Characterisation of lightweight concrete of Tunisian expanded clay: mechanical and durability study

摘要

The objective of this study was to produce lightweight expanded clay aggregates in laboratory and to evaluate their effect in lightweight concrete (LWC). The effect of clay type, mineralogical and chemical structures as well as treatment temperature were examined. After the production of aggregates, following a specific manufacturing process, their physical and microstructure properties were determined. Furthermore, the mechanical properties and the microstructure of LWC were studied. A durability study including water absorption and sorptivity, resistance to the chloride ions penetration, chemical attack and carbonation was conducted. In accordance with the guide for structural lightweight aggregate concrete (ACI 213R-03), the LWC was classified according to its unit weight with qc<2000kg/m(3) (LC 2.0) and compressive strength at the age of 28days (LC16/20). Besides, it had the lowest chloride concentration penetration. The chloride penetration depth and the migration coefficient were lower than those of normal concrete. Its initial water absorption was slightly higher and the depth of carbonation was lower. Finally, the reduction of compressive strength, the weight change and the visual inspection after immersion in sodium chloride and nitric acid were an accelerated test procedure, which indicated the performance of concrete against chemical attack.