Reactive and workable boundaries for olivine-derived amorphous precipitated silica in cement-based materials
File(s)
Author(s)
Ong, Pei B
Dai, Xiaodi
Gan, Gavin
Cheeseman, Chris
Wong, Hong
Type
Journal Article
Abstract
Amorphous precipitated silica (APS) derived from olivine is a potential supplementary cementitious material (SCM), but its performance depends on the production route. This study compares the physicochemical properties and R³ reactivity of APS obtained by centrifugation and isopropanol-assisted separation, then examines how APS replacement level and water-to-binder (w/b) ratio
influence fresh-state behaviour and strength development in pastes. APS obtained by centrifugation showed higher SiO2 content and R³ reactivity than APS separated using isopropanol. The centrifuge-derived APS was then evaluated at 10, 20 and 30 wt.% cement replacement over a range of w/b ratios (0.30–0.90) using mini-slump, rheometry and compressive strength testing. APS increased yield stress and viscosity, raising the lower workable w/b from 0.35 at 10 wt.% to 0.50 at 20 wt.% and
0.625 at 30 wt.% cement replacement. At 10–20 wt.% replacement, 90-day strength activity index (SAI) reached 0.90–1.14 and 0.84–1.05, respectively. At 30 wt.% replacement, the 90-day strength contribution was substantially smaller, and SAI decreased to 0.64-0.76 due to a shift in dilution-controlled behaviour and reduced clinker content. These results define a replacement-dependent strength performance window in which the increased water demand of APS is balanced against its
contribution to later-age strength.
influence fresh-state behaviour and strength development in pastes. APS obtained by centrifugation showed higher SiO2 content and R³ reactivity than APS separated using isopropanol. The centrifuge-derived APS was then evaluated at 10, 20 and 30 wt.% cement replacement over a range of w/b ratios (0.30–0.90) using mini-slump, rheometry and compressive strength testing. APS increased yield stress and viscosity, raising the lower workable w/b from 0.35 at 10 wt.% to 0.50 at 20 wt.% and
0.625 at 30 wt.% cement replacement. At 10–20 wt.% replacement, 90-day strength activity index (SAI) reached 0.90–1.14 and 0.84–1.05, respectively. At 30 wt.% replacement, the 90-day strength contribution was substantially smaller, and SAI decreased to 0.64-0.76 due to a shift in dilution-controlled behaviour and reduced clinker content. These results define a replacement-dependent strength performance window in which the increased water demand of APS is balanced against its
contribution to later-age strength.
Date Acceptance
2026-10-26
Citation
Cement
Publisher
Elsevier
Journal / Book Title
Cement
Copyright Statement
Copyright This paper is embargoed until publication. Once published the Version of Record (VoR) will be available on immediate open access.
License URL
Publication Status
Accepted