title: Structural concretes with waste-based lightweight aggregates: from landfill to engineered materials.
abstract: This research provides possible opportunities in the reuse of waste and particularly muds, coming from both ornamental stone (granite sludges from sawing and polishing operations) and ceramic production (porcelain stoneware tile polishing sludge), for the manufacture of lightweight aggregates. Lab simulation of the manufacturing cycle was performed by pelletizing and firing the waste mixes in a rotative furnace up to 1300 degrees C, and determining composition and physicomechanical properties of lightweight aggregates. The best formulation was used to produce and test lightweight structural concretes according to standard procedures. Both granite and porcelain stoneware polishing sludges exhibit a suitable firing behavior due to the occurrence of SiC (an abrasive component) which, by decomposing at high temperature with gas release, acts as a bloating promoter, resulting in aggregates with particle density < 1 Mg/m3. However, slight variations of mixture composition produce aggregates with rather different properties, going from values close to those of typical commercial expanded clays (particle density 0.68 Mg/m3; strength of particle 1.2 MPa) to products with high mechanical features (particle density 1.25 Mg/m3; strength of particle 6.9 MPa). The best formulation (50 wt.% porcelain stoneware polishing sludge +50 wt.% granite sawing sludge) was used to successfully manufacture lightweight structural concretes with suitable properties (compressive strength 28 days > 20 MPa, bulk density 1.4-2.0 Mg/m3).
authors.affiliation: Centro Interdipartimentale di Servizio per Analisi Geomineralogiche, Federico II University, Via Mezzocannone 8, 80134 Naples, Italy. robdegen@unina.it
authors.forename: Roberto
authors.initials: R
authors.lastname: De'Gennaro
authors.forename: Sossio Fabio
authors.initials: SF
authors.lastname: Graziano
authors.forename: Piergiulio
authors.initials: P
authors.lastname: Cappelletti
authors.forename: Abner
authors.initials: A
authors.lastname: Colella
authors.forename: Michele
authors.initials: M
authors.lastname: Dondi
authors.forename: Alessio
authors.initials: A
authors.lastname: Langella
authors.forename: Maurizio
authors.initials: M
authors.lastname: De'Gennaro
mesh_terms: D019245:Compressive Strength; D003247:Conservation of Natural Resources / Q000379:methods*; D003252:Construction Materials / Q000032:analysis*; D052918:Environmental Restoration and Remediation; D008855:Microscopy, Electron, Scanning; D008903:Minerals / Q000032:analysis; D012037:Refuse Disposal; D012722:Sewage / Q000737:chemistry; D014866:Waste Products / Q000032:analysis*
chemical_list: D008903:Minerals; D012722:Sewage; D014866:Waste Products