Properties and microstructure of alkali-activated red clay brick waste

Sintered red clay ceramic is used to produce hollow bricks which are manufactured in enormous quantities in Spain. They also constitute a major fraction of construction and demolition waste. The aim of this research was to investigate the properties and microstructure of alkali-activated cement pastes and mortars produced using red clay brick waste. The work shows that the type and concentration of alkali activator can be optimised to produce mortar samples with compressive strengths up to 50 MPa after curing for 7 days at 65 °C. This demonstrates a new potential added value reuse application for this important waste material.

Sintered red clay ceramic constitute a major fraction of construction and demolition waste in Spain. In the present work, alkali-activated cement pastes and mortars produced from red clay brick waste, using NaOH and sodium silicate solution as activators. The type and concentration of alkali activator were optimised to produce mortar samples with compressive strengths close to 30 MPa after seven curing days at 65 °C. The mechanical properties were further increased up to 50 MPa by optimising the w/b, b/s and SiO2/Na2O ratios. This demonstrates a new potential added value reuse application for a significant waste material.Figure optionsDownload as PowerPoint slideHighlights
► A new application for a significant waste material has been demonstrated.
► A compressive strength close to 30 MPa was obtained for mortars with 0.45 w/b ratio.
► Compressive strength increased up to 50 MPa by optimising the process parameters.