22.10.2024 Adsorption of superplasticizers in alkali activated materials - Fluorescence microscopic in-situ investigations Back Tools Bookmark Share Alkali-Activated Materials (AAM) have advantages compared to Ordinary Portland Cement (OPC) in terms of CO2 balance and in many cases in terms of durability. This increase in durability is due to the formation of strength-forming phases, which differ from the C-S-H phases in concrete made of OPC. The raw materials used are mineral materials rich in silicon and aluminium, which are ideally present as fine particles and in reactive form. Mainly used precursors are ground granulated blast furnace slag, fly ash or calcined clays. Since these materials belong to the group of latent hydraulic or pozzolanic materials, a stimulation of the chemical reaction is necessary. Alkali activators can be used for this purpose; alkali hydroxide or water glasses are mostly used. Despite the variety of possible combinations of the precursors and alkali activators, there are still no effective superplasticizers known for these systems, if one wants to compare the effectiveness with that of OPC. Most available superplasticizers lose their effectiveness, especially at higher concentrations of the alkali activators. A complex matrix of possible interactions results from the combination of precursors, types and concentrations of alkali activators as well as the types of superplasticizers, which require a high empirical effort in fresh and hardened concrete investigations. In prior investigations the adsorption behaviour of superplasticizers on mineral particles was investigated in-situ by fluorescence microscopy. This method is suitable for time-resolved investigations of the adsorption behaviour of superplasticizers on various precursors and in different alkaline activator solutions. Microscopic investigations were correlated with investigations on fresh pastes as well as other methods concerning the adsorption of superplasticizers. Duration: 26:01Speaker: Dr Alexander WetzelCompany: Universität KasselConference: ECS ConferenceLocation: NurembergDate: 27.03.2023