Influence of calcium and sodium nitrate on the strength and reaction products of the CaO-activated GGBFS system

Autor: Woo Sung Yum, Jung-Il Suh, Sungwon Sim, Yubin Jun, Jae Eun Oh, Seyoon Yoon
Rok vydání: 2019
Předmět:
Zdroj: Construction and Building Materials. 215:839-848
ISSN: 0950-0618
DOI: 10.1016/j.conbuildmat.2019.04.240
Popis: The influence of the added nitrate salts (Ca(NO3)2 and NaNO3) on the CaO-activated ground granulated blast-furnace slag (GGBFS) system was investigated. Both salts significantly increased the early strength of the binder, and the Ca(NO3)2 maintained this tendency until 28 days of curing, whereas NaNO3 did not. At early days, the NaNO3 likely increased pH of samples, resulting in more dissolving GGBFS and formation of C-S-H, while the Ca(NO3)2 slightly decreased pH due to the common ion effect, but because the Ca(NO3)2 supplied additional Ca ions, it also increased the strength. At 28 days, the NaNO3 clearly induced the reduction in C-S-H, which was not the case for the Ca(NO3)2 samples. In addition, the pore size distribution was also significantly dependent on the cation type of nitrate salts.
Databáze: OpenAIRE