Porous structure classification: pore diameter size and pore shape.

High-quality products:

The pore structure is characterized by: tiny and dense pore size, uniformly distributed pores, and round-shaped pores. Under a microscope, it exhibits a closed honeycomb-like structure.

The product features dense and numerous pores, with round-shaped pores, thereby offering high compressive strength and excellent thermal insulation properties.

Poor-quality products:

The pore structure is characterized by large, unevenly sized pores with varying dimensions. The distribution of the pores is uneven, with the shape of the pores displaying elongated ovals in the direction of stretching, or in the thickness or width direction. Under a microscope, the pore openings show partial holes with varying diameters.

Large pores and fewer in quantity, with an elongated-oval shape, resulting in poor compressive strength and thermal insulation properties.