Influence of the volume fraction and the nature of fine lightweight aggregates on the thermal and mechanical properties of structural concrete

• Seven lightweight aggregates from three different natures are investigated.
• The mechanical and thermal properties of concretes are measured.
• The influence of aggregate properties and their volume fraction is discussed.
• Fine lightweight aggregate substitution significantly enhanced thermal properties.
• The optimization of the strength/insulation ratio of concretes is investigated.

The results of investigations on thermal and mechanical properties of lightweight aggregate concretes according to mixture parameter are reported. Seven types of fine and coarse lightweight aggregates from three different natures were used. The aggregates in mixes were a combination of coarse lightweight aggregate with fine normal-weight aggregate and/or fine lightweight aggregate. The replacement of fine normal weight aggregate by fine lightweight aggregate reduces concrete strength but improves its thermal performance. Detailed analysis of the influence of the nature and quality of aggregates on the concrete properties is provided. The experiment data allows to investigate the relation between mechanical properties and thermal conductivity for studied concretes in order to optimize the strength/insulation ratio. A wide range of “insulated” lightweight aggregate concretes is performed whose strength class ranges from LC20/22 to LC40/44 and thermal conductivity ranges from 0.43 to 0.73 W/m K.