Influence of Interparticle Separation Distance on the Fresh and Hardened Behavior of Ecoefficient Cement Pastes

Abstract

An efficient method to produce ecoefficient cementitious mixtures is using particle packing models (PPMs) combined with limestone fillers (LF). Yet, key outcomes obtained in the fresh and hardened states, including slump and compressive strength, are variable and remain mostly not fully understood. Therefore, in this work, the concept of interparticle separation distance (IPS) is employed to describe the overall performance of ecoefficient cement paste mixtures with high LF dosages [up to 81% of ordinary Portland cement (OPC) replacement]. In this scenario, twenty-one cement paste mixtures displaying three water-to-powder ratios (0.32, 0.40, and 0.50), two distribution factors (q=0.21 and 0.37), and three cement contents (100, 150, and 250 kg/m3) were studied. Next, fresh-state properties (i.e., rheological profile and slump flow over time) along with compressive strength were appraised. Densely packed systems containing moderate to high LF dosages have shown to yield better compressive strength results than pure OPC mixtures, yet the inclusion of LF negatively influenced the cement paste mixtures’ slump loss. Thus, the w/p (i.e., in mass) combined with the w/c ratio from Abram’s law was successfully observed as an important parameter to better predict the compressive strength performance of the ecoefficient cement pastes. Results suggest that the fresh state behavior of packed mixtures containing high LF content can be predicted through the IPS/dp; therefore, this parameter might be adjusted to reach targeted viscosity values when proportioning cementitious materials. Finally, the concept of IPScement is proposed to precisely describe fresh and hardened properties of cementitious mixtures with significant dosages of LF and reduced OPC contents.