Using a Physical Model Based on Particle Mobility for Mix Design of Commercial Concretes in Order to Increasing Eco-Efficiency

Concrete greenhouse gas emissions are mostly from cement. A relevant strategy for the concrete greenhouse gas emissions abatement is the increase of the efficiency in the use of its binder. For this, it is important to understand the packing and the mobility of the concrete particles and their effects on its rheological behavior in the fresh state and the mechanical properties in the hardened state. Currently, the mix design methods are empirical, as opposed to this experimental optimization, the computational optimization emerges, based on predictive models. Thus, the objective of the study is to use the physical model based on particle mobility to predict the rheological behavior of commercial concretes. The method consisted in the following steps: characterization of raw materials; eco-efficiency analysis of 60 formulations of a concrete plant using the binder intensity concept; and a parameter estimation for a descriptive model of slump in function of mobility variables. These concrete formulation binder intensities were between 7.5 and 10.5 kg/m³/MPa, in which the rise of specified fck and maximum aggregate size have a positive impact on this index, while the slump growth has a negative effect. For the base formulations, the mobility variable MPT (Maximum Paste Thickness) showed good correlations with the specified slump (R² 0.99), as well as the model presented a good adjustment to the data (R² 0.94). These results allow an improvement in the mix design methodology using computational optimization, which can lead to an increase on the eco-efficiency of the commercial concretes.