摘要
为有效控制干湿循环作用下膨胀土的膨胀性,利用水泥钢渣粉掺合料改良膨胀土.通过室内试验,研究了纯膨胀土(Es)、水泥改良膨胀土(Es-C)、钢渣粉-水泥改良膨胀土(Es-SSP-C)和钢渣粉-水泥-NaOH改良膨胀土(Es-SSP-C-N)在不同养护龄期以及不同干湿循环次数下的无荷载膨胀率、体积质量变化率、无侧限抗压强度(UCS)等物理力学性质的变化规律,并结合扫描电镜(SEM)和能谱(EDS)分析,对改良土内部的微观结构和物质进行探讨.结果表明:3种改良土的无荷载膨胀率均减少95%以上,膨胀达到稳定的时间缩短,其中:Es-SSP-C-N对膨胀土膨胀性的控制效果最佳;经干湿循环作用后,改良土的体积变化率控制在1.6%以内,减小85%,质量变化率远低于未改良土,其中Es-SSP-C的体积、质量变化率最稳定;3种改良土的无侧限抗压强度均有明显提高,其中Es-SSP-C-N的强度最高,Es-SSP-C对多次干湿循环作用下强度劣化的抵抗效果最优;但钢渣粉自身水化周期较慢,约为60 d,掺加少量NaOH可以有效激发其水化活性.
In order to effectively control the swelling characteristics of expansive soil under dry-wet cycles,the cement-steel slag powder admixture was used to improve expansive soil.The samples of expansive soil(Es),cement improved expansive soil(Es-C),steel slag powder-cement improved expansive soil(Es-SSP-C)and steel slag powder-cement-NaOH improved expansive soil(Es-SSP-C-N)were prepared.The change rules of physical and mechanical properties such as no-load expansion rate,volume mass change rate and unconfined compressive strength(UCS)of the samples under different curing ages and different dry-wet cycles were tested.Combined with scanning electron microscope(SEM)and energy spectroscopy(EDS)analysis,the microstructure and material changes of the improved soil were discussed.The tests results showed that the no-load swelling rate of each improved soils were reduced by more than 95%,and the time for the swelling to reach stability was shortened,among which Es-SSP-C-N has the best control effect on the swelling of expansive soil.After dry-wet cycles,the volume change rate of each improved soils were controlled within 1.6%,which is reduced by 85%,and the mass change rate was much lower than that of the expansive soil,the volume and mass change rate of Es-SSP-C is the most stable.The unconfined compressive strength of each improved soils were significantly improved,among which Es-SSP-C-N had the highest strength,and Es-SSP-C had the best resistance to strength deterioration under repeated dry-wet cycles.The hydration cycle of steel slag powder itself was slow,about 60 days,and its hydration activity could be effectively stimulated by adding a small amount of NaOH.
作者
吴燕开
乔晓龙
李丹丹
韩天
苗盛瑶
曹玉鹏
WU Yankai;QIAO Xiaolong;LI Dandan;HAN Tian;MIAO Shengyao;CAO Yupeng(School of Civil Engineering and Architecture,Shandong University of Science and Technology,Qingdao,266590,China;China Railway Construction Engineering Group Shandong Co.,Ltd.,Qingdao,266061,China;School of Transportation,Shandong University of Science and Technology,Qingdao,266590,China)
出处
《西安建筑科技大学学报（自然科学版）》
北大核心
2021年第3期319-329,共11页
Journal of Xi'an University of Architecture & Technology(Natural Science Edition)
基金
国家自然科学基金资助项目(51608312)
山东科技大学科研创新团队基金支持项目(2015KYDT104)。
关键词
干湿循环
改良膨胀土
钢渣粉水泥
无荷载膨胀率
体积变化率
无侧限抗压强度
dry-wet cycle
improved expansive soil
steel slag powder-cement
no-load swelling rate
volume change rate
unconfined compressive strength
