Why do river slope protection bricks exhibit wet expansion phenomenon

River slope protection bricks have good water absorption properties and can quickly infiltrate rainwater into the surface through road surface materials, replenishing groundwater energy in a timely manner. This not only effectively reduces road surface water, but also contributes to ecological balance. If the river slope protection bricks are too wet, they will affect their effectiveness and reduce their service life. If they are too dry, they will also have a certain impact. Only with moderate humidity can they be used for a long time. Let's learn about the specific effects of humidity together.

Water vapor adsorbs onto the capillary walls of the material, forming hydrates or solutions. Some materials form zeolite like structures, while clay minerals and their decomposition products absorb water. All of this may be due to the wet expansion of the river slope protection bricks.
Wet expansion depends not only on the composition of the raw materials for river slope protection bricks, but also on the firing temperature and porosity. When used in a humid environment, repeated heating and cooling can lead to increased swelling. As the water temperature rises and the duration of use prolongs, the expansion of the river slope protection bricks will significantly increase. The diameter of water molecules is about 0.2um, while the particle clusters that form coarse ceramic materials are about 1000 times or even larger than water molecules.
Due to thermal motion, water molecules easily penetrate into the material of river slope protection bricks, promoting the formation of microcracks. When steam or water molecules diffusing along the microcrack wall reach a narrow position, the applied pressure on the crack sidewall increases to over 1000 Pa, leading to crack propagation.
The compactness of river slope protection bricks is good, which can save more heat, regulate surface humidity, eliminate the "heat island phenomenon", mobilize surface water and fire permeability, maintain soil moisture, and improve ecological balance.