Liquid nitrogen frozen cementitious material and its potential applications: Inspired by refrigeration industry

Abstract

Liquid nitrogen frozen cementitious material introduces a novel approach to utilizing cementitious material in engineering construction and maintenance. This process involves the quick-freezing of fresh cement mortar into blocks. Tests were conducted on the thawed cement mortar to evaluate key technical parameters such as compressive strength and fluidity. Microscopic analyses including mercury intrusion porosimetry, scanning electron microscopy, X-ray diffraction and thermogravimetric analysis were conducted for mechanism analysis. The results indicate that quick-freezing with liquid nitrogen has a minimal or negligible impact on the compressive strength and fluidity of cement mortar, with compressive strength decreasing by no more than 4 % and fluidity decreasing by no more than 2 %. The rapid hydration reaction suspended by utilizing the extremely low temperature characteristics of liquid nitrogen is the main contribution. The freezing blocks possess unique properties such as hydration suspending, low-temperature and non-dispersibility as solid, which can be utilized in some special engineering applications such as long-distance transportation, temperature control of large volume concrete or underwater structure repair.