Microwave heating efficiency and frost resistance of concrete modified with powder absorbing materials

Abstract

Microwave deicing technology has the advantages of economy, environmental protection, cleaning, energy saving and so on, and it has future prospects in snow melting and deicing of concrete pavement. In order to improve the microwave heating efficiency of concrete without reducing its practicability, Fe3O4 modified concrete, SiC modified concrete and graphite modified concrete are taken as research subjects. The effects of 3 kinds of powder absorbing materials (PAM: Fe3O4, SiC and graphite) on microwave heating efficiency and frost resistance of concrete are studied by microwave heating test and freeze–thaw cycles test. And the micromechanism of the effect of PAM on the frost resistance of concrete are interpreted using SEM and MIP techniques. The results show that the microwave heating efficiency of concrete increases after adding PAM, the addition of Fe3O4 and graphite reduce the frost resistance of concrete, and the addition of SiC improves the frost resistance of concrete, and the optimal content of SiC is 10%. The PAM can fill macropores but decrease the bonding properties of cement paste. The pore size, percentages of less-harmful pore and harmful pore of concrete increase after freeze–thaw cycles. The pore structure of concrete shows significant fractal features before or after freeze–thaw cycles. And after freeze–thaw cycles, the fractal dimension of pore structure of concrete increases and the pore structure deteriorates.