弯拉荷载作用下UHTCC抗碳化性能研究

Anti-Carbonization Performance of UHTCC under Flexural Loading

为探究超高韧性水泥基复合材料(Ultra High Tough-ness Cementitious Composites,简称UHTCC)受弯拉荷载作用下的抗碳化性能,通过快速碳化试验研究了UHTCC试件在不同碳化龄期下、不同水灰比条件(0.26、0.30)下、不同荷载率(30%和60%)下及不同弯矩位置的抗碳化性能。试验结果表明,随着碳化龄期的增长试件碳化深度逐渐增大;水灰比越大UHTCC的抗碳化性能越弱,水灰比为0.26、0.30的试件在30%荷载率下碳化28 d的深度分别为3.95 mm、7.43 mm。弯拉荷载加速了UHTCC试件的碳化进程,碳化深度随着荷载率的增大而增大,当荷载率由0增加至30%时的碳化深度增值小于荷载率由30%增加至60%时的碳化深度增值。碳化对受弯构件各弯矩位置产生不同的影响,碳化深度随着弯矩的增大呈对数形式不断增大。

In order to explore the anti-carbonization performance of the ultrahigh toughness cementitious composites(UHTCC)under flexural loading.Based on the accelerated carbonization testing,the effects of carbonization time,w/c(0.26 and 0.30),flexural loading rate(30%and 60%)and bending moment on carbonation resistance of UHTCC were studied.The results show that with the carbonation age increases,the carbonation depth of UHTCC increases gradually.The greater is the w/c ratio,the weaker is the carbonation resistance of UHTCC.The carbonation depth of the specimen with 0.26 and 0.30 w/c is 3.95 mm and 7.43 mm at 30%loading rate.The flexural loading accelerated the carbonization rate of UHTCC,and the carbonation depth increases with the increase of loading rate.The increased value of carbonation depth during the loading rate increases from 0 to 30%is less than that during the loading rate increases from 30%to 60%.Carbonation has a different effect on different positions of flexural specimen.Carbonation depth increases logarithmically as bending moment increases.