This paper presents a study of lightweight aggregates microstructure using Scanning Electron Microscope with Energy Dispersive Spectrometer (SEM-EDS). This paper examined the topography of the interfacial zone and the characteristic of the surface pores of the lightweight aggregate concrete. The porous surface of LWA improved the interfacial bond between the aggregate and cement paste by providing interlocking sites for the cement paste forming a dense and uniform interfacial zone.
