摘要
随着混凝土轨枕在我国的广泛应用,混凝土的生产带来大量的能源消耗和碳排放。地聚物作为一种新型低碳材料,能在节能减碳的同时消耗矿渣和粉煤灰等固废。目前,针对地聚物应用于铁路轨枕的相关研究,如混合使用水泥与粉煤灰、矿渣的地聚物混凝土轨枕及其裂缝扩展特性的研究还比较有限。本文设计2种配合比的地聚物混凝土并制造成轨枕,使用数字图像相关(Digital Image Correlation)技术,在轨下截面的三点弯曲实验下分析2种配合比下轨枕挠度、裂缝扩展特性及裂缝宽度发展规律。研究结果表明,2种配合比地聚物混凝土轨枕的抗弯承载力均高于普通混凝土轨枕。相比于普通混凝土轨枕,地聚物混凝土轨枕在较低的静荷载作用下挠度较大,但随着荷载的增加轨枕挠度的增长速度较慢,刚度损失较小,弹性阶段延续的荷载区间更长,这种特征在配合比为Geo50的地聚物混凝土轨枕上更为显著。2种配合比的轨枕微裂纹萌生的荷载相近,分别为130 kN和120 kN。在较低荷载下2种轨枕裂缝扩展相差不大,在较高荷载下配合比为Geo100的地聚物轨枕的裂缝发展加快,裂缝宽度值和增长速度都大于Geo50。配合比为Geo100的地聚物混凝土轨枕主要表现为受弯正截面破坏,配合比为Geo50的地聚物混凝土轨枕主要表现为受剪斜拉破坏。掺入部分水泥代替矿渣和粉煤灰的地聚物能使所制成轨枕在较高的荷载下保持更高刚度和更缓慢的裂缝扩展速度,该方案有助于推动地聚物应用于混凝土轨枕,促进铁路双碳战略贯彻与实施。
The sleeper is an important part of track structure,among which concrete sleepers are the most widely used in China.The use of geopolymer concrete rather than conventional concrete can assist in saving energy and minimizing carbon emissions while using solid waste resources such as slag and fly ash.In the current research on the use of geopolymer in railway sleepers,the research on the geopolymer concrete sleepers mixed with cement,fly ash,and slag were still limited.Geopolymer concrete with two mixture were designed and manufactured into sleepers.Using Digital Image Correlation,the stiffness,crack and crack width extension regulation of the sleeper under the two mixes were analyzed under the three-point bending test of the rail seat section.The results show that among the two sleepers,the geopolymer concrete sleeper with the mix of Geo100 has higher stiffness under lower static load,but yields faster in the later stage.Geopolymer concrete sleepers with the mix of Geo50 have lower stiffness under low static load,but the stiffness loss of the sleeper is smaller with the increase of load.The microcracks appeared with similar loads of 120 kN and 130 kN respectively.Under the lower load,the crack extension of the two kinds of sleepers is not much different.Under the higher load,the crack development of the geopolymer concrete sleeper with the mix of Geo100 is accelerated,and the width and increasing rate are greater than those of Geo50.The geopolymer concrete sleepers with the mix of Geo100 are mainly damaged by bending,and those of Geo50 are mainly damaged by diagonal tension failure.In summary,the geopolymer concrete mixed with cement,slag and fly ash can make the sleeper maintain higher stiffness and slower crack extension speed under a higher load.
作者
韩宜康
王俊逸
张睿哲
井国庆
HAN Yikang;WANG Junyi;ZHANG Ruizhe;JING Guoqing(Nanjing Vocational Institute of Railway Technology,Nanjing 210031,China;School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2024年第1期116-124,共9页
Journal of Railway Science and Engineering
基金
国家自然科学基金资助项目(52027813)。
作者简介
通信作者:井国庆(1979-),男,河北廊坊人,教授,博士,从事轨道结构及轨道力学研究,E-mail:gqjing@bjtu.edu.cn。
