Comparison between Glass Beads and Expanded Perlite

　　China’s annual production of expanded perlite has exceeded 4 million cubic meters, accounting for about 5% of the country’s annual output of thermal insulation materials. It is one of the most widely used lightweight thermal insulation materials in China.

　　Although expanded perlite is widely used in various fields and represents a rapidly growing industry, it suffers from inherent quality defects that often lead to serious common quality problems. For instance, soundproofing, thermal insulation, and heat-insulating layers made with perlite commonly exhibit cracks, voids, and other defects, resulting in poor overall performance. Given the widespread use of expanded perlite and the numerous performance-related shortcomings it presents, we now compare it with Poraver glass microspheres—a new lightweight material that can serve as an effective alternative to expanded perlite.

　　Raw Material Comparison

　　Expanded perlite, as a type of natural mineral, is a non-renewable resource. Poraver glass microbeads are made from recycled household glass, making them more environmentally friendly and easier to source.

　　Comparison of Apparent State and Physical Properties

　　Expanded perlite consists of irregular white or off-white granules with a rough, porous surface and an absorption rate as high as 300%. Precisely because of its highly porous surface, when mixed into masonry mortars and plastering materials, water carries the binding agents deep into the hollow structure of the expanded perlite, filling the cavities and causing the material to lose its thermal insulation performance once it dries. Poraver glass microspheres, on the other hand, are spherical particles with a smooth, white surface. Since their internal pores are closed, their water absorption rate is below 40%.

　　Internal Structure Comparison

　　Expanded perlite is a lightweight, porous insulation material produced by crushing, drying, and high-temperature firing of perlite ore. Its surface is rough, and its internal cavities have a honeycomb-like structure. Even in closed-cell expanded perlite, the internal honeycomb structure remains unchanged. Once the overall structure is compromised, the surface’s sealed condition is lost, yet the material still exhibits a high water absorption rate. Although Poraver glass microspheres have a rough surface, their internal pores are sealed. Even if the particles are broken, the sealed cavities remain intact, effectively preventing excessive water penetration.

　　Comparison with the workability of cement slurry

　　Since both expanded perlite and Poraver glass microspheres have rough, porous surfaces, they are easily enveloped by cement paste. Tests have shown that the higher the proportion of expanded perlite added to thermal insulation mortar, the greater its density actually becomes. This is because expanded perlite itself is brittle; the more it is added, the easier it is to break during mixing due to compression, thereby having a greater impact on the performance of the insulation mortar. Once the mixing time is prolonged, the crushed perlite will release the moisture it has absorbed, causing the mortar to segregate and compromising the original performance of the wet-mix mortar system. In contrast, Poraver glass microspheres feature highly spherical particles with high strength, making them resistant to breakage during mixing. They can be thoroughly mixed with binding materials through mechanical agitation and effectively absorb moisture, ensuring excellent workability of the wet mortar even under relatively high water-to-cement ratios.

　　Intensity Comparison

　　Expanded perlite has low inherent strength and tends to break easily during mechanical mixing when added to mortar, thereby reducing the thermal insulation performance of the material. Moreover, due to its large surface area and high water absorption, expanded perlite particles cause varying degrees of strength loss in mortars and plastering materials after drying. In contrast, Poraver glass microspheres exhibit exceptionally high compressive strength, are resistant to breakage during mixing and application, and possess superior compressive and bonding strengths.