Sustainable applications for utilization the construction waste of aerated concrete

Abstract In the next decades many buildings and structures, constructed from autoclaved aerated concrete (AAC) will reach their end of lifetime, therefore solutions should be developed to recycle the resulting waste material. AAC blocks cannot be reused in the form of building blocks as traditional clay bricks. The typical form of AAC waste is crushed stone or powder. Present study is dealing with the possibilities of the recycling of AAC waste as concrete aggregate, prefabricated concrete tiles, concrete blocks, shuttering blocks and cement supplementary material. The concrete mixes were designed in a way to apply as much AAC waste as possible and to require the least further processing (crushing, pulverizing) of the waste material at the same time. Mechanical (compressive strength), thermal (heat conductivity) and durability (frost and freeze-thaw resistance) properties of the samples containing AAC waste as aggregate or supplementary material were tested. The results indicated that opportunities in applying aerated concrete waste in granular form as aggregate for load bearing purposes are limited, but in powdered form can be highly advantageous. However, if the load bearing capacity is not a strong requirement there are many feasible modes to recycle AAC waste as vertical wall coverings, stumped concrete wall, design exposed concrete or lightweight aggregate concrete. In advance to granular form, adding powdered AAC to normal concrete, the durability attributes were improved.