Measuring packing density and water demand of Portland cement and SCMs by the mixing energy method

Abstract

Wet packing methods evaluate the packing density of fine materials through the determination of the apparent density and voids content of pastes with different water to solids (w/s) ratios. Its goal is to estimate the minimum water demand to achieve the maximum solids concentration in the mixture, a parameter applied to the mix design of cementitious composites based on particle packing theories. Since most methods based on apparent density are time-consuming and require a high volume of materials, this paper aims to evaluate the mixing energy method as an alternative for the wet packing method and to adapt it to be used for SCMs (supplementary cementitious materials). With a reduced time and material to perform the test, results demonstrate a better precision of the mixing energy due to its discrete measurement. The ideal water flow and initial volume of materials to perform the test on cement and SCMs are discussed.

Mix design of eco-efficient high-strength mortars optimized by the compressible packing model

“…Based on these results, it was possible to calculate (Equation 6) the packing density and the water demand for the pastes, presented in Table 3 which also indicates the initial water to solids (w/s) ratio used in the test procedure. Further details on the mixing energy method setup, investigation of the test parameters and power consumption for different SCMs can be verified at Soto et al [56]. The results obtained for the cement and SCMs were used for the proportioning of the mortars studied by particle packing.…”

“…The mixing energy method [56] evaluated the packing density and water demand of the fine materials. Higher energy consumption is expected when the funicular state is reached since the mixture will reach higher shear stress due to the proximity of the particles [24].…”