Effect of the superplasticizer type on the properties of the fly ash blended cement

• Superplasticizer improves consistency of cement paste at lower water/cement ratio.
• The most water reduction is observed for polycarboxylate and polycarboxylate ether.
• Cement prepared using PC and PCE has higher hydration heat and initial setting time.
• Addition of PCE to cement mortar gives cement fly ash Portland cement of class 52.5N.

In the paper the effect of the superplasticizer type on the properties of fly ash blended cement – in terms of hydration heat, setting time and compressive strength – was studied. The used admixtures were sulfonated melamine-formaldehyde condensate (SMF), sulfonated naphthalene-formaldehyde condensate (SNF), polycarboxylate (PC) and polycarboxylate ether (PCE). Control sample was Portland fly ash cement CEM II/A-V 42.5R. Superplasticized Portland fly ash cement mortars were prepared taking the values of standard water of consistency with different addition of each type of superplasticizers used. Results revealed that the decrease in water content required was 15% for SMF, 31% for SNF, 42% for PC and 47% for PCE. Polycarboxylates were found to have to higher efficiency in improving the hydration heat evolution, setting time and mechanical properties of cement than that of traditional superplasticizers SMF and SNF. Addition to control fly ash blended cement polycarboxylate ether-based superplasticizer gives cement CEM II/A-V 52.5N.