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论文类型：期刊论文

发表时间：2019-11-10

发表刊物：CONSTRUCTION AND BUILDING MATERIALS

收录刊物：EI、SCIE

卷号：224

页面范围：336-347

ISSN号：0950-0618

关键字：Accelerated carbonation; beta-Dicalcium silicate; Calcium hydroxide; Tetracalcium aluminoferrite; Calcite

摘要：In-depth understanding regarding the carbonation properties of pure minerals including beta-dicalcium silicate (beta-C2S), calcium hydroxide (CH), and tetracalcium aluminoferrite (C(4)AF) was conducted to explore the types, microstructure, crystallinity of products produced during carbonation, thereby developing a tentative microscopic mechanism of the contribution of carbonation to macroscopic properties. An investigation of changes in pH value and Ca leaching of the pure minerals was conducted to explore the effect of dissolution properties to the carbonation. Results showed that the descending order of the ultimate carbonation degrees of minerals was: (i) CH, (ii) beta-C2S, (iii) C(4)AF. The carbonation degrees and rates were not only controlled by the dissolution properties of the minerals, but also the distribution of the produced CaCO3. The order of the contribution of minerals induced by carbonation to the macroscopic mechanical strength was, in descending order: (i) beta-C2S, (ii) CH, (iii) C(4)AF. This difference was the combined effects of the microstructure, crystallinity, and particle size of calcite. Effects of the compact stack and the strong mechanical bond between the calcite particles were observed in carbonated beta-C2S samples; In contrast, pronounced defects on the calcite particles were observed in carbonated C(4)AF samples. Carbonation is an effective way to reduce the density of which mainly contained phases of beta-C2S and C(4)AF, and to store greenhouse gas CO2 permanently. These findings are meaningful for the further in-depth researches of the carbonation mechanism of materials which primarily contain beta-C2S, CH and C(4)AF phases. (C) 2019 Elsevier Ltd. All rights reserved.