轴心受压粉煤灰混凝土构件徐变系数研究  

Creep Coefficient of Fly Ash Concrete Member Under Axial Compression

作　　者：曹健[1,2,3] 王元丰[1] 安小平[1] 巩健[1] 

机构地区：[1]北京交通大学土木建筑工程学院,北京100044 [2]南昌工程学院土木建筑工程学院,江西南昌330099 [3]交通运输部公路科学研究院,北京100088

出　　处：《中国公路学报》2015年第3期73-81,共9页China Journal of Highway and Transport

基　　金：交通运输部建设科技项目(2011 318 494 160)

摘　　要：为了研究粉煤灰混凝土构件在轴向压应力作用下的徐变效应,自制了试验加载装置,对不同质量分数(掺量)粉煤灰混凝土徐变开展了试验研究。根据徐变B3模型的特点,考虑粉煤灰掺量、水胶比等参数,利用试验结果修正了混凝土徐变B3模型。此外,针对中国现行桥梁设计规范中混凝土名义徐变系数未考虑粉煤灰参数影响的事实,在试验研究粉煤灰掺量对不同龄期混凝土抗压强度影响的基础上,结合各国已有徐变试验数据,对中国现行桥梁设计规范中混凝土名义徐变系数计算公式进行了修正。结果表明:当粉煤灰掺量分别为0,15%和30%,经养护至28d加载时,混凝土徐变随粉煤灰掺量的增大而减小;经修正后的规范徐变系数计算模型可提高粉煤灰混凝土徐变的预测精度。In order to study the creep effect of fly ash concrete member under axial compressive stress,a set of loading equipment was designed and applied to test the creep of fly ash concrete with different mass fractions（mixing amounts）.Based on the characteristics of B3 creep model,B3 creep model was modified by the test results with the parameters of the amount of fly ash and water-binder ratio etc considered.Furthermore,with the reference of current domestic and overseas creep test data,the calculation formula of the nominal creep coefficient of concrete was updated through the analysis of the contribution of the mixing amount of fly ash to the concrete compression strength at different ages,which had not been considered in the Code for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts of China.The results indicate that the creep of fly ash concrete decreases with the increase of mixing amount of fly ash（the amount is 0,15% and 30% respectively）until the fly ash concrete has been loaded at 28 th day since maintenance and the updated model improves the prediction accuracy of fly ash concrete creep.

关 键 词：桥梁工程 粉煤灰混凝土 修正B3模型 徐变系数 修正CEB-FIP 1990模型 

分 类 号：U448.33[建筑科学—桥梁与隧道工程]