Quantitative Analysis of CO 2 Uptake and Mechanical Properties of Air Lime-Based Materials

Sung-Hoon Kang, Yang-Hee Kwon and Juhyuk Moon
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Sung-Hoon Kang: Department of Architecture and Architectural Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea
Yang-Hee Kwon: Department of Traditional Architecture, Korea National University of Cultural Heritage, 367 Baekjemun-ro, Gyuam-myeon, Buyeo-gun, Chungcheongnam-do 33115, Korea
Juhyuk Moon: Department of Civil and Environmental Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea

Energies, 2019, vol. 12, issue 15, 1-12

Abstract: In the cement industry, utilization of a sustainable binder that has a lower energy consumption and carbon dioxide (CO 2 ) emission than Portland cement is becoming increasingly important. Air lime is a binder that hardens by absorbing CO 2 from the atmosphere, and its raw material, hydrated lime, is manufactured at a lower temperature (around 900 °C) than cement (around 1450 °C). In this study, the amount and rate of CO 2 uptake by air lime-based materials are quantitatively evaluated under ambient curing conditions of 20 °C, 60% relative humidity, and 0.04% CO 2 concentration. In addition, the effects of the water-to-binder ratio ( w / b ) and silica fume addition on the material properties of the air lime mortar, such as strength, weight change, carbonation depth, and pore structure, are investigated. Unlike hydraulic materials, such as Portland cement, the air lime mortar did not set and harden under a sealed curing condition, however, once exposed to dry air, the mortar began to harden by absorbing CO 2 . During the first week, most of the internal water evaporated, thus, the mortar weight was greatly reduced. After that, however, both the weight and the compressive strength consistently increased for at least 180 days due to the carbonation reaction. Based on the 91-day properties, replacing 10% of hydrated lime with silica fume improved the compressive and flexural strengths by 27% and 13% respectively, whereas increasing the w / b from 0.4 to 0.6 decreased both strengths by 29% due to the increased volume of the capillary pores. The addition of silica fume and the change in the w / b had no significant impact on the amount of CO 2 uptake, but these two factors were effective in accelerating the CO 2 uptake rate before 28 days. Lastly, the air lime-based material was evaluated to be capable of recovering half of the emitted CO 2 during the manufacture of hydrated lime within 3 months.

Keywords: greenhouse gas; global warming; air lime mortar; hydrated lime; CO 2 uptake; carbonation; calcium hydroxide; calcium carbonate; thermogravimetric analysis (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (2)

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