Unraveling the expansion mechanism in lightweight aggregates: Demonstrating that bloating barely requires gas

•Lightweight aggregate (LWA) bloating has been studied in an archetypical clay.•LWA expansion process consists of three stages: preheating, shrinkage and bloating.•The gas involved in bloating represents less than 0.1% of the original weight.•Only 0.06–0.2% of carbonates or 0.2–1% of Fe2O3 are invol...

Full description

Saved in:
Bibliographic Details
Published in:Construction & building materials 2020-06, Vol.247, p.118583, Article 118583
Main Authors: Moreno-Maroto, José Manuel, Cobo-Ceacero, Carlos Javier, Uceda-Rodríguez, Manuel, Cotes-Palomino, Teresa, Martínez García, Carmen, Alonso-Azcárate, Jacinto
Format: Article
Language:English
Subjects:
Bloating
Expanded clay
Gas release
Lightweight aggregate
Porosity
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:•Lightweight aggregate (LWA) bloating has been studied in an archetypical clay.•LWA expansion process consists of three stages: preheating, shrinkage and bloating.•The gas involved in bloating represents less than 0.1% of the original weight.•Only 0.06–0.2% of carbonates or 0.2–1% of Fe2O3 are involved in bloating.•Adequate viscosity is more decisive for bloating than gas release capacity. Lightweight aggregate bloating process has been studied by a simple experiment using an archetypal clay to know the actual amount of gas involved in expansion. Considering the relationship between gas loss (LOI) and volumetric changes over time, three main stages are identified: 1) a preheating stage of massive gas loss (close to 80% of the total) with hardly any volumetric change; 2) a very brief transition stage, in which sintering (shrinkage) and closed (micro)porosity formation begin, accompanied by a sudden gas loss (close to 100% of the total); 3) the bloating stage itself, in which an appropriate viscosity is reached, allowing the available residual gas (
ISSN:0950-0618
1879-0526
DOI:10.1016/j.conbuildmat.2020.118583