TY - JOUR
T1 - Comparative study on engineering properties of cement-based backfill material for sustainable urban area
AU - Han, Woo Jin
AU - Lee, Jong Sub
AU - Seo, Mi Jeong
AU - Kim, Sang Yeob
N1 - Funding Information:
This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. NRF-2021R1A5A1032433; NRF-2021R1C1C2008932).
Publisher Copyright:
© 2022 Elsevier Ltd
PY - 2022/9/12
Y1 - 2022/9/12
N2 - Backfill materials used in urban areas should have suitable mechanical properties (e.g., strength and flowability) for safety and serviceability of constructed geo-infrastructures. The objective of this study was to estimate the relative permittivity and compressional-wave velocity to correlate them with the unconfined compressive strength of a controlled low-strength material (CLSM) for backfill. CLSMs with fines content (FC) of 30 %, 50 %, and 90 % were prepared in sensing molds instrumented by a time domain reflectometry probe and piezo disk element. The test results show that the relative permittivity decreases with respect to the curing time, whereas the compressional-wave velocity and unconfined compressive strength increase. In addition, the relative permittivity increases as the FC increases owing to the water content, while the compressional-wave velocity and unconfined compressive strength decrease owing to the FC effect on the force chain. In this context, the FC might disturb the load-carrying matrix, and it results in remaining water and delays the curing time within 672 h. From the correlations, the relationship between the unconfined compressive strength and compressional-wave velocity with respect to the relative permittivity can be reliably constructed at an R2 of 0.83. For this reason, it is considered that the water content from the relative permittivity can improve the relationship between strength and stiffness. Consequently, the time domain reflectometry probe can be effectively used for reliable assessment of CLSM strength during curing.
AB - Backfill materials used in urban areas should have suitable mechanical properties (e.g., strength and flowability) for safety and serviceability of constructed geo-infrastructures. The objective of this study was to estimate the relative permittivity and compressional-wave velocity to correlate them with the unconfined compressive strength of a controlled low-strength material (CLSM) for backfill. CLSMs with fines content (FC) of 30 %, 50 %, and 90 % were prepared in sensing molds instrumented by a time domain reflectometry probe and piezo disk element. The test results show that the relative permittivity decreases with respect to the curing time, whereas the compressional-wave velocity and unconfined compressive strength increase. In addition, the relative permittivity increases as the FC increases owing to the water content, while the compressional-wave velocity and unconfined compressive strength decrease owing to the FC effect on the force chain. In this context, the FC might disturb the load-carrying matrix, and it results in remaining water and delays the curing time within 672 h. From the correlations, the relationship between the unconfined compressive strength and compressional-wave velocity with respect to the relative permittivity can be reliably constructed at an R2 of 0.83. For this reason, it is considered that the water content from the relative permittivity can improve the relationship between strength and stiffness. Consequently, the time domain reflectometry probe can be effectively used for reliable assessment of CLSM strength during curing.
KW - Compressional-wave velocity
KW - Controlled low-strength material
KW - Fines content
KW - Relative permittivity
KW - Unconfined compressive strength
UR - http://www.scopus.com/inward/record.url?scp=85134773151&partnerID=8YFLogxK
U2 - 10.1016/j.conbuildmat.2022.128511
DO - 10.1016/j.conbuildmat.2022.128511
M3 - Article
AN - SCOPUS:85134773151
SN - 0950-0618
VL - 347
JO - Construction and Building Materials
JF - Construction and Building Materials
M1 - 128511
ER -