Morphological characterisation of Brazilian expanded clay lightweight aggregate using AIMS

Abstract

Due to the excessively rounded shape of expanded clay, data related to angularity, sphericity and surface texture can help to understand the relationship of these factors with the properties of concrete in the fresh state, such as workability and fluidity. This research sought to characterize the expanded clay in terms of morphology and to compare it with the particularities of the conventional aggregate using the AIMS (Aggregate Imaging Measurement System) equipment. The results indicate that the morphological characterization of conventional coarse aggregates (B0 and B1) are presented with subrounded angulation and moderate sphericity in both particles, whereas the surface texture is rough and harsh, respectively for B0 and B1. For coarse aggregates of Brazilian AE 2215 and AE 1506, the morphological characteristics such as angularity and surface texture were defined as rounded and polished, respectively, in both groups. However, there was differentiation as to sphericity, which is high for AE 2215 and moderate for AE 1506. Compared to the group of conventional aggregates, the lightweight coarse aggregate of Brazilian expanded clay indicates more rounded particles, with medium-high sphericity and surface texture smoother.

Keywords:
Expanded clay; Lightweight aggregate; Angularity; Sphericity; Surface texture