Lee Jeong-Bae, Kim Jun-Hyeong, Min Byeong-Gi, Woo Byeong-Hun
Department of Civil Engineering, Daejin University, 1007 Hoguk-ro, Pocheon-si 11159, Republic of Korea.
Geomarble-Labs, 6-26, Jeonggeum-ro 162beon-gil, Gasan-myeon, Pocheon-si 11167, Republic of Korea.
Materials (Basel). 2023 Dec 22;17(1):53. doi: 10.3390/ma17010053.
The cement industry emits a significant amount of carbon dioxide (CO). Therefore, the cement industry should recycle the emitted CO. However, sequestration by carbonation in cement composites absorbs a very small amount of CO. Therefore, a direct way of achieving this is to improve the absorption performance of CO in cement composites. In this study, to improve absorption, unlike in existing studies, a granulation technique was applied, and the material used was calcium hydroxide (CH). In addition, granulated CH was coated to prevent a reaction during the curing of cement paste. The coated CH granule (CCHG) was applied to 5% of the cement weight as an additive material, and the specimens were cured for 91 days to wait for the coating of CCHG to fully phase-change. The experiment of CO absorption showed an unexpected result, where the use of blast furnace slag (BFS) and fly ash (FA) had a negative effect on CO sequestration. This was because BFS and FA had a filler effect in the cement matrix, and the filler effect caused the blocking of the path of CO. In addition, BFS and FA are well-known pozzolanic materials; the pozzolan reaction caused a reduction in the amount of CH because the pozzolan reaction consumed the CH to produce a calcium silicate hydrate. Therefore, the pozzolan reaction also had a negative effect on the CO sequestration performance combined with the filler effect. The CO sequestration efficiency was decreased between ordinary cement paste and BFS-applied specimens by 45.45%. In addition, compared to cases of ordinary cement paste and FA-applied specimens, the CO sequestration performance was decreased by 63.64%. Comprehensively, CO sequestration performance depends on the porosity and amount of CH.
水泥行业会排放大量的二氧化碳(CO)。因此,水泥行业应回收所排放的CO。然而,水泥基复合材料中的碳酸化固碳吸收的CO量非常少。因此,实现这一目标的直接方法是提高水泥基复合材料对CO的吸收性能。在本研究中,为了提高吸收性能,与现有研究不同,采用了造粒技术,所使用的材料是氢氧化钙(CH)。此外,对造粒后的CH进行了包覆,以防止在水泥浆体固化过程中发生反应。将包覆后的CH颗粒(CCHG)作为添加剂材料,按水泥重量的5%加入,对试件进行91天的养护,等待CCHG的包覆完全发生相变。CO吸收实验得出了一个意想不到的结果,即使用高炉矿渣(BFS)和粉煤灰(FA)对CO固碳有负面影响。这是因为BFS和FA在水泥基体中具有填充作用,而这种填充作用导致了CO通道的堵塞。此外,BFS和FA是众所周知的火山灰质材料;火山灰反应导致CH的量减少,因为火山灰反应消耗CH以生成硅酸钙水化物。因此,火山灰反应与填充作用相结合,也对CO固碳性能产生了负面影响。普通水泥浆体试件与掺加BFS的试件相比,CO固碳效率降低了45.45%。此外,与普通水泥浆体试件和掺加FA的试件相比,CO固碳性能降低了63.64%。综合来看,CO固碳性能取决于孔隙率和CH的含量。