@Article{jrm.2021.015812,
AUTHOR = {Jianbing Zhang, Rongjin Liu, Siyuan Fu, Tianyu Gao, Zhongfei Zhang},
TITLE = {Preparation and Performance of a Fluorine-Free and Alkali-Free Liquid Accelerator for Shotcrete},
JOURNAL = {Journal of Renewable Materials},
VOLUME = {9},
YEAR = {2021},
NUMBER = {11},
PAGES = {2001--2013},
URL = {http://www.techscience.com/jrm/v9n11/42804},
ISSN = {2164-6341},
ABSTRACT = {Based on aluminum sulfate, a fluorine-free and alkali-free liquid accelerator (FF-AF-A) was prepared in this
study. The setting time and compressive strength of three cement types with different FF-AF-A dosages were fully
investigated. The compatibility of the FF-AF-A with the superplasticizers were also investigated, and the early
hydration behavior and morphology of the hydration products of reference cement paste with the FF-AF-A were
explored by hydration heat, X-ray diffractometry (XRD), and scanning electron microscopy (SEM). Test results
indicated that adding the FF-AF-A at 8 wt% of the cement weight resulted in 2 min 35 s initial setting time and
6 min 30 s final setting time. The 1-day compressive strength of the cement mortar with 8 wt% of FF-AF-A
reached 13.5 MPa, which represents an increase of 35% as compared to the strength of cement mortar without
the FF-AF-A, and the 28-day compressive strength ratio was 119%. In addition, the FF-AF-A also showed good
compatibility with different superplasticizer dosages. The results show that, when the FF-AF-A was added to the
cement paste, it promoted the formation of ettringite crystals due to the aluminum ions (Al3+) and sulfate ions
(SO4
2-) reacted with gypsum in the cement, as well as promoted the hydration of tricalcium aluminate (C3A) and
tricalcium silicate (C3S) leading to the overall structure becomes more compact. As a consequence, the hydration
heat rate of the cement sharply increased, the cement paste setting time is shortened, and the compressive
strength of cement mortar is improved.},
DOI = {10.32604/jrm.2021.015812}
}