Force modeling of interparticle pair interaction of spheroid in composite cement

Abstract

The paper discusses the modeling of the forces of interparticle pair interaction of spheroidal agglomerate in composite cement. Based on the calculation of the autohesion forces that make up the spheroidal agglomerate, i.e. the Portland cement (“carrier particles”) and silica fume (“guest particles”), it was found that for uncharged particles the magnitude of the electric interaction forces is negligible in comparison with molecular van der Waals and capillary forces. The bipolar charging of particles in the corona discharge field at a corona electrode potential of +18 and –18 kV sharply increases the electric component of the autohesion force, which in value approaches the value of capillary forces. In this case, the Coulomb attractive forces between oppositely charged particles begin to act before the direct contact of the particles, which contributes to the agglomeration of particles. These calculations are confirmed by the results of scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) of composite cement samples containing Portland cement (75 %) and dry gas purification silica fume (25 %), the number of angular particles of irregular shape decreases for a mixture of these materials processed in the device for surface modification.

Developing Environmentally Sustainable and Cost-Effective Geopolymer Concrete with Improved Characteristics

“…-Technological equipment-laboratory concrete mixer BL-10 (LLC "ZZBO," Russia, Chelyabinsk region, Zlatoust); drying cabinet SPU ShS-160-02 (JSC "Smolenskoye SKTB SPU," Russia, Smolensk); laboratory vibrating platform SMZh-539-220A (LLC "IMASH," Armavir, Russia); -Testing equipment-hydraulic press IP-1000 (NPK TEKHMASH LLC, Neftekamsk, Republic of Bashkortostan, Russia); -Measuring instruments-measuring metal ruler 500 mm; laboratory scales [37][38][39][40].…”

Microfiller Influence on the Modified Cement Granulometric Composition

“…According to the literature data [6], the specific surface area measured by the nitrogen adsorption method varies within 18 ... 25 m 2 /g due to the high cost of silica dust, which, as a rule, exceeds the cost of cement in various European countries -by 2-3 times. In this regard, it is advisable to combine microsilica with other mineral additives -ash, slag, which ensures the production of concretes with the required quality indicators both in the early and late periods of hardening [8][9][10][11][12][13].…”