轨道交通预制U型梁混凝土配合比优化研究及其微观结构分析
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摘要
轨道交通预制U型梁施工对混凝土早期力学性能、耐久性及抗裂性要求严格。通过改变混凝土胶凝材料用量,调整矿物掺料种类及掺量,掺入聚丙烯纤维等方式对混凝土进行配比优化研究,并利用扫描电镜对其微观结构进行观察分析。结果表明:预制U型梁混凝土应采用矿粉、粉煤灰双掺,胶凝材料总量控制在490 kg/m3左右,早期强度及弹性模量满足生产需求,且耐久性良好;聚丙烯纤维的掺入可以在混凝土内形成三维的乱向结构体系,显著提高混凝土的抗裂性。配比优化后混凝土水泥石微观结构致密,水泥石与骨料结合紧密。
The early mechanical properties,durability and cracking resistance of precast U-beam in rail transit were strictly required. How to optimize concrete composition was studied by experiments on the concrete with changing the dosage of concrete cementitious material, adjusting the types and content of mineral admixtures, addding polypropylene fiber. The microstructure of concrete was also analyzed by SEM. The results showed that the early strength,elastic modulus and durability of concrete mixed with mineral powder and fly ash could meet the construction requirements,the appropriate dosage of cementitious material was 490 kg/m3. The polypropylene fiber could be formed into three-dimensional network support system with disordered fiber distribution in the concrete,the crack resistance was improved. The microstructure of optimized cement paste was very dense and the hardened paste was closely bonded with aggregates.
The early mechanical properties,durability and cracking resistance of precast U-beam in rail transit were strictly required. How to optimize concrete composition was studied by experiments on the concrete with changing the dosage of concrete cementitious material, adjusting the types and content of mineral admixtures, addding polypropylene fiber. The microstructure of concrete was also analyzed by SEM. The results showed that the early strength,elastic modulus and durability of concrete mixed with mineral powder and fly ash could meet the construction requirements,the appropriate dosage of cementitious material was 490 kg/m3. The polypropylene fiber could be formed into three-dimensional network support system with disordered fiber distribution in the concrete,the crack resistance was improved. The microstructure of optimized cement paste was very dense and the hardened paste was closely bonded with aggregates.
引文
[1]张立青.先张法预应力混凝土U型梁预制场工艺设计[J].铁道建筑技术,2014(1):19-22.
[2]罗文俊,程龙.城市轨道交通单线U型梁振动与噪声分析[J].铁道工程学报,2017(5):89-93.
[3]董靖.浅谈U型梁在地铁轨道交通工程中的应用[J].建材发展导向,2013(12):57-61.
[4]贺恩怀.槽形梁在城市轨道交通工程中的应用形式[J].城市轨道交通研究,2003(3):68-70.
[5] DUTOIT D,MONTENS S,CHUNIAUD J C,et al. U Shape Prestressed Concrete Decks for LRT/MRT Viaducts[M]. Beijing:China Communications Press,2004:66-67.
[6]张冰.梁上运架梁技术在大跨度薄壁U形梁架设中的应用[J].施工技术,2012,41(5):41-44.
[7]黎庆.南京地铁2号线东延高架线路U型梁结构计算及试验[J].城市轨道交通研究,2009(8):8-14.
[8]刘博.轨道交通U型梁承载能力静载试验及评定分析[J].山西建筑,2017,43(4):190-191.
[9]张立青.先张法预应力混凝土U型梁预制场工艺设计[J].铁道建筑技术,2014(1):19-22.
[10]吴佳,杜红秀,吴均衡,等.桥梁用高性能混凝土早龄期施工控制参数研究[J].混凝土,2016(6):155-157.
[11]高少彬.利用矿物掺合料抑制桥梁混凝土徐变的研究与应用[D].秦皇岛:燕山大学,2017.
[12]李杰.大掺量粉煤灰混凝土弹性模量试验研究[D].杨凌:西北农林科技大学,2010.
[13]龙武剑,周波,梁沛坚,等.颗粒堆积模型在混凝土中的应用[J].深圳大学学报(理工版),2017,34(1):63-74.
[14]李丙明,李兆锋,魏莹,等.钢渣-矿渣-粉煤灰复合微粉的活性试验研究[J].硅酸盐通报,2009,28(3):589-593.
[15]陈瑜,张起森.水泥混凝土早期抗裂性能的研究现状[J].建筑材料学报,2004,7(4):411-4147.
[16]刘凤茹,张海文,何唯平.聚丙烯腈纤维对铁路桥混凝土结构的高性能作用研究[J].铁道建筑技术,2005(5):59-61.
[2]罗文俊,程龙.城市轨道交通单线U型梁振动与噪声分析[J].铁道工程学报,2017(5):89-93.
[3]董靖.浅谈U型梁在地铁轨道交通工程中的应用[J].建材发展导向,2013(12):57-61.
[4]贺恩怀.槽形梁在城市轨道交通工程中的应用形式[J].城市轨道交通研究,2003(3):68-70.
[5] DUTOIT D,MONTENS S,CHUNIAUD J C,et al. U Shape Prestressed Concrete Decks for LRT/MRT Viaducts[M]. Beijing:China Communications Press,2004:66-67.
[6]张冰.梁上运架梁技术在大跨度薄壁U形梁架设中的应用[J].施工技术,2012,41(5):41-44.
[7]黎庆.南京地铁2号线东延高架线路U型梁结构计算及试验[J].城市轨道交通研究,2009(8):8-14.
[8]刘博.轨道交通U型梁承载能力静载试验及评定分析[J].山西建筑,2017,43(4):190-191.
[9]张立青.先张法预应力混凝土U型梁预制场工艺设计[J].铁道建筑技术,2014(1):19-22.
[10]吴佳,杜红秀,吴均衡,等.桥梁用高性能混凝土早龄期施工控制参数研究[J].混凝土,2016(6):155-157.
[11]高少彬.利用矿物掺合料抑制桥梁混凝土徐变的研究与应用[D].秦皇岛:燕山大学,2017.
[12]李杰.大掺量粉煤灰混凝土弹性模量试验研究[D].杨凌:西北农林科技大学,2010.
[13]龙武剑,周波,梁沛坚,等.颗粒堆积模型在混凝土中的应用[J].深圳大学学报(理工版),2017,34(1):63-74.
[14]李丙明,李兆锋,魏莹,等.钢渣-矿渣-粉煤灰复合微粉的活性试验研究[J].硅酸盐通报,2009,28(3):589-593.
[15]陈瑜,张起森.水泥混凝土早期抗裂性能的研究现状[J].建筑材料学报,2004,7(4):411-4147.
[16]刘凤茹,张海文,何唯平.聚丙烯腈纤维对铁路桥混凝土结构的高性能作用研究[J].铁道建筑技术,2005(5):59-61.