Early-age hydration characteristics and kinetics of Portland cement pastes with super low w/c ratios using ice particles as mixing water
Is Version Of
Civil, Construction and Environmental Engineering
The liquid water was replaced by ice particles for preparing homogenous structural Portland cement (PC) pastes at super low w/c ratios from 0.08 to 0.16. For introducing the process of PC hydration, a sophisticated conduction calorimeter was adopted to measure the early-age hydration heat evolution. The hydration kinetic parameters were determined by Krstulovic–Dabic model based on data of hydration heat evolution. The concentrations of K+ and Na+ of the pore solution were measured by ICP-OES. Experimental results showed that the acceleration period of the hydration process of PC paste was improved by increasing w/c ratio due to the improvement of space available for hydration product growth. The hydration mechanism of PC paste changed to nucleation and crystal growth (NG) - diffusion (D) when its w/c ratio below 0.16, representing a more intense hydration reaction than that of PC with a normal w/c ratio of 0.30. The concentrations of K+ and Na+ of pore solution of hydrated PC paste decreased with the increase of w/c ratios, which led to the alkalinity of that decreased with the increase of w/c ratios. In addition, the mechanical properties of hardened PC pastes were enhanced by increasing w/c ratios from 0.08 to 0.16, which could be attributed to the decrease of porosities of hardened pastes.
This article is published as Li, Laibo, Mingxu Chen, Xiangyang Guo, Lingchao Lu, Shoude Wang, Xin Cheng, and Kejin Wang. "Early-age hydration characteristics and kinetics of Portland cement pastes with super low w/c ratios using ice particles as mixing water." Journal of Materials Research and Technology 9, no. 4 (2020): 8407-8428. DOI: 10.1016/j.jmrt.2020.05.082. Copyright 2020 The Author(s). Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0). Posted with permission.
Portland cement, Super low w/c ratios, Early-age hydration, Mechanical properties