Technical and economic characteristics:

Expanded perlite concrete is made by mixing expanded perlite as aggregate, Portland cement or high aluminum in a certain proportion. Expanded perlite concrete has the characteristics of low bulk density, low thermal conductivity, and relatively economical. When used on flat roofs, it can reduce loads, save cement usage, reduce costs, reduce processes, and shorten construction periods. It has been widely used in construction projects. In addition, expanded perlite concrete can withstand low temperatures of about -200°C, making it an ideal thermal insulation material and low-temperature resistant material.
Application features:
1. Applications at low temperatures. Expanded perlite concrete can also be used at very low temperatures (around -200°C), such as in storage of liquefied propane gas. It performs well if the concrete is cooled slowly and does not undergo thermal cycles. The strength of expanded perlite concrete that has been well cured before freezing can be much higher than the same concrete measured at suffocation temperature. Dry concrete is only slightly stronger when frozen. The elastic modulus also increases at lower temperatures, while the thermal expansion coefficient decreases somewhat. It freezes at extremely low temperatures (below about -70°C) and melts at ordinary room temperature. After only 1 to 2 cycles, the strength of concrete will suffer a great loss and cannot be restored. However, it turns out that the strength loss is less if the concrete dries before the temperature cycle begins.
2. Thermal insulation function. Expanded perlite concrete can be used in outdoor air separation tower projects in steel plants, and can also be widely used as cast-in-place heat insulation, thermal insulation, and sound insulation layers on roofs or walls. It can be poured on a flat or uneven surface, or directly on a curved or sloped surface. On flat roofs, the specified drainage slope can be made by changing the thickness of expanded perlite concrete.
Raw material requirements:
The strength of expanded perlite concrete is low, and cement plays a skeleton role in the cement-perlite concrete structure. Therefore, Portland cement and ordinary Portland cement of no less than 425 should be preferred, or early strength should be selected. During summer construction of other cements with high hydration heat, it is better to choose slag Portland cement with lower hydration heat. For concrete with fire-resistant and heat-resistant requirements, it is better to choose high-alumina cement, and the cement is required to be free of moisture and agglomeration. The storage period No more than 3 months. Sodium rosinate foam agent (air-entraining agent). Formulated with rosin, alkali and animal glue.
When selecting expanded perlite concrete, its main technical indicators are the most appropriate strength value and thermal insulation value (thermal conductivity). The physical and mechanical properties of concrete are controlled by its dry bulk density (the main parameter specified in the specification). Expanded perlite concrete with a bulk density of 120~220kg/m3 can achieve an ideal balance between reducing its own mass, appropriate compressive strength, indentation strength and good thermal insulation value. If higher strength and higher holding power are more important than insulation value, a higher bulk density may be specified. For sloped insulated roof coverings, the commonly used bulk density is 300~400kg/m3.