The influence of superplasticizers on the properties of slag-alkali binders
Abstract
The influence of superplasticizers on the properties of slag-alkali binders
Incoming article date: 07.09.2025Concretes based on ground blast-furnace granulated slag activated with alkaline solutions exhibit excellent mechanical properties. However, they have significant drawbacks, such as rapid setting and poor workability during concreting. The effect of various superplasticizers on the properties of pastes prepared from ground blast-furnace granulated slag activated with alkaline solutions was studied. An aqueous solution of sodium silicate and sodium hydroxide was used as an alkaline slag hardening activator. The effect of superplasticizer dosage on the setting time, flowability, and changes in compressive strength of slag-alkali solutions was studied. It was found that properties of the freshly prepared paste, such as the initial and final setting times, increase with increasing the solution-to-slag ratio and with the addition of a superplasticizer. Superplasticizers based on naphthalene sulfonic acid and polycarboxylate ether were found to effectively influence both the setting time, workability, and strength of slag-alkali binder-based compositions. It was established that a slag-alkali composition with a mortar-to-slag ratio of 0.4 exhibits low workability and is not technologically feasible for on-site concreting, while its optimal value is 0.5. A superplasticizer dosage of 2% of the slag mass ensures not only the technological requirements for concreting (the initial and final setting time and concrete mix mobility), but also the strength properties of the formed concrete based on ground blast-furnace granulated slag.
Keywords: metallurgical waste, granulated slag, hardening activator, binder, superplasticizer, setting time, spray, strength