Norlite is an expanded lightweight aggregate made in rotary kilns. The resulting products out of the kiln have different sizes that can have different properties depending on the size (3/4" or so and down), so the "Norlite" can have a range of sizes. Like all lightweight aggregates, it is usually used with some heavyweight/normal weight aggregates (3/8" to sand) depending on the desired use.
The properties of the particles are different. Some of the larger particles have great compressive strength (but can be brittle)and many of the smaller particles are actually pieces of a perfect sphere that are due to the manufacturing and handling process.
Often, this type of lightweight is referred to as "coated", referring to the ideal pristine larger particles that may have the "coated" appearance due to the surface appearance from the firing/expanding process.
It is very unusually to see 100% lightweight because of the sizes and shapes, so blending to get a desired gradation is necessary in most used.
Dick
Engineer and international traveler interested in construction techniques, problems and proper design.
