早期养护方式对超高性能混凝土性能的影响  

Influence of Early Curing Methods on Properties of Ultrahigh-performance Concrete

作　　者：蒋睿 JIANG Rui(Institute of Railway Construction,China Academy of Railway Sciences Co.,Ltd.Beijing 100081,China;State Key Laboratory of High Speed Railway Track Technology,Beijing 100081,China)

机构地区：[1]中国铁道科学研究院集团有限公司铁道建筑研究所,北京100081 [2]高速铁路轨道技术国家重点实验室,北京100081

出　　处：《硅酸盐学报》2020年第10期1659-1668,共10页Journal of The Chinese Ceramic Society

基　　金：国家重点研发计划(2018YFC0705400);国家自然科学基金重点项目(U1934206);中国铁道科学研究院青年基金(2019YJ052)。

摘　　要：研究了20、40、60、90℃湿热以及自热保温5种早期养护方式对超高性能混凝土(UHPC)力学性能与微结构的影响。结果表明:UHPC的早期抗压强度与养护温度正相关,但这种差异随龄期的延长而缩小,早期采用自热保温或90℃养护,所得到UHPC的28 d抗压强度差异不足4%,且两者的抗拉强度均较高。各配比净浆样品的放热速率峰值随着环境温度的提高而增大且出现时间提前,累积放热量在较短时间内达到稳定;4 d时自热保温养护UHPC基体中Ca(OH)2衍射峰强度已较20℃养护方式明显降低,掺合料已较好地参与反应;自热保温养护方式下UHPC水化产物中C–S–H凝胶的Si–O链平均链长与90℃养护试件相当,且基体密实度极高。The effect of curing methods on the mechanical and microscopic properties of ultrahigh-performance concrete(UHPC) was investigated at different curing temperatures(i.e., 20, 40, 60, and 90 ℃) and with thermal insulation. The results show that the compressive strength of UHPC is positively correlated to the early curing temperature, but the difference decreases with the age. The 28 d compressive strength difference of UHPC is less than 4%, and the tensile strength is high after curing with thermal insulation or at 90 ℃ in early stage. The peak value of heat flow of each samples increases with the increase of the ambient temperature and occurs in advance, and the cumulative heat release becomes stable in a shorter time. At 4 d, the intensity of Ca(OH)2 diffraction peak in UHPC matrix after curing with thermal insulation is reduced, compared to that after curing at 20 ℃, indicating that the admixture is well involved in the hydration. The mean chain length of Si–O chain in the C–S–H gel for UHPC after curing with thermal insulation in early age is similar to that for the samples after curing at 90 ℃, and the matrix density is extremely high.

关 键 词：超高性能混凝土 早期养护 自热保温 力学性能 微结构 

分 类 号：TU528[建筑科学—建筑技术科学]