TY - JOUR

T1 - Micro/meso-scale damage analysis of recycled aggregate concrete mixed with glazed hollow beads after high temperatures based on 2D CT images

AU - Miao, Yanchun

AU - Lei, Chuang

AU - Zhang, Yu

AU - Selyutina, Nina

AU - Smirnov, Ivan

AU - Ma, Gang

AU - Liu, Yuanzhen

AU - Lu, Zeyu

PY - 2023/2/1

Y1 - 2023/2/1

N2 - Fire occurrence may result in significant micro/meso-scale damage inside the concrete structure, including coarsening of pores and evolution of cracks. Such micro/meso-scale damage greatly impacts the load-bearing capacity and durability of the concrete structure. The lightweight, high-strength, internally porous, and highly thermally stable glazed hollow beads (GHB) may alleviate the cracking around the pores boundary and the mortar matrix due to their special pressure release effect, thus improving the fire resistance of concrete. In order to further investigate the reinforcing mechanism of GHB to the fire resistance of concrete, the CT scanning tests on recycled aggregate concrete mixed with glazed hollow beads (RATIC) before and after the high-temperature exposure were carried out in this paper. Firstly, the image segmentation method was used to obtain the extraction images of concrete pores and cracks. Then, the evolution trends of the porosity, average pore diameter, crack fraction, crack density, and average crack width were analyzed, and the correlation of these parameters with the residual compressive strength was discussed. Finally, a thermal damage model of RATIC considering the influence of micro/meso-scale damage and temperature was developed. The results showed that the recycled coarse aggregate (RCA) addition aggravates the evolution of the pores and cracks characteristics, while the GHB incorporation can alleviate this phenomenon to a certain extent and improve the high-temperature deterioration resistance of concrete. In addition, the proposed thermal damage model of RATIC has good applicability.

AB - Fire occurrence may result in significant micro/meso-scale damage inside the concrete structure, including coarsening of pores and evolution of cracks. Such micro/meso-scale damage greatly impacts the load-bearing capacity and durability of the concrete structure. The lightweight, high-strength, internally porous, and highly thermally stable glazed hollow beads (GHB) may alleviate the cracking around the pores boundary and the mortar matrix due to their special pressure release effect, thus improving the fire resistance of concrete. In order to further investigate the reinforcing mechanism of GHB to the fire resistance of concrete, the CT scanning tests on recycled aggregate concrete mixed with glazed hollow beads (RATIC) before and after the high-temperature exposure were carried out in this paper. Firstly, the image segmentation method was used to obtain the extraction images of concrete pores and cracks. Then, the evolution trends of the porosity, average pore diameter, crack fraction, crack density, and average crack width were analyzed, and the correlation of these parameters with the residual compressive strength was discussed. Finally, a thermal damage model of RATIC considering the influence of micro/meso-scale damage and temperature was developed. The results showed that the recycled coarse aggregate (RCA) addition aggravates the evolution of the pores and cracks characteristics, while the GHB incorporation can alleviate this phenomenon to a certain extent and improve the high-temperature deterioration resistance of concrete. In addition, the proposed thermal damage model of RATIC has good applicability.

KW - RATIC

KW - high temperature

KW - Micro/meso-scale damage

KW - Pores characteristics

KW - Cracks characteristics

KW - High temperature

UR - https://www.mendeley.com/catalogue/3e4d854d-ba29-3b5f-84e2-91e46a3a4e88/

U2 - 10.1016/j.conbuildmat.2022.130063

DO - 10.1016/j.conbuildmat.2022.130063

M3 - Article

VL - 365

JO - Construction and Building Materials

JF - Construction and Building Materials

SN - 0950-0618

M1 - 130063

ER -