비파괴 기법을 이용한 유동성 채움재의 초기경화특성 평가

Abstract

Controlled Low Strength Material (CLSM) has high fluidity and self-compaction characteristics. CLSM is mainly used for backfilling the excavatedroad. Early-age properties of CLSM should be characterized for fast restoration of the road. In this study, shear wave monitoring and Vicat needletest are performed to investigate the early-age properties of CLSM depending on the setting time. CLSM consists of CSA cement, fly ash, silt andsand, accelerator, and water. Five fly ashes with different chemical properties are used for CLSM samples. The penetration of CLSM along settingtime is obtained through the Vicat needle test. A pair of bender elements are placed in a mold for shear wave measurement, and the change in shearwaves with the setting time is monitored. The experimental results show that, regardless of the type of fly ash, the penetration depth decreases andthe shear wave velocity increases with the setting time. Depending on the type of fly ash, initial and final times and shear wave velocity change. After testing, the correlation between penetration and shear wave velocity is obtained with high coefficient of determination. The shear wavemeasurement technique using the bender element can be used to identify early-age properties.