Applying MICP technology to improve the flexural strength of reinforced LWAC beams after high-temperature damage

Chao-Wei Tang, Chung-Hao Wu, Shu-Ken Lin, How-Ji Chen and Bing-You Wu

Abstract

High temperatures can reduce the flexural strength of reinforced concrete beams. This study uses microbially induced calcium carbonate precipitation (MICP) technology to enhance the flexural strength of thermally damaged lightweight aggregate concrete (LWAC) beams. Two experimental groups (A and B) were prepared with lightweight aggregates (LWAs) that were immersed in nutrient and bacterial solutions, while a control group (C) used LWAs without immersion. The specimens repaired themselves differently after exposure to 500 oC. Groups A and C used the same self-healing method, requiring 28 days of daily water spraying to maintain moisture. Group B employed a cyclic curing method, alternating nutrient solution spraying and air drying over the same period. After 28 days, the relative maximum flexural load ratios for groups A, B, and C were 1.094, 1.134, and 1.056, respectively. Groups A and B showed increases of 3.6% and 7.4% compared to Group C, demonstrating the cyclic curing method's greater effectiveness.

Key Words

beam; biomineralization; flexural strength; lightweight aggregate concrete; self-healing

Address

Chao-Wei Tang: 1) Department of Civil Engineering and Geomatics, Cheng Shiu University, No. 840, Chengching Road, Niaosong District, Kaohsiung 83347, Taiwan (R.O.C.), 2) Center for Environmental Toxin and Emerging-Contaminant Research, Cheng Shiu University, No. 840, Chengching Road, Niaosong District, Kaohsiung 83347, Taiwan (R.O.C.), 3) Super Micro Mass Research and Technology Center, Cheng Shiu University, No. 840, Chengching Road, Niaosong District, Kaohsiung 83347, Taiwan (R.O.C.) Chung-Hao Wu: Department of Civil Engineering, National Kaohsiung University of Science and Technology, No. 415, Jiangong Road, Sanmin District, Kaohsiung City 807618, Taiwan (R.O.C.) Shu-Ken Lin, How-Ji Chen and Bing-You Wu: Department of Civil Engineering, National Chung Hsing University, 145 Xingda Road, South District, Taichung City 40227, Taiwan (R.O.C.)

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