Keywords: rheology

Influence of lignin and its activated forms on the physico-mechanical and rheological properties of bitumen

https://doi.org/10.58224/2619-0575-2026-9-3-1
Abstract
The relevance of the work is due to the need to replace expensive polymer modifiers and involve large-scale waste from the pulp and paper industry in the production of road construction materials. The purpose of the study is a comprehensive assessment of the effect of various types of lignin and activation methods on the physico-mechanical and rheological properties of bitumen. Bitumen of the BND 100/130 brand was used in the work. Samples with the addition of pure lignin (0.3–0.7%), activated lignin, lignosulfonate, as well as complex formulations with the plasticizer ENMA and SBS polymer were studied. It has been shown that the introduction of pure lignin increases the softening temperature and aging resistance, but worsens the low-temperature properties and leads to heterogeneity of the system at concentrations above 0.7%. The activation of lignin increases its reactivity, allowing the introduction of a modifier without loss of uniformity. It has been established that the combined use of activated lignin with SBS and plasticizer provides an extension of the temperature range of working capacity. Rheological tests in accordance with GOST R 58400.1-2019 confirmed the increase of the PG grade from PG 58-28 (initial bitumen) to PG 70-34. The best set of properties is achieved by partially replacing SBS with activated lignin, which confirms the prospects of using lignin as an effective and environmentally friendly component of polymer-bitumen binders.
PDF

Rheological properties and structure formation of a mineral suspension with a complex organic and mineral additive

https://doi.org/10.58224/2619-0575-2024-7-4-48-63
Abstract
This work is aimed at studying the rheological properties and processes of structure formation in highly concentrated mineral suspensions modified with a complex organic and mineral additive based on a fluoroglu-cinifurfural oligomer and nanodiamond silicon dioxide particles.
Methods. The distribution of silicon dioxide particles and their modal size in additives were determined by laser light diffraction on the Mastersizer 3000 device and by dynamic light scattering on the Microtrac S3500 device. The rheological properties of the suspensions were determined using a coaxial cylindrical rotary viscometer of the gearless type “Rheotest-2.1”. The setting time and structure formation of the cement dough were evaluated on a Vika device. The plastic strength of the cement dough was determined using a conical Rebinder plastometer. The compressive strength of cement stone was determined using an automatic hydraulic press “PGM-100MG4”.
Conclusions. It has been established that a complex organic and mineral additive reduces the limiting dynamic shear stresses of mineral mixtures, reduces the plastic strength of mixtures in the initial period and shortens the setting time, providing a balance between deceleration and strength development due to the directional formation of consolidated supramolecular calcium silicate structures that structure the cement matrix. It was found that sili-con dioxide nanoparticles, which are part of a complex organic and mineral additive, do not affect the rheological properties of the system in the initial period, unlike Aerosil particles, which increase the limiting dynamic shear stress of the mixture, due to the high particle dispersion.
PDF