Impact of different superplasticizers on hydration, rheology, mechanical strength, and environmental evaluation of LC3 cements

Abstract

The mineralogical and physicochemical characteristics of the clay can adversely affect the efficiency of polycarboxylate-based superplasticizers, limiting their dispersion capacity. This challenge has increasingly drawn attention within the field of LC3 research. In this context, the present study investigated the effect of different dosages (0.25 % and 0.50 % by weight of anhydrous) of a conventional polycarboxylate ether (PCE) and a modified polycarboxylate formulation combined with a clay-mitigating agent (PCE + CM) on the fresh and hardened properties of LC3 cement pastes. The molecular structure of these polymers played a crucial role in optimizing the performance of the cementitious matrices. The findings revealed that the PCE + CM admixture provided effective adsorption and rheological performance even at low dosages (7.84 Pa), without negatively impacting the hydration kinetics. Moreover, the mechanical strength (44.14–47.93 MPa) and environmental indicators of the LC3 mixtures with PCE + CM were comparable to or exceeded those of ordinary Portland cement (OPC) and the reference LC3 formulation. These results highlight the potential of clay-mitigating admixtures to overcome dispersion challenges in LC3 systems, supporting their scalability and further encouraging the adoption of LC3 cement as a sustainable alternative in the construction industry.