The Effect of Microwave Radiation on the Solidification of C-S-H Gels: Its Influence on the Solidified Cement Mixtures

Gels. 2023 Nov 10;9(11):889. doi: 10.3390/gels9110889.


The present paper deals with the properties of hardened cement mixtures that have been exposed to microwave radiation. Microwaves fall under electromagnetic waves (EMW), and the main reason for using EMW radiation is to accelerate the drying of concrete as well as to reduce the time required to obtain the handling strength after it is removed from the mould. This paper is divided into two main parts. In the first part, three sets of cement samples were made. One set of samples solidified naturally in air and the second and third sets of samples were exposed to EMW radiation, with different exposure times for each. The solidification was then stopped, and the representation of the major minerals was experimentally determined. The second part of the experiment focuses on the properties of the hardened cement mixtures, both in terms of strength and physical properties. The experiment was carried out on two sets of samples. Each mixture was exposed to EMW radiation, the main differences being the exposure time and the position of the samples relative to the EMW generator. The aim of the experiments is to determine the resulting mechanical properties of the samples in comparison with those that were subjected to normal solidification in air. The data from these experiments suggest that microwave radiation can be used to accelerate the curing of concrete specimens, obtaining the handling strength in a relatively short time, but a reduction in the resulting strength can be expected compared to the reference specimens.

Keywords: C-S-H; compressive strength; gel; material drying; mechanical properties; microwave exposure; radiation.

Grants and funding

This research was funded by the Brno University of Technology, Faculty of Civil Engineering, Internal grant agency, grant number FAST-J-21-7238.