内养护剂和膨胀剂组合对混凝土收缩的影响
作者:
作者单位:

1.中冶建筑研究总院有限公司,北京 100088;2.北京科技大学 城镇化与城市安全研究院, 北京 100083;3.中国矿业大学(北京) 力学与建筑工程学院,北京 100083

作者简介:

韩宇栋(1986—),男,安徽安庆人,中冶建筑研究总院高级工程师,硕士生导师,博士. E-mail:hanyudong@cribc.com

通讯作者:

韩宇栋(1986—),男,安徽安庆人,中冶建筑研究总院高级工程师,硕士生导师,博士. E-mail:hanyudong@cribc.com

中图分类号:

TU528

基金项目:

国家自然科学基金资助项目(52178263);北京市科技新星计划(Z201100006820024)


Effect of Internal Curing Agent and Expansion Agent on Concrete Shrinkage
Author:
Affiliation:

1.Central Research Institute of Building and Construction, MCC Group Co., Ltd., Beijing 100088, China;2.Research Institute of Urbanization and City Safety, University of Science and Technology Beijing, Beijing 100083, China;3.School of Mechanics and Civil Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China

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    摘要:

    为在等抗压强度前提下调控混凝土的早期收缩开裂,以膨胀剂(HP-CSA)和由高吸水树脂(SAP)引入的内养护水占胶凝材料相同比例进行组合,设计了各自的内掺量均为0%、4.5%、6.0%、9.0%共4种混凝土配合比,研究了其对混凝土早期收缩的调控规律,并分析了混凝土收缩、力学强度、内部相对湿度和干燥失水率之间的关系.结果表明:混凝土早期收缩和内部相对湿度发展均呈2阶段规律;随“HP-CSA+SAP”组合掺量增加,其对混凝土早期收缩的调控作用逐渐增强,且在阶段I的调控作用更为显著,但28 d时仍不能根除混凝土的净干燥收缩;组合掺量对混凝土早期内部湿度发展的整体影响较小;混凝土28 d内的净干燥收缩与干燥失水率之间基本呈线性正相关.从调控收缩、强度保持和经济性等方面综合考虑,6.0%为最优调控组合掺量.

    Abstract:

    To control early-age shrinkage induced cracking for concrete with equivalent compressive strength, four concrete mixtures were prepared with co-addition of expansion agent (HP-CSA) and internal curing water introduced by superabsorbent polymer (SAP), both of them at the rate of 0%, 4.5%, 6.0% and 9.0% by mass to the dosage of total cementitious materials. The regulation effect of "HP-CSA+SAP" combination on early-age shrinkage of concrete was experimentally investigated. The relationships between shrinkage, mechanical strength, internal relative humidity and water loss rate during drying of concrete were analyzed. The test results show that the developments of early-age shrinkage and internal relative humidity of concrete both follow a two-stage rule. The more the dosage of "HP-CSA+SAP" combination, the better the controlling effect on early-age concrete shrinkage, especially in shrinkage developing stage I. However, as the net drying shrinkage of concrete could not be completely eliminated in 28 d, the influence of the combination dosage of "HP-CSA+ SAP" on the development of early-age internal humidity of concrete is relatively small. The net drying shrinkage of concrete is positively linearly correlated to the water loss rate within 28 d. Considering the performances in shrinkage reducing, strength retention and cost-effectiveness, 6.0% is considered to be the optimal dosage of "HP-CSA+SAP" combination.

    表 2 混凝土配合比Table 2 Mix proportions of concretes
    表 1 膨胀剂的矿物组成Table 1 Mineral composition of expansion agent
    图1 水泥和膨胀剂的粒度分布Fig.1 Particle size distributions of cement and expansion agent
    图2 混凝土自由变形及内部温湿度测量的仪器布置照片Fig.2 Instrument layout photo for measurement of free deformation and internal temperature and relative humidity of concretes
    图3 混凝土自由变形和内部温度随龄期的发展曲线Fig.3 Development curves of free deformation and internal temperature of concretes with age
    图4 混凝土收缩和内部相对湿度随龄期的发展曲线Fig.4 Development curves of shrinkage and interior RH of concretes with age
    图5 混凝土3~28 d的干燥失水率曲线Fig.5 Water loss rate curves of concretes during drying between 3 and 28 d
    图6 混凝土3~28 d内干燥收缩与干燥失水率的相关性Fig.6 Relationship between drying shrinkage of concretes and water loss rate during drying between 3 and 28 d
    图7 混凝土收缩和内部相对湿度2阶段发展模型Fig.7 Two-stage development models of shrinkage and interior RH of concretes
    图8 28 d混凝土收缩及内部相对湿度随“HP-CSA+SAP”调控组合掺量的变化曲线Fig.8 Variation curves of shrinkage and internal RH of concretes at 28 d with dosage of HP-CSA+SAP combination
    图9 不同养护条件下混凝土力学强度随龄期的发展Fig.9 Strength development of concretes under various curing conditions with age
    图10 混凝土1、28 d抗压强度与自收缩相关性分析Fig.10 Correlative analyses of compressive strength and autogenous shrinkage of concretes at 1, 28 d
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引用本文

韩宇栋,李威,岳清瑞,谢月,刘子祎.内养护剂和膨胀剂组合对混凝土收缩的影响[J].建筑材料学报,2023,26(6):604-611

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  • 收稿日期:2022-08-04
  • 最后修改日期:2022-09-27
  • 在线发布日期: 2023-07-06
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