Innovative lightweight concrete hollow blocks: thermal performance analysis

The thermal analysis of buildings opaque walls is strongly linked to the homogeneous and inhomogeneous materials that compose each single layer. Nowadays the insulation panels are the main component used to reduce buildings thermal losses, but the inhomogeneous layer, like hollow blocks, can help to improve the overall thermal performance of the wall if attention is paid to the materials that compose the solid part of the blocks. In this paper the authors describe some results of a research activity concerning the thermal optimization of existing blocks and the design of a new line of innovative lightweight concrete blocks with recycled expanded glass. The innovative blocks are designed to fully satisfy the prescriptions of the Italian legislation in terms of product sustainability (in compliance with European Directive 009/125/CE) and structural and energy performance. Due to the complex geometry of the blocks, the analysis of the thermal performance was carried out with the finite elements method, according to the EN 1745 as well as with the simplified method according to the EN ISO 6946. The thermal analysis of the innovative blocks was preceded by the characterization of the value of the thermal conductivity of the lightweight concrete with recycled expanded glass, by means of guarded hot plate method according to the EN 12664