Influence of quartz powder and silica fume on the performance of Portland cement

Ludmila Rodrigues Costa Tavares,Maria Teresa Paulino Aguilar,Augusto Cesar Da Silva Bezerra,Joaquim Francisco Tavares Junior,Paulo Roberto Cetlin,Leonardo Martins Costa

doi:10.1038/s41598-020-78567-w

Ludmila Rodrigues Costa Tavares, Maria Teresa Paulino Aguilar + Show 4 more

Open Access

https://doi.org/10.1038/s41598-020-78567-w

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Abstract

Supplementary cementitious materials interact chemically and physically with cement, influencing the formation of hydrate compounds. Many authors have analyzed the filler and pozzolanic effect. However, few studies have explored the influence of these effects on hydration, properties in the fresh and hardened states, and durability parameters of cementitious composites separately. This study investigates the influence of the replacement of 20% of Portland cement for silica fume (SF) or a 20-µm medium diameter quartz powder (QP) on the properties of cementitious composites from the first hours of hydration to a few months of curing. The results indicate that SF is pozzolanic and that QP has no pozzolanic activity. The use of SF and QP reduces the released energy at early times to the control paste, indicating that these materials reduce the heat of hydration. The microstructure with fewer pores of SF compounds indicates that the pozzolanic reaction reduced pore size and binding capability, resulting in equivalent mechanical properties, reduced permeability and increased electrical resistance of the composites. SF and QP increase the carbonation depth of the composites. SF and QP composites are efficient in the inhibition of the alkali-aggregate reaction. The results indicate that, unlike the filler effect, the occurrence of pozzolanic reaction strongly influences electrical resistance, reducing the risk of corrosion of the reinforcement inserted in the concrete.

Highlights

Ground quartz particles may have a pozzolanic activity or may only provide a filler effect depending on their particle size and specific surface
This study evaluates the performance of cementitious composites with and without partial replacement of cement by finely ground quartz with negligible pozzolanic activity and a high pozzolanic activity material from the first hours of hydration to 300 days of curing
The partial replacement of cement for silica fume (SFP) and quartz powder (QPP) reduced the maximum temperature reached to reference paste (RP), indicating that these materials can lower the heat of hydration[30,77,78]

Summary

Introduction

Ground quartz particles may have a pozzolanic activity or may only provide a filler effect depending on their particle size and specific surface. Berodier and S crivener[13] indicated, by isothermal calorimetry and scanning electron microscopy (SEM), that quartz samples with diameters d 50 of 4, 13 and 18 μm replacing 20–70% of cement may physically stimulate clinker hydration in the first hours by the filler effect. The use of raw material as a filler can reduce energy consumption in the cement industry, leading to a more sustainable process[31]. In this context, this study evaluates the performance of cementitious composites with and without partial replacement of cement by finely ground quartz with negligible pozzolanic activity and a high pozzolanic activity material (silica fume) from the first hours of hydration to 300 days of curing. The mechanisms that strongly influence the performance of these composites are identified

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