“Collapsible” lightweight aggregate concrete. Part I: material concept and preliminary characterization under static loadings

In this work a granular cementitious composite has been developed, tailoring its performance to low compressive strength as well as to high deformation and energy dissipation capacity. This peculiar performance can be required to the material when employed in post-installed screeds for protection of structures and infrastructures against accidental actions such as impact and blast. The required level of performance can be achieved through uniform grain size distribution, paste content as low as minimum theoretical void ratio and low paste strength. It is believed that the synergy between the aforementioned three requirements can allow for energy dissipation capacity after paste cracking due to both rearrangement of grain meso-structure and, in case, grain crushing. This part I of a companion paper study first of all details the optimization of the material composition, in terms of mix-design variables such as w/c ratio, content of air entraining agent, mixing protocol, paste volume fraction, grain size distribution of the employed lightweight expanded clay aggregate. The mechanical performance of a trial collapsible concrete mix will be then checked. In part II extensive mechanical characterization under static and impact loadings will be performed as pertinent to the intended aforementioned application.