Mechanical and durability properties of high performance glass fume concrete and mortars

- GF was produced with a complete spherical morphology with a 30-200 nm diameter.
- Comparatively to SF, GF improve the fresh properties of cement mortars.
- GF high-performance concrete (HPC) achieves comparable strengths to SF-HPC.
- GF reduces the alkalinity of the pore solution and densifies the cement paste.
- GF controls the chloride penetration, alkali-silica and sulfate attack expansions.

Based on its high content in amorphous silica (SiO2 > 70 wt.%), waste glass is an excellent material for valorization into pozzolanic nanoparticles or the so-called “glass fume” (GF). GF, produced using a scalable radiofrequency induction-coupled-plasma (RF ICP) spheroidization technology, mainly consists in an emulation of silica fume (SF) composed of spherical and amorphous silica-based nanoparticles (dia. of 30-200 nm). To test the impact of GF on the mechanical and durability properties of cement-based materials, compressive strength and rapid chloride ion penetration tests (RCPT) were conducted on high-performance concrete (HPC). Meanwhile, measurements of the resistances to alkali-silica reaction (ASR) and to sulfate attack were performed on mortar bars.As SF, GF increased the compressive strength of HPC at early age (<7 days) by its nucleation and filler effects, but also its high alkali content (11-12 wt.%). At late age (>28 days), GF is characterized by a slower pozzolanic reactivity than SF. However, GF-contained HPC achieve similar compressive strength than SF-contained HPC after 91 days of curing.At early age, GF-contained HPC and mortars yielded lower durability properties (RCPT, ASR and sulfate attack) than SF-contained HPC and mortars due to the slower pozzolanic reactivity of GF. In fact, they yielded similar durability properties compared to the plain cement HPC and mortars (control mixtures). At late age, the alkalinity of the pore solution is reduced and the cement paste is densified by the pozzolanic calcium silicates hydrates (C-S-H) and the durability properties are greatly improved with respect to a control HPC.

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