水泥对铁路桥墩混凝土力学与抗裂性能的影响  

Effect of Cement on the Mechanical and Crack Resistance of Railway Bridge Pier Concrete

作　　者：李书明 邓青山 谢永江 刘竞 张驰 郁培云 LI Shuming;DENG Qingshan;XIE Yongjiang;LIU Jing;ZHANG Chi;YU Peiyun(China Academy of Railway Sciences Corporation Limited,Beijing 100081,China)

机构地区：[1]中国铁道科学研究院集团有限公司,北京100081

出　　处：《铁道工程学报》2024年第7期106-112,共7页Journal of Railway Engineering Society

基　　金：中国铁道科学研究院集团有限公司基金(2021YJ015)。

摘　　要：研究目的:硅酸盐水泥是配制铁路混凝土的主要胶凝材料。为研究不同类型水泥的性能,从水泥角度提升高原铁路桥墩混凝土抗裂性能,系统对比抗裂水泥和普硅水泥在工作性能、水化性能、力学性能、干燥收缩性能和抗裂性能方面的差异,并在实体桥墩中进行对比试验,通过桥墩混凝土内部温度和应变变化规律研究,综合评价水泥对高原桥墩混凝土抗裂性的影响。研究结论:(1)与普硅水泥相比,抗裂水泥的需水量较低,早期水化速率放缓和水化放热量降低,早期水化活性降低,早期强度略有降低,但是后期强度发展稳定并超过了普硅水泥,相同龄期抗裂水泥折压比明显高于普硅水泥,表现出较好的韧性;(2)采用抗裂水泥配制的混凝土的干燥收缩率明显低于普硅水泥,混凝土抗裂性显著提升;(3)在桥墩混凝土中应用抗裂水泥能够降低桥墩混凝土芯部温度,芯部温峰可降低5.0℃,芯部混凝土应变和表层混凝土应变均大幅降低,芯部应变可降低50%,表层混凝土应变可降低40%,从而提升了高原桥墩混凝土的抗裂性;(4)抗裂水泥的应用可作为提高铁路桥墩混凝土抗裂性的有效手段。Research purposes:Portland cement was the main cementitious material for railway concrete.In order to study the performance of anti-cracking cement and improve the anti-cracking performance of plateau railway bridge pier concrete from the perspective of cement,the differences between anti-cracking cement and general silica cement in working performance,hydration performance,mechanical properties,drying shrinkage properties and anti-cracking properties were systematically compared,and a comparative test was carried out in the solid pier.Through the study of the internal temperature and strain change law of pier concrete,the effect of cement on crack resistance of the plateau bridge pier concrete is evaluated comprehensively.Research conclusions:(1)Compared with general silica cement,the water requirement of crack resistant cement is lower,the hydration rate slows down and the hydration heat decreases in the early stage,the hydration activity decreases in the early stage,and the strength decreases slightly in the early stage,but the strength develops stably and exceeds that of general silica cement in the late stage.The bending ratio of crack resistant cement at the same age is obviously higher than that of general silica cement,showing better toughness.(2)The dry shrinkage rate of concrete prepared with anti-cracking cement is significantly lower than that of general silicon cement,and the anti-cracking property of concrete is significantly improved.(3)The application of crack resistant cement in pier concrete can reduce the core temperature of pier concrete,the temperature peak of core can be reduced by 5.0℃,and the strain of core concrete and surface concrete can be significantly reduced,the strain of core can be reduced by 50%,and the strain of surface concrete can be reduced by 40%,thus improving the crack resistance of plateau pier concrete.(4)The application of crack resistant cement can be used as an effective means to improve the crack resistance of railway bridge pier concrete.

关 键 词：抗裂水泥 墩身混凝土 温度 应变 抗裂性能 

分 类 号：TU528[建筑科学—建筑技术科学]