摘要
为保证混凝土在负温环境下的安全可靠,采用力学性能测试、超声波波速测试、扫描电子显微镜(SEM)、X射线衍射(XRD)结合Rietveld精修定量分析等方法,研究了恒负温(-10℃)养护条件下不同纳米SiO_(2)(NS)掺量对硫铝酸盐混凝土性能的影响。结果表明:硫铝酸盐混凝土强度随NS掺量的增加,先升高后降低,在2wt%NS掺量时强度达到最大;当养护温度从负温变为常温时,超声波波速先降低后升高,掺入NS后再次水化(升高段)的超声波波速上升速率均高于空白组,其中2wt%NS掺量的混凝土超声波波速上升速率最快;SEM和XRD发现随NS掺量增加,混凝土内部孔隙结构变得更加致密,钙矾石(AFt)相对含量逐渐上升,其中2wt%NS掺量AFt含量最高,说明NS可以促进负温环境下的硫铝酸盐混凝土的水化。
To ensure the safety and reliability of concrete in a negative temperature environment,mechanical property testing,ultrasonic wave velocity testing,scanning electron microscopy(SEM),and X-ray diffraction(XRD)combined with Rietveld refinement quantitative analysis and other methods were used to study the properties of sulfoaluminate concrete modified with different nanosized SiO_(2)(NS)admixtures under constant negative temperature(−10℃)curing conditions.The results show that the strength of sulfoaluminate concrete increases and then decreases with the increase of NS dosage and reaches the maximum strength at 2wt%NS dosage;When the curing temperature changes from negative temperature to room temperature,the ultrasonic wave velocity first decreases and then increases,and the ultrasonic wave velocity increase rate of rehydration(elevated section)after mixing NS is higher than that of the blank group,in which the ultrasonic wave velocity increase rate of the concrete with 2wt%NS admixture is the fastest;SEM and XRD found that with the increase of NS dosage,the internal pore structure of concrete becomes denser,and the relative content of calcium alumina(AFt)rises gradually,the 2wt%NS admixture AFt content is the highest,indicating that NS can promote the hydration of sulfoaluminate concrete under negative temperature environment.
作者
李恒
王正君
杜英欣
LI Heng;WANG Zhengjun;DU Yingxin(College of Water Resources and Electric Power,Heilongjiang University,Harbin 150080,China;Key Laboratory of Cold Region Hydraulic Engineering,Heilongjiang University,Harbin 150080,China;Heilongjiang Heidai Water Conservancy Engineering Quality Inspection Co.,Ltd.,Harbin 150040,China)
出处
《复合材料学报》
北大核心
2025年第3期1555-1565,共11页
Acta Materiae Compositae Sinica
基金
黑龙江省重点研发计划指导类科研项目(GZ20220138)
黑龙江省生态环境厅科研项目(HST2022GF004)。
