INSULATING CONCRETE, also known as:
Load-bearing and heat-insulating at the same time, it allows the production of homogeneous outer walls and roof constructions as monolithic components.
Bulk density, and classification of concretes:
< 800 kg/m³ = infra-lightweight concrete (insulating concrete)
< 2,000 kg/m³ = lightweight concrete& nbsp;
2,000 - 2600 kg/m³ = normal concrete
[...] With its excellent thermal insulation properties and yet high load-bearing capacity, insulating concrete offers the monolithic solution made only of concrete. Another advantage: structural details are simplified if walls consist of only one mineral raw material.
The decisive factor for the thermal insulation properties of a building material is its thermal conductivity, which is given in watts per meter and Kelvin, or W/(m·K) for short. Air has a very low thermal conductivity. The more air a building material contains, the lower its bulk density – expressed in kg/m³ – and its thermal conductivity. Normal concrete consists of a dense aggregate of rock such as gravel and sand, which is "glued" to the cement glue. The air content is correspondingly low. In lightweight concrete, a porous aggregate ensures a high proportion of air. These aggregates contain up to 85% of the finest air voids. They are extracted, for example, as pumice from natural deposits or produced as expanded clay by firing a low-lime clay or as expanded slate of a clay slate at around 1200 °C in a rotary kiln.
The bulk density of a structure-tight lightweight concrete according to DIN EN 206-1 / DIN 1045-2 is between 800 kg/m³ and 2000 kg/m³. Infra-lightweight concrete offers its excellent thermal insulation properties due to a bulk density of less than 800 kg/m³, which has also given it its name. It is below (= infra) the limits defined by the standard. Accordingly, building with infra-lightweight concrete in Germany still requires approval by the building authorities in individual cases (ZiE). The bulk density, which is further reduced compared to standardised lightweight concrete, is achieved, among other things, by replacing the fine aggregate of sand with expanded glass. Expanded glass is made from waste glass by foaming and has small, gas-filled air voids. In addition, the finest air voids are often introduced into the cement stone by a foaming agent. [...]
Image : Pumice as a possible natural additive in insulating concrete - beton.org<
img src="https://files.baukobox.de/download/6311d7c3e5a7a066223ca719?width=250" width="250">
Image : Expanded clay as a possible industrially produced additive in insulating concrete - beton.org
