arlite, also called ripiolite, expanded clay or leca (in Argentina), is a very light ceramic aggregate "Arid (mining)" manufactured by heating pieces of clay in a rotary kiln) at approximately 1200 °C, the resulting gases expand the volume of the piece, decreasing its density.

It is used in construction to make highly lightweight concrete and blocks, as filler to form slopes on flat roofs, screeds for slabs, and as a thermal insulator.

Clay is also used as a filter in water purification. In gardening it is used for hydroponic growing systems as an inert substrate, replacing a soil substrate, to aerate substrates and as soil drainage.

It was developed in Kansas City "Kansas City (Missouri)") around 1917 for the production in a rotary kiln of an expanded "Acrete (mining)") known as haydite, which was used for the construction of the SS Selma&action=edit&redlink=1 "SS Selma (1919) (not yet drafted)"). Later, another series of aggregates known as gravelite, perlite, etc. were developed.

Its granulometry can vary from 10-16mm, to diameters less than 5mm. In general, the larger the grain size (more expanded), the lower the density of the material, which ranges between 325kg/m³ and 750kg/m³. This density is up to five times lower than that of common clay, around 1500kg/m³.

The clay applied to gardening must only contain expanded clay, eliminating in its manufacturing process metals that could affect the pH balance and electro-conductivity of the plant. This type of clay for gardening can be made with some dye (normally red) to give it a different appearance than that used in construction, being equally valid if it lacks color.

The most notable characteristic of clay is its relationship between weight and resistant capacity. Due to these qualities, it is mainly used as a low-weight filling material in situations where a certain mechanical resistance is necessary. The most typical use of this material is to create slopes to conduct water on flat roofs. The most used application method is mixing clay with approximately 15-20% cement, creating "clay mortar." For the same purpose, it is used as a screed in floors and floors. It is also a common solution in civil engineering works as filler in excavations.