FIRST STUDIES ON A LIGHTWEIGHT AGGREGATE SELF COMPACTING FIBRE REINFORCED CONCRETE FOR STRUCTURAL APPLICATIONS

摘要

Lightweight aggregate concrete (LWAC) is a well-known material, which is rarely used for structural applications; however, the use of steel fibres can improve its performances. Fibres are known to significantly affect the workability of concrete. Therefore, first an investigation has been performed to study the basic properties of a LWA Self-compacting concrete reinforced with steel fibres. Secondly the best concrete formulations have been optimised, in view of structural applications connected to the reinforcement of buildings damaged by seismic events. After a preliminary study on several types of lightweight aggregates (structural and non structural expanded clay, expanded polystyrene and structural terracotta), terracotta lightweight aggregate has been chosen because of its best concrete performances. Fresh and hardened states concrete properties have been studied in relation with the fibre content; the slump flow and L-box tests have been used to evaluate the material properties of the fresh concrete, while mechanical properties of the hardened concrete have been determined. The resulting concrete possesses a high mechanical strength confirmed by the execution of some pump ability tests. A further step will be concerned with the scale up from the laboratory level to a real situation.