Effect of disodium EDTA on hydration and mechanical properties of calcium sulphoaluminate-belite cement. (February 2023)

• Record Type: Journal Article
• Authors: Wang, Jianfeng; Wang, Yan; Liu, Hui; Chang, Lei; Wang, Hui; Wang, Yali; Cui, Suping
• Is Part Of: Cement and concrete research. Volume 164(2023)
• Publication Date: 2023-02
• Subjects: Calcium sulfoaluminate -- Disodium EDTA -- Hydration -- Mechanical properties -- Microstructure; Cement -- Periodicals; Cement -- Research -- Periodicals; Concrete -- Periodicals; Concrete -- Research -- Periodicals; Ciment -- Périodiques; Béton -- Périodiques; Cement; Concrete; Periodicals; 620.135
• DOI: 10.1016/j.cemconres.2022.107041
• Languages: English
• ISSNs: 0008-8846

Abstract

Abstract: Effects of disodium EDTA (EDTA-2Na) on hydration and mechanical properties of calcium sulphoaluminate-belite cement (CSBC) were investigated systematically. Results show that EDTA-2Na addition leads to visible changes in CSBC strength development. 0.50 % EDTA-2Na significantly enhances the compressive strength by 18 % and 23 % compared with the blank specimens at 7 d and 28 d, while reducing the strength at 8 h and 1 d. The content of the main hydration product (AFt) determines the strength development. At the early hydration stage, EDTA-2Na delays hydration of ye'elimite to form AFt, thus decreasing the early hydration degree of CSBC and increasing the porosity to reduce strength. In the presence of EDTA-2Na, the morphology changes of amorphous aluminum hydroxide (AH3 ) facilitate the AH3 -C2 S-CaSO4 reaction to increase AFt content and form a more condensed structure, thus enhancing the late strength. In this way, the strength development of CSBC mortars can be modified and regulated by EDTA-2Na.