Li, Dawang Li, Long-yuan Wu, Jiayu 

作者机构：Shenzhen Univ Guangdong Prov Key Lab Durabil Maine Civil Engn Shenzhen 518060 Peoples R China Univ Plymouth Sch Engn Plymouth PL4 8AA Devon England Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Inst Appl Mech Guangzhou 510632 Guangdong Peoples R China 

出 版 物：《CONSTRUCTION AND BUILDING MATERIALS》 (建筑与建筑材料)

年 卷 期：2019年第222卷

页      面：839-851页

核心收录：

学科分类：08[工学] 081304[工学-建筑技术科学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 0813[工学-建筑学] 0814[工学-土木工程] 

基　　金：China Scholarship Council University of Plymouth European Commission Research Executive Agency via a Marie Sklodowska-Curie Research and Innovation Staff Exchange project [689857-PRIGeoC-RISE-2015] 

主　　题：Concrete Thermo mechanical load Temperature gradient Transient thermal creep Load induced thermal strain Explicit model 

摘      要：The stress-strain constitutive relation of concrete subjected to thermomechanical loads is extremely complicated since its deformation relies on the sequences in which the heat and loads are applied. Existing experiments demonstrated that the development of quasi-instantaneous transient thermal creep, generally referred to as TTC, was dependent on the virgin heating of a mechanically pre-loaded concrete specimen. However, the mechanism behind it is still not fully understood. In this paper, a numerical method is developed to analyze the stress fluctuation and corresponding plastic strain caused by the combination of pre-load and temperature gradient. The results show that the TTC calculated using existing semi-implicit methods is reasonable only at early stage but could be wrong at high temperatures. The sharp increase of TTC beyond around 500 degrees C observed in many tests could be attributed to the implicit inclusion of the extra plastic strain resulted from temperature gradient. By excluding the extra plastic strain generated at different temperature levels, a more accurate formula for calculating TTC is proposed. (C) 2019 Elsevier Ltd. All rights reserved.