ABSTRACT
Lightweight aggregates are granular materials with porous structure used as thermal and acoustic insulation, decoration in landscaping, the production of light fillings, drainage works, light landfills and infrastructure, as well as hydroponics. Manufactured from clayey precursors, sintered at high temperatures, which expand due to a glassy phase to capture the gases generated, being the flux content and substances that form gases, intervening factors of the process. In this context, it was verified the possibility of using granite and marble cutting waste (GMCW) and clay with the objective of developing lightweight aggregates. The precursors were characterized as surface area (BET), laser granulometry, fineness, specific gravity and bulk density in addition to thermal (ADT/TG), chemical (XRF) and mineralogical (XRD) analyzes. Aggregates with 0, 50, 60, 70, 80, 90, and 100% GMCW contents were produced by sintering at temperatures of 1000°C to 1263°C in a muffle furnace. The sintered mixtures were analyzed for their particle density, water absorption, bulk density, modulus of deformation of the lightweight aggregates, swelling index, mass loss, dry shrink index, visual analysis, tensile strength and morphology by scanning electron microscopy (SEM). After sintering, aggregates with particle density less than 2,00g/cm³, water absorption less than 20% and bulk density less than 0,88g/cm³ were obtained, these values being defined as requirements for classifying an aggregate as light and qualified for use in structural concrete. As for the highlighted properties, it was possible to develop lightweight aggregates with high waste content that meet the normative requirements, respectively, with values of 1,56g/cm³, 8% and 0,85g/cm³, in addition to lightweight aggregates presenting tensile strength fourfold higher than the commercial lightweight aggregate.
Keywords
Artificial lightweight aggregate; granite and marble cutting waste; sintering; expanded clay
